Chapter 1: Introduction to Evolutionary Biology

theory of evolution

• the central unifying concept of biology

• affects many other areas of knowledge

• one of the most influential concepts of western thought

basic structure of biological evolution

• evolution

  • populations are made up of individuals with different heritable attributes

  • from generation to generation, these attributes can change in frequency in a population

• evolution can explain the origin of biological diversity at all scales of organization

important conclusions about evolution verified by scientific study

• organisms on earth have changed through time

• changes are gradual not instantaneous

• lineages split by speciation, resulting in the generation of biodiversity

• all species have a common ancestor

• adaptation result form natural selection

• biodiversity and adaptation are products of evolution

biodiversity

• diversity of life on earth

• number and kinds of living organisms in a given area

adaptation

• any trait that makes an organism better able to survive or reproduce in a given environment

• evolutionary process that leads to the origin and maintenance of such traits

major areas of evolutionary study

1. evolutionary history → pattern

2. evolutionary mechanism → processes

microevolution

evolutionary patterns and processes observed within species

macroevolution

evolutionary patterns and processes observed among species

evolutionary history (macroevolution)

goals

• determine the evolutionary relationship of organisms in terms of common ancestry

• identify and understand long-term patterns in evolution

in practice

• use comparative data from sub-disciplines of systematics, biogeography, palaeontology, morphology, development, and molecular biology

evolutionary mechanisms (microevolution)

goals

• determine the particular processes responsible for evolutionary change (e.g. natural selection)

• identify the major forces of evolution

in practice

• uses experimental, theoretical, and comparative studies of genetics and ecology of populations

• focuses primarily on the population level

how is evolution studied?

• evolution of self-fertilization

1. why does self-fertilization evolve? : theory, observation, experiments in the field

2. how did self-fertilization evolve? : genetic crosses, molecular biology, developmental biology

3. when did selfing evolve?: evolutionary history, analysis of genetic differences

4. what are the consequences of evolving selfing? : genome studies

why is evolution relevant?

• children’s questions

• medicine

• agriculture

• environment

• biology

public doubts about evolution

• extremely recent scientific concept (165 years)

• very ‘personal’ implications: direct ramifications about who and where we are from

• violates literal interpretations of religious texts - also true of other sciences as well

*evolution has as much empirical support as any other accepted scientific theory

Grandeur in this View of Life - Charles Darwin, Origin of Species

“there is a grandeur in this view of life, with its several powers, having been originally breathed int a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed las of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.