Topic 9: evolution of land plants

Question 1

name 5 general characteristics of land plants

Answer 1

1. eukaryotes
2. multicellular
3. photosynthetic (photoautotrophs)
4. cell walls made of cellulose
5. alternation of generations

Question 2

name the 2 main groups of lands plants and their subgroups

Answer 2

1. non-vascular plants (eg mosses)
2. Vascular plants
   a) seedless plants:
   - seedless vascular plants
   b) seed plants
   - gymnosperms (eg conifers, pines)
   - angiosperms (flowering plants)

Question 3

explain benefits and challenges to moving to land

Answer 3

benefits:

• spacious
• unfiltered sunlight
• higher CO2 levels
• rich source of mineral nutrients
• relatively few competitors & predators

challenges:

• less water
• need to resist gravity
• reproduction (could move in water, but can’t on land)

Question 4

charophytes and land plants share a

Answer 4

common ancestor

Question 5

name 3 synapamorphic features that land plants have with charophytes

Answer 5

1. rings of cellulose- synthesizing protiens
2. structure of the sperm resembles the sperm of charophytes
3. phragmoplast during cell division

Question 6

name the 7 major characteristics that have evolved in land plants for life on land

Answer 6

1. sporopollenin
2. cuticle, pores
3. stomata
4. embryophytes
5. vascular tissue
6. roots
7. true leaves

Question 7

sporopollenin is a tough polymer that protects ___ in charophytes and ___ in plants

Answer 7

zygote

walls of plant spores

Question 8

name 2 characteristics that are unique to land plants (not in charophytes) that help to conserve water

Answer 8

• waxy cuticle on epidermis

- stomata (pores in the epidermis of leaves)

Question 9

land plants have ____ embryos which are protected where?

Answer 9

multicellular

within tissues inside the female parent

Question 10

what are the embryophyta

Answer 10

group of land plants

- evolved retention of embryo

Question 11

vascular tissue in land plants have ___ to strengthen

Answer 11

lignin

Question 12

what are apical meristems

Answer 12

undifferentiated tissue (hasn’t been told what to do yet) from which new, differentiated cells arise. cells produced by meristems differentiate into various tissues, including surface epidermis and internal tissues

Question 13

what happens when a cell is differentiated?

Answer 13

some genes have been turned on/ off & these are now different from stem cells

Question 14

gametophytes make gametes through

Answer 14

mitosis

Question 15

sporophytes make spores through

Answer 15

meiosis

Question 16

what’s the difference between the ancestral life cycle and the current land plant life cycle?

Answer 16

no multicellular diploid stage in the ancestor

Question 17

why is alternation of generations such an important adaptation

Answer 17

delayed mitosis= many copies though mitosis before making spores
- amplification which is good for harsh environments (more spore= more survive)

Question 18

which form is dominant in the following

• bryophytes (mosses)
• ferns
• gymnosperms
• angiosperms

Answer 18

• bryophytes (mosses): gametophyte
• ferns: sporophyte
• gymnosperms: sporophyte
• angiosperms : sporophyte

Question 19

adaptive radiation occurs when

Answer 19

a single lineage produces a large # of descendant species that are adapted to a wide variety of habitats

Question 20

bryophytes are a mono/para/poly phyletic group

Answer 20

para

Question 21

bryophytes are the following (3) non vascular plants

they lack __ ___ and must exist in ___ environments in order to reproduce (sperm must __ to fertilize egg)

Answer 21

1. liverworts
2. mosses
3. hornworts

vascular tissue
moist (swim)

Question 22

vascular plants are ___ dominant and have modified leaves that bear ___ (spore- producing organ)

Answer 22

sporophyte

sporangia

Question 23

what evolutionary adaptations allowed plants to live & diversify under dry conditions?

Answer 23

seeds! (embryos with stored food)