Bryophyta

Question 1

What are the three main classes of Bryophyta?

Answer 1

The three main classes are mosses (Bryopsida), liverworts (Hepaticopsida), and hornworts (Anthocerotopsida).

Question 2

Where are bryophytes commonly found?

Answer 2

Bryophytes are found on damp banks, trees, logs, bare rocks, and frozen alpine slopes.

Question 3

How do bryophytes absorb water?

Answer 3

Water is absorbed through the surface of the plant as bryophytes lack a vascular system.

Question 4

What is alternation of generations in bryophytes?

Answer 4

It is the life cycle involving a haploid gametophyte phase that produces gametes and a diploid sporophyte phase that produces spores.

Question 5

Which phase is dominant in the life cycle of bryophytes?

Answer 5

The gametophyte phase is dominant in bryophytes.

Question 6

What type of cell wall is found in bryophytes?

Answer 6

Bryophytes have cell walls made of cellulose.

Question 7

Describe the thallus structure in bryophytes.

Answer 7

Bryophytes are thalloid, with undifferentiated bodies resembling leaves or stems but lacking true roots.

Question 8

Why do bryophytes require external water for reproduction?

Answer 8

External water facilitates the movement of flagellated sperm to reach the egg in the archegonium.

Question 9

What are the two main types of liverworts?

Answer 9

Liverworts are categorized into thalloid and leafy liverworts.

Question 10

What is a notable characteristic of thalloid liverworts?

Answer 10

They have a dorsiventrally flattened thallus and grow prostrate.

Question 11

How does Marchantia polymorpha reproduce asexually?

Answer 11

It reproduces via gemmae, which are specialized bud-like structures found in gemma cups on the thallus.

Question 12

What are gemmae, and where are they located?

Answer 12

Gemmae are bud-like propagules found in gemma cups on the thallus surface.

Question 13

What structures develop male and female sex organs in Marchantia?

Answer 13

Male and female gametangia develop on antheridiophores and archegoniophores, respectively.

Question 14

What is the role of the seta in Marchantia?

Answer 14

The seta is a stalk that suspends the sporophyte, aiding in spore dispersal.

Question 15

Describe the process of spore release in liverworts.

Answer 15

The capsule splits open, and elaters twist and untwist to release spores, which are dispersed by wind.

Question 16

What are elaters, and how do they function in liverworts?

Answer 16

Elaters are hygroscopic cells that help in spore dispersal by twisting and untwisting in response to humidity.

Question 17

What is the function of the calyptra in bryophytes?

Answer 17

The calyptra is a protective cap that shields the young sporophyte.

Question 18

How do leafy liverworts differ from thalloid liverworts?

Answer 18

Leafy liverworts have overlapping leaves, while thalloid liverworts have flattened, lobed structures.

Question 19

Where are leafy liverworts most abundant?

Answer 19

They are abundant in tropical forests.

Question 20

What is the protonema, and how does it relate to the life cycle of bryophytes?

Answer 20

The protonema is an early gametophyte stage that develops into a mature gametophyte.

Question 21

Describe the sporophytes of hornworts.

Answer 21

Hornwort sporophytes are elongated, green to black rods that grow from gametophytes.

Question 22

What is the function of rhizoids in bryophytes?

Answer 22

Rhizoids anchor bryophytes to substrates and aid in nutrient absorption.

Question 23

How do hornworts reproduce sexually?

Answer 23

Archegonia and antheridia develop under the gametophyte’s upper surface, where fertilization occurs.

Question 24

What is unique about the chloroplasts in hornwort cells?

Answer 24

Hornwort cells contain one large chloroplast with pyrenoids, similar to green algae.

Question 25

How do bryophytes reproduce asexually?

Answer 25

They reproduce by fragmentation or through structures like gemmae and tubers.

Question 26

Which environmental conditions favor bryophyte growth?

Answer 26

Moist, shaded environments with adequate water availability favor bryophyte growth.

Question 27

What is the significance of pyrenoids in hornwort chloroplasts?

Answer 27

Pyrenoids assist in carbon fixation, enhancing photosynthesis efficiency.

Question 28

Compare haploid and diploid phases in the bryophyte life cycle.

Answer 28

The haploid gametophyte produces gametes, while the diploid sporophyte generates spores.

Question 29

How do hydroids and leptoids contribute to bryophyte physiology?

Answer 29

Hydroids conduct water, while leptoids transport nutrients in some bryophytes.

Question 30

Why are bryophytes considered pioneers in ecological succession?

Answer 30

Bryophytes colonize bare surfaces, aiding in soil formation and facilitating plant succession.

Question 31

What are the genral characteristics of bryophyta?