Plant diversity Flashcards

1
Q

What are plants classified in?

A

Bryophytes
Pteridophytes
Gymnosperms
Angiosperms

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2
Q

what are the key characteristics of plants?

A

Presence/ absence of:
vascular tissue
true leaves and roots
seeds or spores
cones or flowers
fruit

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3
Q

What are non-vascular plants?

A

Without vascular system: xylem and phloem. e.g) Bryophytes

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4
Q

What are Bryophytes?

A

Simplest land plants evolved from green algae.
Seedless, non vascular plants
Go dormant in a dry environment

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5
Q

Where are Bryophytes most common?

A

Damp areas: dependent on water because they have motile sperm

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6
Q

Do Bryophytes have vascular tissue?

A

No
No strengthening tissue: stay small

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7
Q

Do Bryophytes have true leaves or roots?

A

No
Have rhizoids (outgrowth) to anchor
Simple leaf like, with chlorophyll for pss
no cuticle: water absorbed through surface of whole plant

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8
Q

Why are Bryos dependent on water for fertilisation?

A

Motile sperm need water to swim and reach female gamete(egg)

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9
Q

What does it mean if bryos don’t have any vascular tissue?

A

No strengthening tissue therefore will stay small
diffusion

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10
Q

Why do bryophytes have no true leaves or roots?

A

they have no vascular tissue

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11
Q

What are rhizoids and their function?

A

Outgrowths of stem to anchor the plant

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12
Q

What does it mean if a bryophyte doesn’t have true leaves or roots?

A

have rhizoids
simple leaf-like, with chlorophyll for photosynthesis
no cuticle, so water absorbed through surface of whole plant.

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13
Q

Explain bryophytes fertilisation process.

A

Fertilisation —> forms zygote—>embryo grows immediately —>into a sporophyte

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14
Q

How do bryos reproduce?

A

By spores produced in the sporangium of sporophyte

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15
Q

What is a spore?

A

A minute, typically one-celled, reproductive unit capable of giving rise to a new individual without sexual fusion—> it is a characteristic of lower plants, fungi and protozoans
It is also a haploid reproductive cell which gives rise to a gametophyte.

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16
Q

What does the alternation of generations mean?

A

Type of life cycle that occurs in those plants that have a distinct haploid(n) and diploid(2n) stages.

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17
Q

Explain the alternation of generations with moss.

A

Mosses are homosporous (all spores are the same):
Spores all develop into one type of gametophyte.
amongst the tiny “leaves” of the moss plant/gametophyte are simple male sex organs producing motile spend cells, and simple female organs, producing and egg cell.
Two gamete’s fuse to form a zygote that develops into an embryo—> embryo grows immediately into sporophyte.

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18
Q

What is the function of vascular tissue being made up of xylem and phloem?

A

To transport water and food around the plant.

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19
Q

What is the advantage that vascular plants have?

A

Adaptation that allows plants to cope in a dry environment and to grow taller?

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20
Q

What is a true leaf?

A

Organised inside for max sunlight, increase absorption of CO2 for pss.
Dense network of veins containing xylem supplies water for pss, phloem removes sugars.
Waterproof covering, cuticle and stomata—> regulate gas exchange.

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21
Q

What is a true root?

A

Absorb water and minerals from soil.
Root hairs absorb raw materials for pss
Taken via xylem to leaves
Efficient absorption as no water is lost through the whole plant.
Plants grow faster and taller.

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22
Q

What two categories are vascular plants split between?

A

Seedless plants: Lower vascular plants, reproduce by spores, Pteridophytes
Seed bearing plants: Higher vascular plants, reproduce by seeds, gymnosperms.

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23
Q

Example of seedless plants?

A

Pteridophytes ( Ferns, horsetails and club mosses)

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24
Q

Do Pteridophytes have vascular tissue?

A

Yes meaning they can live in dryer places.

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25
What does it mean when a Pteridophyte has true leaves and roots?
Leaves/ fronds well developed pss. Nee leaves coiled in bud Roots fibrous: anchor and absorb water and minerals Stems are horizontal- called rhizomes.
26
How do Pteridophytes reproduce?
By spores Released from dehiscence sporangia that grow on back of sporophylls. Occur in clusters called sori.
27
What do spores germinate into?
Tiny gametophyte.
28
Why do Pteridophytes rely on water for fertilisation?
Produce motile sperm Ferns are found in moist environment.
29
What do Pteridophytes produce and how are they protected?
Produce gametes that are protected in gametophyte
30
What are seed bearing plants?
Spermatophytes More complex E.g) Gymnosperms (come bearing) Angiosperms (flowering)
31
What’s the difference between the gametes of seed plants and lower plants?
Seed plants don’t depend on water while lower plants do.
32
What’s the difference between spores with seed plants and lower plants?
Seed plants are heterosporous while lower plants are homosporous.
33
What are the common features of seed plants and Pteridophytes?
Plant differentiation: root — stem — leaf Both have vascular tissue
34
What are the evolutionary advances of seed plants?
Pollen grain Resistant seeds
35
What are pollen grains produced from?
Produced from microspores
36
Do pollen grains contain female or male gametes?
male
37
How are pollen grains transported to female structures?
Wind, water and animals
38
Why do pollen grains develop pollen tubes?
So non motives make gametes—> ovule Eliminated the need for water
39
What is a seed?
Embryonic plant, food storage tissue, hardened protective coat.
40
What do resistant seeds allow embryos to do?
To lie dormant until suitable growing conditions.
41
What do resistant seeds contain?
Good for initial growth of embryo when seed germinates.
42
Example of a gymnosperm
Conifers (Yelloywood, cedar, pines)
43
Where are gymnosperms sporangia?
in cones Separate make and female cone contain reproductive structures on open spire bearing leaves (sporophylls)
44
What does it mean if Gymnosperms are heterosporous?
Female cone produces megaspores= ovule with female gamete, well protected Male cone produces microspore= pollen grains (male gamete), released and dispersed by air currents. Pollen grain produces pollen tube which take male gamete to female gamete for fertilisation. Seed are exposed on sporophylls of female cone Seeds not enclosed by protective ovary wall as in flowers = naked seeds Embryo protected against desiccation by being inside seed (dormant) until conditions are favourable for germination.
45
Do Angiosperms have True leaves, true roots and vascular tissue?
Yes
46
What two structures distinguish Angiosperms?
Flowers Fruit
47
What does it mean if Angiosperms are heterosporous?
Male anthers produce microspores = pollen grains Female carpels produce megaspore = female gametophyte (ovule inside the ovary) Gametophyte well protected inside the ovary Angiosperm seed surrounded by ovary which forms a fruit
48
What is the purpose of flowers?
Reproductive organs Attract pollinators
49
What is pollination?
The transfer of pollen grains (containing sperm) from the anthers to the stigma
50
What is self pollination?
Transfer of pollen from the anthers to the stigma of the same flower
51
What is cross pollination?
Transfer of pollen from the anther of one plant to the stigma of a flower on another plant but from the same species.
52
How can pollination happen?
Through wind, insects and birds
53
What would it mean if there was no pollination?
No fertilisation—> no fruit or seeds Humans rely on these processes to ensure the next generation of plants
54
Explain pollination by pollinators.
Pollinators are ANIMALS that love pollen from anthers to stigmas Mostly insects (bees and butterflies) but some are VERTEBRATES (mice and birds)
55
Describe the flowers that are used in insect pollination.
Flowers are large, large petals that are brightly coloured Highly scented with nectar guides Stigma is not feathery Small anthers inside flower Petals form landing area for insects
56
What do insects recurve from the nectar of a flower?
sugar
57
What do the pollen grains do?
Stuck to insect and transfer it to another flower
58
Describe the flowers used for bird pollination.
Brightly coloured, often red Elongated corolla tube Sturdy and bigger Produce large quantities of dilute nectar Little to no scent
59
Describe the flowers of wind pollination.
Flowers are small and at the top of long stalks- most grasses, corn and certain lilies Filaments long and flexible, large protruding anthers Produce large quantities of small, light pollen grains Stigmas feathery, long and hang outside flowers Reduced petals, no bright colours, no scent
60
What are the advantages of Asexual reproduction?
Only one parent needed Offspring identical to parent No need for pollination or dispersal
61
What are the disadvantages of asexual reproduction?
Offspring genetically identical (no variation) Weakness transferred to offspring Overcrowding - increase competition for resources
62
What are advantages of sexual reproduction?
Produce genetically different offspring-increase variation in species Better survival chance in unstable environment Prevent spread of disease(genetic resistance)
63
What are the disadvantages of sexual reproduction?
Need 2 sexes Lots of energy wasted on reproductive organs (flowers) Unfavourable mutations can be passed on.
64
What is the significance of seeds?
Allowed seed-bearing gymnosperms and angiosperms to dominate the Earth Produce oxygen, remove carbon dioxide, purify water. They make useful products like food, medicine, fuel and building materials. Formed from a fertilised ovule Ovule contains one or two cotyledons which stores food Seed is surrounded by a testa (protective seed coat)
65
What is the value of seed banks?
Replace plants that are lost Maintain/ restore biodiversity Research in bioengineering Pharmaceutical research