Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOL371 Comparative Biology of Plants and Animals > Plant Diversity > Flashcards

Plant Diversity Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Bryophytes

A
  • Seedless and non-vascular
  • Earliest diverged Embryophytes arose ~475-430 million years ago
  • Mosses have the greatest extant diversity (~10,000 species)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Gametes are “soft” so they require:

A

water for finding each other and for fusion/fertilization and are difficult to disperse when relying on both water and compatible mate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

spores are “hard” therefore:

A
  • Easy to disperse (promotes outcrossing and reduces competition with parent)
  • Greater production of spores leads to a greater chance of having a nearby mate and water for the new gametophytes = higher reproductive potential and expansion/invasion of territory
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Mosses

A
  • highly dependent on water
  • Lack of vasculature keeps them close to their water sources (thrive in rainforests and marshy or wet areas)
  • Serve many purposes in the ecosystem (water retention, insulation, carbon sink, nutrient balance)
  • Various anthropomorphic uses (fuel source, packing/storage material, medicinal properties)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Poikilohydry

A
  • Bryophytes are known as poikilohydric meaning they have little control over their water content (Poikilo = variable, Hydry = water)
  • Great at absorbing water and surviving in very wet/moist conditions but have poor control over water loss when the surrounding area is drying out
  • Basically, they do not restrict water loss
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Bryophytes are Drought Tolerators

A
  • May not be able to be active during dry periods but can withstand periods of drought and then resume when moisture returns
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Drought Tolerator

A

maintain cell wall elasticity and control osmotic balance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Drought Avoider

A

Actively resist water loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Moss Life Cycle

A
  • Life cycle is highly dependent on water (required for gamete release/ejection and fertilization)
  • Sporophytic stage is retained on the female gametophyte
  • Spore dispersal is aided by a lengthening of the sporophyte
  • Spores are released when dry and carried by the wind
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Moss Reproductive Organs

A
  • Gametangia are the gamete producing organs
  • Archegonia produce egg cells
  • Antheridia produce sperm cells
  • The embryo develops into the sporophyte which gives rise to the sporangia (the spore producing organs)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Moss - Protonema

A
  • Instead of 1 spore germinating to form a single gametophyte, moss spores germinate to develop a branched, filamentous, multicellular network = protonema
  • Single protonema can give rise to several buds which develop into individual Gametophytes
  • This clustering of Gametophytes helps provide structural support and increases the amplification of offspring from a single successful reproductive event
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Moss Life Cycle Key Points

A
  • Water is critical to complete the life cycle
  • Gametophyte (n) is the dominant phase
  • Eggs are produced in Archegonia
  • Sperm are produced in Antheridia
  • Flagellated sperm, after being dispersed by active water, swim to the egg
  • Sporophyte retained on the female gametophyte
  • Sporangia produce haploid spores through meiosis -> dispersed (when dry) by wind
  • Spores are coated with sporopollenin
  • Protonema produces multiple buds that develop into gametophytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Bryophyte Importance

A
  • Reduce soil erosion along streambanks, aid in the retention of water in tropical forests and soil formation in the desert and polar regions, and can reduce nutrient loss from soils
  • Some have medicinal properties
  • Can be grown in bioreactors for harvesting of recombinant proteins
  • For studying plant evolution, development and physiology
  • For soil and garden water rentention
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Bryophyte Summary

A
  • Non-vascular plants
  • Have no control over water loss = Poikilohydric
  • Water is critical for survival and reproduction
  • Gametophyte is the dominant phase
  • Flagellated sperm swims to the egg
  • Sporophyte retained on the female gametophyte
  • Key members of the ecosystem
  • Various anthropomorphic uses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Seedless Vascular Plants

A
  • Arose ~425 million years ago
  • First to develop vasculature and true leaves
  • The sporophytic phase becomes dominant
  • Pteridophytes (ferns and allies) have the greatest extant diversity (~9,000 species)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Major Adaptations Added With Seedless Vascular Plants

A
  1. Vascular tissue

2. Root system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Vasculature

A
  • Vascular tissue evolved in a series of gradual steps with progressively more lignin deposition
  • Provide an increasing level of structural support and efficient water transport
  • Main support comes from the lignification of the secondary cell walls (Xylem and Sclerenchyma)
  • Allowed for improved conductance of water and continued upright growth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Vasculature in Ferns and Seed Plants = Tracheids

A
  • Closely packed elongated cells
  • Cells are dead at maturity
  • Thickened secondary cell walls with lignin deposits have gaps = Pits
  • Better structural support
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Vasculature in Angiosperms = Vessels

A
  • Similar to tracheids, but shorter and wider

- Both walls have gaps, more efficient water transfer through the Pits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Non-vascular plants only possessed rhizoids

A

which act to anchor the plant but do not behave as true roots

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Often >50% of overall biomass is below

A

ground level in vascular plants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Root Systems

A
  • Can act as a nutrient reserve and as a backup plant stock
  • The use of stomatal conductance and transpiration allows for negative pressure to create a vacuum to draw up water from the roots into the stem tissue
  • ~90% of the water absorbed by the root is lost through transpiration but allows for sufficient water to be translocated throughout the plant and intake of necessary soil nutrients
  • Drought avoiders
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Evolution of Microphylls (an offshoot of the main vertical axis)

A
  • Vasculature largely exists as a single strand (xylem, phloem, sclerenchyma, and parenchyma in one bundle)
  • Modification of stems to increase photosynthetic surface area
  • Narrow leaves with one strand vasculature (vein)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Lycophytes (Club Mosses, Spike Mosses and Quillworts)

A
  • Highly diverse around 350 mya = Carboniferous Period
  • Present-day lycophytes are small and grow on forest floors in moist conditions
  • Some are poikilohydric
  • All have microphylls
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Carboniferous Period (350-300mya)

A
  • Oxygen levels raised to ~30% (currently ~21%)
  • Microphylls and megaphylls evolved
  • Tree sized Lycophyte forms inhabited swamps
  • Arthropods are still the dominant animal on land
  • High oxygen levels allowed for massive arthropods (2m in length)
  • First seed plants begin to emerge
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Evolution of Megaphylls

A
  • Broader leaf with multiple veins within a web of photosynthetic tissue
  • Much greater photosynthetic area with efficient nutrient transfer capabilities
  • Shared among all of the Pteridophytes and the Seed plants
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Pterophyta (Ferns)

A
  • The most abundant group of seedless vascular plants
  • Familiar plant body is sporophyte stage (2n)
  • Finely divided leaves (fronds)
  • Sporangia often grouped together as Sori on lower surface or margins of fronds
  • Spores develop into gametophytes
  • Antheridia and archegonia develop on the underside of gametophytes
  • Have well-developed vasculature and roots
  • Can survive without continuous moisture
  • Drought Avoiders
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Sporangia

A
  • Found on the underside of the fern frond
  • Groups of sporangia known as Sori
  • Often have a protective covering while developing known as an Indusium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Fern Life Cycle

A
  • Sporophyte phase is dominant
  • Incredibly high production of spores within the sporangia
  • Gametophytes produced are often hermaphroditic
  • Archegonia + Antheridia
  • The sporophyte is retained on the gametophyte but quickly outgrows it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Fern Life Cycle – Key Takeaways

A
  • Single spore develops into a single gametophyte
  • Gametophyte is photosynthetic
  • Archegonia are often formed first = dictate neighbouring gametophyte development
  • Antheridia release flagellated sperm
  • Sporophyte lives for a long time and produces new fronds, most will produce sporangia
31
Q

Importance of Seedless Vascular Plants

A
  • Well equipped to survive in the understory, establish ground cover
  • Common in tropical areas
  • Can be used in cooking
  • Efficient N2 fixation = biological fertilizer in rice fields
  • Medicine and remedies for kidney problems
  • Ornamental plants
32
Q

Seedless Vascular Plants –Summary

A

Lycophytes and Pterophytes

  • Have vasculature, plants are larger and upright
  • Sporophytes dominant
  • Sporophytes produce plant bodies with leaves and roots
  • Small gametophytes (most often hermaphroditic) -> Antheridia and Archegonia
  • Produce flagellated sperm
  • Sporophyte initiated on the gametophyte but quickly outgrows it
  • The gametophyte is often retained
  • Very diverse and persistent
  • Greatest diversity during the Carboniferous period
33
Q

Land Plant Classification

A

Nonvascular plants: lack vascular tissue, gametophyte (haploid) generation is dominant = Bryophytes (mosses)
Vascular seedless plants: well-developed vascular tissues, do not make seeds, sporophyte (diploid) generation is dominant = Lycophytes and Pterophytes
Vascular seed plants: well-developed vascular tissues and produce seeds, diploid generation is dominant = Gymnosperms and Angiosperms

34
Q

Selection for Sporophytes – Genetic Load

A
  • Mutations constantly arise (necessary for variation, most are deleterious)
  • Haploids have no chance of complementing deleterious mutations (mutations have a higher chance of affecting fitness)
  • Diploids have more room to accumulate mutations (complemented by sister chromosome (masking))
  • The haploid phase helps purge deleterious mutations and allows favourable mutations to be passed on
35
Q

Vascular Seed Plants

A
  • Gymnosperms and Angiosperms
  • Arose ~300 mya
  • Account for the vast majority of all extant species
  • Dominate the land
  • Dominant phase = sporophyte
  • Gametophyte extremely reduced
36
Q

Major Reproductive Changes as Seed Plants Dominate Land

A

Non-vascular and seedless vascular vs. vascular seed plants

  • Both have pores with a resistant coat for protection
  • Spores are released to produce gametophyte vs not released to produce gametophyte
  • Spores identical in shape/size vs not identical, male and female
  • Flagellated sperm vs non-flagellated sperm
  • External water required for fertilization vs not required for fertilization
  • Embryos not protected vs embryos protected (seeds)
37
Q

Gymnosperms ~1000 species

A
  • Naked seed plants (Gymno = naked, Spermae = seed)
  • Produces reproductive organs that contain the haploid spores = Male: microspores, Female: megaspores
  • Fertilized ovule becomes the seed
  • Seeds desiccate to attain dormancy prior to dispersal
38
Q

Pollen

A

male gametophyte developed from the microspore on the sporophyte prior to dispersal

39
Q

Ovule

A

Sporophyte structure that houses and protects the megaspore that gives rise to the female gametophyte

40
Q

Conifers: Cone Bearers

A
  • Reproductive structures/organs that contain the haploid spores = cones
  • Spores are not released: Pollen (male gametophyte) is released
  • Male cones house the Microspores = produce male gametophytes (pollen)
  • Female cones house the Megaspores = produces female gametophytes inside the ovule
41
Q

Conifer Life Cycle

A
  • Sporophyte dominant
  • Reproductive organs that contain the haploid spores = Cones
  • Pollen – developed from the microspore on the sporophyte prior to dispersal
  • Pollen develops within protective spore coat and produces non-motile sperm
  • Ovule – Sporophyte structure that houses and protects the megaspore
  • Female gametophyte develops within the ovule to form the archegonia
  • Pollen is deposited in the female cone, a pollen tube grows and releases sperm cells
  • Fertilized ovule becomes the seed
42
Q

Conifer Reproduction – Pollen Tube Growth

A
  • Matured pollen is in a quiescent and dry state = allows for dispersal by wind
  • The mature pollen are winged and are carried to female cones
  • Once it hydrates on the pollination drop of the ovule and is brought to the megasporangium tissue it produces the pollen tube = Grows for several months
  • Archegonium releases pollen attractant chemicals to guide pollen tube growth towards the egg cell
  • Pollen tube ruptures when it has reached the archegonium to release: 1 Tube nucleus, 2 Sperm Cells, and a Sterile Cell
    Only 1 Sperm Cell will fuse with the egg in each archegonium
43
Q

Conifer Reproduction Length

A
  • Whole process takes about 2 years
44
Q

Conifer Reproduction – The Ovule and Fertilization

A
  • Female Cone: Many Scales -> 2 Ovules per scale = 4 megaspores per ovule -> 1 survives
  • 1 megaspore develops into female gametophyte = 2-4 archegonia per gametophyte
  • 4 embryos per archegonium -> <16 embryos compete = mature seed with only one embryo
45
Q

Gymnosperm Seed

A
  • Following fertilization, the ovule housing the embryo and matures into a seed
  • Egg cell + Sperm cell -> Zygote -> 1 dominant embryo (2n)
  • Female Gametophyte -> nutritive tissues (n)
  • Integument -> Protective seed coat (2n)
46
Q

Seeds are major adaptations for uncertain environments

A
  • Long distance transport – reduces parent-offspring competition, promotes outcrossing, and expansion of territory
  • Dormancy – Embryo protected until the right conditions are perceived
  • Protection from predation
47
Q

Conifer Life Cycle –Key Takeaways

A
  • Spores that produce the gametophytes are no longer dispersed
  • Microsporangia -> Microspores that produce male gametophyte (pollen)
  • Pollen desiccates prior to dispersal
  • Ovule houses the megasporangium
  • Megasporocytes undergo meiosis -> 4 Megaspores (1 survives) -> female gametophyte -> archegonia -> egg cells
  • Pollen tubes grow through the megasporangium to reach archegonia
  • Only 1 sperm cell is used
  • Only 1 of <16 embryos will survive per seed
  • Pollination + Fertilization takes up to 2 years
  • Fertilized ovule becomes the seed, female gametophyte becomes nutritive tissue
  • Seed desiccates prior to dispersal
48
Q

Extant Gymnosperms

A
  • The majority of living gymnosperms are woody species
    In order of extant diversity, the major groups are:
    1. Conifers = 550 species, all cone-bearing
    2. Cycads = 185 species
    3. Gnetophytes = 70 species
    4. Ginkgophytes = 1 species
  • All possess vasculature, megaphylls, pollen, seeds, and a dominant sporophytic phase
49
Q

Gymnosperms – Summary

A
  • Gymnosperms: Vascular seed plants with naked seeds
  • Sporophyte dominant phase
  • Evolution of the ovule – houses the megasporangium/female gametophyte
  • Evolution of the pollen – male gametophyte, develops on the sporophyte and grows the pollen tube to release sperm cells
  • Dry pollen are winged and dispersed through wind
  • Embryo retained on the female gametophyte
  • Female gametophyte retained on the sporophyte
  • Seed dries prior to dispersal
50
Q

Angiosperms ~260,000 species

A
  • Covered Seeds (Angio = vessel/container)
  • Incredibly important to humans
  • Sporophyte dominant
  • Produces reproductive organs that contain the haploid spores -> flowers
  • Microspores = Anthers, Megaspores = Ovules
  • Pollen – male gametophyte developed from the microspore on the sporophyte prior to dispersal
  • Ovule – Sporophyte structure that houses and protects the megaspore that gives rise to the Embryos sac (female gametophyte)
  • Ovules develop inside of an ovary
  • After fertilization, the ovule becomes the seed, and the ovary becomes the fruit
51
Q

Angiosperms – Key Adaptations

A
  • Efficient transport of water and nutrients
  • Flowers
  • Double fertilization
  • Ovaries
52
Q

Angiosperm Reproduction –

Flowers

A
  • Compact reproductive organs
  • Often hermaphroditic/bisexual
  • Attractive to pollinators
53
Q

Angiosperm Reproduction – Double Fertilization

A
  • Utilize both sperm cells
  • Produces embryo and nutritive tissue = Endosperm
  • Nutritive tissue only develops if pollination is successful
54
Q

Angiosperm Reproduction – Ovaries

A
  • Houses and protects the ovules
  • The base of the carpel
  • Following fertilization, becomes the fruit
  • Can aid in dispersal and nourishment of the seeds
55
Q

Double Fertilization

A
  • Pollen attractant released from the embryo sac -> guides pollen tube growth
  • One sperm cell from the pollen fuses with the egg, forming the zygote. The other unites with the diploid central cell of the embryo sac to form a triploid cell that gives rise to endosperm
  • Egg cell (haploid, n) + sperm cell (haploid, n) -> Zygote (diploid, 2n) -> Embryo
  • Central Cell (diploid, 2n) + sperm cell (haploid, n) -> Endosperm (Triploid, 3n) -> Nutritive Tissue
56
Q

Angiosperm Reproduction – Animal Pollinators

A
  • Many angiosperms have specific pollinators instead of just wind
  • Pollinators undergo coevolution with angiosperms
  • Plants have evolved to attract pollinators (showy, mimicry, scent, nectar)
  • Animals have evolved various behaviours and body parts for pollination (proboscis/tongues, different mouthparts)
  • Highly specific flowers for pollinators
57
Q

Angiosperm Seeds

A
  • Following fertilization, the ovule housing the embryo, matures into a seed
  • Egg cell + Sperm cell -> Zygote -> Embryo (2n)
  • Central cell + Sperm cell -> Endosperm nutritive tissues (3n)
    2 Integuments -> Protective seed coat (2n)
  • The remaining female gametophytic cells either degenerate or remain as part of the nutritive tissue
  • Seeds will fully dry prior to dispersal to attain dormancy
58
Q

Extant Angiosperms – Major Classes

A
  • Monocots (single cotyledon/seed leaf) ~ 60,000 species

- Eudicots (True Dicots, 2 cotyledons) ~200,000 species

59
Q

Monocots (single cotyledon/seed leaf)

A
  • Grasses, palms, lilies, orchids, bulbs, pineapple, banana
  • Parallel-veined leaves common
  • Floral parts in groups of 3
  • Bundles of vascular tissue scattered in stem
  • Fibrous root system
  • Pollen grain with 1 aperture -> monocolpate
60
Q

Eudicots (True Dicots, 2 cotyledons)

A
  • Most fruit trees, roses, beans, tubers, squashes, asters, cacti, succulents
  • Reticulate veins
  • Floral parts in groups of 4 or 5
  • Bundles of vasculature arranged in a ring
  • Branching roots with a strong tap root
  • Pollen grain with 3 apertures -> tricolpate
61
Q

Major Developmental Differences Between the Seed Plants

A

Gymnosperms vs. Angiosperms

  • Reproductive organs: unisexual cones vs. bisexual flowers
  • Seeds at maturity: exposed/naked vs. covered/contained
  • Integument(s) covering ovule: single vs. 2
  • Female gametophyte: 100s of cells vs. 7 cells
  • Microsporangia housed: on male cones vs inside anthers
  • Primary mode of pollen dispersal: wind vs. animal pollinators + wind
  • Pollination + fertilization length: ~2 years vs. minutes-hours
  • Sperm cell(s) used during fertilization: 1 vs. 2
  • Nutritive tissue for young embryos: remnant female gametophyte (n) vs. endosperm (3n)
  • Xylem is composed of: tracheids vs. vessels +tracheids
  • Phloem composed of: sieve elements vs. sieve tubes + companion cells
62
Q

Angiosperms – Summary

A
  • Angiosperms: Vascular seed plants
  • Have vasculature and covered and protected seeds
  • Sporophyte dominant phase
  • Hermaphroditic flowers are the reproductive organs
  • Pollen microscopic, developed in anthers
  • Female gametophyte small/microscopic and retained on the sporophyte within the ovules, housed in the ovaries
  • Fertilization creates the embryo and the nutritive tissue
  • The embryo is still retained on the female gametophyte
  • More efficient vasculature and faster growing
  • Flowers co-evolved with animal pollinators for cross-pollination
  • The largest groups are the monocots and the eudicots
  • Key Differences: venation/vasculature, floral parts, seed leaves
  • Survive in dry conditions with less water
63
Q

Seeds – Breaking Dormancy

A
  • Seeds are dry and dormant prior to their dispersal from the parent plant
  • Seeds will germinate when they are in suitable conditions (i.e. when they have sufficient water and access to resources)
  • The absorbance of Red Light activates Phytochrome B
  • Repeated/extended Red Light exposure converts sufficient amounts of Phytochrome to the active state to initiate seed germination
  • Reabsorption of far-red light inactivates the Phytochrome
  • Lack of light also causes Phytochrome to revert to the inactive form
64
Q

Seeds need to sense whether or not they will receive

A

enough light to photosynthesize

65
Q

Germination will use up all of the:

A

nutritive tissue present in the seeds

66
Q

If the plant is unable to photosynthesize:

A

once it emerges then it will quickly die

67
Q

Far-red light is not absorbed well by plants

A

reception of Far-red light alone indicates plant coverage overhead (Red light absorbed above) and not enough light for photosynthesis

68
Q

Requirement of water for fertilization and the availability of water

A

From high to low

Aquatic algae -> mosses -> ferns -> gymnosperms

69
Q

Length of Gametophyte (n) generation

A

From long to short

Aquatic algae -> mosses -> ferns -> gymnosperms

70
Q

Relative size of Gametophyte (n) generation

A

From large to microscopic

Aquatic algae -> mosses -> ferns -> gymnosperms

71
Q

Length of Sporophyte (2n) Generation

A

From short to long

Aquatic algae -> mosses -> ferns -> gymnosperms

72
Q

Relative size of Sporophyte (2n) Generation

A

From small to large

Aquatic algae -> mosses -> ferns -> gymnosperms

73
Q

Protection of the zygote/embryo

A

From none to very high protection

Aquatic algae -> mosses -> ferns -> gymnosperms

74
Q

Key trends observed as plants dominate the land

A
  • Longer time spent as diploid sporophyte -> Greater production of spores, handle greater genetic loads
  • Increasing protection of the embryo
  • Decreasing water availability (moving further away from sources) and lower requirement for external water during fertilization

BIOL371 Comparative Biology of Plants and Animals (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions