Forms of Selection

•Disruptive Selection

–Selection eliminates intermediate types.

•Directional Selection

–Selection eliminates one extreme from a phenotypic array.

•Stabilizing Selection

–Selection acts to eliminate both extremes.

•Fitness - Number of surviving offspring passed to the next generation.

Asexual and Sexual Reproduction

•Asexual reproduction occurs when genetically identical cells are produced from a single parent cell by mitosis.

–Fission or Budding

•Sexual reproduction occurs when a new individual is formed through the union of two sex cells (gametes).

–Produce zygote.

–Haploid gametes formed by meiosis in sex organs (gonads).

Asexual and Sexual Reproduction

•Different Approaches to Sex

–Parthogenesis - Virgin birth

•Exclusive

•Switching

–Hermaphroditism - Both Sex organs

•Sequential

–Protogyny

–Protandry