Sexual Reproduction

What is the difference between internal and external fertilization?

Internal fertilization: the egg is fertilized inside the mother External fertilization: the egg is fertilized outside the mother

What are the layers of the gastrula?

1. Ectoderm- skin and nerves 2. Mesoderm- muscles and bones 3. Endoderm- lungs, liver, lining of digestive system

How is an embryo formed? What conditions need to be met?

1. Embryo- enough nutrients 2. Correct temperature 3. Enough moisture so the embryo doesn't dry out 4. Embryo: protected from predators or harmful items in environment

What are the advantages of internal fertilization?

1. Embryo- protected 2. Offspring are more likely to survive

What are the advantages of external fertilization?

1. Little amount of energy required to mate 2. Lots of offspring 3. Offspring can be spread in the environment without competition

What are the disadvantages of external fertilization?

1. Many gametes won't survive 2. Many eggs aren't fertilized 3. Offspring aren't protected and may die

What are the 3 stages of SR? Explain each step.

1. Mating: gametes are brought together at the same place and time 2. Fertilization: egg and sperm join to form a new organism 3. Development: organisms develops as an embryo

What are the disadvantages of internal fertilization?

1. More energy required to find mate 2. Less zygotes- less offspring 3. More energy required to raise offspring

In vitro fertilization (IVF)?

1. When fallopian tubes are blocked eggs and sperm can't meet 2. Egg and sperm are collected in a petri dish 3. Lots of embryo's are implanted so theres a better chance of success 4. Up to 1/3 survive

What is fetal development?

Cell layers differentiate into organs and tissues there are 3 stages: 1. First trimester (0- 12): organs system begin to develop, bone cells form 2. Second trimester (12- 24): Rapid growth from 12-16 weeks 3. Third trimester (24+): Continues growth especially of brain. Fat begins to deposit at 32 weeks to keep baby warm at birth

What is embryonic development and what are the stages?

ED is the early development of an organism (humans- first 2 months after fertilization) 1. Ball of cells- morula 2. Hollow ball of cells- blastula 3. Can develop into any type of cell- stem cells 4. Three layered embryo- gastrula

Gamete intrafallopian transfer (GIFT)?

Egg and sperm are mixed then injected into female and fertilized inside

Intracytoplasmic sperm injection (ICSI)?

Single sperm cell is injected into egg cell, the fertilized egg in than inserted into the woman's uterus

What is artificial insemination (AI)?

Sperm collected from male and injected into the female