Unit 7-Change with TimeUnit 7-Change with Time(Evolution)(Evolution)

EvolutionEvolution

► Change With Change With TimeTime

► The development The development of new types of of new types of organisms from organisms from pre-existing pre-existing types of types of organisms over organisms over timetime

Diversity of lifeDiversity of life

► Wide variety of Wide variety of living thingsliving things

Estimate over 10 Estimate over 10 million speciesmillion species

AdaptationAdaptation

► An An inherited inherited traittrait that that improves an improves an organism’s chance organism’s chance of survivalof survival

Ex. long neck and Ex. long neck and legs of a giraffelegs of a giraffe

Coloration of a Coloration of a mothmoth

Possible ExplanationsPossible Explanations

► LamarckLamarck► Inheritance of Inheritance of

Acquired Acquired CharacteristicsCharacteristics

LamarckLamarck

► Use-DisuseUse-Disuse structures used structures used

developdevelop not used disappearnot used disappear

LamarckLamarck

► Inheritance of Inheritance of Acquired Acquired CharacteristicsCharacteristics Acquired Acquired

characteristics- characteristics- those obtained those obtained during the life of the during the life of the organism- changes organism- changes the body cellsthe body cells

THESE CANNOT BE THESE CANNOT BE INHERITED INHERITED

► Long neck of giraffeLong neck of giraffe

Darwin-Descent With Darwin-Descent With ModificationModification

► Theory of Natural Theory of Natural SelectionSelection

► Those individuals with Those individuals with characteristics best characteristics best suited to their suited to their environment will environment will survive the struggle survive the struggle for existence, those for existence, those not suited will die. not suited will die.

► ““Nature selects” Nature selects” environmentenvironment

► Differences are Differences are present in a species present in a species before the change before the change occursoccurs

Darwin- Theory of Natural Darwin- Theory of Natural SelectionSelection

► 4 Main Parts of 4 Main Parts of Darwin’s ReasoningDarwin’s Reasoning

► 1. Overproduction- 1. Overproduction- organisms produce more organisms produce more

offspring than can offspring than can survive to maturitysurvive to maturity

► 2. Genetic Variation- 2. Genetic Variation- individuals in a species individuals in a species

are different from one are different from one another due to traits another due to traits inheritedinherited

Ex. color, speed, Ex. color, speed, strength, fur, structurestrength, fur, structure

Darwin- Theory of Natural Darwin- Theory of Natural SelectionSelection

► 3. Struggle to 3. Struggle to Survive- Survive- OverproductionOverproduction Limited resourcesLimited resources Competition Competition Leads to a struggle Leads to a struggle

for existencefor existence

Darwin- Theory of Natural Darwin- Theory of Natural SelectionSelection

► 4. Differential 4. Differential Reproduction-Reproduction- ““Survival of the Survival of the

Fittest”Fittest” Only the fit surviveOnly the fit survive Those best adapted Those best adapted

to the environmentto the environment

Darwin- Theory of Natural Darwin- Theory of Natural SelectionSelection

► Fittest- Fittest- those best adapted those best adapted

to the environmentto the environment► Favorable traits are Favorable traits are

passed on to future passed on to future generations-generations- since these traits are since these traits are

inherited and not inherited and not acquired they will be acquired they will be passed onpassed on

Darwin- Theory of Natural Darwin- Theory of Natural SelectionSelection

►Giraffe Giraffe