Reproduction Flashcards
reproduction
an organism’s ability to produce offspring that resemble it
sexual reproduction
requires two individuals who produce gametes
Asexual reproduction
organisms reproduce exact copies of themselves-no need for gametes-no genetic var, unless mutation
vegetative reproduction (no seed required)
through runners-a stem that runs along the ground- has buds
Cell division
all cells in living organisms are a result of cell division-makes growth & regeneration possible
stem cells
potential to turn into other cells: can divide (same) & differentiate(other cells)
Mitosis
cells create new copies of themselves
1. cell copies chromosones inside nucleus
2. sister chromatids detach-go to different sides of cell
3. nuclear envelopes for arnd them
4. cell membrane formed between cell divides
mitosis occurs when
- asexual reproduction
- injury healed by reproduction of cells
- multicellular organism develops
- fertilized ovum begins to develop
pollination & fertilization
genomes of gametes joined together in fertilization = form diploid (zygote)
External pollination->outside female: fish & frogs
Internal pollination-> genomes joined together inside female
Meiosis
process of producing gametes (sperm & egg cells)
1. replicate dna replicate each of 23 chromosones x shape
2. line up in centre in random order
3. cell splits with random set of chromosones=>first division
=> second division
1. chromosones line up at center and two arms of c go to opposite side- are split apart
2. four cells(gametes)
=> haploids (23 chromosones)
chromosones
contain genetic info
=> two copies 23(paternal) & 23(maternal)
Asexual (yay nd nay)
yay: fast reproduction- saves energy and efficient
nay: no genetic variation - vulnerable to changes in environment
sexual(yay nd nay)
yay: increases survival and reproduction in changing environment - genetic variation – EVOLUTION
nay: uncertain nd slow- large amount of material & energy- finding partner & competition
