Asexual vs. Sexual
lots of offspring quickly, large colonies can form to out-compete, lots=many may survive if conditions change, less energy |
disease/mute=death, compete for food and space, bad condition=wiped out |
genetic diversity, ext: little energy to mate, more offspring can exist after disaster, int: more protection and care |
int: more energy/risk to mate, fewer produced, ext: gams,embryos, offs are unprotected |
DNA
Chromatin |
condensed DNA |
Chromosomes |
condensed chromatin |
Nitrogen bases |
"steps of DNA"; a with t, c with g |
Homologous pairs |
chromes that are the same shape, size, have same genetic info in same spot; one from ea. parent |
asexual reproduction
binary fission |
mitosis in prokaryotes |
budding |
buds in multicelluar can detach through repeated mitosis and form separate org. |
frag. |
part of multicelluar breaks off due to injury and becomes separate org. |
veg. |
stems, leaves, or roots are used to asex. repro. |
spores |
spores grow into new org. |
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Mitosis
Interphase |
Cell grows and develops/ DNA replication |
Prophase |
Spindle fibres attach to centromeres/nuclear membrane disappears |
Metaphase |
Chromosomes align at equator |
Anaphase |
Sister chromatids pulled to poles |
Telophase |
Fibres disappear/ nuclear membrane re-appears |
Cytokenisis |
contents of cell evenly divides |
DNA replication
During late interphase Dna unwinds with enzymes/ bases are paired with new bases. |
Fertilization: Pros and Cons
external |
very little energy mate, lots of offspring, spread widely in evrionment (less comp.) |
many gametes die, many eggs aren't fertilized, offspring are unprotected |
internal |
embryo protected, offspring's parents will protect |
more energy, fewer zygotes, more energy to raise |
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Meiosis
Prophase 1 |
Homo chromes pair |
(crossing over) |
Metaphase 1 |
Homo chromes align on opposite sides of equator |
Anaphase 1 |
Homo chromes pulled to opposite poles |
(Indep. assortment) |
Telophase 1/2 |
Cell divides into 2 then 4 cells |
Anything that's homologous is in meiosis1. Otherwise, it's the same as mitosis.
1st 8 weeks of embryo development
morula |
week 1 (end) |
ball of cells |
blastula |
week 2 (end) |
hollow ball of cells, cell can develop to any kind |
gastrula |
3 layers of cells (differentiation) |
ecto: skin/ nerves, mes: muscles/bones, end: lungs/liver/digestive system lining |
stages of sexual reproduction
mating |
egg and sperm come together at same time and place |
fertilization |
gametes fuse to create a zygote |
development |
embryo develops |
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