lamarck vs. darwin

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Lamarck vs. Darwin Introduction to change in organisms

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Lamarck vs. Darwin. Introduction to change in organisms. What is a theory?. The most probable explanation for a large set of data based on the best available evidence Summarizes a hypothesis or group of hypotheses that have been supported with repeated testing. - PowerPoint PPT Presentation

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Page 1: Lamarck vs. Darwin

Lamarck vs. Darwin

Introduction to change in organisms

Page 2: Lamarck vs. Darwin

What is a theory?

The most probable explanation for a large set of data based on the best available evidence

Summarizes a hypothesis or group of hypotheses that have been supported with repeated testing

Page 3: Lamarck vs. Darwin

What is a species?What is a population?

Species – group of a single type of organisms that interbreed and are reproductively isolated

White-tailed deer

Population – refers to a group of organisms of a particular species living in a certain area.

White-tailed deer on Mt. Nebo

Page 4: Lamarck vs. Darwin

Lamarck’s Theory Jean Baptiste Lamarck: 1800’s

Believed: Change Occurs Over Time inheritance of acquired

characteristics acquired changes were passed

to offspring Law of Use and Disuse

If a body part were used, it got stronger

If body part NOT used, it deteriorated

Examples: Body builders or pierced ears

Page 5: Lamarck vs. Darwin

Lamarck’s Theory of Evolution Giraffes all had

SHORT necks originally

Giraffe’s Necks got LONGER from stretching for food

“Acquired” trait (long necks) then passed to offspring

Giraffe population became long-necked

Page 6: Lamarck vs. Darwin
Page 7: Lamarck vs. Darwin

Lamarck’s Theory of Evolution More examples

Traits Acquired During Ones Lifetime Would Be Passed To Offspring

Clipped ears and tails of dogs could be passed to offspring!

Page 8: Lamarck vs. Darwin

Lamarck’s Mistakes Was he correct??

NO! Traits are passed down from one

generation to the next by GENES, not by an individual’s life experiences or activities

Lamarck did NOT know how traits were inherited (Traits are passed through genes)

Genes Are NOT Changed By Activities In Life

Change Through Mutation Occurs Before An Organism Is Born

Page 9: Lamarck vs. Darwin

Voyage of the Beagle

Charles Darwin Born Feb. 12, 1809 Joined Crew of HMS

Beagle, 1831 Naturalist 5 Year Voyage

around world Astounded By

Variety of Life

Page 10: Lamarck vs. Darwin

Voyage of the Beagle

During His Travels, Darwin Made Numerous Observations And Collected Evidence That Led Him To Propose A Revolutionary Hypothesis About The Way Life Changes Over Time

Page 11: Lamarck vs. Darwin

Darwin’s Belief’s Survival of the fittest OR

natural selection Food and resources are

limitedSo organisms have to

COMPETE to get them (lions fight for food, space, mates …)

• OVER PRODUCE too many organisms

• Not all offspring will survive only the MOST FIT (not always the strongest!)

Page 12: Lamarck vs. Darwin

What happened to the giraffe’s? Survival of the fittest or natural

selection Natural selection said the giraffes

with short necks had less food to eat

Why? the food resources changed to leaves

only on the upper branches What happened?

short necks could not reach upper branches and did not survive (couldn’t pass on genes)

Long neck giraffes survived & reproduced because they were able to reach the food

Page 13: Lamarck vs. Darwin
Page 14: Lamarck vs. Darwin

• Evolution is the slow, gradual

change in a population of organisms

over time…

a looooooooong time!

Page 15: Lamarck vs. Darwin

Where do Where do

we see we see

this this

change?change?

When there is an unequal unequal ability of ability of individuals to survive and reproduce …individuals to survive and reproduce …

This leads This leads to a to a gradual change gradual change in a in a population with population with favorable characteristicsfavorable characteristics accumulating over generations accumulating over generations

Most fit “Most fit “naturallynaturally” selected” selected New species evolvesNew species evolves

Page 16: Lamarck vs. Darwin

Natural Selection

How does Selection occur? Selection of the most fit can occur

from several factors:Variations exist among

individuals in a populationCompetition for limited resourcesOverpopulationPredation/Disease

Page 17: Lamarck vs. Darwin

Example of Natural Selection

A classic example of natural selection is the Peppered moths during Industrial Revolution in Europe

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