evidence for the theory of evolution

Question 1

evidence

Answer 1

• 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

Question 2

fossil evidence

Answer 2

• paleontological evidence

- micro and macro evolution

Question 3

how does the fossil evidence show that evolution has occured?

Answer 3

• detailed information of systematic change
• descent with modification
• similarities in fossil types
• example : the modern horse developing from a dog-sized ancestral species

Question 4

what can be seen in the fossil record?

Answer 4

• increased complexity
• increase diversity
• more extinct species
• existence of intermediate forms
• increase in size

Question 5

increasing complexity

Answer 5

• prokaryotes
• eukaryotes
• invertebrates
• fish
• land plants
• amphibians
• reptiles
• mammals
• humans
• cambrian explosion : large diversification of complex, multi-celled organisms

Question 6

increase in diversity

Answer 6

• 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)

Question 7

more extinct species

Answer 7

• 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

Question 8

intermediate forms

Answer 8

• show a link between groups
• groups may give rise to others by evolutionary processes
• mammal-like reptiles (in Karoo)
• archaeopteryx (reptile and bird)

Question 9

does evidence from fossils provide conclusive proof of evolution?

Answer 9

• 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

Question 10

evidence from biogeography to show evolution has occurred

Answer 10

• different regions with similar climatic conditions contained very different animals and plants

Question 11

what were these evolutionary patterns?

Answer 11

• 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

Question 12

biogeography of fossils

Answer 12

• 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

Question 13

evidence from genetics

Answer 13

• 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)

Question 14

comparitive anatomy evidence

Answer 14

• 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

Question 15

embryology

Answer 15

• 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

Question 16

vestigial organs

Answer 16

• homologous structure is functional
• tailbone in humans
• appendix in humans (narrow tube attached to large intestine)