1. Evolution Species – Can you define what a species is?

2. Evolution Species – an interbreeding group of organisms that is genetically distinct and isolated from other groups of organisms. Evolution - (biological definition) - ?

3. Evolution Species – an interbreeding group of organisms that is genetically distinct and isolated from other groups of organisms. Evolution - (biological definition) - a change in allele frequencies over time

4. Possible Causes of Evolutionary Change 1) Mutation – new allele created – minor, slow rate, most deleterious and lost immediately 2) Gene flow in and out of population  A population is a subgroup of a species within which members mate randomly  Emigration and immigration between populations with slightly different allele frequencies can affect changes 3) Random genetic drift  Each generation, random events may cause some to die, survivors will have only a portion of the original set of alleles in a pop. Therefore, some alleles will be lost by random chance. 4) Selection (natural, sexual, and artificial selection)

5. Natural Selection  Differential reproductive success of individuals within a species occurring because of genetic or hereditary differences among them.  In order for natural selection to work the following is necessary: 1. Genetic variance in the trait being acted upon 2. Differential survival and reproduction of offspring due to that genetic variance

6. 1. Genetic Variance in the Trait Phenotypic variation in a trait is due to 3 different factors - the influence of environment, the influence of genes, and their interaction. Vp = phenotypic variance Vp = Ve + Vg + Vi

7. 2. Differential survival and reproduction of offspring 1. All animals can over reproduce 2. Populations, however, tend to remain stable 3. Limited resources, cause some to die 4. Therefore there is a struggle for existence

8. Natural Selection Outcome Thus: 5. Variable traits caused by genetic variability result in some being better competitors (for whatever reason) 6. Differential survival and reproduction of offspring leads to changes in genetic makeup of succeeding generations

9. Genetics of Behavior Evidence for a genetic basis of behavior - necessary for evolution of behavior: 1. Difference in behavior among different strains and mutations 2. Effects of artificial selection on behavior 3. The behavior of interspecies hybrids 4. Instinctive behavior 5. Twin Studies

10. 1. Strain differences Strain - inbred lineage of some animal such as of house mice. By repeatedly mating closely related individuals, you can get a strain of animal that lacks genetic variability - homozygous at most loci on chromosomes.

11. Southwick (1968) – used A/J – non aggressive mice & CFW – aggressive mice Exp) cross-fostered the mice to totally control for environmental influences Outcome: offspring behavior remained true to the genetic lineage.

12. Rothenbuhler (1964) – honeybees 2 strains, non-hygienic - was susceptible to “foul brood” disease,  While hygienic strain exhibited the ability to identify sick brood, rip open the pupal cap and remove the sick larva  Simple crosses indicated that the non-hygienic trait was dominant

13. Two traits involved: uncapping cells and removing brood hygienic X non-hygienic = F1 all non-hygienic F1 back cross with hygienic parent: UuRr X uurr ¼ hygienic, ¼ removed brood if cap removed, ¼ uncapped cell only, ¼ non-hygienic 2 genes: U – doesn’t uncap cells u – uncaps cells R - doesn’t remove brood r – removes brood

14. 2. Artificial selection 1. An animal is chosen for its behavioral phenotype (observed trait). 2. Those with desired traits are bred; those with undesired traits are not allowed to pass on their genes. 3. Humans control selection Examples: milk production in cows, friendliness in dogs, meat production in pigs, fancy feathers in pigeons, etc.

15. 3. Interspecies hybrids a. Dilger (1962) worked with lovebirds produced sterile hybrids b. Agapornis personata (Fischer’s lovebird)– cuts strips of nesting material and carries them back to the nest in its beak c. Agapornis roseicollis (Peach-faced lovebird) – cuts strips, tucks them under flank feathers and carries more than one at a time to the nest. Vera Appleyard Gwen Powell

16. Fig. 37.2: Addison Wesley Longman, Inc.

17. Greater and Lesser Prairie Chickens http://www.youtube.com/watch?feature=pla yer_detailpage&v=pJCy0d94YS0http://www.youtube.com/watch?feature=pla yer_detailpage&v=pJCy0d94YS0 http://vimeo.com/39386702 http://www.youtube.com/watch?v=Lcu7btvi Ol0&feature=player_detailpagehttp://www.youtube.com/watch?v=Lcu7btvi Ol0&feature=player_detailpage

18. 4. Instinctive behavior Some animals perform species- specific behaviors without an opportunity to learn the behavior. –Nest and web construction behavior –Courtship displays –Territorial defense and migration –Nursing in mammals –Patterns of development

19. Example 2: Blackcap warblers inherit the direction of migration and over wintering sites (most fly from Europe to over wintering sites in central Africa). A small population spends the winter in Great Britain. The hand- reared young of these birds instinctively fly west when shown the night sky during the fall migration period.

20. 5. Twin Studies Identical twins = monozygotic twins – single fertilized egg that splits Fraternal twins = dizygotic twins – two fertilized eggs (as related a non-twin siblings) Ht, IQ, even criminal behavior and homosexuality have a high degree of genetic influence Photograph by Martin Schoeller for National Geographic Magazine

21. Resemblance (correlation) in height of children of the same parents: –Siblings (52 pairs)60% variation = genetic –Dizygotic twins (52)64% (h 2 = 0.64) –Monozygotic twins (50)93% (h 2 = 0.93) IQ – 384,482, and 687 pairs, respectively: –h 2 = 0.53, 0.63, and 0.87, respectively Autism – h 2 – 0.7

22. Homosexuality – 161 homosexual men and 170 adoptive brothers (reared in same house) or twins (reared apart) –52% of monozygotic twins reared apart = also homosexual –22% of dizygotic twins reared apart = also homosexual (9.2% non-twin biol brothers) –11% of adoptive brothers reared together were homosexual Overall it’s estimated that homosexual behavior has about 50% heritability

23. Conclusions There are different types of evidence that suggest genes play a major role in the development of behavior It follows then that natural selection can and does act on behavior and Behavior can evolve just as an animal’s physical characteristics can

24. Macroevolution Phylogeny – the history of descent of a group of taxa (genera, families, orders, etc.) a. traits can be homologous – similar due to common ancestry (= homology) b. traits can be analogous – no common ancestry, but similar due to convergent evolution (= analogy) c. typically referring to morphological and genetic characteristics, but behavior can also be considered a trait and used to understand a group’s phylogeny

26. Construction of a Phylogenetic Tree