What are the 3 categories of vascular plants and what separates them?
Gymnosperms=seeds and pollen appear
Angiosperms=flowers and fruit appear
What problems did ancestral plants encounter when they moved from water to land?
1. Drying out
2. Falling over
3. must be anchored, non-motile,
4. seed/spore dispersal
5. protection of gametes
What are some general (apply to all plants) adaptions in plants?
1. Stomata: help prevent drying out, access to nutrients
2. cuticle (waxy surface): prevents drying out
3. roots: overcome problem of anchoring, access to water/nutrients
4. apical meristems: unspecialized cells at top
5. Dependent Embryos: provides protection from elements,provides nutrients to growing embryo, prevents drying out
6. Sporangium: covers embryo and keeps spores from being released to early.
What are some specialized (only in vascular plants) adaptions in plants?
1. Vascular tissue and lignin: helps transport molecules
2. Pollen and seeds (only in gymnosperms and angiosperms)
3. Flowers and fruits (only angiosperms): fruits provide a source of nutrients
What are the 2 types of angiosperms and what makes them different?
Monocots: one cotyledon
Dicots: two cotyledons
What are the 4 types of tissues in plants and their purpose?
1. Dermal: protection, prevention of water loss, gas exchange
2. Ground: support, storage, photosynthesis
4. Meristem: unspecialized cells
What are some differences between the xylem and the phloem?
Xylem: one-way transport of water and nutrients, composed of dead cells, made up of tracheids and vessel elements.
Phloem: two-way transport of sugars, hormones, proteins, etc. composed of alive cells. Made of sieve-tube elements and companion cells.
Source= where sugar is made, sink=where sugar is needed.
How does water/nutrients get to the xylem?
It can take two paths: intracellular and extracellular. The plasma membrane on the outside of the roots is selectively permeable. Minerals transport using active transport, water travels using osmosis.
The casparian strip is a waxy barrier that helps retain water.
What are the three properties that allow water to move from the roots to the shoot?
1. Transpiration: the pulling of water from roots to shoots through evaporation.
2. Cohesion: hydrogen bonds form to allow water to stick to itself.
3. Adhesion: hydrogen bonds form that allow water to stick to other polar molecules
How does water move from the roots to the shoot according to the cohesion-tension theory?
1. The stomata open, and water is evaporated.
2. Cohesion causes the water molecules to form a chain
3. adhesion causes the water to stick to the wall of the xylem and oounter-act gravity.
How much water does one tree transport in a day on average?
Why might the stomata close or open?
The stomata close on dry and hot days to slow water transport. They are able to sense temperature and light.
When the stomata are open, they are simultaneously losing water while gaining CO2, so they need to balance the need for water with the need for photosynthesis.
How does maple sap flow out of the tree?
Maple sap travels through the xylem, and at night when it freezes, it gets pulled into the shoots. During the day, the sap drains back down by gravity.
How does phloem sap move?
Sugar moves from cells to the phloem through active transport. It moves through the phloem by a pressure gradient.
What are the parts of a seed?
Embryo=forms new plant
Cotyledon =stores energy, supplies food to growing embryo
How do plants go through sexual reproduction?
Diploid Sporophyte makess diploid spores, which go through mitosis to make haploid gametophytes. This forms haploid gametes, which each combine with another gamete to form a zygote. The zygote goes through mitosis to form a multicellular diploid sporophyte, and the cycle starts all over.
How to angiosperms go through sexual reproduction?
A plant produces pollen grains (male gametophytes) and an egg within a female gametophyte. The pollen grains are dispersed off of one plant and fertilize the egg of another plant.
What are the four types of modified leaves in a angiosperm?
Stamen: male parts
Carpel: female parts
How is pollen made by an angiosperm?
1 diploid cell inside the pollen sack divides by meiosis and forms 4 haploid microspores. Each one of these divides by mitosis and forms a pollen grain with a hard outer shell. Inside each pollen grain, the generative cell divides by mitosis to form 2 sperm.
How do angiosperms make the female gametophyte?
One diploid cell divides by meiosis to for four haploid spores. Only one survives. The megaspore divides by mitosis 3 times to form one egg cell, one large cell with 2 haploid nuclei, and other cells.
How does fertilization work in angiosperms?
The pollen lands on the stigma, and a pollen tube forms down to the ovule. One sperm combines with the central cell and forms a triploid, the other sperm combines with the egg and forms a diploid zygote.
What are the benefits of dormancy?
1. makes sure that environmental conditions are good
2. allows time for the seed to be dispersed
3. retains seed coat as protection
If a seed germinates while still in fruit, there will be issues with mold/infection.
What are the stages of germination?
1. seed absorbs water
2. seed swells and breaks coat
3. enzymes activate
4. enzymes release stored energy, root forms, and then shoot forms
What environmental cues tell the seed to germinate?
fire, moisture, sunlight, temperature, chemicals in animal digestive system
What is the difference between monocots and dicots in the germination process?
Monocots: shoot is protected by a sheath
Dicots: shoot forms a protective hook.
Why is pollen dispersal important?
genetic variation: prevents inbreeding
How is pollen carried?
80% of the time by biotic (insects, birds, animals)
20% of the time abiotic (wind, water)
What is the advantage of using a live pollinator?
Carries the pollen farther away, more efficient
What adaptations do flowers have? Their pollinators?
1. target or pattern of color for the pollinator to land on
2. flexible stem bends over and smothers pollinator in pollen
3. flowers that count on hummingbirds to carry pollen have more nectar because hummingbirds need more food.
Pollinators use pollen as a food source for eggs
Why is fruit dispersal important?
Expanding the range
What are hormones?
chemicals secreted by a cells in low concentration to produce an effect in another cell. It's how cells communicate. hormones link environmental signals and genes.
one hormone is one molecule.
What determines the outcome of a hormone? What are the outcomes?
What other hormones it is combined with, their relative amounts, and location. One hormone can have multiple effects, and most processes are controlled by multiple hormones.
hormones effect cell division, elongation, and differentiation.
What are auxin and cytokinin?
auxin is produced in the apical meristem and elongates the shoot and inhibits the growth of the lateral buds. cytokinin has the opposite effect.
What does abscisic acid and ethylene do?
Abscisic acid prevents seeds from germinating. Ethylene cause fruit to ripen and leaves/petals to fall off.
since plants are stationary, what is the only way they can respond to the environment?
What are the three types of tropisms in plants?
1. gravitropism: directional growth in response to gravity 2. thigmotropism: altered growth in response to touch 3. phototropism: growth towards the light (occurs only in shoots)
What is photoperiodism?
a response of plants to the amount darkness (night) received; determines when flowering begins based on what season it is
darkness determines if a plant flowers or not. what are the 3 types of plants that have different requirements for darkeness?
day-neutral long-day: there is a maximum amount of consecutive darkness that will prevent it from flowering. must be less than a certain amount of darkness to flower. long-day: there is a minimum amount of darkness that will prevent it from darkening. must meet or exceed this min to flower.
are adaptations always beneficial? explain
NO! adaptations have benefits and costs, and they are balanced in function and form.
What are the 4 tissue types in animals?
Epithelial: protection and exchange Connective: support, strength, 'glue'-cells in an extracellular matrix. loose and fibrous (dense)-tendons/ligaments, specific purpose depending on location Muscle: contraction. smooth-involuntary, heart-invol., sketetal-volontary Nerve: sense and transmit info, made of neurons and glial (support) cells
What is the Integumentary system?
forms external body covering (skin, hair, nails)
senses external environment
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