University:
Indiana University East
Course:
BIOL-L 101 | Introduction to Biological Sciences I
Academic year:

2022
Views:

87

Pages:

5
Author:

Charlee Buchanan

Natural Selection and Evidence of Evolution Evolution ● includes all of the changes in the characteristics and diversity of life that occur throughout time Lamarck's Theory of Evolution ● One of first scientists to understand that change occurs over time ● Stated that changes are adaptations to environment acquired in an organism’s lifetime ● Said acquired changes were passed to offspring ● Organisms could change the size or shape of organs by using them or not using them Natural selection is a result of 4 factors: ● The potential for a species to increase in number ● The genetic variation of individuals in a species due to mutation and sextual reproduction- heritable ● Struggle for existence ○ Each species compete regularly to obtain food, living space ● Survival of the fittest ○ Fitness – ability of an individual to survive and reproduce in its specific environment ■Fitness results in adaptation Adaptation ● A variation that allows an individual to survive better than other individuals Natural selection leads to evolution ● The successful traits will spread through the population. ● Over time, natural selection, results in changes in the inherited characteristics of a population ● This change in the frequency of alleles in the population is evolution. Natural selection- Important points ● When individuals move into a new environment natural selection may result in adaptation to the new conditions ● Individuals do not evolve; populations evolve ● Natural selection can only work on heritable traits ● Environmental factors are variable ○ Ex: sickle cell allele ● Natural selection is not random. It occurs in response to environmental pressures and results in adaptation ● Things can change Descent with modification ● A single common ancestor that branched out to all different species Vestigial Structure ● A body part that no longer has a function ○ Their ancestors may have used it Fossils ● Life has changed over time Homologous Structures ● Structures that have different mature forms, but develop form the same embryological tissues Analogous Structures ● Serve the same function but look differently ● This tells us that we have very different species that evolved the same way ○ This is called convergent evolution- which is the evolution of the same biological trait in unrelated lineages ■They have similar environmental pressures for this to occur Comparative Biochemistry ● Similarities in DNA and proteins ● Amino acid sequences can be compared among various species for minor changes ● The more similar the code, the more closely related