42.1
How Do Animals Reproduce Without Sex?
897
Budding and regeneration produce new
individuals by mitosis 897
Parthenogenesis is the development
of unfertilized eggs 898
42.2 How Do
Animals Reproduce Sexually? 899
Gametogenesis produces eggs and sperm
899
Fertilization is the union of sperm
and egg 901
Mating bring eggs and sperm together
903
A single body can function as both
male and female 904
The evolution of vertebrate reproductive
systems parallels the move to land
904
Reproductive systems are distinguished
by where the embryo develops 905
42.3 How Do the Human Male and Female
Reproductive Systems Work? 906
Male sex organs produce and deliver
semen 906
Male sexual function is controlled
by hormones 909
Female sex organs produce eggs, receive
sperm, and nurture the embryo 909
The ovarian cycle produces a mature
egg 910
The uterine cycle prepares an environment
for the fertilized egg 911
Hormones control and coordinate the
ovarian and uterine cycles 911
In pregnancy, hormones from the extraembryonic
membranes take over 912
Childbirth is triggered by hormonal
and mechanical stimuli 912
42.4 How Can Fertility Be Controlled
and Sexual Health Maintained? 913
Human sexual responses have four phases
913
Humans use a variety of methods to
control fertility 914
Reproductive technologies help solve
problems of infertility 916
Sexual behavior transmits many disease
organisms 917
