Principles of Development

Question 1

Gametogenesis

Answer 1

formation of gametes

Question 2

where is the germ plasm formed?

Answer 2

originally form in yolk sac in vertebrates. millions of diploid cells start on the outside. haploid cells are then created working their way one. only thousands remain. females keep a 1:1 meiosis ratio. males keep 4:1 meiosis ratio

Question 3

What does the germ plasm end up forming?

Answer 3

gametes & the gonads

Question 4

spermatogenesis

Answer 4

formation of sperm

Question 5

where is sperm released?

Answer 5

seminiferous tubules of testes

Question 6

spermatoza

Answer 6

mature sperm

Question 7

oogenesis

Answer 7

formation of eggs

Question 8

oogonia

Answer 8

undeveloped eggs

Question 9

eggs are supported by…

Answer 9

follicle cells (nurse cells) they surround, support, and defend

Question 10

when are eggs released?

Answer 10

ovulation

Question 11

telolecithal oocytes

Answer 11

has much yolk. (birds reptiles, some fish)

Question 12

isolecithal oocytes

Answer 12

has little yolk (starfish, mammals)

Question 13

mesolecithal oocytes

Answer 13

has intermediate (amphibians, some fish)

Question 14

what creatures use external fertilization?

Answer 14

frogs, fish

Question 15

internal fertilization happens where?

Answer 15

in ovarian tubules in mammals

Question 16

who stores sperm ?

Answer 16

invertabrate females

Question 17

sea urchins disparity of gametes

Answer 17

females - 4 million eggs per batch

males- 100 billion sperm per batch

Question 18

human disparity of gametes

Answer 18

females- usually one egg at a time

males- 100 billion sperm at a time

Question 19

important aspect of natural selection:

Answer 19

many sperm never reach an egg

Question 20

first step of sperm penetration

Answer 20

loss of protective coverings on head of sperm

Question 21

what must occur before fertilization is possible

Answer 21

loss of protective covering on head of sperm

Question 22

what part of the sperm contains the DNA

Answer 22

the head

Question 23

one method some sperm use to penetrate the egg

Answer 23

use of enzymes

Question 24

polyspermy

Answer 24

one egg being fertilized by several sperm

Question 25

embryological stages

Answer 25

egg, zygote, clevage, morula, blastula, gastrula, neuralation

Question 26

clevage

Answer 26

early mitotic division , rapid and well organized, average cell size becomes smaller

Question 27

Types of cleavage

Answer 27

hoboblastic | discoidal meroblastic

Question 28

hoboblastic

Answer 28

type of cleavage in microlecithal eggs throughout the embryo in sea urchins and amphibians

Question 29

discoidial meroblastic

Answer 29

type of cleavage in telolecithal eggs. cleavage is incomplete in yolk. embryo forms a small disc on surface of yolk in birds, reptiles, and mammals.

Question 30

morula

Answer 30

stage of embryonic development where the embryo is a solid ball of cells

Question 31

blastula

Answer 31

stage of embryonic development where the embryo is a hollow ball of cells. the internal cavity is blastered, size of blastocoel is smaller with more yolk, restriction of cells fates beginning

Question 32

gastrula

Answer 32

stage of embryonic development where surface cells often sink through pore called blastopore. much taxonomic significance. then the rearrangement of cells into the three germ layers

Question 33

blastopore

Answer 33

forms mouth or anus

Question 34

the three germ layers

Answer 34

ectoderm (outside), mesoderm, endoderm

Question 35

when do the three germ layers form?

Answer 35

gastrula

Question 36

neuralation

Answer 36

the last stage of embryonic development. neural tube forms into the central nervous system. cells are smaller than originals.