Plants Flashcards
1
Q
When did life move onto land?
A
500 million years ago
2
Q
What are taxonomic levels?
A
Classing things into bigger or smaller boxes
3
Q
What were the first forms of life? When did they appear?
A
Prokaryotes, 3.5 billion years ago
4
Q
When did eukaryotes appear?
A
1.8 billion years ago as single-celled, 1.3 billion years ago they became multicellular
5
Q
What is the difference between prokaryotes and eukaryotes?
A
Prokaryotes don’t have membrane-bound nucleus and organelles but eukaryotes have these
6
Q
What is the phylogenetic tree?
A
Also called the tree of life, shows how all known life forms are related to each other through evolutionary history. Like a family tree. Every living thing can be traced back to a single ancestor.
7
Q
What is taxonomic classification?
A
A hierarchical ‘filing system’for all forms of life, names for groups of organisms. Reconstructing the evolutionary relationship.
8
Q
What is systematics?
A
The field of biology that includes phylogenetics and taxonomy, forming hypotheses on how the species groups from all kids of taxonomic levels are related to each other.
9
Q
What are the taxonomic classifications in order?
A
Domain, kingdom, phylum, class, order, family, genus, species
10
Q
What is the singular word for species?
A
Both singular and plural
11
Q
What is the singular word for genera?
A
genus
12
Q
What is the singular word for phylum?
A
phyla
13
Q
What is verticle gene transfer?
A
DNA inherited from parents (reproduction)
14
Q
What is horizontal gene transfer?
A
DNA is obtained from other genomes through transpoable elements like viruses. Viruses and parasitic flowers can do this by stealing the host’s DNA.
15
Q
What is alteration of generations?
A
Two multicellular stages (hapliod and diploid) that alternate
16
Q
What is a branch/node on a phylogenetic tree?
A
Event in which a species changes through evolution. All connected. Connection between branches are called nodes, nodes represent speciation events.
17
Q
What is a lineage?
A
One or more connected branches, groups of organisms through evolutionary time.
18
Q
What is a branches further in the phylogenetic tree?
A
Internal branches, ancestral species. Extinct
19
Q
What is a branches at the tip of a phylogenetic tree?
A
Terminal branches, species groups as seen today
20
Q
What is at the base of the phylogenetic tree?
A
Root of the tree, the common ancestor of everything included on the phylogenetic tree.
21
Q
What are sister taxa?
A
two species/species groups that are each other’s closest relatives in the phylogenetic tree
22
Q
What is relativity?
A
Sharing a more recent ancestor with each other, makes more closely related species/species groups that share ancestors further down the phylogenetic tree
23
Q
What is an ancestral species?
A
A species that gave rise to other species
24
Q
What are plants also called?
A
Embryophytes and plante
25
What are plants related to?
Chorophytes
26
What are the advantages for plants living on land?
More nutrients available from soil, able to grow bigger, more stable environment, more sunlight and CO2, no initial predators, escaping the tidal zone, less initial competition
27
What are the disadvantages for plants living on land?
Lack of water, lack of structural support
28
What is the haploid stage?
Gametophyte stage
29
What is the disploid stage?
Sporophyte stage
30
What is a haploid?
(n) 1 pair of chromosomes
31
What is a disploid?
(2n) 2 pairs of chromosomes
32
What is the basic lifecycle of all plants?
* gametophyte (n) > (mitosis) gamete (n) + gamete (n) > (fertilization) zygote (2n) > (mitosis) sporophyte (2n) > (meiosis) spore (n) *
33
What does antheridia produce?
Sperm
34
What does archegonia produce?
Eggs
35
What is the sporangium?
Organ of the sporophyte that produces spores. It is a wall that protects spores from drying out. Both are diploid, spores are haploid.
36
What do spore walls have?
Spore walls composed of polymer sporopollenin
37
What plants have spores?
All plants have spores, all spores of these plants have sporopollenin
38
What do gametophytes produce?
Gametes
39
What do sporophytes produce?
Spores
40
What do you remember when writing Latin/scientific species names?
First letter of genus is capitalised, the whole name is italicized.
41
What is polarity?
The direction of the evolutionary change.
42
How did plants enable other species' survival on land?
Global cooling, making more oxygen and providing a food source
43
What are plesiomorphies?
Ancestral character traits. E.g. nonvascular plants do not have an extensive vascular system
44
What do bryophytes not have?
True roots or leaves. They also lack a vascular system. These systems are the gametophyte stage of their lifecycle and not the sporophyte unlike in vascular plants.
45
What are traits?
Derived. Character: E.g. vascular system, character states (values of trait) absest or present. Blue Vs brown eyes. A trait that arose in the most recent common ancestor of a particular lineage and was passed along to its descendants.
46
What are rhizoids?
Nonvascular plants have these. They have structures that look like roots but are very thin, single-celled structures.
47
What is the difference between charophytes and noncharophytes?
Both charophytes and plants have distinctive circular rings of proteins embedded in the plasma membrane. Noncharophytes have linear sets of proteins
48
What is the female parent in plants called?
Gametophyte.
49
Where does the plant zygote develop?
In the female gametophyte, where embryo develops from zygote in it's tissues. Parental tissue protects zygote and provides nutrients.
50
What are the groups/phyta of plants?
Nonvascular plants, seedless vascular plants, seed plants
51
What are included in nonvascular plants?
Liverworts, mosses, hornworts
52
What are non vascular plants also called?
Bryophytes
53
What are included in seedless vascular plants (lycophytes)?
Club mosses, spike mosses, quillworts
54
What are included in seedless vascular plants (monilophytes)?
Ferns, horsetails, whisk ferns
55
What are included in seed plants?
Gymnosperms, angiosperms
56
Difference between gymnosperms and angiosperms?
Gymnosperms have seeds not enclosed in chamber (naked seed), angiosperms have huge class of flowering plants with seeds that develop inside chambers (originating inside flowers)
57
Origin date of plants?
470 mya
58
Origin date of vascular plants?
425 mya
59
Origin date of seed plants?
360 mya
60
What is a monophyletic group?
Composed of an ancestral species and all it's descendants (indirectly or directly evolved from this ancestor). All member groups are more closely related to other member groups rather than non-member groups
61
What is a monophyletic group also called?
A clade
62
What is a paraphyletic group?
Composed of an ancestral species and some (not all) of it's descendants. Some member groups are more closely related to non-member groups than other member groups
63
What is a paraphyletic group also called?
A grade
64
What do rhizoids do?
They do not absorb much water but they anchor the plant in place.
65
What are leaves in nonvascular plants?
They are very thin and not true leaves as there is no vascular system. Cannot have thick leaves or roots without one.
66
What derived character traits do bryophtes have with other plants?
mulitcellular and dependent embryos, apical meristems
67
What is maximum parimsony?
We should first investigate the simplest explanation that is consistent with facts. It's also called Occam's razor, solving problems by shaving away unnecessary complications
68
What's the difference in sporophytes with nonvascular and vascular plants?
Vascular plants have much more dominant sporophytic structures.
69
What are the two main parts of vascular plants?
Shoot system and root system
70
What are the points where leaves attach to stems called?
Nodes
71
What are the spaces between points of attachment called?
Internodes
72
What is dermal tissue?
Like skin, outer layer on plants. Protects everything on the inside of the plant
73
What is the epidermis?
Outermost layer of cells, has another on top called a cuticle (waxy layer)
74
What are stomas?
Small openings for gas exchange
75
What is replaced when woody tissues grow?
The epidermis and cuticle are replaced by a periderm (woody tissue) As a plant aged the epidermis is shed and replaced by periderm
76
What is vascular tissue?
Xylem, phloem, associated cells. A lot like human vascular system
77
What do plants need to function?
Hydration (H2O) and energy (sugars)
78
What is ground tissue?
What's left. Used for storage, support and photosynthesis
79
What are the two types of growth in plants?
Primary and secondary growth
80
Where does primary growth occur?
Happens in undifferentiated tissue systems called apical meristems.
81
Where are apical meristems found?
Tips of stems/branches called apical buds, right where each leaf attaches to a stem or branch called axillary buds, and tips of roots called root tips. They produce cells for primary growth.
82
What do apical buds do?
Extend branches and stems also grow new leaves. They are little factories of cells that allows stems or branches to grow longer
83
What do axillary buds do?
New branches. Produces new branches when stem starts branching, this gets activated and starts forming. Some axillary buds can also form a thorn to a flower.
84
What do root tips do?
Extend root tips, form new roots to allow roots to grow further into the soil
85
What is primary growth?
Responsible for all or most plant growth (depends on plant) things growing longer
86
What do woody plants have other than primary growth?
Secondary growth. It allows the plant to extend in diameter/girth. Only woody plants do this.
87
What does the root cap do?
It's at the tip of a root, the function is to protect the very delicate apical meristem which can be easily damaged and will stop root growth if it is. It also secretes a polysaccharide slime that lubricates the soil around the tip of the root
88
What is the zone of elongation?
It's typically a few millimeters behind (above) the tip of the root is the zone of enlongation. New cells form and move further onwards (up the plant) to grow the root. The cells elongate (sometimes more than ten times their original length), this is where most root growth occurs as this elongation pushes the root tip further into the soil. The root apical meristems keeps adding cells to the younger end of the zone of elongation.
89
What do roots do?
Transfer water + dissolved nutrients to the rest of the plant cells. Also reaches water further underground
90
What are root hairs?
They are on the epidermis layer of the root. They increase surface area and allow more absorption from the ground. They typically make up to 70-90% of the total root surface area. They are the most prominent feature of the epidermis.
91
What is pith?
Ground tissue in the center of the plant. Internal to the vascular structures.
92
What is cortex?
Ground tissue around the outer rim of a plant. External to the vascular structures. It allows extracellular diffusion of water, minerals and oxygen from root hairs inwards because there are large spaces between cells.
93
Why do xylem need thick cell walls?
It adds structure and allows transport upwards. Lignin adds to the structure and is very important for strength
94
What's the difference between xylem and phloem cell's appearance?
Xylem cells are much bigger and have thick cell walls that stain red thanks to the lignin. Phloem are much smaller with thinner cell walls and surround xylem cells
95
What are phloem fibers?
They act like a retaining wall to keep everything well structured. Very important the whole vascular system in trees as nutrients travel so far
96
What is xylem?
Cells that transports water and dissolved nutrients from the roots 'upwards' to the rest of the plant. Their thick cell walls are dead at maturity. They use negative pressure to act like a straw, pulling water up from the top of the plant. The water molecules have a column and the one at the top holds it together.
97
What happens to water at the top of a plant?
It gets evaporated out of the plant via the stoma in the leaves or is used to replenish the leaves. The water molecule beneath then gets pushed up in it's place as the column moves up
98
What is phloem?
Transports sugars from the leaves 'downwards' to other parts of the plant (roots, growing areas). They have thinner cell walls that are living at maturity. Unlike xylem it doesn't need to fight gravity.
99
What's the visual differences between primary and secondary growth?
Young, thin, green is primary growth. Older, thicker, brown is secondary growth.
100
Where does secondary growth occur?
In parts that become woody. The growth takes place in the lateral meristems (vascular cambium and cork cambium)
101
What does the vascular cambium do?
It produces secondary xylem and phloem. It grows these outwards from itself, pushing primary xylem into the centre and the primary phloem outwards.
102
What is bark?
Secondary phloem and epidermal cells that are breaking off, getting replaced by secondary and eventually primary phloem. It should be noted that "cork" is incorrectly referred to as bark. In plant biology, bark includes all tissues external to the vascular cambium. Its main components are the secondary phloem and, external to that, the most recent periderm and all the outer layers of periderm. As the process continues, older layers of the periderm are sloughed off, as evident in the cracked, peeling exteriors of many tree trunks.
103
What is wood?
Secondary xylem that has been pushed into the middle of the tree
104
Where is the living parts of woody plants?
In the small circle of the vascular cambium, the rest is dead cells
105
What do growth rings look like?
Not in all plants, seen in species that evolved in temperate regions where there is a contrast of warm summers and cold winters. In winter, the cells don't grow that big (so cells produces are relatively small) In summer, cells that grow are a lot bigger, creates an alteration of smaller and bigger cells throughout the seasons.
106
How is seasons and age are tracked with growth rings
Seasons can then be tracked, but age can also be tracked by counting rings and comparing the sizes
107
How does cork cambium grow?
With secondary growth, the cork cambium forms further towards the outside of the stem/branch. New cambium grows to protect the phloem.
108
What is a tissue?
a group of cells consisting of one or more cell types
109
What is an organ?
Several types of tissues that together carry out a particular function
110
What does the cuticle do?
Protects the plant, but the waxy layer also prevents water loss
111
What does the epidermis do in the roots?
Minerals and water enter through the epidermis, especially with the root hairs
112
What does the epidermis do in the shoot?
In shoots, specialised epdiermis cells are called gaurd cells, also called trichomes
113
Are the functions of trichomes?
They can have different functions, including hairlike ones that reduce water loss in desert plants and reflect excess light. Other trichomes that defend against incests by making shapes tgar are hard to climb/move on or glands that secrete sticky or toxic compounds
114
What are parenchyma cells?
Primary walls that are thin + flexible, most lack secondary walls. Perform most metabolic functions of a plant, synthesizing/storing various organic products. Fleshy fruits comprised mainly of parenchyma cells. These can divide and differentiate into other types of plant cells when needed, like in damage repair.
115
Where does photosynthesis occur?
Photosynthesis occurs within the parenchyma cells in a leaf
116
What are collenchyma cells?
Grouped in strands, helps support young parts of the plant shoot. Enlongated cells with thicker primary walls, unevenly thickened. Provide flexible support without hindering growth. Found in young stems and periloes often (just below the epidermis) Enlogates with the stem and leaves they support
117
What are sclerenchyma cells?
Supporting elements in a plant, much more frigid. The secondary cell wall in these cells is produced after cell elongation has ceased. It's thick and contains large amounts of lignin. They cannot elongate once mature, so are present in parts pf the plant that has stopped growing. Many of these cells are dead, produces secondary walls before cell death.
118
What is lignin?
A strengthening polymer, offers support and structure.
119
What are the two types of sclerenchyma cells?
Sclereids: boxier, irregular shape, very thick lignified secondary walls, important for hardness to nutshell (seed coats)
Fibers: Grouped in strands, long, slendered, tapered.
Both are important for support/strengthening
120
Is lignin present in bryophytes?
No, only in vascular plants
121
What are stomas?
An opening that allows water (H2O) to evaporate and CO2 in. Allows evapotranspiration to take place as well as photosynthesis, leftover oxygen from glucose creation is also released from the stoma.
122
What are guard cells?
There are two around each stoma, connected at both ends to regulate their size and shape. Dry conditions cause limp guard cells, closing the stoma. When the leaf is flush with water, the guard cells plump up and bow from each other, opening the stoma to allow gases in and out as well as water out.
123
What do the cells of the xylem do?
Water-conducting cells. There are two types, tracheids and vessel elements. Both are tubular, elongated cells that are dead and lignified at maturity. Which helps support the vessels, preventing collapse under the pressure of water transport
124
What do tracheids do?
They occur in the xylem of all living plants. Walls are often interrupted by pits. They are long thin cells with tapered ends
125
What are pits in xylem cells?
Thinner regions where only primary walls are present. This allows water to migrate laterally between neighbouring cells through these pits. It allows water to move though cells without needing to cross thick secondary walls.
126
What do vessel elements do?
Most angiosperms and a few gymnosperms and a few seedless vascular plants have vessel elements. Walls are often interrupted by pits. They are generally wider, shorter, thinner walled and less tapered than the tracheids. They are aligned end to end forming pipes known as vessels. The end walls of the vessel elements have perforation plates that enables water to freely flow through vessels.
127
What do the cells in the phloem do?
Sugar-conducting cells. Alive at maturity, in seedless vascular plants and gymnosperms. Sugars, other organic nutrients are transported through long, narrow cells in the phloem of angiosperms. These nutrients are transported through sieve tubes which consist of chains of cells called sieve tube elements or sieve tube numbers.
128
What are sieve tube elements?
They are cells in the phloem that lack a nucleus, ribosomes, a distinct vacuole and cytoskeletal elements. This reduction in cell contents enables nutrients to pass more easily through the cell.
129
What are the end walls between sieve tube elements called?
Sieve plates. They have pores that facilitate the flow of fluid from cell to cell along the sieve tube.
130
What is alongside each sieve tube element?
A nonconducting cell called a companion cell, which is connected to the sieve tube elements by numerous plasmodesmata. The nucleus and ribosomes of the companion cell serve not only that cell itself but also the adjacent sieve tube element. In some plants, the companion cells in leaves also help load sugars into the sieve tube elements . Which then transport sugars to other parts of the plant.
131
What is indeterminate growth?
Growth throughout life/nonstop growth (except for when plants have periods of dormancy).
132
What is determinate growth?
Stopping growing after a certain size. This is in places like leaves, thorns and flowers.
133
What are lateral meristems?
They do secondary growth and include the vascular cambium and the cork cambium. The vascular cambium adds vascular tissue (secondary xylem/phloem), the cork cambium replaces the epidermis with the thicker, tougher periderm.
134
How do cells grow in the meristems during the growing season?
Cells in the apical and lateral meristems divide frequently during the growing season, generating additional cells. Some new cells remain in the meristem to produce new cells. Other cells differentiate. These cells that remain in the meristem are called stem cells or initials.
135
What does cells displaced from the meristem do?
They may divide several more times as they differentiate into mature cells. During primary growth, these cells give rise to three tissues called (primary meristems) the protoderm, ground meristem and procambium (which will produce the three mature tissues of a root/shoot (dermal, ground and vascular tissues)
136
Example of winter twig growth?
Shoot top has dormant apical bud, enclosed by scales for protection. In spring, bud sheds scales begining new spurt of primary growth, produces series of nodes and internodes. Each growth segment has nodes which are marked by scars left from fallen leaves. About scar is axillary bud/branch formed by axillary bud, further down are bud scars, from formed protective scales
137
What can flowering plants be categorised as in lifecycle times?
Annuals (complete lifecycle from germination to death in a year or less like rice), biennials (these require 2 growing seasons for life cycle, flowering/fruiting in their second year, like turnips) perennials (live many years and include trees, shrubs and some grasses)
138
What is an advantage of annual growth?
It allows the plant to put most of their resources into reproduction as they die after producing seeds.
139
What do vascular and cork cambiums look like?
They are cylinder that are one cell thick. When a cambium cell divides, sometimes both daughter cells remain in the cambium and grow, increasing the cambium circumference (from top it's outwards)
140
What does it mean when the vascular cambium and the cork cambium become active in a stem?
Primary growth has ceased in that area as secondary growth has now started
141
What is most of the cells in secondary growth?
Secondary xylem (wood)
142
What happens to the cells when vascular cambium cells divide?
Sometimes one daughter cell becomes a secondary xylem cell to the inside of the cambium or a secondary phloem cell to the outside of the cambium. Usually many more xylem cells are produced
143
What are herbaceous plants?
Non woody. No woody stems/parts, only primary growth.
144
What is the zone of differentiation?
Just above the zone of elongation. When the cells in the zone of elongation are even fully finished elongating, they will be pushed up into the zone of differentiation where they will begin specializing in structure and function. As this occurs, three primary meristems become evident (clearly seen). In this area, cells complete their differentiation and become distinct cell types.
145
What is the protoderm?
Outermost primary meristem, gives rise to the epidermis which is a single layer of of cuticle-free cells covering the root.
146
What is the ground meristem?
It gives rise to ground tissue. Ground tissue of roots, consisting mostly of parenchyma cells, is found in the cortex.
147
What is the endodermis?
The innermost layer of the cortex, a cylinder one cell thick that forms the boundary with the vascular cylinder
148
What are eudicots?
Flowering plants with two seed leaves upon germination. They also have ground tissue called pith and have their vascular bundles around the outer layer where the cortex is, in a ring.
149
What are monocots?
Flowering plants with one seed leaf upon germination. Their vascular bundles are more scattered and they do not have a pith or cortex.
150
What does the procambium do?
Gives rise to the vascular cylinder that consists of the xylem and phloem tissues, they are surrounded by a cell layer called the pericycle.
151
Where do lateral roots grow from?
The pericycle. They will then push their way out, bursting from the side of the root
152
What do the leaves of an apical bud do?
Protects the apical meristems below them
153
Where do lateral shoots grow from?
The axillary bud meristems on the stems' surface and do not disrupt other tissues
154
Where do leaves develop from?
Leaf primordial (singular is primordium)
155
What is leaf ground tissue called?
Mesophyll. It consists mainly of parenchyma cells that are specialised for photosynthesis.
156
What are the two mesophyll layers that are found in eudicots?
Palisade mesophyll and spongy mesophyll.
157
What is palisade mesophyll?
It's located beneath the upper epidermis, consists of one or more layers of elongated, chloroplast rich cells that are specialised for light capture
158
What is spongy mesophyll?
It's located inward from the lower epidermis, it consists of irregularly shaped cells that have fewer chloroplasts. These cells form a labyrinth of air spaces (they get bigger towards the stoma) through which gases circulate to and from the layer.
159
What is each vein in the leaf enclosed in?
A protective bundle sheath, a layer of cells that regulates the movement of substances between the vascular tissue and mesophyll.
160
The secondary growth process of a woody stem.
1) Primary growth from the activity of the apical meristem is complete here. The vascular cambium has formed and its cell divisions will give rise to the bulk of the secondary growth 2) Although primary growth continues in the apical bud, only secondary growth occurs in this region. The stem thickens as the vascular cambium forms secondary xylem to the inside and secondary phloem to the outside 3) Some stem cells of the vascular cambium give rise to vascular rays 4) as the vascular cambium diameter increases, the secondary phloem and other tissues external to the cambium can't keep pace because their cells no longer divide. As a result, these tissues including the epidermis will eventually rupture. A second lateral meristem, the cork cambium, develops from parenchyma cells in the cortex. The cork cambium produces cork cells which replace the epidermis. 5) In year 2 of secondary growth, the vascular cambium produces more secondary xylem and phloem. Most of the thickening is from secondary xylem. Meanwhile, the cork cambium produces more cork. 6) As the stem's diameter increases, the outermost tissues exterior to the cork cambium rupture and are sloughed off. 7) In many cases, the cork cambium reforms deeper in the cortex. When none of the cortex is left, the cambium develops from phloem parenchyma cells 8) Each cork cambium and the tissues it produces from a layer of periderm. 9) Bark consists of all tissues exterior to the vascular cambium.
161
What are vascular rays?
Radial files of mostly parenchyma cells that connects secondary xylem and phloem. They move water and nutrients between them, store carbs and aid in wound repair.
162
How does growth rings work in temperate regions with early wood?
Wood that develops early in spring known as early (or spring) wood usually has secondary xylem cells with large diameters and thin cell walls has a structure that maximises delivery of water to leaves.
163
How does growth rings work in temperate regions with late wood?
Wood produced later in the growing season is called late (or summer) wood. It has thick-walled cells that do not transport as much water but provide more support. Growth rings vary in thickness depending on the seasonal growth. Trees grow well in wet/warm years but may grow hardly at all in cold/dry years. Thick rings indicate warm years, thin rings indicate cold years, so these rings can also be used to study climate changes
164
How does growth rings reflect climate?
Because there is marked contrast between the large cells of the new early wood and the smaller cells of the late wood of the previous growing season, a year's growth appears as a distinct growth ring in cross section. Therefore researchers can estimate a tree's age by counting growth rings.
165
How do the roots of woody plants differ from the shoots?
Woody roots have the same meristems and tissues. However, the ground tissue of the roots not divided into pith and cortex, and the the cork cambium arises instead from the pericycle, the outermost layer of the vascular cylinder.
166
What are lenticels?
Dotting the periderm are small, raised areas called lenticels, in which there is more space between cork cells, enabling living cells within a woody stem or root to exchange gases with the outside air. They often appear as horizontal slits.
167
What are lycophytes?
Fern allies. Spike mosses, club mosses and quillworts.
168
What happens as a tree or woody shrub ages?
Older layers of secondary xylem no longer transport water and minerals, these layers are called heartwood because they are closer to the core/center of the stem/root. The newest, outer layers of secondary xylem still transports xylem sap and therefore known as sapwood. Sapwood allows a large tree to survive even if the center of its trunk is hollow. Because each new layer of secondary xylem has a larger circumference, secondary growth enables the xylem to transport more sap each year, supplying an increasing number of leaves. Only the youngest secondary phloem, closest to the vascular cambium functions in sugar transport.
169
What are monilophytes?
Ferns. Adders tongue, horsetails, whisk ferns and true ferns.
170
What stage is dominant in vascular plants?
The sporophytic stage.
171
What stage is dominant in nonvascular plants?
The gametophytic stage.
172
Early stages of secondary growth?
The epidermis is pushed outward, causing it to split, dry and fall off the stem or root. It is replaced by tissues produced by the first cork cambium, a cylinder of dividing cells that arises in the outer cortex of stems and in the pericycle in roots. The cork cambium gives rise to cork cells that accumulate to the outside of the cork cambium. As cork cells mature, they deposit a waxy, hydrophobic material called suberin in their walls before dying. Because cork cells have suberin and are usually compacted together, most of the periderm is impermeable to water and gases, unlike the epidermis. Cork thus functions as a barrier that helps protect the stem or root from water loss, physical damage and pathogens.
173
What does being dominant in a life cycle mean?
Larger structure or around much longer in the life cycle.
174
What does the sporophyte do in seedless vascular plants?
The sporophyte quickly outgrows the gametophyte, then the gametophyte cannot produce enough energy to sustain itself, so it dies off. It got outcompeted by the sporophyte it gave rise to.
175
What are the features of seedless vascular plants?
Seeds absent, sperm with flangella (plesiomorphs), xylem phloem, lignin, sorophills, dominant sporophytic srage, free living spororphytem, root, leaves (synapomorphines)
176
What is a plesiomorph?
A term used in phylogenetics to describe an ancestral character state that is shared by members of a clade. It can also be referred to as a primitive or ancestral trait.
177
What is a synapomorph?
A characteristic present in an ancestral species and shared exclusively (in more or less modified form) by its evolutionary descendants, possession by two or more organisms of a characteristic inherited exclusively from their common ancestor.
178
What are sporophylls?
Modified leaves bearing sporangia, allows many more sporangia to be produced as these leaves grow big
179
What can be seen underneath fern leaves?
Some fern leaves when flipped over can be empty (sterile leaves) but other leaves when flipped over will have clusters of sporangia on the underside. Each cluster produces many spores.
180
What is a fertile fern leaf (leaf with sorus)?
Frond
181
What is a sorus?
A cluster of sporangium, sometimes with an indusium (flap or lid of tissue for protection)
182
What do lycophytes have instead of sorus?
They have small cone structures called strobili. It has scales on the outside and sacs of spores inside, much more clustered.
183
Do flowering plants also have sporophylls?
Yes
184
What is homosporous spore production?
Some. Sporangium only produces one type of spore. One type of sporangium gives rise to a bisexual gametophyte, which means that gametophyte produces eggs and sperm cells.
185
What plants have homosporous spore production?
Bryophytes, monilophytes and many lycophytes.
186
What is the cycle for homosporous spore production?
Sporangium on sporophyll > Single type of spore > Typically a bisexual gametophyte > Eggs OR Sperm
187
What is heterosporous spore production?
Different. Megasporangium and microsporangium look quite different. Megasporangium are often much larger than microsporangium
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What is the cycle for heterosporous spore production?
Megasporangium on megasporophyll > Megaspore > Female gametophyte > Eggs
OR
Microsporangium on microsporophyll > Microspore > Male gametophyte > Sperm
189
What plants have heterosporous spore production?
Seed plants and some lycophytes.
190
What happens in the sporangium before spores are released?
Meoisis
191
What are mircrophylls?
Small often spine-shaped leaves with a single strand of vascular tissue. All lycophytes and only them have this.
192
What are megaphylls?
Leaves with highly branched vascular system. Almost all vascular plants have these.
193
What is sori?
Singular use of sorus
194
What are strobili?
In many lycophytes and in most gymnosperms, cone-like structures are formed.
195
What is the single use of strobili?
Strobilus
196
What are the sporophylls of angiosperms called?
Carpels and stamens
197
Gametes of land plants are...
Haploid and formed by cells of the gametophyte that undergo mitosis
198
What is an archegonium?
A female gametangium
199
Which group of organisms is most closely related to the land plants?
Charophytes
200
Which of the following is NOT a synapomorphy that the bryophytes share with the vascular plants?
The absence of true roots and leaves
201
In contrast to other groups of land plants, bryophytes don’t have true leaves, because the ‘leaves’ of bryophytes:
Are not produced by the sporophyte
202
When and why does the peristome of a moss capsule open?
When it is dry and in order to release spores
203
The seedless vascular plants form a monophyletic group. True or false?
haploid and part of the gametophytic generation
204
Are the following structures diploid or haploid?
Gametophyte → Haploid,
Sporophyte → Diploid,
Spore → Haploid,
Sporangium → Diploid,
Seta → Diploid
205
What does the vascular cambium produce?
Secondary xylem and secondary phloem
206
From the center of a stem of a woody plant towards the outside, what is the correct order of tissues?
Primary xylem -> secondary xylem -> vascular cambium -> secondary phloem -> primary phloem
207
Which structures can be found in the sori of ferns?
Sporangia
208
The sporangia of pterophytes display homosporous spore production. This means that:
Only a single type of spore is produced that will develop into a gametophyte with antheridia and archegonia.
208
Which evolutionary trend can be observed when the gametophytes and sporophytes of mosses, ferns and seed plants are compared?
Through evolutionary time, the sporophyte stage of the plant life cycle has become increasingly more dominant.
209
Which step in the evolution of the seed resulted in the origin of the pollen grain?
Endospory
210
What is an ovule?
A megasporangium + megaspore + integuments
211
What is contained within the pollen grain?
male gametophyte
212
What is formed by the megaspore?
female gametophyte
213
What structure produces the microspores?
microsporangium
214
From the outside of a typical flower towards its centre, you will find the following structures:
sepals, petals, stamens, pistil
215
Which parts can ALL be found in the ovule of a pine tree?
Megasporangium, archegonium, micropyle, megaspore
216
Which character state indicates that the cycadophytes are gymnosperms?
Seeds with haploid food reserves
217
Which gymnosperm phylum is characterised by simple leaves, the absence of female cones and the presence of motile sperm cells?
Ginkgophyta
218
The microsporophylls of gymnosperms are homologous to which parts of the angiosperm flower?
The stamens
219
An imperfect flower is always incomplete. True or false?
True
220
After fertilization, the carpels of a flower will become the:
Fruit
221
Animal pollination was a major evolutionary development, because...
it is a more effective and efficient pollination system than wind pollination
222
What is double fertilization?
The process in which one sperm cell fertilizes an egg cell and another sperm cell merges with the polar cells of the female gametophyte.
223
A plant with bisexual flowers is always monoecious. True or false?
True
224
Which character would you be looking at if you want to determine whether a plant is a moss or a hornwort?
Presence of a seta
225
Which of the following best describes an epiphytic plant?
A plant that is not rooted in the soil and instead grows on another plant
226
Which of the following taxa is a group of seedless vascular plants?
Lycophytes
227
What is the effect of apical dominance on a plant?
Stems and branches grow in length rather than branching
228
Which adaptation has evolved multiple times indepently in plants that grow in nitrogen-poor environments?
Carnivory
229
What do you need to look at to determine the leaf arrangement of a plant?
The number of leaves per node
230
The position of which structures needs to be examined to determine whether a plant has simple or compound leaves?
Axillary buds
231
Which of the following adaptations is NOT characteristic of xerophytes?
Symbiosis with nitrogen-fixing bacteria
232
Taking both extant and extinct lineages into account, which plant group is presumably most closely related to the angiosperms?
Bennettitales
232
What is the evolutionary relevance of the fossil species Archaefructus sinensis?
This fossil species helps to understand the early evolution of the woody plants, The reproductive morphology of Archaefructus sinensis may help us to understand the origin of flowers, the age of these fossils provides more information about the timing of the diversification of the angiosperms
232
Tricolpate pollen is a synapomorphy for the:
Eudicots
233
'Darwin's abominable mystery' refers to:
A lack of a good explanation for the sudden appearance of Angiosperms and their rapid diversification in the fossil record
234
What are epiphytes?
Plants that use other plants as a substrate (a surface or material an organism grows on) but are not necessarily parasitic
235
How do fern leaves look when growing?
Leaves grow as it's tip (called the fiddlehead) unfurls
236
Fern reproduction is...
Homosporous
237
Horsetail reproduction is...
Homosporous
238
Whisk fern reproduction is...
Homosporous
239
What happens to fern gametophytes?
In some species, the fern sporophyll detaches itself from the gametophyte and the gametophyte shrivels and dies.
240
What do horsetails have in some species?
Separate fertile (cone-bearing) and vegetative stems
241
What are whisk ferns missing?
They do not have roots, each yellow knot on the stem consists of three fused sporangia
242
What do monilophytes and seed plants have in common?
They have roots that can branch at various points along the length of an existing root
243
How do monilophytes and lycophytes roots differ?
monilophyteshave roots that can branch at various points along the length of an existing root while lycophytes roots branch only at the growing tip of the root, forming a y shaped structure
244
How are fern spores produced?
Sporocyte cells have 2 sets of chromosomes, 1 from each parent (diploid). The nucleus devices twice (a process called meiosis) each daughter nucleus now has 1 set of chromosomes. The cells becomes a tetrad (cluster of 4), the tapetum breaks down, depositing a protective coat of sporopollenin. With this layer, the tetrad becomes a spore.
245
What is the fern sporangium made up of?
Sporangium has an outer protective jacket cells, a band called the annulus. On the other side, there are thinner more delicate walls where delicate lip cells form. Below the jacket, there are 2 layers of cells called tapetum, these nourish the fertile tissue within.
246
How are fern spores released?
The annulus (the backbone of the sporangia) begins to dry out, and tension/pull between its wall and the water molecules increases. Thin outer walls are pulled inwards, and thick inner walls resist. This pull causes an accordion-like contraction, making the thin lip cells on the other side tear open. The annulus shortens, and the tear enlarges opening the spore casing more (like an egg) As more tension builds, the water molecules cannot hold themselves anymore, causing their bonds to break. The annulus snaps back, catapulting the spores out, like a spring mechanism.
247
What are gametophytes like in seed plants?
They are reduced (usually mircoscopic) and are dependent on surrounding sporophyte tissue for nutrition.
248
What are sporophytes like in seed plants?
The sporophyte is the dominant structure (the whole plant), having the gametophyte rely on it. This allows the plant to grow much bigger.
249
Angiosperm reproduction parts?
Microscopic female gametophytes (n) inside the central area of a flower, microscopic male gametophytes (n) inside the attene of flowers. Sporophyte is the whole plant (2n)
249
Gymnosperm reproduction parts?
Microscopic female gametophytes (n) inside ovulate cone, microscopic male gametophytes (n) inside pollen cone. Sporophyte is the whole tree (2n)
249
What is resource allocation strategy?
Putting all/most of the plant resources into one egg/spore rather than many. It's like putting 100 eggs into a soft hoodie vs 1 egg in a protective case. The 1 egg will survive much better.
250
What is wood like for a plant?
Wood is like a skeleton for a plant, they cannot grow tall without the structure wood provides.
251
What is endospory?
Female or male gametophyte that does not germinate from the megaspore by the remains surrounded by the spore wall.
252
How did the evolution of seeds go?
Homospory > Heterospory (female gametophyte develops from spore) > Endospory (male gametophyte germinates from microspore) > Endospory (male. First pollen grains, multiple megaspores) > One megaspore (rest are abortive. Megasore is released from sporangium) > Megaspore not released from sporangium (integument absent) > Integument present > Ovule grows out to be a seed when fertilised
253
What does an ovule include?
megasporangium, megaspore and integuments
254
What is an integument?
Protective laters of the sporangium
255
What is the adaptive significance of seeds?
Food supply, protective coat (from drought, UV radiation), dispersal unit, can go dormant and still grow later, the seed can travel. Food supply is the female gametophyte.
256
What is the adaptive significance of pollen?
Protective coat (drought, UV radiation), independence of water as a transport agent, allows plants to grow and reproduce in dry environments
257
What do only angiosperms produce?
Flowers and fruits
258
Where is the megasporangium maintained?
Seed plants retains the megasporangium within the parental sporophyte (integument)
259
How many integuments do gymnosperms and angiosperms have?
Gymnosperms have 1, angiosperms have 2 layers.
260
Where is the male gametophyte in pollen?
It's inside the pollen grain. Sporopollenlin in the pollen wall protects the pollen grain as it travels by wind or being picked up by animals
261
What is pollination?
It's the transfer of the pollen to the part of the seed containing the ovules. The pollen tube reaching down into the ovule and fertilising the egg with sperm is fertilisation
262
What happens when a pollen grain germinates?
It gives rise to a pollen tube that discharges sperm into the female gametophyte within the ovule.
263
What differs with sperm of gymnosperms and angiosperms?
They are missing the flagella
264
What are the linages of gymnosperms?
Cycadophyta (cycads), Ginkophyta (ginko), Coniferophyta (conifers), Gnetophyta (gnetophytes)
265
Where did gymnosperms evolve?
In drier environments, where they have adaptions to dealing with drought
266
What gymnosperms does not have motile sperm?
Coniferophyta (conifers), Gnetophyta (gentales, gnetophytes). Very long time between pollination and fertilisation
267
What are the diagnostic character traits of gymnosperms?
Mostly plesiomorphies (seeds not enclosed in a carpel, seeds not in a case, sitting on top), sporangia organised in cones/strobili, ovules with single integument, motile sperm
268
What does the sporophyte do in seedless vascular plants?
The sporophyte quickly outgrows the gametophyte, then the gametophyte cannot produce enough energy to sustain itself so it dies off. It got outcompeted by the sporophyte it gave rise to.
268
Gymnosperm means?
Naked seed
269
What does being dominant in a life cycle mean?
Larger structure or around much longer in the life cycle.
270
How are ovules places in gymnosperms?
The ovules are sitting on top of the megasporophylls and are not enclosed by it, they are a 'naked seed'
270
How are sporangia organised in gymnosperms?
In cones/strobili
270
What's the megasporophyll on gemnosperms?
Ovuliferous scale
271
What does megatron mean?
Unrelated
271
What does ovuliferous mean?
Ovule-bearing
271
What is the megastrobilus?
Female cone in gymnosperms
271
What are ovulves?
Seeds before they are fertilised once fertilised, they then grow into seeds, mostly plesiomorphies
271
What does meosis always do?
Always turns something diploid into something haploid
271
How long does ferilisation take in gymnosperms?
The time between pollination and fertilisation can take a long time, up to a year
271
What is pollenation?
The act of pollen arriving near the ovule
272
What happens to the female gametophyte in seeds?
Young embryo eats its mother gametophyte as inside the seed, the gametophyte becomes the food source
272
How does the male side of gymnosperms go?
Mature sporophte (2n) > Pollen cone > Microsporangia > Microsporangium (2n) containing microsporophytes > pollen grains (n)
273
How does the female side of gymnosperms go?
Mature sporophyte (2n) > Ovule cone > Ovule > Megasporocyte > Megasporangium > surviving megaspore > archegonium > zygote > seed > seedling
274
What structure/organ does the female gametophyte produce?
The archegonium and this produces an egg
275
Where does the spore always grow in?
The gametophyte, no matter the lifecycle
275
What are cycadophyta?
Sister group of all gymnosperms. Widespread in tropical regions. They look like palm trees but aren't them.
276
When did cycadophyta appear?
C. 290 MYA
277
What are cycadophyta's diagnostic characters?
Absence of lateral branches (synapomorphy), compound leaves (plesiomorphy), circinnate vernation (plesiomorphy), motile sperm cells (plesiomorphy)
278
What do black bars on the phylogenetic tree indicate?
A derived character train (synapomorphy)
279
What is circinnate vernation?
Fiddlehead bit, when young plant is rolled up like a fiddlehead
280
What are compound leaves?
Leaves that are dissected, not a single blade but it is deeply incised
281
What are simple leaves?
Low but not all the way divided to the central leaf stalk
282
What are ginkgophyta?
Sister group of the Coniferophyta + Gnetophyta, one extant species that's native to China
283
When did ginkgophyta appear?
C. 200 MYA
284
What are ginkgophyta's diagnostic characters?
Simple leaves, female cones absent, motile sperm cells (plesiomorphy)
285
What are coniferophyta?
Paraphyletic. Worldwide.
285
What is the droplet outside the ovule on gymnosperm cones?
It's called a pollination droplet, it's a sticky substance that allows the sperm to swim on a pollen grain to fertilise the ovule. Droplet is an opening between integuments
285
What are coniferophyta's diagnostic characters?
Simple leaves, very hard in texture and linear, needle-like structure or awl- shaped, often perennial. Very thick cuticles on these leaves, it makes the leaves very robust structures. Thick cuticle allows these plants to grow in dry regions/deserts as well as high revelations since it stops the plant from drying out (helps since it stops water loss, high elevations also freeze minimising water gain) Non-motile sperm cells (synapomorphy with gnetophytes) These leaves also gave low surface to volume ratio. It decreases photosynthesis but its made up for by having more leaves on the plant
285
When did coniferophyta appear?
C. 200 MYA
286
What is low surface to volume ratio?
Few cells outside compared to the inside, so less cells are exposed to the environment. This strategy minimises water loss.
287
What are gnetophyta?
Monophyletic, found in tropics and deserts.
288
What are gnetophyta's diagnostic characters?
Pressence of vessels (special xylem cells)
289
What are Ginkos phyla?
Phylum Ginkophyta
289
What are cycads phyla?
Phylum Cycadophyta
290
What are Conifers phyla?
Phylum Coniferophyta
291
What are Gnetophytes phyla?
Phylum Gnetophyta
292
What are Liverworts phyla?
Phylum Hepatophyta
293
What are Angiosperms phyla?
Plylum Anthophyta
293
What are Moses phyla?
Phylum Bryophyta
294
What are Lycophytes phyla?
Phylum Lycophyta
295
What are Hornworts phyla?
Phylum Anthocerophyta
296
What are Monilophytes phyla?
Phylum Monilophyta
297
What characterises angiosperms?
Flowers, fruits and double fertilisation
298
Periath function?
Is to protect reproductive parts deep inside, may have another function (to attract pollenators) Corolla can also have these two functions as well
298
What are Calyx?
Collective term for the sepals
299
What are the corolla?
Collective term for the petals (together called Parianth)
300
What are sepals?
Flowering bits on the outside
301
What are petals?
Further inwards together
302
What is is called when you can't distinguish between petals and sepals?
Tepals
303
What are stamen composed of?
Anther and filament
304
What does the anther do?
The most important part as pollen grains are produced in this
305
What does the filament do?
It positions the anther in a way that pollination can easily occur. The length of the filament can tell us what kind of pollinator we'd see on a plant
306
Carpel info...
Can be one or multiple, free from each other or fused. These form one or more structures called pistols.
307
What are the three parts of pistols?
Ovary at the bottom (inside this lies the ovules, all seed plants have them), On top of the ovary is the style (helps transport the pollen to the ovule and also helps position the stigma), at the tip of the style is the stigma (often a sticky surface for pollen grains to attach to)
308
How do flowers diversify (how much they differ from each other)?
Size, sex, shape, number of floral parts, pressence or absence of floral parts
309
What does imperfect mean in flowers?
Incomplete flowers. Male or Female. Means flower is missing one of these , so flowers with just carpels or flowers with just stamens. Some flowers have separate male and female only flowers which only produce male or female flowers. Petals, sepals, stamens or carpels missing also called having fewer than 4 whorls
310
What does perfect mean in flowers?
Complete flowers with all parts of both sexes.
311
What does it mean when a flower is radially symmetric?
Different places of symmetry, can cut up flower into many different ways and still have mirror images. The sepals and petals are all of the same size and shape.
312
What does it mean when a flower is bilaterally symmetric?
Most flowers. If the flower is cut in half, you get mirror images. Differences in peral and sepal sizes. The two halves are the same
313
What are the characterises angiosperms?
Stamen with 2 lateral thecae (two angiosporangia each), reduced 3-nucleate male gametophyte (it is very small) at maturity, the male gametoyphye has just two cells at maturity (a tube cell and a generative cell that divides creating 2 generative nuclei which forms sperm cells). Male gametophyte doesn't need to stay aliveas long as the time between pollination and fertilisation is very short hence it doesn't need to stay alive long. Inside anthers is microsporangia . Gametophytes in flowers super small + simple. Carpel formation. Oluvbes with two integuments (inner and outer integuments). Reduiced 8-nucleate female gametophyte (it is composed of just 8 cells/nuclei) Double fertilisation, fruits
313
What does merous mean?
Numbers in groups. E.g 5-merous = groups of 5.
314
Megaspore is a...
Modified leak-life structure
315
Flower reproductive evolution went like...
In the earliest ancestors of flowering plants, megasporophyll would surround the ovule sitting on top of it, ultimately entirely enveloping it and enclosing it. Forming a bit of a tube or a sac-like structure/bottle- shaped structure structure inside which the ovules were sitting, nicely protected./ This structure is called a carpel. Carpelos are just scales in pine cones that are folded around the ovules. Later in evolutionary time, carpels start differentiating and specialising. The bottom bit is where we find the ovules and its called the ovary. The ovary after the ovules have been fertilisted and becomes seeds, will become the fruit. On top of the ovary is the style, on top of the style is the astigmatic surface that collects the pollen grains
316
What does the ovary become in flowers?
The fruit
317
Specialisation allows plants to have incompatibility reactions which are...
Ways to make sure only grains of same species will germinate or are able to form a pollen tube, it also prevents self-fertilisation
318
Development of male gametophyte (in angiosperms)...
Inside pollen grain. Microsporangium (pollen sac) > Microsporocute, 2n > (Meiosis) 4 microspores, n > Each of 4 microspores, n > (Mitosis) Generative cell, n with male gametophyte, nucleus of tube cell, n
319
Development of female gametophyte (in angiosperms)...
Embryo sac.
1) Ovule containing megasporangium, 2n, megasporeocute, 2n, Integuments on outside, 2n, and micropyle, (meiosis for 2)
2) One surviving megaspore (n) (mitosis for 3)
3) Female gametophyte (embryo sac) inside integuments, 2n, and ovule. Inside ovule is 3 antipodal cells, n, 2 polar nueclei, n, 1 egg, n, and 2 synergies, n.
320
Double fertilisation is?
Sperm exits the nuceli via pollen tuibe and explore female gameto[phyte until it finds an egg. One sperm merges with an egg nucleus. The second sperm merges with two of the nuclear of the female gameophte called the polar nuclei, this creates an endosperm (3n). the endosperm is a structure that is a source of nutrition for the embryo.
321
Why is endosperm a triploid?
Endosperm is a triploid, being so can allow this tissue used for the embryo (to feed on) to develop quickly.
322
Do angiosperms sperm swim?
No, they are delivered close to the ovules via the pollen tube.
323
What are fruits?
Matured ovary long with fused accessory structures. All angiosperms and only angiosperms have fruits. These fruit structures originate directly from the ovary, a fruit in essence is a pregnant ovary. As the seed is growing inside, the ovary also grows. Some other structures of the flower fuse with the ovary and become a fruit as well. The wall of the ovary is called the pericarp (composed of different layers that might look different on each fruit (endocarp, mesocarp and exocarp.)
Endocarp on the inside, exocarp on the outside, and mesocarp in the middle.
324
What do stone fruit seeds have?
Inside stone fruit, the seed has an extra layer of protection from the ovary growing an extra layer.
325
How are angiosperms pollenised?
Some have wind pollination, but most have pollination by animals (plesiomorphic character state)
326
Flowers like to use what substance as a treat for pollinators?
Nectar. Plants have it in certain places to attract certain pollinators
327
What do orchids use to attract pollinators?
They use mimicry, the flower does not have nectar. Tget can also physically mimic its pollinators themselves so they mate with the flower, spreading the flower's pollen.
328
What is pollination syndrome?
Suits of characters that a plant species produces that helps us predict what the pollinator of the plant species might be. Holds true often enough for it to be helpful but there are always exceptions
328
Bee flower preference?
Open, purple or yellow coloured flowers with visual guidelines.
329
Bird flower preference?
Long-tubed flowers with nectar at the foot of them, often in red. Some flowers like red mistletoe only want smart birds that can twist the flower buds open to reach its nectar
330
Bat flower preference?
Large flowers on exposed inflorescences. They often like grey/beige plants
331
Flies flower preference?
Foul smell to them, dark or flesh/red coloured flowers to mimic rotting animals.
332
Wind flower preference?
Inconspicuous, exposed small flowers, reproductive bits hang outside the flower
333
What is important for seed dispersal?
Animals are, they are important for transporting seeds like they are for pollen. Plants also have involved fruits to attract certain seed dispersers
334
Bird fruit preference?
Red colours, also yellows
335
Lizard fruit preference?
fruits with two colours (white + green)
336
What do dry fruits do?
They hitchhike on animals (mostly mammals) walking by. Some disperse by falling. Some have wing structures that allows them to be taken further. While others have fluff, like daisies which takes them far via the wind.
337
What are dry fruits?
Nonfleshy, not made to be eaten unlike fleshy fruits.
338
What is another unique way of seed dispersal?
Via the ocean current/tides to wash up on another beach to begin germination. Coconuts do this
339
What happens after seed dispersal?
When reaching its resting place, some seeds will start germinating immediately. Others will have a period of dormancy (sleeping). This adaptation helps a seed to not germinate when conditions are unfavourable for the sporophyte growth.
340
What environment is Coniferophyta adapted to?
Cold, dry environment. They are adapted by having leaves that are long thin needles covered by a waterproof cuticle to help minimise water loss through evaporation. They maintain most of their leaves throughout the year, which means they can photosynthesize and grow during cold periods when other trees are dormant. They produce a resinous antifreeze in their sap so they can still transport nutrients through their system in freezing weather
341
Do gymnosperm sperm use pollen tubes?
Yes. Their sperm uses pollen tubes to reach the egg, they have to digest through the female cone to reach them.
342
What are seed cones?
Female cones
342
What are pollen cones?
Male cones
343
What is a herb?
A nonwoody plant. It will never be woody.
344
What is a tree?
Woody plants with single main stem called a trunk
345
What is a shrub?
A woody plant with more than a single main stem
346
Can plants start off as shrubs and become trees?
Yes
347
What is a vine/liana?
A climbing plant (a vine means nonwoody climber)
348
What is an epiphyte?
A plant that goes upon another plant, they've developed roots specifically for attachment to other plants. Not always parasites but can be.
349
Are parasitic epiphytes host-specific?
Can be
350
Are nonparasitic epiphytes host-specific?
No
351
Form and function is?
The principle that an organism's structure (form) is directly related to its function. So the direct relationship between the structure of a thing and how it functions.
352
What happens with woody epiphytes?
They can just be epiphytic in their first stage of their life, but then become self-sustaining through roots as they start on the side of a tree and grow downwards to the ground. As they grow in diameter they can also strangle and kill their host.
353
What is another function of roots?
To store carbohydrates
354
What is a taproot?
A root system with one main root and several smaller lateral roots. Good for water deep underground
355
What is fibrous roots?
No clear main root. Good for water near the surface.
355
What is succession?
A plant taking over the ecosystem, usually from a disturbance (like a flood or wildfire), so a top plant is replaced.
356
What can help plants survive extreme environments?
Highly specialised roots.
357
What do meristems do if unactivated?
They sit in a dormant state until activated
357
What do plant roots do with other fungi?
Plant roots typically form a mutualistic relationship (species living together and benefiting each other) with mycorrhizal fungi. Some plant species also form roots with nodules in which symbiotic bacteria live.
358
What is apical dominance?
Both auxins and cytokin hormones are fighting each other, a tug of war. Signals saying to stay dormant, other signals saying to start growing. The ratio between both is what happens. Cutting/pruning a branch means auxins are less produced (cut off when pruned) so cytokins win and signal for growth.
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What are auxins?
produced by the apical bud. Contributes to inhibition of development of axillary buds
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What are cytokins?
produced by the roots. Contributes to single to start development of axillary buds into branches
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What do all leaves have?
They all have an axillary bud associated with them, it may sit dormant its whole life or may get leaves to start growing.
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What is a thorn
A modified branch
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What is a rhizome?
An underground creeping stem. Can also assist in vegetative reproduction (bits of plant breaking off and continuing to grow)
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What is a tendril?
A modified branch or leaf for support or climbing
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What are cacti leaves?
They are spines, they are not there for photosynthesis. Photosynthesis is taken over by the steam and internodes.
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What are leaves for the plant?
Solar panels
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Where can swollen stems be found?
They can be found in dry environments, these are used for either photosynthesis or water storage.
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What is a compound leaf composed of?
More than one leaf bundle. Often looks like little leave blades, called leaflets.
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What is a simple leaf composed of?
Only one leaf blade
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What is the rachis?
Central axis of lead (a branch)
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How to tell leaves from leaflets?
Leaf: axillary bud associated with them
Leaflet: No axillary bud associated
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What are the two types of compound leaves?
Rachis present or rachis absent
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What is an alternate leaf arrangement?
One leaf per node.
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What is opposite leaf arrangement?
Two leaves per node, usually opposite from each other
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What is a whorled arrangement?
More than two leaves per node
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What is a dentate?
Dentate means toothed. Leaf margin is not entire. Teethm bumps and spike, can be tapered, triangular and forward pointing
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What are entire leaves?
not lobed or deeply incised. Can be regular or irregular. The whole margin is smooth, doesn't have teeth to bumps.
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What are extra-floral nectaries?
Sugar-producing glands associated with vegetative structures
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What are accessory structures?
Extra bits and pieces
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What are domatia?
Leaf-associated chambers that house arthropods
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What are carnivorous plants?
Plants that eat animals. They do this by trapping usually insects. They live in nutrient-poor environments particularly environments starved of nitrogen. Insects' exoskeleton is very rich in nitrogen so getting this from insects helps the plants
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What are halophytes?
Plants that grow/live in salt-rich environments. They usually have fleshy parts with a low surface-to-content ratio to reduce desiccation by salt. Salt-rich environments include along coats. They also have a thick cuticle
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What are xerophytes?
Plants that live in dry environments. They usually have fleshy parts with a low surface to content ratio to reduce desiccation by drought
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Desiccation means?
Removal of moisture from something
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What is a spine?
A modified leaf. Protects plant and flowers. They are different from thorns
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What does photosynthetic parts being absent mean?
Likely means a parasitic plant that steals water and even sometimes sugars from its host plant vis tapping into host's phloem and xylem
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What is a hemi-parasite?
A parasitic plant that photosynthesises
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What is a prickle?
Modified epidermis. The prickes of roses helps them climb and protects them against herbivores
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What is chemical defense?
Anti-herbivore defence using secondary metabolites in Ragworts. Laex ('milk') is white sap that is full of chemicals that deter herbivores
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What may Bennettitales be?
The connection between gymnosperms and angiosperms
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What is the oldest angiosperm?
Amborella. It may give clues to what the ancestor to all angiosperms looks like. Symplesiomorphies with gymnosperms (e.g. vessels absent). These have vessel elements (specialised for water transport) instead of advanced vascular systems as seen in modern angiosperms. These have unfused carpels.
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What are symplesiomorphies?
Shared ancestral character states
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What are water lillies?
Aquatic plants, synapomorphy with other angiosperms (except Amborella): vessels. Symplesiomorpghies with Amborella (carpels partially fused).
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What are Star anise and their relatives?
Symplesiomorphies with Amborella and water lillies (carpels partially fused).
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What are magnoliids?
Synamorphies mostli
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What are eudicots?
Synapomorphy is tricolpate pollen (Pollen grain with three openings)
Sunapomorphies with monocots: Fewer floral parts than basal angiosperms and magnoliids
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What kind of pollen does monocots have?
Monosulcate pollen (pollen grain with one opening)
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Lifecycle of a pine...
1) In most conifer species, each tree has both ovulate and pollen cones
2) Microsporocytes divide by meiosis, producing haploid microspores. A microspore develops into a pollen grain (a male gametophyte enclosed within a pollen wall)
3) An ovulate cone scale has two ovules, each containing a megasporangium.
4) Pollination occurs when a pollen grain reaches the ovule. The pollen grain then germinates, forming a pollen tube that slowly digests its way through the megasporangium.
5) While the pollen tube develops, the megasporocyte undergoes meiosis, producing four haploid cells. One survives as a megaspore.
6) The megaspore develops into a female gametophyte that contains two or three archegonia, each of which will form an egg.
7) By the time the eggs are mature, sperm cells have developed in the pollen tube, which extends to the female gametophyte. Fertilisation occurs when sperm and egg nuclei unite.
8) Fertilisation usually occurs more than a year after pollination. All eggs may be fertilised but usually only one zygote develops into an embryo. The ovule becomes a seed, consisting of an embryo, food supply and seed coat. When fetilisaed, the scales of each ovulate cone then separate and the seeds are dispersed by the wind
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Flower structures?
Starting at the base of the flower are the sepals, which are usually green and enclose the flower before it opens (like a rosebud). Interior to the sepals are the petals, which are brightly coloured in most flowers. Flowers that are wind pollinated such as grasses lack in general bright colours.
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What are the two types of fertile floral organs?
Stamens and carpels. They are both sporophylls.
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What are sporophylls?
Modified leaves that are specialised for reproduction.
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What are stamens?
They are microsporophylls, they produce microspores that develop into pollen grains containing male gametophytes. The filament is the stalk attached to the anther where pollen is produced.
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What are carpels?
They are megasporophylls, they produce megaspores that give rise to female gemetophytes
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What does pistil refer to?
Is sometimes used to refer to a single carpel (a simple pistill) or two or more fused carpels (a compound pistil)
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What are Bennettitales?
it and other similar lineages of extinct woody seed plants did not have carpels or flowers so are not classified as angiosperms.
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What are basal angiosperms?
Amborella, water lillies and star anise.
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What are the differences between monocots and eudicots?
1) Monocots= One cotyledon Eudicots= Two cotyledons
2) Monocots= Veins parallel Eudicots= Veins netlike
3) Monocots= Vascular tissue scattered Eudicots= Vascular tissue arranged in a ring
4) Monocots= Fibrous root Eudicots= Taproot
5) Monocots= Pollen grain with one opening Eudicots= Pollen grain with three openings
6) Monocots= Floral organs in multiples of three Eudicots= Floral organs in multiples of four of five
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What are determinate shoots?
Flowers are these. They cease growing after the flowers and fruits have formed
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Sepals and petals are sterile...
sporophylls/modified leaves
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What does biotic mean?
Living pollinating agent
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What does abiotic mean?
Nonliving pollinating agent
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What is a proembryo?
Early embryo
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What is imbibition?
The uptake of water due to the low water potential of the dry seed (seed germination is initiated by this)
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What happens with the ovary during fruit development?
During fruit development, the ovary wall becomes the pericarp, the thickened wall of the fruit. In some fruits, such as soybeans, the ovary wall dries out completely at maturity, whereas in other fruits, such as grapes the ovary remains fleshy. In others like stone fruits, the inner part of the ovary becomes stony, the outer part stays fleshy.
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What are simple fruit?
a simple fruit develops from a single carpel (or several fused carpels) of one flower. Includes peas or lemons.
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What are aggregate fruit?
An aggregate fruit develops from many separate carpels of one flower. Includes raspberries and blackberries.
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What are multiple fruit?
A multiple fruit develops from many carpels of the many flowers that form an inflorescence. Includes pineapples and figs.
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What are accessory fruit?
An accessory fruit develops largely from tissues other than the ovary. In the apple fruit, the ovary is embedded in a fleshy receptacle. Includes apples.
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What is inflorescence?
The complete flower head of a plant, including stems, stalks, bract and flowers, a group of flowers tightly clustered together
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What is bract?
A modified leaf or scale
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What is a receptacle?
The thickened part of a flower stalk from which the the flower grows (the part of a flower stalk where the parts of the flower are attached)
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What do taproots allow a plant to do?
It allows plants to grow taller since it anchors them better which prevents the shoots of the plant from toppling over.
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What's the stem's function?
The stem's function is to elongate and orientate the shoot in a way that maximises photosynthesis for the leaves, can also elevate reproductive structures
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What are rhizomes?
A horizontal shoot that grows just below the surface. Verticle shoots emerge from axillar buds on the rhizome
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What are stolons?
They are horizontal shoots that grow along the surface (above ground). These 'runners' enable a plant to reproduce asexually as plantlets grow from axillary buds along each runner.
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What are petioles?
petioles joins the leaf to the stem at a node. Many monocots and grasses lack this, instead the base of the leaf forms a health that envelops the stem.
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What are tubers?
Enlarged ends of rhizomes or stolons specialised for storing food
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What kind of veins do monocots have?
Most have parallel major veins at equal diameters that runs down the length of the leaf blade.
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What kind of veins do eudicots have?
These generally have branched networks of veins arising from a major vein that runs down the centre of the leaf blade
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What is a simple leaf?
A simple leaf has a single, undivided blade. Some simple leaves are deeply lobed.
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What is a compound leaf?
In a compound leaf, the blade consists of multiple leaflets. A leaflet has no axillary bud at its base. In some plants, each leaflet is further divided into smaller leaflets.
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What are tendrils?
Modified leaves, some are modified stems
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What are storage leaves?
Bulbs such as an onion have a short underground stems and modified leaves that store food
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What are reproductive leaves?
These leaves grow plantlets which fall off and germinate (asexual reproduction).
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What are stele?
Collective term for the vascular tissue of a root or stem
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What are annuals?
complete lifecycle from germination to death in a year or less like rice
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What are biennials?
these require 2 growing seasons for life cycle, flowering/fruiting in their second year, like turnips
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What are perennials?
they live many years and include trees, shrubs and some grasses
