Chapter 5- Evolution And Biodiversity Flashcards
What is th mechanism of evolution?
By natural selection
What provides evidence for evolution?
The fossil record
There are 3 parts of evidence of evolution, what is the 1st?
1) the sequence in which fossils appear match the sequence in which they would be expected to evolve
Bacteria and simple algae appearing first, fungi and worms and land vertebrates
There are 3 parts of evidence of evolution, what is the 2nd?
2) sequence fits in with the ecology of groups- plant fossils before animals, plants on land before animals
There are 3 parts of evidence of evolution, what is the 3rd?
Many sequences of fossils are known, which link together existing organisms with their likely ancestors
What does selective breeding of domesticated animals show?
That artificial selection can cause evolution
What is artificial selection?
Massive changes between domesticated animals and the wild version of them- explanation is that the change has been achieved simply by repeatedly selecting for and breeding the individuals most suited to human use
What does evolution of homologous structures by adaptive radiation explain?
Similarities in structure when there are differences in function
What is convergent evolutions
There are similarities between structures of animals like fish tales and whales and these are know as analogous structures- when studied there actually very different however interpretation is that they have had different origins and have become similar because the perform the same or similar functions
What are homologous structures do to with evolution
Can look different and perform a different function but they are called a ‘unity of type’ as an example in the forelimbs of humans, bats, horse, mole and porpoise is that they have the same bones in the same relative positions despite on the surface looking very different
What is the evolutionary explanation of homologous structures
Adaptive radiation- they have had the same origin, from an ancestor that had a pentadactyl or 5- digit limbs - become different because they form different functikns
What are rudimentary organs?
Organs that have no use anymore so are gradually being lost
What are the adaptions of amphibians, reptiles, birds and mammals with their pentadactyl Lims?
1) reptiles- crocodiles walk or crawl on land and use their hind limbs for swimming
2) Birds- penguins use their hind limbs for walking and their forelimbs as flippers for swimming
3) Mammals- echidnas use all four limbs for walking and use their forelimbs for digging
4) amphibians- frogs use all four limbs for walk f and hindlimbs for jumping
What can populations of species gradually diverge into?
Separate species by evolution
How can populations of species diverge into separate species?
If two populations of a species become separated so that they do not interbreed and natural selection then acts differently on the two populations, they will evolve in different ways
What is the process of speciation?
Two populations of species, evolve- characteristics gradually become different until they become reconsibly different - if populations merge and do not interbreed it would be clear they have evolved into separate species
What is more evidence of patterns of variation?
Continuous variation across the geographical range of related populations matches the concept of gradual divergence
Explain the development of melanistic insects in polluted areas
Dark variations of typically light coloured insects are called melanistic - examples= Biston betularia- widely used as an example of natural selection- as the melanistic variety becomes better cAmouflaged the then the pale one - why?- they fly at night and try to mate, during the day they’re on trees, birds and other predators hunt during the day etc
When does evolution occur?
When heritable characteristics of a species change
