Final Exam Flashcards
1
Q
the bryophytes
A
Phylum Hepatophyta (Liverworts)
Phylum Anthocerotophyta (Hornworts)
Phylum Bryophyta (Mosses)
- Gametophyte stage dominant; dioecious; thallose and leafy forms
- Sporophyte stage attached to gametophyte
- Low to mid level of tissue differentiation
- No tracheids; leaves simple
- Small size
- Earliest members of land plants
- High humidity/access to water important
- Mosses common in forests, edge of fields
- movement to land was accompanied by the two multicellular generations: one specialized for fertilization and the other for dispersal
2
Q
fertilization and dispersal
A
-all have water fertilization and air dispersal minus a select few
Water fertilization and water dispersal:
-green algae and most closely related to green algae
Air fertilization and air dispersal:
-gymnosperms
-angiosperms
3
Q
byrophyte sporophyte
A
- Bryophyte sporophyte stage grows from the gametophyte
- Sporophytes receive water and nutrients from the gametophyte
- Sporangium is the organ producing meiospores for wind dispersal
4
Q
byrophyte phylogeny
A
- Bryophytes are paraphyletic and form a phylogenetic grade below vascular plants
- Mosses are sister group to the vascular plants
5
Q
summary of the three byrophytes
A
Liverworts, Phylum Hepatophyta,
- include the most primitive plants and range from forms with dichotomously branching thalli (ca 1000 spp) to leafy moss-like forms (ca 8000 spp)
Hornworts, Phylum Anthoceratophyta,
- are a small group ( ca 500 spp) with multilobed flattened thalli and elongated narrow sporangia (shaped like horns of some antelope)
Mosses, Phylum Bryophyta
- in the narrow sense, include a large number of small leafy plants (ca 14,500 spp) producing sporangia with a central sterile column. Mosses differ greatly in colour, stem and leaf traits, habit orientation and habitat preferences
6
Q
life cycle of liverwort
A
diploid
-saprophytic
fertilization –> zygote –> sporophyte with sporangium –> meiosis within sporangium
haploid
-gametophytic
spores released –> archegonium or antheridium forms –> sperm fertilizes egg
7
Q
phylum byrophyta (mosses)
A
- Gametophyte stage dominant; dioecious
- Sporangium has central column
- Low to mid level of tissue differentiation
– Mostly no tracheids, but some conductive tissue differentiation
– Leaves simple to somewhat differentiated into tissues
– Small size - 14,500 spp
8
Q
life cycle of moss
A
diploid
fertilization –> sporophyte/ sporangium supported by gametophyte –> meiosis
haploid
haploid spores –> dispersal –> gametophyte –> sperm release –> fertilization
9
Q
peat moss (sphagnum)
A
- Peat moss is ecologically and economically valuable
- Leaves are one cell thick and have two kinds of cells
- Live photosynthetic cells
- Dead water-storage cells
- Peat mosses lower the pH to 4.5 preventing decay; peat bogs are unique habitats
- Packets of peat were used in folk medicine and in feminine hygiene pads
- Peat is harvested from dried bogs and used in the horticulture business.
- Addition of peat to southern Ontario soils greatly improves their water retention and lowers the pH
10
Q
kettle bogs
A
- Kettle bogs are deep depressions filled
with dead peat that can be many m thick - They form when blocks of glacial ice
are left behind surrounded by sand
and gravel - The surface mat is not solid and you
can bounce on it
11
Q
tracheophytes
A
- Silurian period (~419-444 mybp)
- Xylem present in fossil record from mid-Silurian
- “forests” at the time were bryophytes and early vascular plants along the edges of water
- Became much more widespread into the Devonian (420-360 mybp)
- No leaves or roots
- Sporangia at terminal end of dichotomously branching stems
- Some likely gave rise to ferns & seed plants
- Vascular Plants aka. plants with plumbing
- Synapomorphy
- Tracheids
- vascular tissue -(xylem and phloem)
- Dominant free-living sporophyte
- Same basic life cycle among all vascular plants despite incredible diversity
- Divided into three groups for convenience
- Fern Allies
- Ferns
- Seed Plants
12
Q
anatomy of vascular plants
A
- Vascular plant stems have a number of basic tissue types
- Vascular tissues lie in a ring near the outside of the stem
- Extends from tip of the roots through the stem and into veins within leaves
13
Q
xylem
A
- Xylem cells carry water and dissolved nutrients from the roots to the shoots; tracheids = primary cell type; vessels are more specialized; both are dead cells
14
Q
phloem
A
Phloem carries photosynthates, hormones and other materials to all parts of the plant
15
Q
trends in life cycles
A
- shift from dominant haploids to dominant diploids
- shift in the need for free water for fertilization
- development of vasculature
16
Q
nomenclature of tracheophytes
A
- Although many different classification schemes have been proposed, most textbooks recognize about 15 Phyla of living and extinct tracheophytes
- Some schemes recognize just one Phylum Tracheophyta, as is done in Biol 165
- DNA sequence studies and cladistic analyses have led to significant revisions in thinking about relationships among groups of vascular plants, particular among the fern allies
- Rhyniophyta is paraphyletic with different orders being basal to other groups
17
Q
early vascular plants (all extinct)
A
- Earliest vascular plants underwent dramatic divergence in the Devonian
- The Rhyniophyte Grade
- the most primitive vascular plants dichotomously branching stems terminal simple sporangia or synangia
- Subph. Lycophytina Class Zosterophyllopsida
- overtopping, dichotomous branching sessile sporangia on lateral or main stems
- Trimerophyte Grade
- basal to Subph. Euphyllophytina overtopping, dichotomous branching terminal sporangia on lateral branches
- Through the Devonian, the terrestrial surface of the Earth became green
- “mossy forests” gave way to shrub-like forests (<1m tall), moving inland from water sources
- Lycophytes, horsetails and ancestors of modern seed plants are common
- Plants now have roots, leaves and grow tall – have woody tissues –> 1st trees
18
Q
lycophytes, ferns, horsetails
A
- The lycophytes and the ferns and horsetails are the first two lineages of vascular plants.
- Both depend on swimming sperm for fertilization and disperse by spores that are released into the air
- Lycophytes and ferns are dissimilar to bryophytes as both gametophyte/sporophyte generation is free-living and produces its own nutrients
- more primitive kinds of extant (living) vascular plants; all groups first appeared in the upper Devonian Period
- All living species have small sporophytes except for some kinds of ferns and some fossil fern allies
- Lycophyte fern allies are microphyllous; monilophyte ferns and horsetails are megaphyllous
- Spores are produced in large thick-walled sporangia (eusporangiate), except in some orders of ferns
- The gametophytes are small and free-living (= sporophyte dominant)
19
Q
leaves
A
- Leaves are organs of plants adapted for photosynthesis
- Microphylls are simple out-growths of the stem and have a simple vasculature
- Megaphylls are really modified branching systems and have a complex vasculature; these are highly varied
20
Q
fern allies
A
- All living species are small except for a few tree ferns
- Are intermixed phylogenetically (only recently agreed to form a monophyletic group)
21
Q
fossils of fern allies
A
- Fossil genera in several Classes were large tree- sized plants that formed the co-dominant vegetation of forest ecosystems throughout the world during the Carboniferous Period (350-280 mybp)
- Carboniferous Period plants formed vast coal deposits that are mined today
22
Q
lycophyta or lycopsids
A
- The extant Class Lycopsida includes ground pines, ground cedars, club mosses, spike mosses, quillworts and all their fossil relatives
- All have kidney bean-shaped sporangia
- All extant lycophytes are small herbaceous perennial plants, but some Carboniferous members were large tree-sized plants with secondary growth
- Sporangia are eusporangiate (thick walled), borne on leaves (sporophylls) that are usually grouped into cones (strobili)
- Gametophytes are often cylindrical and subterranean and live in a symbiotic relationship with fungi
23
Q
lycophytes hetero vs homo spory
A
- Some lycophytes are homosporous (one kind of spore);
- Some are heterosporous (two kinds of sporangia & spores)
- Heterosporous taxa have unisexual (dioecious) gametophytes that develop inside the spore wall (endosporal)
24
Q
life cycle of lycopodium
A
tetrad of spores –> gametophyte –> fertilization in archegonium –> sporophyte –> strobilus –> meiosis
25
life cycle of selanginella
meiosis forms micro and mega spore --> mature male gametophyte forms from microspore and releases sperm --> sperm fertilize megaspore --> zygote --> sporophyte --> strobilus
26
Subphylum Euphyllophytina
* All megaphyllous vascular plants
* Ferns and some ”fern allies (Moniliforms)
* Seed Plants and ancestors (Lignophytes)
* Seed Ferns
* Cycads
* Gingko
* Conifers (pines, firs, spruces, etc.)
* Gnetophytes
* Flowering Plants
27
horsetails
- Small herbaceous plants with reduced leaves and no secondary growth; only ca 25 living spp. of Equisetum
* Living species have homosporous sporangia borne in strobili with whorls of branches; spores are large and green; gametophytes are free-living and leafy-lobed
28
horsetail stems
- Leaves and branches are arranged in whorls; stems are distinctly jointed (node-internode difference); most have hollow internodes
29
life cycle of equisetum (horsetail)
jumping spore --> bisexual gametophyte --> fertilization --> adult sporophyte --> meiosis
30
horsetail fossils
- Fossils species were small woody-stemmed plants to large tree-sized plants with secondary growth; both common in Carboniferous Period
- Calamites was a woody tree-sized horsetail common in the Carboniferous Period
31
traditional ferns
- All ferns traditionally were members of the Division/Phylum Pteridophyta (a.k.a, Polypodiophyta); there are about 15,000 spp of extant ferns; most are tropical
* Ferns have a rich fossil record going back to the late Devonian
- Mostly when you look at a fern you see megaphyllous leaves (called fronds in technical “fern terminology”)
32
fern stems
- Ferns lack secondary growth and usually have short stems oriented either vertically or horizontally
- tree ferns and a few other tropical species have larger stems up to a 1 m in diameter and 3-10 m tall
- tree ferns are held up by their bark with persistent frond bases and adven-titious roots forming a sheath around the trunk
33
fern leaves (fronds)
- Ferns leaves can be simple or compound, the compound leaves can be divided 1-6 times
* Size ranges from a 0.5 mm to 6 m
34
fern sporangia and sori
- Ferns sporophytes produce spores in sporangia borne in clusters called sori on the under side of the blade or borne on fertile leaflets
* The size, shape and position of sori are used to classify genera and species of ferns
* Some sori have a protective covering (indusium); variation in indusium shape and point of attachment are also used in classifying and identify ferns
- Most ferns are homosporous; two Orders produce eusporangiate sporangia and three produce leptosporangia sporangia (which are smaller, thin walled and produce fewer spores)
35
life cycle of a fern
diploid
fertilization --> sporophyte (nutrients from gametophyte) --> sporangia on leaves --> meiosis
haploid
spores --> dispersal --> gametophyte --> sperm released towards egg
36
basic stem anatomy
- vascular plant stems have a number of basic tissue types
* the oldest vascular plants had simple stems
* seed plants have the most complex in terms of numbers of specialized kinds of cells
- A plant that must grow in diameter to grow tall
* An increase in a plant’s diameter is referred to as secondary growth
37
the first seed tree
- Near the end of the Devonian Period (355 mybp) a new kind of plant evolved for the first time, the tree.
- The first trees were “experiments” combining wood and growth features like conifers with fern-like reproductive structures.
- These first trees are treated as progymno- sperms, the earliest members of the lignophyte clade
38
seed plants
- Seed plants include gymnosperms (seed ferns, cycads, ginkgos, conifers, gnetophytes and fossil relatives) and angiosperms (flowering plants)
* Seed plants are the dominant group of plants on the planet today and have been for the last 230 or so million years
* Seeds plants are heterosporous; the female gametophyte is retained within the sporophyte and is never free-living
39
seeds
- A seed is a post-fertilization ovule, which is the protective sporophyte tissue layer(s) that surround(s) the megasporangium, the female gametophyte and the embryonic next-generation sporophyte
40
a seed is a little plant in a box with its lunch
seed: ovule after fertilization
plant: embryonic sporophyte
box: seed coat / ovule integuments
lunch: endosperm
41
three generations within one seed
1. Protective seed coat, formed tissues surrounding megasporangium (sporophyte)
2. Embryo, develops from the zygote and is the next sporophyte generation
3. Haploid female gametophyte, provides nutrients for the embryo
42
gymnosperm ovule diagram
look in notes (lecture 15 slide 25)
43
seed diversity
- Size of seeds vary greatly
* Often small seeds allow wider dispersal and remain dormant for long periods
* Dormancy – seed accepts pollen but delays germination until conditions are favourable
44
pollen
- Pollen grains are the immature male gametophyte of seed plants
* Pollen grains are the products of meiosis, spore wall formation and gametophyte development; pollen grains have 2-4 nuclei at the time of release
* POLLINATION = transfer of pollen from the pollen sacs (= microsporangia) to the micropyle (opening in ovule integument) of the ovule (gymnosperms) or to the stigma of the ovary (flowering plants)
45
pollen cones and stamens
- Pollen sacs (microsporangia) are borne on pollen cone scales of pollen cones in gymnosperms
- In flowering plants, they are called anther sacs and are borne on stalks called filaments; together these form stamens
46
pollen dispersal
-wind
-animals
-insects
47
seed ferns
- Seed ferns were the first kind of seed plants; the oldest occur in the upper Devonian
* Seed ferns were common in the Carboniferous Period and gave rise to the Cycadophyta, Coniferophyta and Ginkgophyta by beginning of the Permian Period in the late Paleozoic Era
* Seed ferns were also common in the early and mid Mesozoic Era
* They probably gave rise to the Flowering plants (Angiosperms) in the late Jurassic or early in the Cretaceous Period (120-130 mybp)
48
cycads
- Cyads are a small group of cone bearing gymno- sperms with distinctive habit, stem anatomy and reproductive structures
* Cycads usually have thick palm tree like trunks
* Leaves are large and compound; leaf vasculature begins from multiple points around the stele and girdle the stem before entering the leaf stalk
-relics of the past
49
ginko
- The Ginkgopsida includes just one extant species Gingko biloba possibly no longer existing in the wild
* It is reported to occur naturally in remote mt valleys in Zhejiang province in the Tianmu Shan Reserve
* Ginkgos are dioecious; plants produce either only pollen cones or paired naked ovules on stalks
- Ginkgos have a fossil record going back to the Paleozoic; they were once much more common and grew in Canada
50
conifers
* The Pinopsida includes many living (550 spp) and extinct species of cone bearing trees and shrubs that are ecologically and economically very important
* Conifers first appeared in the fossil record during the Carboniferous Period, were dominant trees of the Triassic and Jurassic Periods, and have shared dominance with flowering plants since the mid Cretaceous
* Most spp are monoecious, but some are dioecious
51
life cycle of pinus
diploid
fertilization --> fertilized ovule develops into seed --> dispersal --> germination -- > male gametophytes develop within pollen cones, female gametophytes develop within ovulate cones
haploid
meiosis --> multicellular male gametophyte (pollen), haploid spores (ovule) --> pollen fertilizes egg
52
fertilization in gymnosperms
- Arrival of pollen stimulates development of ovule; in Pine, fertilization 13 months after pollen arrives
- Germination = growing pollen tube into ovule tissue
- Two pollen nuclei migrate through tube; 1 fuses with egg = zygote, 1
53
gnetophytes
* Unusual conifers
* Often considered as a sister group to the flowering plants but more recently are within the the conifers and basal to that group.
* DNA studies are still ambiguous.
54
flowering plants
- Angiosperms are the largest group of plants with an estimated 250,000-300,000 species divided into more than 400 families
* This is the most recently evolved major group of plants, first appearing in the fossil record during the lower Cretaceous Period about 125 mybp
* Set of diagnostic features (synapomorphies): ovary wall, double fertilization, distinct leaf venation, distinct pollen wall traits, shared arrangement of flower parts, and highly reduced male and female gametophytes
* First 30-40 million years: angiosperms not widespread
* ~100 million years ago was the start of the rise of angiosperms to dominance
* Monocots and eudicots are two major modern groups
55
why are angiosperms so successful
* Efficient morphology
* Reproduce quickly even with limited nutrients
* Flowers and association with pollinators
* Fruit and dispersal
56
flower morphology
4 whorls
Outer 2 whorls: sepals and petals
Inner 2 whorls: stamens (male) and carpels (female)
57
double fertilization
- pollen tube grows to connect with the ovule
- one sperm nucleus fuses with the egg
- second sperm nucleus fuses with the 2 haploid nucleus and forms the 3n endosperm
58
life cycle of lilium
flower: meiosis in anthers produce pollen grains, meiosis in ovary produces ovule
Ovary: pollen lands on stigma for pollination and creates pollen tube to reach the ovule
ovule: double fertilization takes place to produce the seed
seed: grows into mature monoecious sporophyte
59
fruits
* Fruits develop from the ovary after fertilization; in some kinds additional floral tissue or plant parts are included in the fruit; fruit types relate to methods of dispersal
* Fleshy fruits are dispersed by animals and are usually brightly coloured and have a strong odour
* Dry fruits either function as dispersal units or split open to release seeds that are the dispersal units
* Cereal grains are the fruits of members of the grass family and are the primary food of most people either directly or indirectly
* Fruit serves two roles: 1) Protect immature seed from animals; 2) Enhance dispersal
60
dry fruits
- Dry fruits can be dispersed whole or in parts, or they split open to release seeds are then dispersed by wind, water, or animals
61
grasses
* Cereal Grains are fruits of grasses (monocots) that can be gathered or cultivated as a food for humans
* Harvested grain can be eaten immediately or stored dry for future consumption or planting
* Wheat is the “best” grain in food value (Asian Minor)
* Rice is the staple of the most people (China)
* Maize (corn) was domesticated in Mexico and Peru
* Sorghum is the traditional cereal grain of Africa
* Barley, Rye, Oats, and Millet are cereal grains grown in ecologically harsh environments
* Human civilization was founded on cereal grains
62
classification of flowering plants
* The “Div. Magnoliophyta” for many years was been divided into 2 classes (dicots and monocots) and 11 subclasses
* Most recent textbooks follow Arthur Cronquist’s 1981 system; Flora North America follows this system; it is incorrect!
* DNA sequence studies indicate that the monocots are monophyletic, but the dicots are paraphyletic and consist of a basal grade of paleo herbs, shrubs and trees (including monocots) and a large monophyletic group called informally the “eudicots”
63
pollination of flowering plants
* Pollination by wind, water and animals of many sorts; much diversity due to adaptions to different pollinators by related species of flowering plants
* Flowering plants utilized both insects and vertebrates as pollen vectors
* Pollinators visit flowers in order to obtain a reward, usually either pollen or nectar, a 10-20% sugar solution
* Co-evolution of flowers and pollinators has resulted in much of the diversity of flowering plants
* Co-evolution has also resulted in some very specific co-dependent relationships
- some have reverted to wind pollination
64
phylogeny of stramenopiles
* Clade includes some heterotrophs (protozoa) and autotrophs (algae)
* How this happened is needlessly complex for our class, and even though I mention it in the lesson, I don’t think we need to cover this anymore...
* Stramenopiles are an interesting lineage containing many evolutionary puzzles!
* Two synapomorphies are indicated; the 1st involved the capture of a red alga that became the chromophyte chloroplast with chlorophylls a and c
- A 2nd synapomorphy is the morphology of their biflagellate motile cells (zoospores and gametes):
* One whiplash-type flagellum (the end is slight modified)
* One tinsel-type flagellum with lateral appendages
* Cell often kidney bean shaped
* Flagella usually attached to concave side of cell
* Name "stramenopiles" referring to the “straw hairs” on the flagella
65
stramenopile algae
- diatoms
- golden browns
- browns
- yellow greens
66
bacillariophyta
* The most diverse (#species) stramenopiles are the diatoms.
* Recognized by their distinctive skeletons of silica, diatoms are responsible for 25% of all photosynthesis on Earth.
* More than 10,000 known diatom species thrive in environments that range from wet soil to the open ocean
67
diatoms
* Chloroplast source: secondary capture
* chlorophylls a, c; carotenoids
* chrysolaminarin storage product
* flagella in sperm only, 2 then 1 tinsel- type
* silica and pectin in cell wall
* marine and fresh water; benthic or pelagic
* unicells and simple colonies
* 10,000 spp
68
morphology of diatoms
- Diatoms live in "glass" boxes called frustules made of nearly pure silica
- Each frustule consists of two valves or thecae
- Surfaces of the thecae are finely sculptured (epithecae and hypothecae)
* Surfaces sculpturing is finely detailed
* The patterns are visible under the light microscope
* The finest details are revealed only with the SEM
69
ecology of diatoms
- perhaps the most numerous, and most important primary producers in the oceans
- ubiquitous in freshwater
70
diatomaceous earth
- Remains of marine diatom frustules form deposits that are mined (up to 6 million frustules/mL)
- Diatomaceous earth is used in water filters, deodorants, as abrasives in toothpaste, as reflectants in highway paint, and as insulation
- Deposits of fossils may indicate the presence of oil or gas
71
chrystophyta
* Golden-brown Algae
* Chloroplast source: secondary capture-3 membranes around plastid
* chlorophylls a, c; carotenoids, fucoxanthin
* Chrysolaminarin storage product
* retain their flagella - 1 long tinsel-type flagellum; 1 short
* whiplash-type flagellum (only 1 in derived spp)
* silica and pectin in cell wall
* mostly fresh water
* 1000 spp.
* classification needs revision
* asexual and isogamous sexual reproduction
*They can be important in some habitats and are morpho-logically very diverse
*Synura forms motile spherical colonies; these produce fishy-smelling ketones and aldehydes and can add an unpleasant odour to drinking water
72
phaeophyta
* Brown Algae
* Chloroplast source: secondary capture (3 membranes)
* chlorophylls a, c; carotenoids, fucoxanthin
* Laminarin storage product
* 2 lateral flagella; 1 tinsel-type, 1 whiplash-type
* cellulose, pectin and alginic acids in cell wall
* almost all marine; only 3 freshwater spp.
* some are very large
* 1500 spp.
73
three types of brown algae life cycles
* isomorphic alternation of generations
* heteromorphic alternation of generations
* no alternation of generations – sporothalli only [diploids forming gametes via meiosis]
74
isomorphic alternation of generations brown algae
* small filamentous thalli
* plurilocular mitosporangia and gametangia
* unilocular meiosporangia
Phaeophyta
- Large group with species growing as true tissues (parenchymatous) and filamentous algae packed close together (pseudoparenchymatous)
75
life cycle of ectocarpus
-isomorphic alternation of generation
Diploid
fertilization --> sporothallus --> asexual reproduction by plurilocular sporangium --> sexual reproduction by unilocular sporangium --> meiosis
Haploid
meiospores --> gametothalli --> plurilocular gametangium --> gametes (isogamy) --> fertilization
76
laminaria
* Brown Algae
* Order Laminariales (kelps, seaweeds)
* heteromorphic alternation of generations
* sporothalli dominant - some are very
large
* oogamous - gametothalli filamentous, small
* common-dominant below intertidal zone
* simple tissue differentiation
77
life cycle of laminaria
-heteromorphic alternation of generations
Diploid
fertilization --> young sporothallus --> macroscopic sporothlli --> meiosis in meiosporangium
haploid
meiospores --> male gametothallus with antheridium, female gametothallus with oogonium (oogamy)m --> fertilization
78
postelsia
- Unusual member of the Laminariales because it grows on rocks in the intertidal zone where it is exposed to the air on a regular basis
- Other genera occur below the low tide level and are submerged
79
fucus
*Brown Algae
*Order Fucales (wracks, rockweeds, seaweeds)
* oogamous - sporothalli only, gametes are the products of meiosis
* common-dominant in intertidal zone
80
life cycle of fucus
-no alternations of generations
zygote --> adult sporothallus --> meiosis in antheridium and oogonium --> fertilization
81
oomycota
* Traditionally considered one of the groups of “lower fungi” – Pseudofungi
* Not related to the true fungi
* Oomycetes are sexually oogamous
* Reproduce asexually via zoosporangia and heterokontous zoospores
* 8 orders (two we will discuss)
– Peronosporales - downy mildews
– Saprolegniales - aquatic water moulds
82
downy mildews
* The terrestrial Downy Mildews have morphologially converged with powdery mildews (asexually reproducing ascomycetous fungi)
* The terrestrial Downy Mildews cause great damage to crops and are of great economic importance; they have caused mass starvation and forced mass migrations of human populations
83
potato blight
- Potato Blight is caused by the terrestrial oomycete Phytophthora infestans
- In 1845-1846, blight destroyed the potato crop and the stored spuds and resulted in mass starvation in Ireland
- 1,000,000 people died; 1,000,000 left
Ireland for elsewhere by 1850
- Immigrants to NA had a great impact on the economy
84
SAR
* Some basal phyla to this group as well, such as the Cryptophyta (possibly the Haptophyta) that still require some research
* Potential multiple endosymbiotic origins of chloroplasts (mostly of the red lineage)
* Phylum Dinoflagellata may have tertiary chloroplasts
85
cryptophyta
* Unicelluar eukaryotes often grouped with the algae
* Seen in both freshwater and marine habitats
* All are photosynthetic and this group is pivotal in understanding the endosymbiotic origin of chloroplasts - particularly secondary endosymbioses
86
alveolate clade
* Alveolates are a recently recognized group of three long-recognized Phyla
* Ultrastructure studies show that all three groups share a system of sacs underneath their cell membranes. The closely packed sacs are called alveoli
-ciliates, dinoflagellates, apicomplexa
87
alveolate types
- Ciliates (Phylum Ciliophora) are of the most numerous heterotrophic protist group with >13,000 species
- Apicomplexans (Phylum Apicomplexa) are parasites and disease-causing protists with complex life-cycles that have a apicoplast
- Dinoflagellates (Phylum Dinoflagellata) are photosynthetic protists formerly grouped with algae by botanists, only about 50% are photosynthetic
88
ciliophora
* rows of cilia (kineties) on cell surface
* most have a cytostome or “cell mouth” surrounded by oral cilia
* most species are free-living occurring in temporary puddles, ponds, estuaries, lakes, salt marshes, oceans and even hot springs and Antarctic ice
* habitats can be fresh, saline, clean, polluted and even sewage treatment plants
* >13,000 species (1100 genera)
* divided into 3 subphyla, 8 classes and 47 orders
* Reproduction by asexual and conjugation (sexual reproduction)
89
ciliophora nucleus
* exhibit nuclear dualism:
* 1) large macro-nucleus that is physiologically/transcriptionally active and has 1000s of copies of genes; divides free of mitosis (amitotically); controls the cell phenotype; polygenomic (xn)
* 2) smaller diploid (2n) micro-nucleus whose meiotic products are exchanged during conjugation; transcriptionally inactive; divides by mitosis or meiosis
90
paramecium and tetrahymena
- Paramecia have two nuclei.
- The large macronucleus has thousands of copies of each gene and serves as the “factory” for producing RNA to synthesize proteins.
- The small micronucleus is reserved for conjugative sexual reproduction
- Food particles are captured and eaten through phagocytosis.
- As part of the food web, ciliates are important in moving nutrient to larger things (i.e. juvenile animals)
91
asexual ciliate reproduction
-everything splits in half including both nucleus
92
apicomplexa
* 2400 species, probably many more to be described since very host specific, many have an apicoplast
* Lacking structures for motility (flagella and cilia)
* Anterior end of the cell has apical complex – group of membrane- bounded organelles used for host cell invasion
* first members described in late 1600’s by van Leeuwenhoek (oocysts in rabbits)
* parasites with complex to very complex life cycles
* endoparasites of either invertebrates or vertebrates (including humans)
* in many species, spores are formed to allow transfer from one host to another
93
life cycle of apicomplexa
-diphasic
-zygote (2n) --> meiosis --> zoite --> gamont --> gamete --> zygote
94
plasmodium vivax
* Malaria is caused by the protozoan Plasmodium vivax (Phylum Apicomplexa: Class Sporozoa)
* The complex life cycle involves two hosts and six different stages; all but the zygote are haploid
* In humans, initial asexual reproduction of sporozoites in the liver and repeated asexual cycles in blood cells by merozoites cause the disease symptoms
95
Bioluminescence
-bioluminescence is produced by several dinoflagellate genera
-light is produced as a byproduct of the chemical oxidation of a pigment, luciferin
- the reaction involves ATP and is catalyzed by an enzyme called luciferase
96
Dinoflagellates
* eukaryotic; special nuclear features
* Chloroplast source: secondary/tertiary captures
* chlorophylls a, c; carotenoids
* starch, lipids
* 1 flagellum in girdle; 1 flagellum in sulcus
* cellulose and pectin in cell wall
* mostly marine
* Important symbiont in corals - Zooxanthellae
* >2500 spp.
97
Dinoflagellates in the food chain
- They are very important as both phytoplankton and zooplankton due to their abundance
- Only the diatoms are more important as primary producers in the oceans
- The heterotrophic taxa are often the first herbivores in the food chain
98
red tides and dinoflagellates
- Blooms of dinoflagellates occur under the right conditions with cell densities so high (millions/L) that the water turns colour
- Blooms produce the RED TIDES recurrent along the coasts of North America and Japan
- Multiple millions of kg of fish are killed
- Live fish are toxic if eaten (ciguatoxin --> ciguatera)
99
Dinoflagellates and shell fish
- Toxins in the dinoflagellates accumulate in filter- feeding shellfish such as clams, mussels and oysters.
- Molluscs are not susceptible, but eating these organisms causes serious illness and deaths in humans (PSP - paralytic shellfish poisoning)
100
Rhizaria
- Phylum Cercozoa
- Phylum Foraminifera
101
Cercozoa
* Cells are amoeboids and flagellates that feed using pseudopodia
* Also includes one algal order, Chlorarachiniophytes, that have a secondary capture (secondary endosymbiosis) of a green alga.
* Four membranes & a nucleomorph!
102
Foraminifera
* granular reticulopods that form interconnecting net
* ubiquitous marine heterotrophs from high tide zone to abyssal depths, tropical to polar
* can undergo kleptoplastidy
* range in life cycles with some complex sexual life cycles (2n asexual/ 1n sexual)
* calcareous or arenaceous (silica) shells fossilize well; abundant in Paleozoic and later marine sedimentary rocks; useful in stratigraphy and paleoecology
* 35,000-40,000 species (1200 genera; 120 families): about 4000 living species
103
fossils
* Many SAR (and other marine algae) have inorganic coverings that fossilize well
* This forms a record of evolution that both predates and parallels the better-known fossil record of animals.
* Fossils in sedimentary rocks as old as 1800 million years have signs of eukaryotic cells containing complicated cell wall structures
104
decomposers
- Organisms that obtain energy by breaking down complex organic matter are decomposers
* Without decomposers, the planet would accumulate vast numbers of dead heterotrophs and autotrophs
* Saprophytes consume dead organisms and organic matter
* Parasites do not wait for the organism to die
105
fungus
* The study of fungi is call Mycology
* Fungi are not plants, although traditionally they have been lumped with them; in fact, they are more closely related to metazoan animals
* Fungi are heterotrophic decomposers; most of the biomass produced by autotrophs is broken down directly by fungi and bacteria; only some of the biomass is first consumed by animals (consumers)
106
fungi thallus
- The term "fungus" has been applied to organisms that have a diffuse "body" or thallus made up of numerous fine branching tubes called hyphae.
* Collectively the hyphae form the mycelium (the fungal equivalent of a body). The walls of a hyphal tube are composed mainly of chitin and/or cellulose
107
mycellium
- The mycelium is the fungal equivalent of a body, the fine stringy mass of individual hyphae
- Portions of the mycelium of the Honey Mushroom Armillaria form stringy runners under the bark of the host conifer
- Can extend up to 100 m or more,
producing reproductive organs over a large area and live for 100s of years
108
fungi metabolism
* Fungi secrete exozymes through the wall of the hyphal tips onto the food substrate, which is digested externally and then absorbed by the hyphae
* Many fungi store organic nutrients in the form of glycogen as do animals
109
fungi feeding
* Fungi have evolved three different modes of heterotrophic existence: saprobic, parasitic and mutualistic
* Mutualistic combinations of fungi and algae form lichens (“dual organisms” now TRIPLE)
110
saprobes
* Saprobes decompose dead wood and leaves, or things people have produced for their own use such as cloth, paper, paint, or most anything else organic except plastics
* Saprobic fungi are used by humans in the production of wine, beer, bread, some gourmet cheeses, soy sauce, some antibiotics, immuno-suppressants, anticholesterol drugs, organic acids, and many other useful chemicals
111
fungi facts
* More than 90% of all vascular plants are dependent upon specific fungi (mycobionts) for proper growth in poor low-phosphorus soils; fungal hyphae form external or internal associations with the plants roots, producing distinctive mycorrhizae
* Many mushrooms produce toxic substances that can be lethal even in small quantities
* Without fungi, massive amounts of biological material would pile up
112
chytridiomycota
* Phylum Chytridiomycota (sometimes treated as the Chytridioprotista) is another group of fungi - also called Chytrids
* Directly related to the Eumycotan fungi (basal to this group)
* Have been treated as Protoctista in the past
* Haploid dominated life cycle and a diploid phase consisting of the zygote which functions as both a resting spore and a meiosporangium
- Chytrids have been shown to be one of the causes of the reduction in the diversity of amphibians around the planet in recent years; chytrids also parasitize algae, plant pollen and fish
113
chytrids morphology
* Chytrids are parasites but without hyphae like those of higher fungi
* Some forms produce assimilative structures called rhizoids (but most do
not)
* Simpler forms are unicellular
* More complex forms are coenocytic (like Rhizomycelium)
114
chytrid zoospores
- Chytrids produce uniflagellate asexual zoospores, which produce either more asexual individuals or male and female gametothalli
-holocarpic: inside the host
-eucarpic: outside the host
115
Eumycotan fungi
* Eumycotan is not a taxonomic name, however in the past the Kingdom Eumycota was used. This group does not include the Chytrids or other basal groups.
* Eukaryotic fungi form spores that are resistant to desiccation and have no flagellate cells at any point in their life cycle
* About 75,000 species have been described, but estimates of the total number run into the millions (most are ascomycetous conidial fungi)
116
the whole fungus
* Eumycotan fungi have both sexual and asexual reproductive structures which nearly always look very different
* The teleomorph is the sexual phase of the fungus; higher classification of eumycotan fungi is based on the traits of the teleomorphs
* The anamorph is the asexual phase of the fungus; in many cases, it may be the only phase known; very different looking teleomorphs can have very similar anamorphs
117
holomorph
- Teleomorph-Anamorph connections have been determined for thousands of eumycotan fungi
- The Botanical Code of Nomenclature accepts latin names for both the teleomorph and the anamorph; thus thousands of fungi have two “official names”
- telemorph + anamorph = holomorph
118
phylum zygomycota
* Saprobes that colonize terrestrial substrates such as bread (inside, not on the surface), overripe fruit, and dung (coprophilous - dung loving)
* A few zygomycetes are parasitic on humans causing diseases known as mucormycoses
* Hyphae are thick, non-septate and delicate, collapsing in dry air
* The teleomorphs of zygomycetes are similar, but the sporangia of the anamorphs are highly varied due to different adaptations for dispersal
119
reproduction in zygomycetes
- Sexual reproduction (teleomorph) involves conjugation (fusion) of morphologically similar gametangia (branches of the hyphae) to form a zygosporangium (zygote that undergoes meiosis)
120
zygomycetes mitosporangia anamorphs
- Mitospores are adapted to different
kinds of dispersal
- Some are ingested by animals and need to be partially digested in order to germinate on the dung dropped by the animal
121
life cycle of bread mold; rhizopus
anamorphic phase
- sporangiophores and mitosporangia asexually reproduce
- hyphae can have sexual reproduction
telemorphic stage
-hyphae --> gametangia --> zoosporangium --> meiosis
122
land plants
* complex multicellularity
* chlorophylls a, b; carotenoids
* alternation of generations
* archegonium with single egg cell
* simple to complex embryo
* ~325,000 spp.
* abundant fossil record; 450 mybp
* sometimes treated as Phylum Embryophyta
123
multicellularity
Complex multicellularity
evolved at least six
separate times:
1. Animals
2. Green algae that gave
rise to vascular plants
3. Red algae
4. Brown algae
5. Fungi (2 times)
