i.ii.iii.iv.

A.B.C.D.

TEST CORRECTIONSTEST CORRECTIONS• 1/3 pts back if done correctly1/3 pts back if done correctly

• Multiple choice:Multiple choice:– Write questionWrite question– Look up answer in notes/book!Look up answer in notes/book!– Clearly write letter for correct answer AND Clearly write letter for correct answer AND

the answer itselfthe answer itself– Be neat! Highlight, underline, indent, etc…Be neat! Highlight, underline, indent, etc…

Short AnswerShort Answer• Write questionWrite question• Write # pts earned/#pts availableWrite # pts earned/#pts available

– Example: “earned 2/8”Example: “earned 2/8”• Summarize your earned pts & incorporate Summarize your earned pts & incorporate

new points into a complete, thorough new points into a complete, thorough answer.answer.– Underline or highlight the NEW pointsUnderline or highlight the NEW points– Do NOT copy straight from the markscheme or Do NOT copy straight from the markscheme or

you will not get ptsyou will not get pts– Make it MAKE SENSE, paragraphs, sentences!Make it MAKE SENSE, paragraphs, sentences!

5.4 Evolution5.4 Evolution

REALLY cool site...

• http://www.johnkyrk.com/evolution.html

5.4.1 5.4.1 DefineDefine evolution evolution

• cumulativecumulative change in the change in the heritableheritable characteristicscharacteristics of a of a populationpopulation..

– Small changes, upon small chgs, Small changes, upon small chgs, – Over many generationsOver many generations – Gene-controlled factorsGene-controlled factors– NOT an individual!NOT an individual!

Range of eye complexity in living mollusk species (left to right): a pigment spot, as in the limpet Patella; a pigment cup, as in the slit shell mollusk Pleurotomaria; the "pinhole-lens" eye of Nautilus; a primitive lensed eye, as in the marine snail Murex; and the complex eye—with iris, crystalline lens, and retina—of octopuses and squids.

5.4.1 5.4.1 DefineDefine evolution evolution• 5 “sub theories”

– Evolution: all life is and has been perpetually changing

– Common descent: if traced back far enough, all life has common ancestor

– Gradualism: evol change is slow & gradual

– Multiplication of species: speciation leads to diversity of life; pops adapt to locations, become reproductively isolated from other pops

– Natural selection: produce genetic variation & select for/against

• Explain evolution of a Explain evolution of a species by natural selection species by natural selection in response to in response to environmental change.environmental change.

(Total 7 marks)(Total 7 marks)

• species show variation;species show variation;variation is inherited;variation is inherited;species have the potential to produce morespecies have the potential to produce moreoffspring than can survive;offspring than can survive;this leads to a struggle for existence / survival;this leads to a struggle for existence / survival;resources are limited;resources are limited;those that are best adapted (on average) survive to reproduce;those that are best adapted (on average) survive to reproduce;this leads to a population adapted to the environment;this leads to a population adapted to the environment;as the environment changes those that are bestas the environment changes those that are bestadapted will leave more offspring;adapted will leave more offspring;this will cause the species to evolve to a new adaptation / this will cause the species to evolve to a new adaptation / change in gene frequencies;change in gene frequencies;

• [7][7]

5.4.2 5.4.2 OutlineOutline the evidence for evolution provided by the fossil record, ... the evidence for evolution provided by the fossil record, ...

PBS: Whales in the Makinghttp://www.pbs.org/wgbh/evolution/library/03/4/quicktime/l_034_05.html

5.4.2 5.4.2 OutlineOutline the evidence for evolution provided by the evidence for evolution provided by the .. selective breeding ...the .. selective breeding ...

• Selective Breeding: By Humans! (Art. Sel.)– Animals, plants

selected for breeding b/c desirable traits future generations w/higher freq of trait

– Cows w/high milk yield– Dog breeds– Corn– Select for...– Select against...

5.4.2 5.4.2 OutlineOutline the evidence for evolution provided the evidence for evolution provided by ... homologous structures.by ... homologous structures.

Analogous = Analogous =

not a recent not a recent common ancestor; common ancestor;

convergent evo.convergent evo.

So, how does So, how does natural selection natural selection

work??work??

____________ & ____________ & ____________________________________

5.4.3 5.4.3 StateState that populations tend to produce more that populations tend to produce more offspring than the environment can support.offspring than the environment can support.

5.4.3 5.4.3 StateState that populations tend to produce more that populations tend to produce more offspring than the environment can support.offspring than the environment can support.• More than needed to keep species around• More than K can support, ltd resources• Intraspecific competition

– Some have competitive advantage • (traits, behaviors, symbioses)

• More fit (competing for resources, fighting disease, etc.) = More likely to successfully reproduce

• Freq of these alleles higher in next generation

5.4.4 5.4.4 ExplainExplain that the consequence of the potential that the consequence of the potential overproduction of offspring is a struggle for overproduction of offspring is a struggle for survival.survival.

• Some individuals selected FOR, some selected AGAINST– Survivors (FOR) form new breeding

population– Increases freq of advantageous alleles

5.4.5 5.4.5 StateState that the members of a species show that the members of a species show variation.variation.

• Populations show variation... differences in phenotypes!

Varying forms of a trait... Varying forms of a trait...

(flower color, teeth shape)(flower color, teeth shape)

5.4.6 5.4.6 ExplainExplain how sexual reproduction promotes how sexual reproduction promotes variation in a species.variation in a species.

5.4.6 5.4.6 ExplainExplain how sexual how sexual reproduction promotes variation reproduction promotes variation in a species.in a species.

• MIXING IT UP w/MEIOSIS!• Random asstmt of chromosomes in

Metaphase I– 2^n combinations of chroms in daughter cells– 8,388,608 in humans!!

• Crossing-over in Prophase I – New combos of alleles on a chrom.

• Random fertilization any gamete can fert any gamete from the other indiv

• Other source of variation??Other source of variation??

• MUTATIONSMUTATIONS