Lecture 11: Mosses and Land

Question 1

Land plants

Answer 1

Multicellular photosynthetic autotrophic eukaryotes that can survive and reproduce on LAND

Question 2

What are the two important innovations that enablede the move of plants to land?

Answer 2

Sexual reproduction on land
The ability to survive on land and in contact with air

Question 3

Plants have become less dependent on ____.
Also, a key feature of reproduction on land was the evolution of

Answer 3

• Water for reproduction over time. For example, green algae requires water for gametes and spores to swim
• The embryophyte which are organisms that have a structure that nourishes and protects developing embryo. All land plants are embrophytes have life cycles that include the alternation of generation

Question 4

What were two major innovations that enabled life on land?

Answer 4

-The waxy cuticle layer that helps a plant retain moisture along with a series of pores for gas exchange
-Vascular tissue was formed in response to the new heterogenous environment which transports water and nutrients throughout the body of a plant (support the plant body and helps avoid drying out)

Question 5

What are the 4 main groups of land plants

Answer 5

1. Non vascular plants
2. Seedless vascular plants
3. Gymnosperms- seeds
4. Angiosperms- flowering plants

Question 6

In addition to the embryophyte, what are the innovations that evolved before all of the nonvascular plants diverged from other plants?

Answer 6

1. A waxy cuticle layer that helps retain moisture
2. The presence of exchnage pores known as stomata usually found in leaves
3. Chemical group called flavonoids which provided protection against UV (not as important)

Question 7

Non-vascular plants
- Why do they not survive well in very moist environments?

Answer 7

embryophytes that have a waxy cuticle layer and some have stomata
- The lack of vascular tissue makes the transport of water from soil to leaves difficult. They are often short so the moisture is near the plant

Question 8

Alternation of Generations for mosses/non-vascular plants

Answer 8

1. Gametophyte is still dominant (for now!)
2. Male and female gametophytes are independent (different male and female producing spores)
3. Sperm develops into antherdium (male reproductive organ), eggs develop in archegonium (shelters the egg)
4. Egg is fertilized when sperm swims into archeonia which is where the zygote is developed into an embryo
5. Sporophyte grows out of the archegonium and is physcially attached and is dependent on gametophyte for nutrients and water

Question 9

Are mosses dependent on water?

Answer 9

Yes, they are still dependent on water as the motile sperm requires water to swim into the archegonium for fertilization