Intro to Natural Selection Sept 2008 “Survival of the fittest”
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Intro to Natural Selection
Sept 2008Survival of the fittest
Get set: What have you learned?Survival depends on: Being able to obtain adequate amount of food and water.Being able to protect ones self from predation.Having characteristics to deal with the environment (climate, soil, plants, other animals.)Being able to reproduce to keep the species alive.
What happened to the animals in round 1 of the Staying Alive simulation?Toothpickta could not obtain enough food when climate changes affected their natural food source.Toothpickta became extinct.
What happened to the animals in round 2 of the Staying Alive simulation?Tweezarian had slight variations in their pinchers.Variations (mutations) are random some are helpful, some are not.Those with the helpful variation thrive and the tweezarian population eventually all display the improved variation.
What happened to the animals in round 3 of the Staying Alive simulation?Non-native species can be invasive.Native plant/animals can be affected when non-native species are introduced.Over-feeding can cause a disaster for the entire ecosystem.
A scientific ExplanationA theory is based on a number of observations or experiments.A theory attempts to explain natural phenomenon.
Natural Selectionthe process by which individuals that are better adapted to their environment survive and reproduce more successfully than less well-adapted individuals do.
Charles Darwin An English naturaliststudied animals on Galapagos IslandWrote the famous book: On the Origin of Species by Means of Natural Selection.Had a major impact on scientific community.
SPECIATIONTHE FORMATION OF NEW SPECIES
AS NEW SPECIES DEVELOP, POPULATIONS BECOME REPRODUCTIVELY ISOLATED
REPRODUCTIVE ISOLATION MEMBERS OF 2 POPULATIONS CANNOT INTERBREED & PRODUCE FERTILE OFFSPRING.
These squirrels live on opposite sides of the Grand Canyon. This is an example of allopatric speciation.
Fig. 23.6Four species of leopard frogs: differ in their mating calls. Hybrids are inevitable.
Hawaiian HoneycreepersFOUNDER SPECIESAn example of adaptive radiation these species all diverged from a common ancestor (founder species)
SPECIATION IN DARWINS FINCHESSPECIAITON IN THE GALAPAGOS FINCHES OCCURRED BY:
- FOUNDING OF A NEW POPULATION, - GEOGRAPHIC ISOLATION which led to -- REPRODUCTIVE ISOLATION and
CHANGES IN THE NEW POPULATIONS GENE POOL due to COMPETITION.
Can species combines in new and different ways today?
TigonResult of male tiger and female lion mating in captivity. Offspring are infertile. Separated both geographically and ecologically.
LigerResult of male lion and female tiger mating in captivity. Offspring are infertile.
Closure: Summarize What youve learned:Name 4 parts of Natural Selection.Explain how speciation can occur.