Natural Selection

a population can change over generations if individuals that posses certain heritable traits leave more offspring than other individuals

evolutionary adaptation

an accumulation of inherited characteristics that enhance organisms' ability to survive and reproduce in specific environments (result of natural selection)

evolution

a change over time in the genetic composition of a population (enough change>> new species)

taxonomy

the branch of biology concerned with the naming and classifying of organisms

catastrophism

each boundary between strata represents a catastrophe, such as a flood or drought, that destroyed many of the species living at that time

gradualism

he idea that profound change can take place through the cumulative effect of slow but continuous processes.. eg valleys formed through river running through rocks

uniformitarianism

the same geologic processes are operating today as in the past, and the the same rate

descent with modification

all organisms descended from an ancestor that lived in the remote past. As the descendants of that ancestral organism spilled into carious habitats over millions of years, they accumulated diverse modifications, or adaptations that fit them to specific way of life

What are the 3 inferences based of 5 observations?

1. Population size would increase if all individuals reproduced sucessfully.

2. Populations tend to remain stable in size

3. Resources are limited

   1. Production of more individuals than environment can sustain>> struggle for existence>> only fraction of offspring survive

4. Members of population vary in characteristics

5. Much variation is heritable

   1. Individuals whose inherited traits give them a high probability of surviving and reproducing in a given environment have higher fitness>> more offspring

   2. Unequal ability of individuals> gradual change in population> favorable characteristics accumulate over generations

artificial selection

humans modify species over generations by selecting and breeding individuals tht posess desired traits

Homology

characteristics in related species have underlying similarity even thought they may have very different functions (result of common ancestry)

homologous structures

variations on a structural theme that was present in common ancestor

vestigial organs

structures of marginal, if any, importance to the organism; remnants of structures that served important functions in the organism's ancestors

comparative embryology

the comparison of early stages of animal development

molecular homologies

all forms of life use same genetic machinery of DNA and RNA and genetic code is essentially universal

biogeography

losely related species tend to be found in the same geographic region, whereas the same ecological niches in distant regions are occupied by very different (though sometimes similar looking) species

endemic

species that are found nowhere else in the world