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14 Cards in this Set
- Front
- Back
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Impact of changes in physical conditions on evolution? |
-Australia. Increased temperature and decreased rainfall resulted in more woodlands and grasslands. Ancient kangaroo had to develop high crested molars to grind the tougher vegetation -England. Industrial revolution polluted environment causing sooty backgrounds for peppered moths to hide in. Light coloured ones died and dark ones passed on genes. |
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What chemical changes impacted on evolution? |
-Insecticides producing DDT resistant mosquitoes and blowflies resistant to dieldrin and organic phosphates -Increase in soil salinity resulting in plants that tolerate salinity eg saltbush to thrive over less tolerant -Rabbits and myxamatosis |
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How has competition for resources impacted evolution? |
-Native species die out due to competition with introduced species eg European rabbit and bilby, Bitou bush and the Acacia. -Populations change behavioral patterns such as breeding to avoid direct competition. This can produce sub-species such as different types of fruit flies confined to a specific tree. |
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How is evolution supported by paleontology? |
-Living organisms have changed over time -Radioactive dating shows how old fossils are. This can be used to show how a species has changed -There is a gradual change from simple to complex life, indicating development of life on earth as a gradual unfolding (apart from Cambrian explosion) |
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How is evolution supported by transitional forms? |
-Organisms that indicate development from one group of organisms to another eg fish to amphibians these are between stages of evolution. -The crossopterygian fish has bones in its fins, suggesting it could 'walk' on land. -Archaeopteryx was a flying dinosaur with feathers. Mixture of reptile and bird characteristics. |
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How is evolution supported by biogeography? |
-Barriers like seas prevent interbreeding therefore new species may be produced. -Cassowary, ostrich and kiwi all have common DNA, suggesting common ancestor despite being on other parts of the world. Each adapted to their niche -Proteaceae family plants found in both Australia and South Africa. |
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How is evolution supported by comparative embryology? |
-All vertebrates posess throat gill pouches at some stage of development -Basic vertebrate pattern of six pairs of aortic arches is modified later during development |
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How is evolution supported by comparative anatomy? |
Common structures suggest common ancestry -Pentadactyl limb. Five finger like bones with two lower limb bones. Most land vertebrates possess this. Believed to be from lobe-finned fish. -Xylem. Ferns, conifers and angiosperms all have xylem. |
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How is evolution supported by Biochemistry? |
Many animals possess similar molecules- haemoglobin, RNA, hormones. -Assessing compatibility of blood, amino acid sequencing and DNA hybridisation help identify relationships. |
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What is Darwin / Wallace's theory of evolution by natural selection and isolation? |
-In any population there is variation. Organisms with favuorable characteristics survive in greater numbers and reproduce and pass on these characteristics -The next generation will have more of these characteristics. Over time they will become more common and therefore better adapted to environment. -This may result in a new species being formed. E.g. Darwin's 14 species of finches. |
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What is divergent evolution? |
Divergent evolution is the change in a population over time so that different groups arise from a common ancestor. Eg Darwin's finches. |
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What is covergent evolution? |
Convergent evolution is when organisms that are not closely related develop similar traits due to their similar environments -E.g. sharks, dolphins, seals, penguins and turtles all have streamlined bodies and fins/flippers. |
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How would you model natural selection? |
Coloured toothpicks represented organims with a certain colour. These were scattered on the grass and had to be picked up within 30 seconds (this is a predator). It was found that orange toothpicks were chosen the most and green the least. |
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What technologies have contributed to understanding evolution? |
-DNA hybridisation allows scientists to determine genetic similarity, mapping out evolutionary pathways more accurately. -Amino acid sequencing. Studies on haemoglobin show that four polypeptides is identical for humans and chimpanzees. |
