lecture 1 - evolution Flashcards
how did Darwins theory solve the species relationship problem?
time - the time between a species shared a common ancester, the more recent the similar
- made ppl think as previously they viewed the world as static
what is the problem of design?
Organisms everywhere appear well-adapted for their surroundings
e.g. the arctic fox - when snows has white fur, when no snow - malts its fur so that it can blend into diff environments
what is the problem of design relating to bats?
Bats use echolocation to find prey in the dark – bat has to be able to produce loud high frequency noises – has to be able to receive the reflected sound waves – needs some auditory apparatus, neural apparatus to interpret and determine the distance away it is – needs ability to turn its hearing off when making the echolocation noise so that it doesn’t deafen itself
what is the problem of design relating to whales - vestigial structures?
a whale has a pelvis but they have no need for one
what is a vestigial structure?
something that had a need in the past but doesnt anymore
what did darwin realise about adaptation and vestigiual structures?
Can explain why things are fitted to their environment and these vestigial structures – selection can change but takes a while for the animal to fit its environment
what is darwins theory in a nutshell?
1 - Variation - were all diff
2 - Heredity - passed from parents to offspring
3 - Competition - individuals produce at diff rates
4 - Natural Selection - some ppl will survive better in environments where they are found
what does homologies mean?
similarities between organisms due to common ancestry – e.g. human and whale pelvis
what are analogies?
similarities due to parallel selective pressures – e.g. just living in the same environment – fish, whales, sharks – teardrop shape so that they can move through the water w/o drag
who developed darwins incomplete theory?
Mendel - experiments with pea plants that showed how there was physical properties that moved from one plant to the next
why was darwins theory incomplete?
he didn’t understand heredity and genetics
what is the modern synthesis?
Bringing together of Darwinism and mendels work
what are common objections or misunderstandings?
1 - evolution is just a theory
2 - there are gaps in the record
3 - something like this is to complex to arise by chance
4 - evolution is all about the past, but what I care about is the present
why is ‘ evolution is just a theory’ wrong?
galapagos finches - diff sized beaks, ones with the biggest survived as they could eat the big seeds
- gradual changes slowly add up into big adaptations
why are ‘there are gaps in the records’ wrong?
Should be gaps as fossilisation is a chance production – if it happened to all of us we would have too many fossils
why is ‘something like this is too complex to arise by chance’ wrong?
Echolocation – too complex to arise by chance – natural selection – favours those to survive in a particular environment
Eye – so many diff components – how could you work with half an eye – multiple stages of eye evolution showing that it can evolve gradually – if they hadn’t evolved they would look very diff to how they do today
why is ‘evolution is all about the past, but what I care about is the present’ wrong?
Function of nausea and vomiting in pregnancy is to keep the baby safe
Higher aversions for things that are more likely to have parasites which will harm the baby e.g. meat
