Evolutionary Relationships

Evolutionary Relationships

1. Evolution; how might a new species evolve? individual have different traits within a population. A specific trait could link to higher fitness in individuals (refers to adaptation). such traits have spread within a population by naturally occurring selection (refers to natural selection. New species, Species different based on series of traits.

2. Adaptation; Adaptation needs to have functions related to higher fitness

3. Evolution; is the prices that indicates such changes over time. Adaptation; a trait that confers higher fitness to individuals than others existing alternatives within the population, spreads by natural selection. Natural selection; the process that occurs when individuals defer in their traits and the difference are correlated with differences in reproductive success.

4. evolutionary relationships; can help us better understand when and how specific behaviour evolved

5. Similarities in traits; shared ancestry? different evolutionary origins.

6. homology; similarity due to being related (organisms of the same taxon share a trait) e.g. wings of birds. Anatomical similarities = morphological homology. Developmental (embryonic) similarities= ontogenetic homology. Similarities in DNA,RNA and proteins= molecular homology.

7. Homoplasy; similarity not due to being related (e.g. organisms of different taxa have traits that resemble each other but have evolved independently (parallel evolution).

8. Analogy; similarity due to function not due to common ancestor. wings of insects, birds and bats are all analogous. e.g. Marsupials vs (placental) mammals.

9. Evolutionary tress; help us to understand evolutionary relationships, based often on genetic data, represented the history of evolutionary lineages

10. Evolutionary tree of primates; each node leads to a split into two taxa/ lineages, new species then emerged within these two lineages and additional series continuously emerged over millions of years.

11. Homologies; which characteristic did we obtain from ancestral non human primates. 3 sets of primates characteristics (Benton 1990); adaptations for like on tress; mobility (mobile shoulder joint allow primates to rotate their arms), grasping (opposable thumb, big toe, flat nails instead of claws, Reproductive specialisations; birth to a single offspring or twins, long parental investment prior and after birth, social contact with infants is central for learning social skills, complex visual system; eyes on front of face, binocular vision that allows depth perceptions (good for tree living animals)

12. Neurological demands; Brain size, neocortex- differences between primates and most other mammals.

13. Linking behaviours to evolution; if behaviours are explained at an evolutionary level, there must be some consideration of genetics. Principles of genetic inheritance; Gregor Medel (19th century monk), genes= units of heredity, that maintain structural format through generations, they are are a part of the chromosome. Genes are made of DNA, DNA codes for the synthesis of RNA, RNA codes for synthesis of protein. Genotype= internal genetic code (blueprint), instructions for making proteins, cells etc. Phenotype= 'outward manifestation', physical appearance, behaviour etc.

14. Genetic impact on our behaviour; Human Genome project (1990-2003)- Multiple genes affecting personality traits, specific genes= specific phenotypes.

15. Phylogenetic continuity involving human behaviours? An example; reconstructing the evolution of laughter and smiles. why study positive expressions; social cohesion and communication; Development of an array of important skills (Fredrichson 2001). Laughter and smiles; indicators of joy, pervasive tools of communication, Part of out language (Venting and Today 2004).

16. Laughter in great apes? A human vocalisation evolved from ancestral ape vocalisation.

17. Smiles in great apes; dominating claim on evolution of smiles of past 40+ years (Van Hooff 1972). Human smiles emerged from silent bared- teeth (submissive displays), Upper lips raised. A more parsimonious; Human laugh faces directly evolved from the open-mouth faces of laughing ancestral apes.

18. Reconstructing the evolution of laughter and smiles; a multimodal expression of humans that most likely evolved from ancestral apes. Gradual changes in form towards more positively perceived expressions.

19. Summary; Evolutionary tress help us understand when and how specific behaviour (or other traits) emerged. No species represents the end product in evolution. Evolution is ongoing process. Similarities it traits across taxa do not necessarily indicate common ancestry. If behaviours can be explained at an evolutionary level, then they must have a genetic basis.