11.1 Reproduction

1
11.1 Reproduction

• 2 types
• Definitions
• Advantages
• Disadvantages
• Examples

2
ASEXUAL REPRODUCTION

• involves a somatic cell (body cell) splitting in
  half by mitosis (each new cell is genetically
  identical to the original).
• result genetically identical offspring (clone)
• the only changes come from mutations.
• 1 parent.
• advantage rapid, efficient, and doesnt rely on
  outside forces.
• disadvantage no genetic diversity ? unable to
  adapt to a changing environment.
• examples bacteria (binary fission), hydra
  (budding), water fleas (parthenogenesis),
  starfish (fragmentation)

3
SEXUAL REPRODUCTION

• 2 parents
• 2 parents each form haploid reproductive cells
  called gametes (produced by germ cells), which
  join (fertilization) to form offspring (zygote).
• meiosis a special type of cell division that
  produces gametes (sex cells) ? egg XX and sperm
  XY.
• meiosis takes each of the parent genes and gives
  them a random shuffle ? this means that the new
  individual has a totally unique combination of
  genes (the offspring will have traits of both
  parents but are not exactly like either parent).
• advantage genetic recombination ? genetic
  diversity ? organisms can adapt to a changing
  environment.
• disadvantage opposite of asexual advantages

4
Definitions

• Homologous chromosomes similar pair of
  chromosomes
• with 1 exception, each pair of chromosomes are
  exactly alike in size, location of the
  centromere, and in banding pattern (same genes!)
• What is the 1 pair that can differ?
  ANSWER THIS QUESTION!!!
• Diploid cell any cell that has 2 complete sets
  of chromosomes (2n) contains both chromosomes
  from each homologous pair ex. somatic cells
• Haploid cell any cell that has only 1 complete
  set of chromosomes (n) contain one chromosome
  from each homologous pair (one from each
  parent) ex. gametes (XY, XX).

5
More

• Meiosis a form of cell division in which the
  of chromosomes is reduced by half.
• reduction division
• parent cell ? daughter cell
• 2n n

6
Karyotype