Theories of evolution

what is evolution?

the change in genetic composition of a population from generation to generation (descent with modification) over a long period of time

what are the 3 theories of evolution?

theory of Lamarck Darwin - Wallace theory Neo Darwinism

when did Lamarck publish his hypothesis?

1809

what are the 2 principles in the theory of Lamarck?

use and disuse inheritance of acquired characteristics

describe use and disuse with example

the parts of the body that are used extensively become larger and stronger. If not used they deteriorate. eg:- giraffe stretching its neck to reach leaves on higher branches

describe the inheritance of acquired characteristics

organisms acquire characteristics during their lifetime as adaptations to that environment and pass those characteristics to the next generation. eg:- long, muscular neck of the giraffe evolved over many generations as giraffes stretch their necks even higher

what is another name for Darwin- Wallace theory?

theory of natural selection

what 2 phenomena did Charles Darwin observe from the environment?

-populations of a species vary in characteristics among inheritance traits -each species produces more offspring than their environment could accommodate

what did Darwin interpret from his 2 observations?

• Certain traits of a population which are capable of exhibiting qualities for better survival and their reproduction produces more offspring -variation in abilities for survival and reproduction among a population may enhance the abundance of favorable characteristics in that population

what are some favorable characteristics for survival and reproduction?

-escaping from predators - defense -tolerating physical conditions- stress conditions -obtaining food -resistance against diseases -fertilizing probability -number of offspring produced

what are the steps of the process of natural selection?

-overpopulation -variation -competition and survival of the fittest -natural selection of favorable traits

What is Neo-Darwinism?

generally denotes the integration of Charles Darwin's theory of natural selection, Mendelian genetics as the basis of biological inheritance and knowledge of population genetics