Ideas About Evolution Describe Lamarck’s hypothesis of acquired characteristics and Darwin’s theory of natural selection. Identify why variations in organisms are important. Compare and contrast gradualism and punctuated equilibrium

Early Models of Evolution group of organisms that share similar characteristics and can reproduce among themselves, producing fertile offspring SPECIES change in inherited characteristics over time EVOLUTION NATURAL SELECTION process by which organisms with traits best suited to their environment are more likely to survive and reproduce inherited trait that makes an individual different from other members of the species VARIATION any variation that makes an organism better suited to its environment ADAPTATION

Lamarckism Characteristics developed during a parent’s lifetime are inherited by the offspring. Evidence does not support this.

Darwin’s Finches

Darwin’s Finches competed The Galapagos finches ______________________ for food. Those that had _____________________, ______________________ that allowed them to get food were able to _________________ longer and _____________________ more. Over time, groups of finches became separate ___________________. advantages beak shapes survive reproduce species

Darwin’s 5 Principles of Natural Selection 1. Organisms produce more offspring than can survive 2. Differences, or variations, occur among individuals of a species 3. Some variations are passed to offspring 4. Some variations are helpful. Those with helpful variations survive and reproduce better. 5. Over time, offspring of individuals with helpful variations make up more of a population and may become a new species.

Variation vs. Adaptation

Variation vs. Adaptation DEFINITION AN INHERITED TRAIT THAT MAKES AN INDIVIDUAL DIFFERENT FROM OTHER MEMBERS OF ITS SPECIES ANY VARIATION THAT MAKES AN ORGANISM BETTER SUITED TO ITS ENVIRONMENT EXAMPLES

Polar Bear Two layers of fur Small ears Black skin Sensitive nose Long claws Webbed feet

Cuttlefish camouflage http://www.youtube.com/watch?v=pgDE2DOICuc

Variation vs. Adaptation WHAT HAPPENS HOW IT LEADS TO CHANGE CHANGES IN GENE SOURCES OVER TIME, GENETIC MAKEUP OF A SPECIES MAY CHANGE WHEN NEW INDIVIDUALS ENTER AN AREA THEY CAN BRING IN DIFFERENT GENES AND VARIATIONS GEOGRAPHIC ISOLATION MOUNTAINS AND LAKES CAN ISOLATE INDIVIDUALS FROM THE POPULATION OVER SEVERAL GENERATIONS, VARIATIONS NOT COMMON IN LARGE POPULATION MAY BECOME COMMON IN ISOLATED POPULATION http://www.youtube.com/watch?v=MAZfEdthTlo

Gradualism vs Punctuated Equilibrium Rapid change with few mutations Slow, ongoing process Both show evolution Continuous series of mutations Bacteria can change in just a few generations Intermediary forms - gradual change

Clues About Evolution Identify the importance of fossils as evidence of evolution Explain how relative and radiometric dating are used to estimate the age of fossils List examples of five types of evidence for evolution

Clues About Evolution a type of rock made from pieces of other rocks, minerals deposited from a solution, or plant and animal matter SEDIMENTARY ROCK RADIOACTIVE ELEMENT element that gives off a steady amount of radiation as it slowly changes to a nonradioactive element study of embryos and their development EMBRYOLOGY HOMOLOGOUS similar in structure, origin or function structure that does not seem to have a function and that may have functioned in the body of an ancestor VESTIGIAL

Green River Formation

Green River Formation

Clues About Evolution Relative age of the rocks Show what organisms looked like Information obtained from fossils Show that evolution has happened Habits and behaviors of ancient life

Relative Dating Youngest Oldest

Relative Dating

Clues About Evolution Homologous Structures Embryology Other clues about evolution DNA Vestigial Structures

Embryology

Homologous Structures

Convergent Evolution

Vestigial Structures