ANTB14: Evolutionary Anthropology Lecture 1

Flashcards on Evolutionary Anthropology Lecture 1

Unifying Principle of Biology

The unifying principle of biology is that all species are descended from a common ancestor and are thus related.

Primate Diversity Today

Humans, bonobos, chimpanzees, gorillas, orangutans, siamangs, and gibbons.

The First Hominins

Bipedal walking and blunt canines; ~6-7 million years ago.

The Australopiths

Successful group, terrestrial bipeds, but still good climbers; ~4 million years ago.

The Genus Homo

Early on (2.8-2 million years) similar to the australopiths but different teeth, diet and tool use; later Homo erectus (2 million -~100,000 years) had humanlike body proportions and marked a major increase in brain size.

The Origin of Homo sapiens

From a complex lineage of transitional species around 200-300,000 years ago.

The Evolution of Homo sapiens

Geographically widespread and phenotypically, culturally, linguistically, technologically diverse.

Course Goals

Understand of the process and mechanisms of evolution and apply them to primates; Read and interpret evolutionary trees; Describe the place of Primates on the tree of life and use anatomical features to place different primate in their correct taxonomic group; Describe the basic outline of primate evolution over the past ~65 million years, including major evolutionary developments and taxa; Identify key primate species and evaluate and compare anatomy across taxa; Make inferences about behavior in fossil species using the comparative method.

Theory in Science

A broad overarching explanation, built on hypotheses that are tested using the scientific method and are very strongly supported by a lot of evidence.

The Modern Synthesis

Bringing together ideas about evolution, natural selection, and genetics/Mendelian inheritance.

Microevolution

Evolution happening on a small scale within a single population affecting changes in allele frequencies.

4 Processes of Microevolution

Mutation, genetic drift, gene flow and natural selection.

Macroevolution

Evolution at levels higher than the population; large-scale history of life on Earth.

Connects Micro- to Macroevolution

Speciation.

Extinction

A natural process in the life of a species.

End Ordovician Extinction

Caused by changes in sea levels and atmospheric and ocean chemistry; affected 85% of marine organisms.

Late Devonian Extinction

Caused by climate change; affected marine invertebrates and fish.

Permian-Triassic Extinction

Caused by volcanic activity, climate change, meteorite impact; Earth’s worst mass extinction (the “Great Dying”); 95% of all species went extinct.

End Triassic Extinction

Caused by volcanic activity and global warming; wiped out many amphibians and mammal-like reptiles – marks an adaptive radiation of dinosaurs.

Cretaceous-Tertiary Extinction

Caused by large meteorite impact; led to the extinction of the dinosaurs.

Evolutionary Anthropology

Study of the evolution of the behavioral and biological traits of humans, our primate relatives, and our ancestors as well as our current biological similarities and differences.

Culture

A set of learned behaviours transmitted between generations with non-genetic means to adapt to environment.

Behaviour

Responses to internal or external stimuli, shaped by evolutionary forces.

Subfields of Evolutionary Anthropology

Human biology, osteology/skeletal biology, primatology, palaeoanthropology.

Evolution

Change through time; descent with modification; change in allele frequencies from one generation to the next.

Gene

Segment of chromosome’s DNA that codes for protein or trait.

Allele

Alternative form of a gene at a particular locus of homologous chromosomes.

Genotype

The alleles that an individual has.

Phenotype

The physical expression (incl. behavior).

Homozygous

Two copies of the same allele for a gene.

Heterozygous

Two different alleles for a gene.

Mendelian Traits

Traits are discrete and controlled by a single gene.

Polygenic Traits

Phenotype is determined by more than one gene; continuous variation.

Pleiotropic Traits

Change in one gene impacts multiple traits.

Epigenetics

Change in gene expression without a change in the DNA sequence; environmental influences on gene expression.

Mutation

Mutation is the ultimate source of all new genetic variation in a population. Mutations are random and can be harmful, neutral, or beneficial.

Genetic Drift

Genetic drift is the random change in allele frequencies due to chance events. It has a greater effect on small populations and can lead to the loss of genetic variation.

Gene Flow

Gene flow is the movement of alleles between populations. It can introduce new genetic variation into a population and reduce genetic differences between populations.

Natural Selection

Natural selection is the process by which individuals with certain heritable traits survive and reproduce at a higher rate than others. It leads to adaptation and can change allele frequencies in a population.

Species and Speciation

A species is a group of organisms that can interbreed and produce viable, fertile offspring. Speciation is the process by which new species arise.

Adaptive Radiation

Adaptive radiation is the rapid diversification of a lineage into many different forms, each adapted to a different ecological niche.