10.C BIO, HN Darwin Presents His Case (PART C)

Inherited variation

Members of each species vary from one another in important ways. Darwin argued these small differences among individuals within a species mattered.

Artificial selection

Selection by humans for breeding of useful traits from the natural variation among different organisms

Natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

Struggle for existence

Competition among members of a species for food, living space, and the other necessities of life

Fitness

Ability of an organism to survive and reproduce in its environment

Survival of the fittest

Process by which individuals that are better suited to their environment survive and reproduce most successfully; also called natural selection

Adaptation

Inherited characteristic that increases an organism's chance of survival that can be structural, physiological or behavioral

Structural adaptation

A physical structure possessed by organism gives it an advantage to survive. For example, large teeth/claws on a lion, spines on a cactus

Physiological adaptation

A chemical advantage possessed by the organism that gives it an advantage. For example, penicillin and sickle cell anemia resistance.

Behavioral adaptation

A behavior exhibited by the organism gives it a competitive advantage. For example, migration of birds to warmer climate, hibernation of bears, storing of nuts by squirrels in the winter

Darwin's Theory of Evolution

Modification by Natural Selection
States that evolution occurs via a process called natural selection.

Descent with Modification
States that newer forms appearing in the fossil record are the modified descendants of older species.

Common descent

Principle that all living things were derived from common ancestors

Common ancestor

An ancestral species from which later species evolved

Descent with Modification

Principle that each living species has descended, with changes, from other species over time

Fossil

Preserved remains or evidence of an ancient organisms

Fossil record

Information about past life, including the structure of organisms, what they ate, what ate them, in what environment they lived, and the order in which they lived

Biogeography

The study of the geographical distribution of fossils and living organisms

Homologous structure

Structures in different species that have different mature forms but develop from common embryonic structures, share a common ancestry, and result from divergent evolution.

Analogous structure

Structures that have the same function but different structures that result from convergent evolution

Vestigial structure

Remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species.

Embryology

Among different species, there are similarities in embryo appearance and anatomy. This concept supports the theory of evolution.

Molecular Genetics

DNA, RNA and amino acid comparisons are made between organisms; the MORE alike the organisms are the CLOSER the relationship; the LESS alike the organisms are the more DISTANT the relationship