6.1 reproduction and stuff

Question 1

meiosis overall definition

Answer 1

cell division that takes place in the reproductive organs of animals and plants
results in the production of sex cells (gametes), with only half the orginal number of chromosomes, so they are called haploid cells

animal gametes = eggs and sperm
plant gametes =eggs and pollen

Question 2

meiosis happening

Answer 2

male and female gametes fuse to fomr a zygote, which then divides by mitosis to form an embryo
chromosomes line up, pulled apart, then line up again, pulled apart
so 4 gentically unique daughter cells, 2 divisions

Question 3

mitosis vs meiosis

Answer 3

one cell division, vs 2 cell divisions
both chromosomes replicate, which copies the genetic information
2 daughter cells produced, vs 4
asexual reproduction vs sexual reproduction
genetically identical cells ,vs genetically unique cells
produces diploid cells, vs haploid cells
one cell division vs 2

Question 4

asexaul reproduction

Answer 4

mitosis
in bacteria, asexual reproduction = binary fission

no fusion of gametes
one parent only
rapidly produce many offspring
all offspring are clones

advantages: rapidly colonise an area if well-adapted to the environment

disadvantages: all offspring are clones so all vulnerable if environment becomes unfavourable (climate change, new pathogen)

Question 5

sexual reproduction

Answer 5

two parents, fusion of gametes to combine genetic information from a male and female organism
lots of variation in the offspring due to meiosis (chromosomes assort themselves randomly into gametes) and fertilisation (it is random which sperm fertilises which egg)

survival advantage when there is environmental change, e.g. new disease—some individuals resistant, and some not resistant so only some would survive instead of none

Question 6

asexual vs sexual reproduction

Answer 6

one parent needed so less energy required, vs two partes are needed so more time and energy required
no genetic variation in offspring vs genetic variation in offspring occurs
noevolutionary advantage as all offspring are genetically identical, vs a survival advantage due to natural selection from the varied offspring
reproduction is faster so many offspring can take advatage of favourable conditions, vs reproduction is slower
only involves mitosis, vs involoves meiosis
no fusion of gametes, vs fusion of gametes