Lecture 18: Evolution of Land Plants (Midterm III)

Question 1

are algae plants? if so what are they

Answer 1

no; photosynthetic protists

Question 2

most plants are ____ but a few have returned to ________ habitats

Answer 2

terrestrial; aquatic

Question 3

plants supply ____ and are the source of most ____ for land animals

Answer 3

oxygen; food

Question 4

what is the importance of plants?

Answer 4

they are the bottom(base) of most food webs on the planet

Question 5

which organism represents a transition toward terrestrial plants

Answer 5

charophytes (phylum charophyceans)

Question 6

Plants evolved from protists generally, but more specifically

Answer 6

green algae

Question 7

what helped charophycean ancestors make the move to land?

Answer 7

1. their ancestors (green algae) lived at the waters edge where they had access to unfiltered sun, more CO2, nutrient rich soil and fewer herbivores + pathogens

Question 8

what challenges did charophyceans face and how did they adapt?

Answer 8

1. land let to a scarcity of water and lack of structural support
2. they adapted by having a layer of durable polymer called sporopollenin which exposed zygotes from drying out

Question 9

the movement of plants to land had what effect on other divergences?

Answer 9

explosion in available habitats and niches

Question 10

the evolution of plants toward land meant what 2 things?

Answer 10

• less dependence on free water
• seed stage more packaged in a protective coat

Question 11

name the 6 shared characteristics between charophyceans and land plants

Answer 11

1. multicellular
2. eukaryotic
3. photosynthetic
4. autotrophic
5. cell wall of cellulose
6. biochemical details

Question 12

What are the 4 derived traits of plants

Answer 12

1. alternation of generations (multicellular dependent embryos)
2. walled spores produced in sporangia
3. multicellular gametangia
4. apical meristems

Question 13

sporangia

Answer 13

tissues that produce spores

Question 14

gametangia

Answer 14

multicellular tissue that produce gametes

Question 15

apical meristems

Answer 15

• actively dividing tissues on the top & bottom of plants
• responsible for vertical growth

Question 16

how does alteration of generations work

Answer 16

1. diploid sporophyte goes through meiosis and becomes haploid spores
2. spores undergo mitosis which become haploid gametophyte
3. haploid gametophyte produces N gametes, sperm and egg which fuse through **fertilization **and form diploid (2n) zygote

Question 17

each turn in the alternation means a new

Answer 17

generation

Question 18

spore walls contain ____ which makes them resistant to harsh environments

Answer 18

sporopollenin

Question 19

gametes are produced within organs called

Answer 19

gametangia

Question 20

female gametangia name and function;

Answer 20

archegonia; produce eggs and are site of fertilization

Question 21

male gametangia name and function;

Answer 21

antheridia; site of sperm production & release

Question 22

sperm travel from where to where; what constraint is there

Answer 22

antheridia to archegonia; **must have water to travel **

Question 23

cells from the apical meristems differentiate into

Answer 23

various tissues

Question 24

Plants diversified into two main types based on what?

Answer 24

presence or absence of vascular tissue (“pipes”)

Question 25

two main types of plants and all subcategories

Answer 25

1. non-vascular plants (bryophytes = mosses, liverworts, hornworts)
2. vascular plants
   a. seedless
   - lycophytes (club mosses and relatives)
   - monilophytes = pterophytes (ferns and relatives)
   b. seed plants
   i. gymnosperms: “naked seed plants”, incl. conifers
   ii. angiosperms: flowering plants

Question 26

what is a seed

Answer 26

an embryo and nutrients surrounded by a protective coat

Question 27

seed plants form a clade; true or false

Answer 27

true