evidence for the theory of evolution Flashcards
1
Q
evidence
A
- fossil records
- biogeography
- DNA and molecular biology
- Homologies and comparative anatomy
- embryology
- vestigial organs
- biodiversity
- physiology
- develop detailed histories of evolution in organisms
- demonstrate evolutionary relationships
2
Q
fossil evidence
A
- paleontological evidence
- micro and macro evolution
3
Q
how does the fossil evidence show that evolution has occured?
A
- detailed information of systematic change
- descent with modification
- similarities in fossil types
- example : the modern horse developing from a dog-sized ancestral species
4
Q
what can be seen in the fossil record?
A
- increased complexity
- increase diversity
- more extinct species
- existence of intermediate forms
- increase in size
5
Q
increasing complexity
A
- prokaryotes
- eukaryotes
- invertebrates
- fish
- land plants
- amphibians
- reptiles
- mammals
- humans
- cambrian explosion : large diversification of complex, multi-celled organisms
6
Q
increase in diversity
A
- old fossil rocks contain low diversity
- younger fossil rocks contain high diversity
- cladogenesis : newer organisms descended from common ancestors formed by branching a variety of modified descendents
- novelties / key innovations : development of a new genera and species (bony skeleton; four limbs; amniotic eggs; feathers; hair)
7
Q
more extinct species
A
- natural phenomenon
- no adaptation to changing environment
- species die and are replaced by later forms
- 1 to 10 million years to become extinct
- 99.9% of species to ever live are extinct
8
Q
intermediate forms
A
- show a link between groups
- groups may give rise to others by evolutionary processes
- mammal-like reptiles (in Karoo)
- archaeopteryx (reptile and bird)
9
Q
does evidence from fossils provide conclusive proof of evolution?
A
- very few individuals become fossils
- hard-bodies organisms more likely to become fossils
- most fossils are of aquatic form
- are informational enough to show descent with modification
- shows a specific order and no reverse in times of origin
10
Q
evidence from biogeography to show evolution has occurred
A
- different regions with similar climatic conditions contained very different animals and plants
11
Q
what were these evolutionary patterns?
A
- clustering pattern of ‘closely allied’ species : eg. zebra species in Africa
- very different collections of plants and animals in regions with similar conditions : eg. Old World Monkeys with narrow noses and downward facing nostrils; New World Monkeys with broad noses with outward facing nostrils
- distribution of species on oceanic islands : strong evidence of descent by modification
12
Q
biogeography of fossils
A
- extinct species fossil similarly resembled those of living animals in the region : eg. megatherium and the sloth
- Wallace’s line : a line separating north and south Malay archipelago describing a separation in organisms from movement showing two descent by modification groups
13
Q
evidence from genetics
A
- comparing chromosomal and mitochondrial DNA
- all organisms have descended from a common ancestor
- organisms are related very closely : all organisms have DNA and RNA; genes encoded to make identical proteins
- organisms are related to each other by varying degrees : more sequences shared, closer related vice-versa
- eg. Chimpanzees and humans (cytochrome similarity)
14
Q
comparitive anatomy evidence
A
- internal and external structures
- homologies (acquired features)
- homologous structures must be similar in fundamental structure, position and development
- divergent or adaptive radiation evolutionary paths : amphibians, aves, mammals all shared common ancestor and had same bones
- analogous structure : similar in different organisms as a result of evolving in similar environments
- convergent evolution : not similar ancestors but similar environments : eg. Bats and insects
15
Q
embryology
A
- hard to tell difference between embryos of fish, bird, pig and human
- supports common ancestor
- nerve cord that becomes spinal cord
- gill slits
- fish-like heart
- tail
