Reproduction Continued

Types of Reproduction Sexual - A from of reproduction in which a new individual is produced is produced by the union of nuclei of two specialized sex cells. Asexual - reproduction with only one parent, the offspring are identical to the parents. Exact genetic copies.

Regeneration The growth of a new tissue or destroyed parts or organs. Example 1 - starfish that loses a ray can grow a whole new one, given time Example 2 - Lizards are also capable of regeneration of lost limbs or tails. When a part of an organism regenerates into a new organism it is asexual reproduction

Sporulation (asexual) Sporulation refers to the process in which any cell of an organism produces one or more reproductive cells inside its cell walls. (spores – reproductive cells) Only found in plants and fungi Most commonly in Bread Molds (fungi)

Binary Fission (asexual) This process replicates the original cell produces two identical daughter cells. Make an exact genetic copy (clone) The cytoplasm splits equally between the two new cells E. Coli bacteria reproduce by binary fission Most commonly done by prokaryotes

Budding (asexual) This process is one cell turns in to a new organism Exact genetic copy (clone) Unequal split of cytoplasm Examples: The hydra produces buds and yeast cells bud to reproduce.

Vegetative Propagation (asexual) It is a process by which new plant "individuals" arise or are obtained without production of seeds or spores. Using a part of the original plant to make a new plant Leaves turn into a new plant Roots extend and turn into a new plant Stem can turn into a new plant The new plants are exact copies of the original plant (clones)

Virus Reproduction A virus cannot reproduce on its own. It needs a host cell to take over and use the organelles in the cell to produce more viruses.

2 types of Fertilization Internal fertilization - when fertilization takes place inside the Female. allows fertilization to occur on land. Watery environment is found inside the female. Humans and land dwelling organisms External fertilization – when fertilization occurs outside of the female. fertilization usually occurs in water Fish and amphibians

Sexual Reproduction Internal Fertilization

Development - Differentiation What happens during this time? Fusion of egg and sperm forms the zygote The zygote undergoes division to increase numbers of cells It becomes more complex It grows in size The cells undergo changes in gene expression and so change with time/place in the embryo; this is called differentiation Differentiation occurs all through development Determination is the process by which an unspecialized cell becomes specialized Some cells do not change; these are stem cells

Nutrients and waste exchange for a growing fetus The umbilical cord and the placenta provide the developing fetus with all of the nutrients it needs The placenta also gets rid of wastes that are produced by the fetus At the placenta the baby’s blood and mother blood never mixes just comes very close to one another to exchange substances (Nutrients and wastes) Harmful materials can also be transported to the developing baby through the placenta if the mother comes into contact with it. (Alcohol, drugs, environmental pollutants)