7th Grade Evolution & Natural Selection

Ancestor

Ancestor

A organism from which others have descended.

Cladogram

A tree-like diagram that displays evolutionary relationships among living species and their ancestors.

Comparative Anatomy, DNA analysis, and Fossil Record

3 major lines of evidence for theory of evolution

Comparative Anatomy

the study of anatomical similarities and the differences in species. In simpler words, the comparing body structures of two species

Homologous structurs

Body structures that have a common origin but do not have the same function.

Analogous structures

Structures that share the same functions but do not come from the origin.

Vestigial Structure

Structures that have lost a purpose/function. We do not need them.

Embryology

The study of unborn animals in a very early age of development. Considered evidence of evolution because of similarities of very different organisms.

Biochemistry

Most powerful form of evidence of evolution. Nucleic acids such as DNA and RNA are analyzed.

Adaptations

Inherited traits that help organisms survive and reproduce in its environment.

Evolution

The process of how organisms acquire adaptations over time.

Charles Darwin

proposed that natural selection is the process for evolution and noted the differences in finches’ beaks on the Galapagos Islands in 1859.

Natural Selection

The process by which organisms with favorable adaptations survive and reproduce at a higher rate than organisms with less favorable adaptations.

Overproduction

Populations producing more offspring than can survive to adulthood and reproduce

Genetic Variation

Individuals in a population can vary.

Speciation

Favorable adaptations accumulate

1 main idea behind natural selection

Favorable adaptations are selected

Competition

Overpopulation causes members of the same species, as well as other species, to compete for limited resources like food, water and a place to live.

Selective Breeding

Humans choose how animals adapt.

Selective Breeding

Takes a short period of time, cause by humans.

Natural Selection

Takes over a long period of time, caused by nature.