Lab 6: Alternation of Generations

Question 1

What is the function of SAAF (sperm activating and attracting fator)?

Answer 1

released within the hermaphrodite to bring sperm to the Archegonium

Question 2

What is antheridiogen?

Answer 2

A hormone released that supresses the growth of more hermaphrodyte

Question 3

As gametephyte density increases there should be a _________ % of males.

Answer 3

high

Question 4

What are the three benefits that come from antheridiogen

Answer 4

1. increase cross fertilization and genetic variability
2. decrease competition between hermaphrodytes
3. synchronizes timing for reproduction

Question 5

The larger heart shaped Gametophytes are what sex?

Answer 5

hermaphrodite (both)

Question 6

What are the archegonia?

Answer 6

The female sex organ

Question 7

What is antheridiogen?

Answer 7

a special chemical secreted by the hermaphrodites

Question 8

Why might pheromones like SAAF be necessary for fertilization in plants like ferns but not for conifers?

Answer 8

Plants that have flagella need pheromones because they need to get to a specific place, whereas conifers get to the archegonia by chance.

Question 9

What is chemotaxis?

Answer 9

interactions with phermones that get sperm to the egg

Question 10

What types of cells are produced in the antheridia?

Answer 10

sperm

Question 11

What is the function of the water applied to the gametophytes? How is this adaptive?

Answer 11

Sperm need to swim and water is needed to activated SAAF, which is beneficial because it means that fertiliztion will not occur uncless condition are right

Question 12

In these plants, manilophyta, what happens when the sperm fertilizes the egg? (What does it turn into?)

Answer 12

A sporophyte

Question 13

Is it normal to have a much lower number of gametophytes than spores?

Answer 13

yes, many spores will not germinate

Question 14

What could be the reasons for germination of some spores and not others?

Answer 14

moisture and temperature

Question 15

What could be the reason for more gametophytes than spores when counted?

Answer 15

spores are small and there is a good chance they were not seen until their gametophyte stage

Question 16

What is the predicted relationship between spore density and gametophyte germination?

Answer 16

That as spore density increases gametophyte germination will increase as well.

Question 17

What was the reason that in lab there were so many hermaphroditic gametophytes instead of only a few in the area?

Answer 17

All the seeds were planted at the same time and because of this the hermaphrodite was not able to mature enough to let off enough antheridiogen to stop other gametophytes from forming

Question 18

Where are the archegonias located on the hermaphrodite?

Answer 18

The cooch. (in between the crack of the glove)

Question 19

What is the cooch of the hermaphrodite called?

Answer 19

The notch meristem

Question 20

How do sperm cells find their way to the archegonia and ultimately to the egg cell at the base?

Answer 20

via SAAF and they swim there