Development and Differentiation

An egg and a sperm cell combine in the process called… …Fertilization - results in genetic recombination Egg cell (haploid) Sperm cell (haploid) Zygote (diploid)

After fertilization, the zygote divides by mitosis MITOSIS DIFFERENTIATION BEGINS the zygote divides by mitosis

After mitosis… The cells begin to take on specific functions. This process is called differentiation. leads to the various cell types Ex. blood cells, kidney cells, and nerve cells

As a result Every cell of an organism has the same DNA But depending on the cell type, some genes are turned on and which are turned off This is called gene expression

Each cell has a full cookbook Pull out and make one recipe

Gene expression can change due to signals from inside and outside the cell Hormones Temperature Chemicals

In the alligator snapping turtle (bottom left), more males develop at moderate temperatures than very cool or very warm ones. But temperatures at which maleness is determined varies among species.

Human Development Embryonic development occurs in the uterus After 2 months the major organs have formed and the embryo becomes a fetus

The placenta allows for the diffusion of nutrients, oxygen and waste between mother and baby

Sonogram

This is when the baby is most susceptible to damage. In the early stages of pregnancy, when the baby’s major organs are not fully developed This is when the baby is most susceptible to damage. The following can interfere with the baby's development: Alcohol prescription and recreational drugs Infection Nutritional deficiencies X-rays or radiation therapy

Reproductive Technology help some couples to become pregnant In vitro fertilization (IVF) Egg donors Sperm donors Surrogate