Plants Lesson 3 Flashcards
The most diverse type of plant?
Flowering plants
Angiosperms
They have covered seeded. The covering is called a fruit. They are the flowering plants.
When did anthophyta (angiosperms) arose?
150 mya. <20% of plants by 105 mya. >80% of plants by 65 mya.
Angiosperm Terrestrial Revolution
The diversification of the angiosperms coincided with a dramatic diversification of other organisms. Increase in angiosperm fuelled the increase of other species.
When did eudicots and monocots split?
125 mya
What organism increased the most with the Angiosperm Terrestrial Revolution?
Beetles
The Angiosperm Terrestrial Revolution and
the origins of modern biodiversity?
Today 85% of plant, animal and fungal species live on land rather than in the sea, half of these live in tropical rainforests. An explosive boost to terrestrial diversity occurred from c. 100–50 million years ago. The rise of angiosperms triggered a macroecological revolution on land and drove modern biodiversity … to new, high levels, a series of processes we name here the Angiosperm Terrestrial Revolution.
What did the explosive boost to terrestrial diversity occurred from c. 100–50 million years ago cause?
The biosphere expanded to a new level of productivity (more energy is produced). Coincided with innovations in flowering plant biology and evolutionary ecology, including: their flowers and efficiencies in reproduction; coevolution with animals, especially pollinators and herbivores; photosynthetic capacities; adaptability; and ability to modify habitats.
Explaining angiosperm diversity & species number?
-Insect pollination.
-Flexibility in seed production and dispersal. -Greater genetic and phenotypic flexibility in cell and shoot elongation.
-More complex mechanisms for activating and repressing the genes.
-Greater complexity of the flower
Division Anthophyta – flowering plants?
300,000 (named), 400,000 (estimated) species. Reproductive organs in flowers. Sporophyte dominant
Heterosporous (seed plants). Microgametophyte =
pollen! Megagametophyte: 8 nuclei and 7 cells big. Triploid (3n) endosperm (gives nourishment to the seed).
Whorl
A set of structures that come out of one spot.
How many whorls do flowering plants have?
4: Sepal (green and photosynthestic), Petal, Androecium, Gynoecium.
Androecium
House of men. Contains the stamen (all the male structures), anther (sporangium and makes pollen), and filament (holds the anther).
Gynoecium
House of women. Contains the stigma (where pollen lands and travels down), the ovules, and the ovary (fruit when mature). AKA pistil & carpel.
Hermaphroditic
Means both male and female. The flower is.
Do eudicts and monocots look similar?
No, they look very different.
Examples of monocots?
Grasses: Maize, Wheat, Rice, Bamboo.
Orchids, Irises, Lilies, Palms, Barley
Examples of eudicots?
Oaks, Maples, Dandelions, Sunflowers, Legumes (peas and beans), Melons, Potato, Poppies, Roses.
Monocot Characteristics
One cotyledon (seed).
Veins usually parallel.
Vascular tissue scattered.
Root system usually fibrous (no main root).
Pollen grain with one opening ( sperm comes out of).
Floral organs usually in multiples of three.
Eudicot Characteristics
Two cotyledon.
Veins usually netlike.
Vascular tissue usually arranged in ring.
Taproot (main root) usually present.
Pollen grain with three openings.
Floral organs usually in multiples of four or five.
Stigma
Female structure that receives pollen.
Style
Female structure that has the stigma on it.
Why are the male and female not close to each other on the flower?
To prevent self-fertilziation. Self-fertilziation causes offspring to be more homozygous, this results in deceased fitness.
How many angiosperms are hermaphroditic?
85%
Monoecy
Separate male & female flowers on the same individual. One house. ie. paper birch.
Dioecy
Male & female sex organs on different individuals. Two house. ie. Willow.
Pollination
Arrival of pollen on stigma (flowering plants) or on receptive female cone (conifers). Occurs only in seed plants (of course!) because only seed plants have pollen.
How do conifers pollinate?
By wind
How do flowering plants pollinate?
Insects (bees, moths, butterflies, flies, beetles, …). Birds (hummingbirds, honeycreepers, …). Bats
Wind. It’s moved in many different ways.
What does pollination in angiosperms need?
A reward for pollinator (like nectar or pollen) and advertisement by plant (like showy flower and possibly order). Both of these are costly, and are needed to get the animal to move the pollen for them.
Pollination Syndroms
Integrated sets of floral traits (e.g., morphology, colour, odour, size, rewards) associated with particular pollinator groups. An example of convergent evolution as the traits have evolved separately many times. Can thus occur in unrelated plant species.
Pollination by bees
Usually pretty general.
Shape: various: can be highly specialized or not
Color: various, including yellow, blue, orange (not red because they can’t see it)
Odor: none or highly specialized. When they do care about it it’s super specific. one type of bee = one type of flower.
Pollination by bats or moths
Specific needs because they can come out at night.
Shape: tubular, open at night
Color: yellow or white
Odor: strong & sweet
Nectar: large quantity
Pollination by birds
Shape: tubular
Color: red most common, also yellow
Odor: none
Nectar: large quantity, often weak (20% sugar). It’s the reward, because it drinks it.
Pollination by wind
The wind doesn’t care about looks or reward.
Shape: not showy (very reduced petals)
Odor: none
Nectar: none
Pollen: very large quantity because it has no direct targets.
Examples: grasses, ragweed
Ragweed
Has a head of several flowers. Each head is either making a lot of pollen or receiving lot of pollen. The lots of pollen causes allergies.
The variation of pollination in plant species?
Pollinated by many animal species. Pollinated by one animal species. Provide no reward: deceit pollination
Pink lady’s slipper orchid
Example of deceit pollination. Has 6 petals and one is highly modified. The petal is very showy and the bee that has pollen on its back is tricked to go up the lady slipper and is forced through it and touches the female tissue. The bee gets no reward. The best place for them is near blueberries because the bee’s are in a frenzy.
Orchids
Pollen in 2 packets (pollinia). Reward: Nectar or None: deceit pollination
Sphinx Moth
It steals nectar without transferring pollen.
Angiosperm lifecycle
It starts with a mature flower in a sporophyte plant (2n). On the female side the ovary goes through meiosis then it as a megasporangium (2n) with a megaspore (n) in it. The female gametophyte has 8 nuclei ( 2 are the central cells and one is the egg). Then on the male side the mircosporangium goes through meiosis. The gametophyte divides many many times to make a pollen tube. How only 2 sperm are functional in it. The pollen travels down the style meets the egg and then double fertilization occurs. Then the seed grows into a germinating seed then back to mature flower.
Parts of the seed in the flowering plant?
Embryo (2n)
Endosperm (3n)
Seed coat (2n)
Double fertilization
One sperm makes the new sporophyte, the other unites with the central cell to make the endosperm.
How is the endosperm triploid?
Central cell (2n) + Sperm (n) = Endosperm (3n)
How do sperm travel down the tube?
Because the sperm nuclei don’t have cell walls.
Why does the style exist?
To distinguish strong pollen grains from weak.
Ovules become what?
Seeds
Ovaries become what?
Fruits
The Inspo for Velcro?
Cockleburr
Dispersal of seeds by wind?
Maple and cottonwood
Dispersal of seeds by water?
Coconut and water lily
Dispersal of seeds by animals?
Blueberry and cockleburr
Fruit
Anything with seeds from flowering part.
Fruit examples with more than 1seed?
*watermelon
* zucchini
* squash
* banana
* bell pepper
* grape
* pea pod
* apple
* orange
* tomato
Fruit examples with one seed?
Grass grain (wheat, corn, rice).
Coconut
Cherry
Peach
Acorn
Endosperm is the principal foodstuff of
civilization?
More than half of (direct) daily calories worldwide. Especially 3 cereal grasses: rice, wheat & corn (maize). Domesticated ~10,000 years ago.
Why did endosperm (like wheat and rice) increase?
Because of its importance and better breeding practices.
Conquest of the land?
- Cuticle
- Sporopollenin
- Jacketed sex organs (antheridia, archegonia)
- Embryo retention
- Stomates (= stomata)
- Vascular tissue (xylem, phloem)
- Seed & Pollen
- Flower
- Fruit
3 variations on altern. of generations?
Sporophyte dependent on gametophyte (moss). Then large sporophyte and small independent gametophyte (fern). Then reduced gametophyte dependent on sporophyte (seed plants).
Two systems in vascular plants?
Roots (below ground) and shoots (above ground). They are defined by their different structure.
Node
Where another structure emerges.
Petiole
Holds heat.
Iris rhizome
Rhizomes grow underground. Vertical shoots emerge from axillary buds at nodes.
Strawberry stolon
Stolons grow along surface. Plantlets form at nodes: asexual reproduction.
Potato tuber (stolon or rhizome)
Storage. ‘eyes’ are axillary buds at nodes.
Types of roots
Prop roots
Storage roots
Green roots
Pneumatophores
Strangling aerial roots
