NATURAL SELECTION, EVIDENCE OF EVOLUTION, AND EVOLUTIONARY BIOLOGY 10.3, 10.4, and 10.5

ARTIFICIAL SELECTION Humans making use of genetic variation in plants and animals by acting as the selective agent What in the world does that mean? What 3 examples of artificial selection you encounter every day?

HERITABILITY The ability of a trait to be passed down to successive generations Examples of heritable traits in dogs? Examples of heritable traits in humans?

STRUGGLE FOR SURVIVAL Resources are usually limited, but organisms tend to have more offspring than could ever survive What are some organisms that have many offspring but only a few survive? Why would some organisms do this?

4 PRINCIPLES OF NATURAL SELECTION Variation – heritable differences, that exist in every population are the basis for natural selection Overproduction – having many offspring. Increases chance of survival, but also competition

4 PRINCIPLES OF NATURAL SELECTION Adaptation – a variation that allows an organism to survive better than those it is competing against Descent with modification – over time species will have adaptations well suited for their survival. They will continue to pass these on as long as the environment remains favorable for those adaptations.

EVIDENCE OF EVOLUTION FOSSILS!!! Show that organisms have changed over time Many “intermediates” have been found that kind of link species together

GEOGRAPHY Plants and animals in one area can be similar, but not identical to plants and animals in nearby areas Different ecosystems lead to change in organisms if they migrated in Similar fossils can be found in completely different parts of the world May have been connected at one point in time

EMBRYOLOGY The study and comparison of larvae or embryos of different organisms Many vertebrate embryos can be very difficult to tell apart from each other Supported Darwin’s theory of organisms having a common ancestor Why?

ANATOMY The study of an organism and its constituent parts Basically looking at its bones and organs and comparing them to other stuff Why would this be important?

HOMOLOGOUS STRUCTURES Similar structures that appear in different organisms but have different functions

VESTIGIAL STRUCTURES Structures that may have been used before but no longer needed May still be present, but not really used Examples in humans? Examples in other organisms?