Evolution by Way of Natural Selection

Incorrect Theories of Evolution: Lamarck

•Lamarck proposed an ______mechanism for how organisms evolve

-Believed organisms could pass on ______traits to offspring.

–Simple life forms continually came into existence from ______

–Continually become more complex

–More "perfect" -- as they ______into new ______

•He ______pointed out that change in species is linked to an organism’s ______.

Who Was Charles Darwin

•______

•______

•______

•______

•______

Darwin’s Observations

•Animals on the coast of S. America:

– Resembled those on the nearby islands

–Evolved ______…Or…

–Descended w/ ______after separating from a ______.

Growth of Populations

•Darwin was influenced by Thomas Malthus

•He wrote: “Populations grow as much as the ______.”

Evolution by Natural Selection

•The process of: “Survival of the Fittest”

•Organisms that ______to their environment survive while those that
do not adapt ______

•N.S. leads to ______in a population.

•Adaptation = ______

•Fitness = ______

•YOU CANNOT AQUIRE AN ADAPTATION, MUST BE AN ______.

Natural Selection Video:

1. Genetic Variation

a. ______

b. ______

2. Overproduction of Offspring
a. ______

b. ______

3. Struggle for Existence
a. ______

b. ______

4. Differential Survival & Reproduction
a. ______

b. ______

Darwin’s Ideas Updated

1) Change Within Populations

•N.S. causes the frequency of certain ______in a population to change over time.

2) Species Formation

•Under certain conditions, change within a species due to ______can lead to new species.

3) The Tempo of Evolution

•______is a process of evolution in which speciation occurs gradually

•Punctuated Equilibrium is a process in which speciation occurs ______between periods of little or no change.

Examples of Evolution--

1) Factors in Natural Selection

•Organisms w/traits helping them survive—reproduce & ______

2) Evolution of Antibiotic Resistance

•Exp. show that evolution through N.S. has occurred within populations of antibiotic-resistant ______

–Tuberculosis bacteria, Influenza

3) Evolution in Darwin’s Finches

•Experiments show that evolution through N.S. has occurred in ______in Darwin’s Finches

Formation of New Species

1) Speciation = begins as a population adapts to its environment.

2) Forming Subspecies = Populations of the ______species that ______b/c of adaptations to different living conditions are called: subspecies.

•Newly formed subspecies are on the road towards speciation.

3) Maintaining New Species

•Reproductive isolation through ______keeps species from breeding with one another.