Presentation on theme: "As the 19th century dawned, it was generally believed that species had remained unchanged since their creation However, a few doubts about the permanence."— Presentation transcript:
Result Darwin's training and travel opportunities allowed him to formulate and support his ideas on Natural Selection.
Fig. 22-5 NORTH AMERICA EUROPE AFRICA AUSTRALIA GREAT BRITAIN SOUTH AMERICA ATLANTIC OCEAN PACIFIC OCEAN Cape of Good Hope Tierra del Fuego Cape Horn Tasmania New Zealand Andes Equator The Galápagos Islands Pinta Marchena Genovesa Santiago Daphne Islands Pinzón Fernandina Isabela San Cristobal Santa Fe Santa Cruz Florenza Española
Evolution Success Measured By Survival Reproduction Whoever lives long enough and has kids is the “winner” in evolution.
Requirements In order for Natural Selection to work, you must have: – Inheritable Variations within a population. – Long periods of time (according to Darwin).
Comment Acquired characteristics may allow a species to evolve "outside" of Natural Selection. Ex: culture, learning
Evidences for Evolution Direct observation of evolutionary changes. Fossils Homology Convergent Evolution Biogeography Molecular
Discussion Why is it that individual organisms cannot be said to evolve?
Though an individual may become modified during its lifetime through interactions with its environment, this does not represent evolution. Evolution can be measured only as a change in proportions of heritable variations from generation to generation.
How does Darwin’s theory of evolution relate to: Overproduction of populations? Limited resources? Heritable variation?
Species have the potential to produce more offspring than survive (over- reproduction), leading to a struggle for resources, which are limited. Populations exhibit a range of heritable variations, some of which confer advantages to their bearers that make them more likely to leave more offspring than less well-suited individuals. Over time this natural selection can result in a greater proportion of favorable traits in a population (evolutionary adaptation).
Next time…. Quiz and How Evolution is supported by an overwhelming amount of scientific evidence