chapter 26.2

Question 1

the cuticle

Answer 1

a coating of waxy lipids that retards water loss

Question 2

stomata

Answer 2

small closable openings in leaves and stems that are used to regulate gas exchange and water loss

Question 3

gametangia

Answer 3

multicellular organs that enclose plant gametes and prevent them from drying out

Question 4

embryos

Answer 4

young plants contained within a prote4ctive structure

Question 5

pigments

Answer 5

that afford protection against the mutagenic ultraviolet radiation that bathes the terrestrial environment

Question 6

spore walls

Answer 6

containing a polymer that protects the spores from desiccation and resists decay

Question 7

mutually beneficial association with fungi (mycorrhizae)

Answer 7

that promotes nutrient uptake from the soil

Question 8

spores

Answer 8

that develop into multicellular haploid organisms

Question 9

sporangia

Answer 9

cells contained within specialized reproductive organs of the sporophyte

Question 10

gametophyte

Answer 10

multicellular haploid plant , produces haploid gametes by mitosis

Question 11

gametangia

Answer 11

eventually gametes form within specialized sex organs

Question 12

archegonium

Answer 12

is a multicellular , flask shaped female sex organ that produces a single egg

Question 13

antheridium

Answer 13

is a male sex organ in which sperm , each bearing two flagella are produced in large numbers

Question 14

liverworts

Answer 14

have left gametophytes

Question 15

mosses

Answer 15

the most familiar of the nonvascular land plants

Question 16

stomata

Answer 16

are a synapomorphy of mosses and all other land plants except liverworts

Question 17

peat

Answer 17

partially decomposed plants matter

Question 18

hornworts

Answer 18

sporophytes look like little horns

Question 19

explain what is meant by “alternation of generations” . why do we not use this phrase for humans ?

Answer 19

“alternation of generations” refers to a life cycle in plants where they switch between two forms: a sporophyte(which makes spores) and a gametophyte 9which makes gametes. These to generations alternate in the plants development. Humans don’t have this cycle because we only exist in one form , producing gametes that directly combine to form a new individual. In plants , the gametes and spores develop into distinct alternation phases of the life cycle

Question 20

describe key adaptations of plants to the terrestrial environment , and describe the distribution of those adaptations among the liverworts , mosses and hornworts

Answer 20

key adaptations of plants to the terrestrial environment include the development of a waxy cuticle to prevent water loss, stomata for gas exchange , and structures like roots and vascular tissues for support and nutrient transport. Liverworts have a simple cuticle and some lack stomata, while mosses and hornworts have both cuticles and stomata , though none of these groups have true vascular tissue like tiger plants. These adaptations allow them to survive in moist environments , but they remain limited to areas with sufficient weather