2Charles Darwin Evolution is change over time. The naturalist Charles Darwin was the first person to write a thorough collection of evidence supporting evolution.Darwin’s theory serves as the basis of all biological research today.Happy 203rd Birthday!!!2/12/1809
3Charles DarwinDarwin spent 5 years exploring South America and its remote islands, such as the Galapagos, on the HMS Beagle, starting in 1831.
4Charles DarwinDarwin made observations about the diversity and uniqueness of organisms.Many of the animals on the Galapagos were similar, but not identical to animals in mainland South America.Darwin thought maybe the animals in the Galapagos originally came from South America and over time, they had evolved.
5Charles Darwin Mainland South America Galapagos Islands Cormorants (sea birds)can fly.Cormorants are unable to fly.Iguanas have smaller claws for climbing.Iguanas have larger claws to grip rocks.
6Charles DarwinDarwin found giant tortoises on all the Galapagos Islands, but nowhere else.He reasoned that each new population changed slightly, or evolved, to fit its unique environment on the island.
12Charles DarwinSelective breeding is ON-PURPOSE breeding of plants and animals to get offspring with desired characteristics.This does not lead to a new species - the organism can still breed with other members of its species.
14Charles Darwin Evolution has been directly observed by humans. Over just a couple hundred years,wolves evolved into a little Pekingese.Just think what millions of years can do!!!
15Darwin’s Theory of Natural Selection Evolutionary Biologists are like detectives.They come on the scene AFTER the fact, but can figure out what happened because of clues left behind.
16Darwin’s Theory of Natural Selection Because of probability and genetics, some organisms have special traits that give them a survival advantage.If you survive longer, you produce more offspring.Over many generations, those GOOD traits would be common in the species.
19Darwin’s Theory of Natural Selection Sometimes changes occur in genes and a new trait is created.If the trait is beneficial, the organism may survive and pass the trait on to the next generation.Genetic variation is necessary for evolution to occur.
21Darwin’s Theory of Natural Selection Although resources are limited, animals often produce more offspring than could survive.Darwin decided this was a natural process that selected which organism survived, and called it natural selection.
23Darwin’s Theory of Natural Selection Adaptation refers to traits that increase the likelihood of surviving and reproducing in a particular environment.
24Darwin’s Theory of Natural Selection Four steps or requirements of Darwin’s theory of evolution by natural selection:Step 1: OverproductionStep 2: VariationStep 3: Inherited variationStep 4: Natural selection
25Darwin’s Theory of Natural Selection Overproduction – Organisms produce more offspring than can be supported by the available food, water, and shelter in an environment. Many will die due to natural events such as predation, competition, and starvation.
26Darwin’s Theory of Natural Selection Variation – Offspring vary in traits such as color and size.(as shown in a hypothetical fish population below)
27Darwin’s Theory of Natural Selection Inherited Variation – This is only genetic variation, traits that are passed from parent to offspring. Sources of variation include mutations, formation of gametes, and sexual reproduction.
28Darwin’s Theory of Natural Selection Natural Selection – Individuals with inherited variations that are better to survive and reproduce in a particular environment will have more offspring, and thus pass on these favorable traits, than individuals without those features.
30B their similarity to those on the mainland 5.1 Natural SelectionWhat did Darwin observe about the tortoises and finches in the Galapagos?A their large sizeB their similarity to those on the mainlandC their adaptations to their environmentsD their friendliness
31What is necessary for evolution to occur? A selective breeding 5.1 Natural SelectionWhat is necessary for evolution to occur?A selective breedingB genetic variationC populations isolated on islandsD none of the above
32What is not a main source of genetic variation? A differences in diet 5.1 Natural SelectionWhat is not a main source of genetic variation?A differences in dietB sexual reproductionC mutationsD gamete formation
33What is evolution?A adaptations to particular environmentsB genetic change in a population over timeC natural selectionD differences in traits
34What is necessary for natural selection to occur? A genetic variationB constant environmental conditionsC isolate populationsD shortage of offspring
35Which of the following is NOT one of the main sources of genetic variation in a population? A mutationsB learned abilitiesC formation of gametesD sexual reproduction
36B environmental factors C both D neither SCI 3.aWhat causes evolution?A genetic variationB environmental factorsC bothD neither
37A they have no natural predators B there are more of them SCI 3.eWhat is one reason exotic species can sometimes outcompete native species?A they have no natural predatorsB there are more of themC the new environment is more favorableD the natives are not adapted
38A overproduction of offspring SCI 3.bWhich of the following did not contribute to Darwin’s development of the theory of natural selection?A overproduction of offspringB competition with exotic species in the GalapagosC an essay on human population growthD similarities and differences of species in the Galapagos