EVOLUTION: The process by which organisms gradually change over time due to different traits inherited from ancestral organisms. It is driven (caused) by differences in both survival and reproductive rates for those organisms—the mechanism that results in evolution of organisms is called Natural Selection.
 DNA : Hereditary Material
 Gene Pool: common group of genes shared among member of a population
 Common Descent: species come from the same group of ancestors.
 Fitness: traits or behaviors that allow organisms to survive and reproduce in their environment
 Artificial Selection: humans selecting specific desired traits and breeding only the individuals that possess those traits.
 Natural Selection: organisms that are best adapted to their environment produce more offspring, passing on those traits that gave them beneficial adaptations.
 Adaptation: a trait that increase fitness.
 Niche: an organism’s habitat and its role in that habitat.
 Species: members of a group that look and behave in a similar fashion and can reproduce with one another—producing offspring that also survive and reproduce successfully.
 Allopatric speciation: new species forming in geographically separated areas.
 Sympatric speciation: new species forming in the same place due to non-geographic barriers—so, the timing of having babies is different, or the courtship behaviors are different, etc.
 Population: members of the same species living in an area where they can reproduce and produce viable, reproductive offspring.
 Phenotypic variation: members of the same species that look different from one another.
 Adaptive Radiation (Divergent Evolution): groups of organisms gradually look and behave differently from their ancestral group and other related groups because they live in different environments.
(So, even though they don’t look or act the same, they’re still “family”).
 Convergent Evolution: groups of organisms look alike because they live and use similar environments, but they are NOT closely related (They might look alike but they’re not related!).
 Homologous structures: structures that have different functions or appearances but had similar origins and are found in closely related species (like: arm – seal flipper – bat wing – dog forepaw)
 Analogous structures: structures that have similar functions and appearances but came from different, evolutionarily unrelated organisms (like: bat wing – bird wing – butterfly wing).
 Mutations (change to the genetic blueprint); genetic changes that result in changes in the organism.
 Vestigial organs: organs which may no longer be useful and are now reduced in size.
A Brief History of Evolutionary Study
 Carolus Linnaeus (mid-1730-1760’s)—devised the systematic classification system and binomial nomenclature (the naming system of genus and species)
 Lamark: Proposed the Theory of Inheritance of Acquired Characteristics (1800)—the “use it or lose it” theory of inheritance.
 Malthus: Population sizes are regulated by competition for resources and resource availability (1800)
 Darwin: Origin of Species and Descent of Man with Modification (1859)...and then Wallace too
 Mendal: principles of inheritance and the Father of Genetics. (1865)
 Watson, Crick, Wilkens, Franklin, Pauling: the structure of DNA is identified (1953)
Speciation: Making a New Species!
1. 2. 3.
Immigration: A group leaves its larger “home” group and moves to a new location
Founders arrive: The smaller group arrives at a new location
Reproductive Barrier: Something blocks the sub-group from going back and forth between its new home and the larger, main group from which it originally came.
 Geographic barrier: a mountain range, river, boulders, etc. that prevents the two groups from interbreeding.
 Temporal barrier: the timing of selecting mates or having babies changes so it’s no longer the same as that in the original group.
 Mechanical barrier: something prevents mating