Catalyst: If the answer is False, explain why. True or false. Populations tend to be stable in size. True or false. All individuals in a species are exactly alike. True or false. Different traits can be inherited. True or false. Resources are unlimited. True or false. Natural selection is when organisms with superior traits survive to pass those traits onto offspring.

Evidence for Evolution

5 areas of scientific study provide evidence for evolution. 1.) Fossil Record 2.) Comparative Anatomy 3.) Comparative Embryology 4.) Molecular Biology 5.) Biogeography

Fossil Record The progression of forms observed in the fossil record is consistent with other inferences about the major branches of descent in the tree of life.

The Darwinian view of life Fossil Record The Darwinian view of life Predicts that evolutionary transitions should leave signs in the fossil record Paleontologists Have discovered fossils of many such transitional forms

Comparative Anatomy The study of anatomical structures and evolutionary relationships. Homologous structures Analogous structures Vestigial structures

Comparative Anatomy Homologous structures: are anatomical resemblances between organisms that represent variations on a structural theme that was present in a common ancestor Figure 22.14 Human Cat Whale Bat

Comparative Anatomy Analogous structures: superficial similarities that reflect an adaptation reflective of similar environments, not a descent from a common ancestor

Vestigial structures: remnants of structures that served important functions in the organism’s ancestors

Comparative Embryology Closely related organisms go through similar stages in their embryonic development. All vertebrate embryos go through a stage in which thy have gill pouches and tails.

Molecular Biology Scientists examine the nucleotide of DNA and amino acid sequences of proteins from different species. Closely related species share higher percentages of sequences than species that are distantly related.

Molecular Biology More than 98% of DNA sequences are identical in humans and chimpanzees.

Biogeography The use of geography to describe the distribution of species.

Biogeography: Divergent Evolution After the supercontinent Pangaea separated, similar species diverged due to different environments.

Biogeography: Convergent Evolution Unrelated species from different regions around the world converge or begin to look alike when found in similar environments.

Divergent Convergent Parallel Evolution Evolution Evolution

Connection: Biogeography and Comparative Anatomy Types of comparative anatomy can also be classified as convergent and divergent evolution, which structure is an example of divergent evolution? Convergent evolution?