AIM: How Is Internal Fertilization and Development Different from External Fertilization and Development

Sexual Reproduction: Sperm A fertilized egg cell is called a Zygote Characteristics of Sexual Reproduction: 1)Is the creation of a new individual from parents 2 2) Offspring are not genetically to the parents identical Egg Zygote Fertilization

INTERNAL FERTILIZATION Eggs and sperm meet inside the female’s body Occurs in most land vertebrates Ex. Reptiles, birds, mammals

EXTERNAL FERTILIZATION Eggs fertilized outside female’s body Occurs mostly in aquatic environments –Ex. Fish, amphibians HAZARDOUS – many eggs and sperm are produced so some survive Eggs and sperm may not meet, they may be eaten or environmental conditions may change

Embryonic Development An embryo is a developing offspring. Development can be either INTERNAL or EXTERNAL, depending on the organism.

What is the difference between internal and external development? What is the difference between internal and external fertilization?

INTERNAL DEVELOPMENT Embryo develops inside the female, placenta provides nourishment

Human Fertilization Internal fertilization – male penis is used to introduce sperm into female’s vagina.

Where does fertilization usually occur? Fertilization occurs in the fallopian tubes (oviduct)

How many eggs are released a month by a female? Normally one egg is released per month, however, sometimes TWO can be released at the same time. Ovulation

What happens after fertilization? The embryo travels to the uterus and implants itself in the uterus lining