The Fossil Record

The evolution of a structure, behavior, or internal process that enables an organism to respond to stimuli and better survive in an environment. A trait that gives an organism an advantage in the struggle for survival.

Adaptation in species develop over many generations and can be physiological or structural.

Can a human tell the difference between three

types of candies?

Mimicry Lab

Milk chocolate M&M – mmmmmmmm yummy good!

Skittles – tasty but will make you sick every time

Dark chocolate M&M – you DIE!!

3 •Species• an advantage•natural selection •fitness•alleles•adapting

2•natural variations•change•variation•favored trait •produce more offspring•new trait•organisms

1•Evolution•favored trait•genetic mutation•alleles •favor•reproduce •survival advantage•thousands or millions of years

Organisms have ___2___ of many traits and sometimes the environment can ___1___one ___2___over another. Other times a __1__can occur and a ___2___will appear that gives an organism ___3___in the environment. Those with the ___1__have a __1___and often live long and___2___. These organisms have a high level of ___2___ in the environment in which they live. As these organisms continue to______1____, passing on the __1___for the__2___, the frequency of those___3___ increases so that over time the species will__2___. This process is known as_____3____. A species ___3__ to its environment can take___1___. This is known as___1___. __3___evolve___2___ adapt.

Punctuated Equilibrium Gradualism

The biological species concept is based on inter-fertility, rather than physical similarity.

Can They

Reproduce?Eastern Meadowlark

Western Meadowlark

SPECIATIONA species is defined as being reproductively

isolated from other species.

HABITAT ISOLATION

BEHAVIORAL ISOLATIONTEMPORAL ISOLATION

MECHANICAL ISOLATION

GAMETIC ISOLATION

The Mechanics – attempts to reproduce may be made but because anatomy is incompatible reproduction can’t occur

Allopatric speciation, a species emerges due to geographic isolation

SPECIATION

Parapatric speciation adjacent populations become distinct species. Come in contact along a common border but prefer to mate with own kind – weak hybrids

Sympatric speciation species form within the range of a parent species. Something other than geographic isolation

Geographic barriers can start the process of

speciation

Ammospermophilus harisi

Ammospermophilus leucurus

Two species of garter snakes live in the same area but because one lives mainly in water and the other is primarily terrestrial they rarely encounter each other.

Gamete Isolation – The gametes do not form a zygoteChromosomal changes due to mutations

More common in plants

Western Spotted skunk

& Eastern

Spotted skunk

Share a habitat but mate at different times of the year Western = summerEastern = winter

CourtshipWhat lights your fire?

Many species have elaborate rituals for attracting a mate – what works for one

species doesn’t necessarily work for others

Species that were once similar to an ancestral species become increasingly distinct adapting

to different environmental conditions

Unrelated species occupy similar environments in different parts of the world. Develop similar

characteristics due to similar environmental pressures.

MASS EXTINCTIONIt’s all over!!