Bishops Grade 12 Life Sciences Revision lessons

1. Bishops Grade 12 Life Sciences Revision lessons Evolution – including Evolution by Natural SelectionandEvolution by Natural Selection CONTINUED andHuman Evolution 66 marks out of 150 on Paper 2

2. Content from CAPS & exam guidelines summarized – All of Evolution by Natural Selection • Introduction - define evolution, biological evolution, evidence. State the difference between a hypothesis and a theory. • Evidence for Evolution – define/list/state/describe how fossils, biogeography, homologous structures and genetics are evidence for evolution • Variation – define, describe mechanisms that bring about variation and importance • Origin of the idea about origins - historical development and comparisons • Lamarckism (Jean Baptiste de Lamarck) – state 2 laws, statereasons for rejection • Darwinism/gradualism (Charles Darwin –1809–1882), list observations and deductions, describe natural selection, compare Lamarckism and Darwinism • Punctuated equilibrium (Eldredge and Gould)- define, describe theory, analyse graph, compare punctuated equilibrium to gradualism • Artificial selection (selective breeding) – define, describe using an example, compare to natural selection • Speciation – define, describe using an example • Reproductive isolating mechanisms – explain how they prevent species mixing • Evolution in present day times – link directly to natural selection, describe using an example

3. Content from CAPS & exam guidelines summarized – All of Human Evolution • Evidence of common ancestors for living hominids including humans: 1. Interpret a phylogenetic tree to show the place of the family Hominidae in the animal kingdom 2. State/describe characteristics that humans share with African apes egsimilarities 3. Tabulate/describe anatomical differences between African apes and humans includes reference to bipedalism. 4. Describe lines of evidence that support the idea of common ancestors for living hominids including humans: Ardipithecus, Australopithecus, Homo. Describe/tabulate fossil evidence (skull, spine, pelvis, arms, legs), describe genetic evidence (mitochondrial DNA) and describe cultural evidence (tool-making) • Out of Africa hypothesis: state the hypothesis • Give evidence for the Out of Africa hypothesis – fossil and genetic (mitochondrial DNA) • Know and describe the timeline for the existence of different species of the genus Homo and the significant features of each type of fossil • Interpretation of phylogenetic trees proposed by different scientists showing possible evolutionary relationships as it applies to hominid evolution • Importance of the Cradle of Humankind: 1. Know the main fossil sites in South Africa and examples should be studied to see evolutionary trends. 2. Mention scientists such as White, Dart, Broome, Tobias, Brain, Ron Clark, Berger, Keyser and what they discovered

4. Links to other chapters in Life Sciences • Link to Genetics and Reproduction • Variation – link to Meiosis, Genetics and Reproduction • Link to Fossils and fossil record in Grade 10 • Link to Biodiversity in Grades 10 and 11 • Human Origins – link to Skeleton in Grade 10 • LINK TO THE SCIENTIFIC METHOD IN ALL AREAS OF EVOLUTION

5. Evolution: a summary Living organisms change over time BECAUSE changes occur in the environment The REASON that living organisms can change is because VARIATION exists in a POPULATION Those organisms in the population that are best adapted to the environmental conditions will survive and REPRODUCE Over time the differences between populations become so great that new species form And pass their genes onto the next generation. Sometimes this takes place over a long time: mammals Sometimes this happens quickly: HIV/AIDS and TB Evidence supports this

6. Phylogenetic trees Phylogeny :The evolutionary relationships among organisms; the patterns of lineage branching produced by the true evolutionary history of the organisms being considered. Many of the phylogenies you encounter are the "family trees" of groups of closely related species, but we can also use a phylogeny to depict the relationships between all life forms.

7. Variation Define a species and a population. Describe how each of the following contributes to variation amongst individuals of the same species: • Meiosis: - Crossing over - Random arrangement of chromosomes • Mutations • Chance fertilisation • Random mating Differentiate between continuous variation and discontinuous variation.

8. 2N 1N 2N 2N 1N 1N Second Division ('Mitotic' division) Gametes (eggs or sperm) Crossing over may occur at this stage in meiosis First Division (Reduction division) Intermediate cell Intermediate cell Sources of variation Meiosis Random arrangement may occur at metaphase 1 • The purpose of meiosis is to produce haploid sex cells which are all different to each other Random arrangement may occur at metaphase 2

9. Sources of variation Mutations Mutations can alter the cell’s chemistry Chromosome Cell • Mutations are alterations in the DNA of chromosomes. • Many mutations may be neutral or 'silent' (i.e. they have no observable effect on the organism). • Harmful mutations become evident because they may lower the survivalcapacity of the organism. • Beneficial mutations usually bring about variation Mutation Nucleus This may cause an observable change in the organism’s: • physiology • anatomy • behavior

10. Sources of variation

11. Lamarckism (Jean Baptiste de Lamarck 1744–1829) Describe what is meant by each of the following 'Laws' used by Lamarck to explain evolution: • 'Law' of use and disuse • 'Law' of the inheritance of acquired characteristics Give reasons for Lamarck's theory being rejected. Lamarck’s “Laws’ • Law of use and disuse: • Organs’ become modified or adapted according to use • Used more- became bigger • Not used – smaller and disappeared • Law of inheritance of acquired characteristics: • modifications brought about by use or disuse were able to be transmitted to offspring. • i.e animals adapted to their environment • Passed these on to next generation DISCREDITED Reminder that the context must be mentioned in the paragraph or essay

12. Darwinism (Charles Darwin –1809–1882) State the observations upon which Darwin based his theory: 1. Organisms of a species produce a large number of offspring egproduce more offspring than survive to adulthood 2. Populations remain more or less constant in numbers 3. The offspring show a great deal of variation 4. Of the large number of offspring produced, only a few survive 5, Characteristics are inherited from surviving parents to offspring Conclusions From his four observations Darwin was able to deduce two main conclusions A. All organisms are involved in a struggle for survival.B. Some individuals are better adapted to their environment than others. What determines natural selection? Thus the ENVIRONMENT naturally selects those genes that increase the chances of survival to adulthood and therefore reproductive success.

13. Darwinism: Natural Selection • In a large population individuals of the same species will show a great deal of variation. • These individuals will compete for available resources ( eg food and shelter) • When the environment changes, some individuals have characteristics that are better adapted to the environment. • This will enable them to compete more successfully for the available resources/ protect themselves form the new environmental conditions. • The better adapted individuals in the changed environment will therefore survive long enough to be able to reproduce and pass their genes onto the next generation. Those with unfavourable characteristics will become extinct in this environment. • If natural selection continues form one generation to the next there will be continual, gradual changes in the appearance of the population. • This is supported by the presence of transitional fossils • Reminder that the context must be mentioned in the paragraph or essay

14. NB ancestor

16. Compare Gradualism and Punctuated Equilibrium Similarities between Gradualism and Punctuated EquilibriumBoth involve natural selection Both a form of evolution over a period of timeVariation exists in both Differences between Gradualism and Punctuated Equilibrium 1. Gradualism occurs continuously with regular small changes over time Punctuated equilibrium has periods of no change (equilibrium) followed by short periods of a lot of change. 2. Gradualism relies on the presence of transitional fossils Punctuated equilibrium relies on the absence of transitional fossils

17. Artificial selection (selective breeding) Link to Genetic Engineering • Define artificial selection • Artificial selection is when humans control the breeding of domesticated animals and plants for human use (adapted from MTG) • Artificial selection is the purposeful selection and breeding of certain characteristics to make a species more useful to humans (adapted from textbook) • Describe artificial selection in one example • of a domestic animal OR crop • Similarities between Artificial and Natural Selection – describe/state • Both refer to  processes that determine which genetic traits pass from one generation to the next.Natural selection and selective breeding both result in a certain set of traits becoming more prominent within a population • Differences between Artificial and Natural Selection – • tabulate, differentiate in sentences

18. Formation of new species Define a species and a population. See next slide Differentiate between speciation and extinction and state the effect of each on biodiversity. Give a general account on speciation through geographic isolation as follows: • If a population of a single species • becomes separated by a geographical barrier (sea, river, mountain, lake), • then the population splits into two populations. • There is now no gene flow between the two populations. • Since each population may be exposed to different environmental conditions, • natural selection occurs independently in each of the two populations • such that the individuals of the two populations become very different from each other • Genotypically and phenotypically. • Even if the two populations were to mix again, • They will not be able to reproduce with each other. • They have thus become different species. Reminder that the context must be mentioned in the paragraph or essay

19. Species and Population • A biological species is:a group of interbreeding (or potentially interbreeding) individuals, reproductively isolated from other such groups. OR A group of organisms that are able to interbreed and have fertile offspring • Population: A group of organisms found in the same area at the same time that are able to interbreed and have fertile offspring

20. Keeping species separate (Mechanisms of reproductive isolation) When one species gives rise to two new species (speciation), the two species cannot reproduce with each other even if they mix. They remain as separate species due to mechanisms that restrict gene flow between them. Describe how each of the following reproductive isolation mechanisms help in keeping species separate: • Breeding at different times of the year • Species-specific courtship behaviour (animals) • Adaptation to different pollinators (plants) • Infertile offspring (e.g. mules) Reminder that the context must be mentioned in the paragraph or essay

21. Evolution in present times Explain that natural selection and evolution are still occurring in present times by using any ONE of the following examples: • The use of DDT and the consequent resistance to DDT in insects which can be explained in terms of natural selection • Bill (Beak) and body size of Galapagos finches • The development of resistant strains of tuberculosis-causing bacteria (MDR and XDR) to antibiotics due to mutations (variations) in bacteria and failure to complete antibiotic courses • HIV resistance to anti-retroviral medication Reminder that the context must be mentioned in the paragraph or essay

22. Key point/processes/graphics – Human Origins Interpret a phylogenetic tree to show the place of the family Hominidae in the animal kingdom

23. Key point/processes/graphics – Human Origins Tabulate anatomical differences between African apes and humans as it applies to the following characteristics: • Bipedalism (foramen magnum, spine and pelvic girdle) • Brain size • Teeth (dentition) • Prognathism • Palate shape • Cranial ridges • Brow ridges List characteristics that humans share with African Apes Also a big change in body proportions: from the long arms and short legs of apes to the short arms and long legs of humans

24. Key point/processes/graphics – Human Origins Describe the following evidence that support the idea of common ancestors for living hominids including humans: • Cultural evidence: tool making • Genetic evidence: slide 23 • Fossil evidence: slides 24 onwards

25. Mitochondrial DNA Textbook p 249

26. Key point/processes/graphics – Human Origins THE FOLLOWING SLIDES REFER TO: • FOSSIL EVIDENCE • FOSSIL SITES • PHYLOGENETIC TREES • EVIDENCE OF HOMINID ANCESTORS – EVOLUTIONARY TRENDS

28. Ardipithecus sp. Earliest hominid ancestor to learn Site: northern Ethiopia Dated fossil: 5 – 4 mya and see phylogenetic tree Look for: bipedal characteristics Refer to Evolutionary trends in: Cranial capacity very Very small brain Forward position of foramen magnum Prognathous jaw Pelvis bipedal Teeth large Large brow ridges Longer arms Shorter legs No tools Fossils only found in Africa Ardipithecus ramidus (Artist: J. Matternes) (Source: Dr T White, UCB) Nickname: “Ardi”

29. Australopithecus afarensis More recent hominid ancestor to learn Site: Ethiopia Rift Valley Dated fossil: 4 – 2,7 mya and see phylogenetic tree Look for: bipedal characteristics Refer to Evolutionary trends in: Cranial capacity 375 – 550ml Forward position of foramen magnum Pelvis - bipedal Prognathous jaw Large brow ridges Teeth large canines Arm length – still long Legs – still short No tools Fossils only found in Africa Australopithecus afarensis Nickname: “Lucy”

30. Australopithecus africanus More recent hominid ancestor to learn Site: Taung, Cradle of Humankind. Dated fossil: 3 – 2mya and see phylogenetic tree Look for: bipedal characteristics Refer to Evolutionary trends in: Cranial capacity 428 – 625ml Forward position of foramen magnum Pelvis bipedal Prognathous jaw Brow ridges not as pronounced Teeth large canines Arm length – longer Legs –shorter No tools Fossils found in Africa only Only found in Africa Nickname: “Mrs Ples” Australopithecus africanus Nickname: “Taung Child” (Source: svt.ferrand.free.fr)

31. Australopithecus sediba – the direct ancestor of Homo? Is it a transitional fossil (Sources: Prof L.R. Berger; IHE, Wits Univ.; Science; J. Gurche)

32. Homo habilis More recent hominid ancestor to learn Site: Rift Valley Dated fossil: 2,2 – 1,6 mya and see phylogenetic tree Look for: bipedal characteristics Refer to Evolutionary trends in: Cranial capacity 650ml Forward position of foramen magnum Pelvis bipedal Teeth smaller Long arms, short legs FIRST Tool making Oldest fossils found in Africa Homo habilis Nickname: “Handy Man” (because of Stone Tools) (Source: svt.ferrand.free.fr)

33. Homo erectus More recent hominid ancestor to learn Site: Java and Swartkrans Dated fossil: 2 – 0.4 mya and see phylogenetic tree Look for: bipedal characteristics Refer to Evolutionary trends in: Cranial capacity 900ml Forward position of foramen magnum Pelvis bipedal Less prognathous jaw Teeth are smaller Arm length shorter Leg length longer Tool making Found all over the world Homo erectus (Source: livelikedirt.blogspot.com) Acheulian industry stone Tools of Homo erectus

34. Homo sapiens Site: Blombos Cave, Border Cave Dated fossil: 200 000 yrs ago and see phylogenetic tree Look for: bipedal characteristics Refer to Evolutionary trends in: Cranial capacity 1200ml + Pelvis – wider & stronger = bipedal Spine – S shaped NO prognathous jaw Curved jaw No brow ridges Teeth smaller Arm length shorter Longer legs Tool making Found all over the world Homo sapiens

35. Drier Step 3 drier Step 2 drier A. sediba Step 1 drier (Source: P. de Menocal, 2004)‏

36. Out of Africa hypothesis – what evidence support this hypothesis?

37. Possible questions – Section A Learn Definitions

38. Possible questionsSection A • Sample of Section B questions Be prepared to answer a variety of questions comparing skulls, pelvic girdles etc of HUMANS, AUSTRALOPITHECUS AND CHIMPANZEES in any combination

39. Possible questions – Section B • Drawings to draw including graphs: Unlikely to be asked to draw any structures BUT can be asked to draw graphs see slide 35 • Drawings to interpret: See slide 35 and slide 38 • Tables to interpret: See slides 36 and 37 • Definitions REMINDER THAT SCIENTIFIC METHOD CAN BE APPLIED IN EVOLUTION QUESTIONS

40. Possible questions - Section B

41. Possible questions – Section B

42. Possible questions – Section B

43. Possible questionsSection B • Sample of Section B questions Be prepared to answer a variety of questions comparing skulls, pelvic girdles etc of HUMANS, AUSTRALOPITHECUS AND CHIMPANZEES in any combination

44. Possible questions – Section C