SA3

Eons Eras Periods Epochs

The preserved impressions of an organism • Trace fossils • Body fossils

The preserved impressions of an organism (hints showing an organism existed)

Fossils formed the actual organism

List of fossils, arranged according to time period

Where fossils are found Forms in layers or strata Glued together by chemical reactions and pressure

Ordering fossils in terms of their age

Finding the exact age of rocks or fossils in mya

Measuring the percentage of radioactive isotopes in a substance

An unstable form of an elemental atom Decay to stable atoms at a known rate - half-life

Any change in heritable structures of a population or species over time

Evidence of organism with shared characteristics with both ancient and modern form Can show evolutionary history of species

Biogeography Similarities in morphology & biochemistry

The study of where in the world plants and animals live

The slow movement of land masses over time

Pangea ‘supercontinent’ Laurasia and Gondwana Modern World

When a new species is formed as a result of genetic isolation caused by a geographical barrier

When gene flow between members of a population is reduced by one of the following 3 factors: • Habitat differentiation • Sexual selection • Polyploidy

• Mutation • Genetic drift - Bottleneck effect - Founder effect • Gene flow

• geographic barriers • temporal barriers • behavioral barriers • morphological barriers • gamete mortality

• reduced hybrid viability • reduced hybrid fertility • hybrid breakdown