Evolution

Enduring Understandings

1. The theory of evolution is now widely accepted due to many forms of scientific evidence.

2. A species evolves over time due to characteristics being favoured by selection pressures increasing the chance of survival. It is not individuals that change.

3. Genetic diversity helps a species to survive changes in selection pressures due to variation that already exist in populations.

4. Evolution is ongoing.

5. Humans may be able to assist in the conservation of species by understanding the impact of selection pressures on species.

Students will know:

1. A species is defined as organisms with similar characteristics that can reproduce and produce fertile offspring. (MS)

2. Speciation is the formation of a new species. (US)

3. Charles Darwin proposed the theory of evolution after many scientific studies of organisms including finches. (R)

4. Darwin's theory includes the theory of "the survival of the fittest" which involves only the organisms with characteristics that enable them to survive in their environment passing on their genes to the next generation. (R)

5. The “fittest” means that certain characteristics favour survival. (MS)

6. Natural selection is the process by which favoured characteristics increase the likelihood of survival in the presence of certain selection pressures. (R)

7. The first understanding of natural selection is that variation exists in a population. (M)

8. Selection pressures are environmental factors (abiotic and biotic) that determine whether characteristics are favourable for survival. (MS)

9. Some religious beliefs and the theory of evolution opposed each other and thus religion and most of society put up much resistance to the theory of evolution. (R)

10. The theory of evolution become the accepted theory as more evidence has been uncovered over time. (EA)

11. The evidence of evolution includes fossils, anatomical similarities, embryology, biogeography, and genetic relatedness. (MS)

12. Fossils exist as actual remains, hard parts of the organism, impressions or indirect evidence such as footprints. (MS)

13. Fossilisation requires remains being quickly covered with sediment and a lack of oxygen. (M)

14. Fossils can be dated using relative dating and dating using radioactivity. (MS)

15. Relative dating estimates the age of the fossil by layer of earth it is in and using the other fossils also in that layer. (R)

16. Dating using radioactivity is more accurate than relative dating. (US)

17. Dating using radioactivity estimates the age of fossils by comparing the ratio of the radioactive isotopes to other isotopes. (M)

18. Biogeography is the process of studying the geographical distribution of living species and fossils, used as evidence of evolution. (U)

19. Plate tectonics is the moving of the tectonic plates and the distribution of fossils, animals and geological substances has allowed this to be mapped. (R)

20. Related species often have similar structures (anatomically similar) so comparative anatomy can be used as a way of determining relatedness (R)

21. Homologous structures are similar structures that are found in different organisms that indicate a common ancestor. (MS)

22. The pentadactyl limb is an example of a homologous structure - wings, arms, fins. (R)

23. Anatomical structure relates closely to function. (R)

24. Vestigial structures are anatomical structures that are no longer used but remain. (US)

25. Vestigial structures may be similar to functioning structures in other species and can indicate a common ancestor. (R)

26. At different stages of embryo development, similarities can be observed between species. (R)

27. Comparative embryology involves comparing embryos at different stages and similarities indicate a common ancestor. (R)

28. The greater percentage of amino acids (in a protein) or DNA bases in common between species, the more closely related the species are. (R)

29. Divergent evolution is when members of a species are separated (usually a geographical barrier) and can't interbreed, so they evolve differently due different selection pressures. e.g. Darwin's finches (R)

30. Phylogenetic trees show the speciation events over time and provides information on the relatedness of species - the more recent the branching the more closely related. (M)

31. The lengths of lines in a phylogenetic tree represent time. If the line doesn’t continue to the present day the species underwent extinction. (M)

32. Convergent evolution is when unrelated species have similar characteristics due to a common environment. e.g. fins of sharks and dolphins (R)

33. Analogous structures are similar structures that perform the same role, but have evolved in unrelated species (convergent evolution, e.g. bat and butterfly wings) (R)

34. Artificial selection is when humans use selective breeding techniques to breed organisms with desirable features. (R)

35. Artificial selection generally results in faster changes to the percentage of organisms with the desired characteristic than natural evolution. (M)

36. Artificial selection can result in less genetic variation and can amplify other characteristics which may be a disadvantage to the species. (M)

Students will be skilled at:

1. Using modelling and simulations to investigate and describe natural selection and evolution.

2. Identifying characteristics that will be favoured for survival for different selection pressures.

3. Identifying homologous, vestigial and analogous structures.

4. Identifying and describing the different types of evolution.

5. Evaluating information from secondary sources, in particular, anatomical similarities, embryology and comparing DNA/amino acid sequences.

6. Critically analyse the validity of artificial selection.

7. Drawing and analysing phylogenetic trees.

8. Analysing graphs of radioactive half-life to estimate age of fossils and organic remains.

9. Selecting appropriate radioactive isotopes that could be used to determine age of fossils and organic remains.