Evolution by Way of Natural Selection
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.