variation and evolution Flashcards
what is species variation?
members of the same species have small differences. (genetic and environmental)
what is genetic variation?
animals and plants inherit genes from the mother and father causing genetic variation. (such as eye colour, blood group, inherited disorders)
what is environmental variation?
conditions an organism lives and grows in causes differences between members of the same species.
what is a mutation?
changes to the sequencing of DNA.
what is survival of the fittest?
organisms with the most suitable characteristics for the environment are better competitors for resources and are more likely to survive.
what is speciation?
the development of new species from natural selection. (when populations of the same species are too different to interbreed)
what is extinction?
a species that doesn’t exist anymore?
why can a species become extinct? (5)
- the environment changes too quickly.
- a new predator kills them all.
- a new disease kills them all.
- they can’t compete with a new competitor.
- a catastrophic event kills them all.
what is selective breeding?
when humans artificially select plants or animals to breed. (so specific characteristics stay in the population)
what is a negative of selective breeding?
less different genes in the gene pool. (inbreeding - if one organism is killed by disease all others will also)
what is genetic engineering?
transferring a gene for a characteristic from one organism into another.
how does genetic engineering work?
- enzymes cut a gene out of the DNA of an organism.
- the gene is inserted into a vector. (such as a virus or bacteria plasmid)
- when the vector is introduced to the target organism the gene is inserted into its cells.
how can plants be cloned? (2)
tissue culture - a few plant cells are put in a growth medium with hormones that grow into new plants.
cuttings - cuttings from parent plants are planted.
how can animals be cloned? (2)
embryo transplants
1. sperm cells and egg cells are artificially fertilised.
2. the embryo is split lots of time before any cells are specialised.
3. the cloned embryos are implanted into other animals.
adult cell cloning
1. taking an unfertilised egg cell and removing the nucleus.
2. the nucleus from an adult body cell is inserted into the egg cell.
3. the new egg cell is electric shocked making it divide.
4. when the embryo is a ball of cells it is put into a womb to grow.
what are the negatives of cloning?
less different genes in the gene pool.
unhealthy clones.
