EVOLUTION Evidence of Change

Living Things are Adapted to Their Environment ADAPTATIONS: traits that make living things able to survive its environment. can be physical or behavioral

Physical Adaptation

Behavioral Adaptation

Evolution modern organisms have descended from ancient organisms.

Charles Darwin: “Origin of Species” HMS Beagle 5 year voyage, started 1831 99.9% of all species are extinct. Very analytical/observant

Darwin’s questions: Where did this diversity of life come from? Why have many of them disappeared?

Darwin’s Points C.O.V.A 1. OVERPRODUCTION More offspring produced than survive. not enough food or space for all offspring. Exs. Fish eggs, dandelions, insects etc.

Darwin’s Points 2. COMPETITION Struggle to survive. Competition for food, water, space, soil, mates.

Darwin’s Points 3. VARIATION Organisms of same species are similar. But they have differences (Variations) If a group of people are running from a bear its not important to be the fastest. Just faster than some.

Darwin’s Points 4. Natural Selection is always taking place Survival of the fittest Organisms best suited to their environment 1.survive 2.reproduce 3.pass on their traits Organisms less fit reproduce fewer offspring

Patterns of Evolution Convergent Evolution: unrelated species become more similar as they adapt to the same kind of environment Analogous structures associated with convergent evolution Shark fins/Porpoises………fish/mammal Divergent Evolution: two or more related populations or species become more and more dissimilar; habitats differing can = new species

Patterns of Evolution Adaptive Radiation: type of divergent; many related species evolve from single ancestral species Galapagos Finches Artificial Selection: breeding of organisms by humans for specific phenotypic characteristics Speeds up divergence; dogs (Canis familiaris) All species today from divergence over long periods of time

Charles Darwin

Convergent Evolution

Evidence for Evolution Similarities in early development Similarities body structure Similarities in chemical compounds

Similarities in early development Embryos are organisms at early stages of development Embryos of many different animals appear similar during early stages of development

Similarities Body Structure Homologous structures: Limbs in many species are based on the same pattern of bones. Each limb is adapted in a different way to help the organism survive. Vestigial Organs: traces of organs that are no longer used by animals. For ex: small legs in snakes, appendix, lump in the corner of eye, miniature tail bones.

Similarities in Chemical Compounds All organisms use DNA to carry information from one generation to the next.