3.1 Exploring Plant Diversity Flashcards
importance of plants
-Form the base of almost all food chains
-Provide food, fuel and fibre
-Found within medicines (e.g. Aspirin)
-Release O2
-Cycle nutrients
-Clean air, purify water, absorb carbon and detoxify soil
-Some can clean up pollution that seeps into the environment
what are 3 characteristics that all plants share?
-eukaryotic
-cell walls contain cellulose
-carry out photosynthesis
evolution of plants
Transformed from aquatic, algae-like plants by evolving:
-Formation of an embryo
-Ability to stand upright and grow
-Vascular tissues to transport nutrients, water, and waste
-Strategies to reduce water loss
-Strategies to disperse reproductive structures without water current
Fossil and biochemical evidence indicate;
______________ are the oldest group of plants
__________ the youngest
green algae; flowering plants
oldest evolved plants to newest evolved plants
green algae
mosses & relatives
ferns & relatives
cone-bearing plants
flowering plants
vascular plants - sexual reproduction
-spores
-seeds not enclosed in fruit (gymnosperms)
-seeds enclosed in fruit (angiosperms)
alternation of generations
-most plants have a life cycle that alternates
between diploid and haploid forms
Diploid = 2 sets of chromosomes
Haploid = 1 set of chromosomes
____________________________ produces egg and sperm cells called gametes
Haploid generation (gametophyte)
______________________ produces spores
Diploid generation (sporophyte)
Conifers
-Conifers also go through alternation of generations
-They have two separate cones, male and female, that are the gametophytes
-Zygote produces a seed
-Sporophyte is dominant
spores
-haploid but they can develop into a new organism
-can develop tough coats that enable them to persist in unfavourable conditions
gametes
are haploid so they must fuse with another gamete to form a zygote (that is now diploid)
true or false: Sporophytes are usually the dominant generation (*except for mosses)
true
major groups of plants
5 groups:
Green algae
Mosses
Ferns
Seed plants
Flowering plants
green algae is found in _________ around edges of __________
shallow freshwater; ponds and lakes
green algae have
cell walls and photosynthetic pigments
green algae are modern relatives of ______
plant ancestors
true or false: algae undergo alternation of generations
false
mosses
seedless non-vascular plants
mosses are the first to branch off from ___________
aquatic ancestors
true or false: mosses don’t have seeds, stems, or rigid support structures
true
because mosses are non-vascular, they are ____
short
in mosses, _______ are the dominant generation, called ________
gametophytes; bryophytes
true or false: in mosses, sperm and eggs are produced in the same structure
false… separate structures
in mosses, how do sperm get to eggs?
they’re flagellated and must swim through water to meet eggs
ferns
seedless vascular plants
ferns have vascular tissue, therefore they are _____
taller
what is the dominant generation in ferns?
sporophyte
what is the gametophyte called in ferns?
prothallus
gametophyte in ferns has ________________ structures
sperm and egg producing structures
true or false: in ferns, sperm are flagellated
true
where are spores found in ferns?
on the underside of the sporophyte leaf
seed plants
gymnosperms
gymnosperms are ______ and contain ___________
vascular; “naked” seeds
true or false: gymnosperms are protected in an ovary
false
examples of gymnosperms (seed plants)
Ex. Pine, spruce, fir, cedar
seeds
plant embryos packaged in a protective coat with a food supply
tree
Highly developed diploid sporophyte
in gymnosperms, where do gametophytes live
Gametophytes live in the cones on the sporophyte
pollen
small male gametophytes (which don’t require water to move)
which group was the first to have seeds
gymnosperms
flowering plants
angiosperms
“Enclosed seed” =
inside an ovary
what was the last group to evolve
angiosperms
what does flowering plants coincide with in terms of evolution?
Coincides with rise in mammals in animal kingdom
what are the reproductive structures in angiosperms?
flowers
why are angiosperms the most effective?
Most effective, use animals to transport
how did flowers evolve?
Flowers evolved as a mechanism to hold the gametophytes, and protect and disperse the seed (via fruit)
Flowers are designed to _______ animals/insects to ______ and _______ seeds
attract; pollinate; disperse
Change in plant growth and rainforest destruction can affect …
precipitation, weather patterns, and microclimates
plants and rainforests can eventually repair themselves (to an extent) IF …
negative human impacts cease
What differentiates a plant from the species of
other kingdoms?
- Plants are eukaryotic.
- Plants have cell walls that contain the carbohydrate cellulose.
- Plants carry out photosynthesis, using the pigment chlorophyll to transform sunlight into chemical energy
A plant lives in two environments:
air and soil
what do plants use to transform sunlight into chemical energy for photosynthesis
chlorophyll
What group of algae is most closely related
to plants?
green algae
evolution of plants diagram
-plant ancestor
Green Algae
-embryo formation
Mosses and Relatives
-true water-conducting tissues
Ferns and Relatives
-seeds
Cone Bearing Plants
-flowers: seeds enclosed in fruit
Flowering Plants
Why must a bryophyte have open water to be
successful?
The bryophytes do not have any rigid support structures, such as lignin-reinforced cell walls or vascular tissues, that allow most modern terrestrial plants to stand tall and transport water great distances upward against the force of gravity to leaves and shoots
this is why they need to be close to the ground near water to be successful and survive
what is lignin?
a chemical that hardens cell walls, allowing them to
stand upright
which group of plants represent these today:
Primitive plants lacking leaves, stems, seeds, or
any rigid tissue evolve from algal ancestors and begin to colonize areas where water and land meet
mosses
which group of plants represent these today:
Plants begin to develop lignin, a chemical that hardens cell walls, allowing them to stand upright, and vascular tissues to transport water and nutrients. This allows plants to move farther away from water bodies
ferns
which group of plants represent these today:
The development of seeds, plant embryos encased
in a protective covering along with a food supply, helps plants spread to diverse terrestrial habitats by allowing plant embryos to be dispersed without
drying out.
seed plants (gymnosperms)
which group of plants represent these today:
The final major period of plant evolution begins with the appearance of flowering plants. Flowers are a reproductive structure that attracts animals to help spread plants’ seeds farther afield
flowering plants (angiosperms)
What is the function of the vascular tissue
in plants?
transport water and nutrients, allows plants to be taller
Vascularization
Vascularization, the formation of tubes to carry fluid throughout an organism, was the next step in plants’ invasion of land, allowing plants to reach greater heights by connecting above-ground
shoots and underground roots
What resources are necessary for a plant
to grow?
sun, water, height (capture more sunlight=more successful)
Today, biologists divide seedless vascular plants into three phyla:
ferns, club mosses, and horsetails
Why are plants considered the foundation of
most ecosystems?
Plants form the critical base of food chains in nearly all ecosystems. Through photosynthesis, plants harvest the energy of the sun, providing both food and habitat for other organisms.
Why are green algae but not brown algae
considered part of the plant kingdom?
green algae have cell walls and photosynthetic pigments identical to plants and brown algae do not
Which group of plants appears to be the most
successful? Justify your answer
angiosperms because their seeds are protected in ovaries (flowers) and their seeds (ovary develops into fruit) get dispersed by other animals
Most plants have roots, but mosses do not.
Name and describe the function of the
underground growth in mosses
Why can ferns grow several metres tall but
mosses cannot?
because of vascularization and mosses don’t have it
Vascularization, the formation of tubes to carry fluid throughout an organism, was the next step in plants’ invasion of land, allowing plants to reach greater heights by connecting above-ground
shoots and underground roots
List two key adaptations that distinguish
angiosperms from earlier plants
seeds enclosed in an ovary (flower)
ripened ovary of a flower used for seed dispersal (fruit)
Alternation of generations is a key
characteristic common to most plants. Which
group of plants does not exhibit this life cycle?
green algae
Describe the process of alternation of
generations.
spores(n) –> gametophyte plant(n) –> sperm(n) + eggs(n) –> fertilizaton –> sporophyte plant(2n)
n - haploid
2n- diploid
Describe the trend in gametophyte size as
plants become more removed from water
get smaller
Suppose you were given a plant that is haploid,
small, and has flagellated sperm. What type of
plant would it be? Explain how you came to
this conclusion
fern gametophyte because mosses and ferns both have flagellated sperm but because ferns evolved later than mosses, their gametophytes are smaller
Why is the gymnosperm seed a less successful
reproductive strategy than the angiosperm seed?
because on days when there’s no wind, the seeds don’t get dispersed but for angiosperms, the seeds are in fruit and they attract animals that disperse them
Why is the dispersal of the seed a key factor in
the success of angiosperms?
attracts animals that disperse the seed for it
Suppose a bacterium that targets the
production of lignin tissue were to infect all
plants. How might this affect the evolution
of future plants?
lignin is a chemical that hardens cell walls, allowing them to stand upright
-without lignin, none of the plants would be tall or able to stand on their own, and would affect plant growth and development, which could lead to a decrease in plants
Describe how deforestation can contribute to
climate change
-rainforests get their name from all the
water vapour in the air around them.
-much of this water vapour becomes
precipitation.
-thus, changes in plant growth and destruction of rainforests can alter precipitation and weather patterns.
