Chapter 26 & 27 Plant Diversity

Question 1

What is the closest relative to land plants? What characteristics show that they are related?

Answer 1

Green algae

• shallow water habitats led to occasional drying
• adaptations to periodic droughts led to thick cuticles
• can withstand air

Question 2

What challenges did plants need to overcome in order to be terrestrial (adapted to land)

Answer 2

-leaves for photosynthesis
-gametangia to protect gametes
- cuticle to keep from drying out
-stomata allows for gas exchange
-lignin gardens cell walls
-shoot
Roots
-vascular tissue

Question 3

Bryophytes

Answer 3

• mosses liverworts and hornworts
• waxy cuticle prevented dehydration
• dependent on watery environment
• sperm must swim through water to fertilize the egg

Question 4

Pterophyta/Tracheophyta

Answer 4

• ferns and horsetails
• vascular tissue
• phloem
• xylem
• root system
• don’t need to be in water/ near
• use spores to reproduce

Question 5

Gymnosperms

Answer 5

• conifers, cycads, gnetophytes, ginko

- cones to disperse offspring with wind

Question 6

Angiosperms

Answer 6

• flowering plants
• seeds are enclosed within an ovule (fruit)
• use pollinators to disperse their pollen

Question 7

What is the difference between a gametophyte and sporophyte?

Answer 7

• gametophyte is haploid and produced gametes

- sporophytes are diploid and produce spores

Question 8

What is the advantage of producing seeds?

Answer 8

-provides the embryo with nutrients and water, it is enclosed in a protective case, nutritive tissue

Question 9

How do the seed of gymnosperms differ from the seeds of angiosperms?

Answer 9

-gymnosperms develop their seeds in cones and angiosperms develop their seeds in fruits. Gymnosperms do not make fruits

Question 10

What is the advantage to producing flowers?

Answer 10

-flowers make fruits and attract pollinators such as bees who are needed to pollinate crops

Question 11

What is the difference between a perfect and imperfect flower

Answer 11

• imperfect flower: dioecious either has only male or only female parts on flower, not both. Monoecious has separate male and female parts on sane plant
• perfect flower: has both male and female structures

Question 12

Why is using a specific pollinator advantageous to just relying on wind or water?

Answer 12

• using specific pollinators ensures the sperm reaches the correct species
• wind: huge amount of sperms will not reach the correct destination

Question 13

Why are fliers and insects considered to be coevolved?

Answer 13

-the flowers morphology is defined by the pollinator

Question 14

What are some methods plants use to bring pollinators?

Answer 14

-bribery: plant offers something to pollinator such nectar that is used as food and a safe place to deposit eggs
Trickery: plant deceives pollinator into carrying pollen from one plant to another, no payoff for the pollinator. Looks like an insect to mate with or gives off rotting smell so flies will lay eggs

Question 15

What is double fertilization?

Answer 15

-2 separate fusions of male nuclei from the pollen grain with female nuclei in the ovule. Delivers 2 haploid sperm cells. One SuperM fuses with egg and one sperm fuses with large cell

Question 16

What is a fruit? What is its purpose?

Answer 16

-a mature ovary that carries the seed and is used to disperse the seeds

Question 17

How are seeds dispersed

Answer 17

• water dispersal: floats on water
• spring-loaded dispersal: dry pods that split/pop open explosively and propels seeds through air
• wind: fruits break in half outgrowth of ovary wall has thin lightweight wings and the wind spins them away
• animal: seeds have spines/hooks that make them stick to animals, animals eat fruit and discards the seeds

Question 18

Why is dispersal away from parent plant so important?

Answer 18

-it limits competition between parent and offspring

Question 19

Why does a plant develop defenses?

Answer 19

-they can’t move and need to protect themselves from animals that might eat them

Question 20

What are some Anatomical defenses

Answer 20

-spines, thorns, sticky sap or amber

Question 21

What are some chemical defenses

Answer 21

Toxins and hallucinogens

Question 22

How do we use plant defenses to our advantages?

Answer 22

-smoke weed and salicin bark of willows can be used to make medicine such as aspirin