Unit 7-Change with Time (Evolution)

Evolution ► Change With Time ► The development of new types of organisms from pre-existing types of organisms over time

Diversity of life ► Wide variety of living things  Estimate over 10 million species

Adaptation ► An inherited trait that improves an organism’s chance of survival  Ex. long neck and legs of a giraffe  Coloration of a moth

Possible Explanations ► Lamarck ► Inheritance of Acquired Characteristics

Lamarck ► Use-Disuse  structures used develop  not used disappear

Lamarck ► Inheritance of Acquired Characteristics  Acquired characteristics- those obtained during the life of the organism- changes the body cells  THESE CANNOT BE INHERITED ► Long neck of giraffe

Darwin-Descent With Modification ► Theory of Natural Selection ► Those individuals with characteristics best suited to their environment will survive the struggle for existence, those not suited will die. ► “Nature selects” environment ► Differences are present in a species before the change occurs

Darwin- Theory of Natural Selection ► 4 Main Parts of Darwin’s Reasoning ► 1. Overproduction-  organisms produce more offspring than can survive to maturity ► 2. Genetic Variation-  individuals in a species are different from one another due to traits inherited  Ex. color, speed, strength, fur, structure

Darwin- Theory of Natural Selection ► 3. Struggle to Survive-  Overproduction  Limited resources  Competition  Leads to a struggle for existence

Darwin- Theory of Natural Selection ► 4. Differential Reproduction-  “Survival of the Fittest”  Only the fit survive  Those best adapted to the environment

Darwin- Theory of Natural Selection ► Fittest-  those best adapted to the environment ► Favorable traits are passed on to future generations-  since these traits are inherited and not acquired they will be passed on

Darwin- Theory of Natural Selection ► Giraffe