evolution and variation (ch12) Flashcards
what does the theory of evolution state
that all species evolved from simple life forms that developed 3 billion years ago
what was lamarcks theory
inheritance (genetically passing on) of acquired characteristics and characteristics that arent used eventually disappear
why is lamarcks theory false
implies that all organisms gradually become more complex and simple organisms disappear
what is darwins theory
genetic variation -> too many organisms need to compete for food and water -> natural selection (those who are best adapted survive)-> animals best adapted for environment have the most competitive environments -> more likely to survive and pass on allele
what is mutation
a change in genetic material
what is natural selection
process by which evolution takes place and only those who are most fitted to the environment survive (peppered moth example)
what is variation
any difference between individuals in a species
how do you answer a 6 mark natural selection question
1)start with mutation
2) competitive advantage (state what it is and how it helps them)
3)more likely to survive and reproduce to pass on allele
4)specify answer to example
define species
a group of organisms with similar characteristics and interbreed to produce fertile offspring (donkey+horse are infertile since theyre seperate species)
how do species change
-when small populations become isolated to a different environment by:
1) geographical isolation (ex: island formation or mountain ranges)
2)deforestation
3) construction of new roads
how does speciation occur
1) small population becomes geographically isolated
2) different environmental conditions they must adapt to
3) mutation -> variation in new population
4)new population can no longer interbreed with the old one and produce a fertile offspring
how do animals adapt in cold climates
larger than usual to have a small SA:V and reduce energy transfer
very insulated blubber from the inside and thick fur coat on the outside
huddle to reduce exposed surface area
how do animals benifit from camouflage
-predators avoid being seen by prey and prey hide from predators
how do animals adapt in hot and dry climates
-large SA:V to transfer as much energy to environment as possible
-dont sweat often to reduce water loss
-thin fur and little body fat to make it easier to transfer energy and cool down
what happens if plants are in hot and dry conditions
photosynthesis and respiration take place too rapidly and the plant looses water
how do plants change their surface area to adapt to environments
-broad leaves with large surface area collect dew
- most animals in dry areas have a small sa:v ratio and curled leaves to cut down on water loss
how do cuticles help plants adapt to their environment
they have a waxy layer coating the leaf that stops water from evaporating
how are cacti adapted to suit their environment
leaves are reduced to spikes that discourage animals from eating them and they have a large spine full of water storage tissue
how do plants collect water
they often have a large root sytem to absorb as much water as possible from the soil
what happens if organisms loose to their competitors
they either die , migrate or find a new stratigy
what are the 4 main things animals compete for
water
food (prey compete not to be eaten and predators compete for prey)
why is it a problem when animals only have 1 food source
all animals in the same species need to compete for it (intraspecific)
why do animals need their own territory
so they can have more space to breed and increase their species
what is meant by intraspecific
when animals from the same species compete for resources
