Chapter 21

Question 1

Females

Answer 1

individuals that produce large gametes

Question 2

Males

Answer 2

individuals that produce small gametes

Question 3

Gametes

Answer 3

specialized sex cell (sperm and egg in humans) that contain half as many chromosomes as other body cells and is therefore haploid

Question 4

Gonads

Answer 4

the male and female sex organs; testicles in human males or ovaries in human females

Question 5

Ovaries

Answer 5

produce eggs in females

Question 6

Testes

Answer 6

produce sperm in males

Question 7

Zygote

Answer 7

results from the fusion of two gametes

Question 8

Gametogenesis

Answer 8

the production of gametes

Question 9

Menstrual Cycle

Answer 9

the cyclic changes in the uterus in response to hormones

Question 10

Menstruation

Answer 10

the sloughing off of the endometrial lining in response to no fertilized egg

Question 11

Development

Answer 11

the series of events that take place after fertilization

Question 12

Cleavage

Answer 12

the period of rapid cell division that occurs during animal development

Question 13

Embryo

Answer 13

the development stage commencing after the first mitotic divisions of the zygote and ending when body structures begin to appear; from about the second week after fertilization to about the ninth week

Question 14

Ectoderm

Answer 14

the outer layer and gives rise to the skin, nervous system, and sense organs

Question 15

Mesoderm

Answer 15

the middle layer and gives rise to the bulk of the body

Question 16

Endoderm

Answer 16

the inner layer and gives rise to the digestive and respiratory organs.

Question 17

Placenta

Answer 17

membrane produced by a developing fetus that releases a hormone to extend the life of the corpus luteum