Evolution

Belief: OptionalUnderstanding & Participation:

Required

Incorrect Correct

Learning Target: Early Ideas About Evolution

I Can… Describe the various pre-Darwinian ideas about evolution and discuss how those ideas contributed to Darwin’s Theory of Evolution through the process of natural selection.

I Will…• Define relevant vocabulary terms• Identify the early naturalists and describe their

understanding of evolution.• List important ideas of uniformitarianism that

contributed to evolutionary theory.• Contrast gradualism and catatrophism.

Learning Target: Early Ideas About Evolution

Theory –• In common public usage –• An idea or notion – “I have a theory

about that…”• In Science –• An explanation that has been

confirmed to such a degree, by observation and experiment, that

knowledgeable experts accept it as fact e.g. gravity, relativity, electricity.

Learning Target: Early Ideas About Evolution

There were many ideas about biological and geological change prior to Charles Darwin’s

Theory of Evolution by Natural Selection.

Evolution – the process of biological change by which descendants come to differ from their ancestors.• Parents only donate one copy of their genes to their

offspring.• Offspring inherit two genes (one from each parent).• Genotype is the actual genes present in the organism.• Phenotype if the physical expression of the genes.

• Affected by; type of allele dominance, gene interactions (polygenic, epistatic), and environmental factors.

Review

Learning Target: Early Ideas About Evolution

Population – a group of the same species of organism located in the same geologic area.

Species – a group of organisms genetically similar enough to reproduce viable, fertile offspring.

Review

Key Concept: Populations evolve Individuals DO NOT evolve

• Baring mutations or intentional alteration of somatic cell DNA• The genes you inherit are yours

for your life and in every cell of your body.

Learning Target: Early Ideas About Evolution

Carolus Linnaeus – 1700s Swedish botanist • Developed classification system for organisms based on

grouping organisms by similarities and using evolutionary relationships.

• Abandoned common belief that organisms were always in their present form and did not change.• Hybridization (plant experiments)

Learning Target: Early Ideas About Evolution

Georges Buffon – 1700s French naturalist • Proposed that species share a common ancestor instead of

arising separately.• Rejected the idea that the Earth was only 6000 years old.

Learning Target: Early Ideas About Evolution

Eramus Darwin – 1700s / Charles Darwin’s Grandfather • Proposed all living things were descended from a

common ancestor.• More-complex forms of life arose from less complex

forms.

Learning Target: Early Ideas About Evolution

Jean-Baptiste Lamarck – 1800s French Naturalist • Proposed all organisms evolved toward perfection and

complexity. Inheritance of Acquired Traits• Did not believe that species became extinct, but just

evolved into different forms.• Proposed that environment caused behavior

to change leading to greater use or disuse of structures and organs.• Result organ grows bigger or smaller

Learning Target: Early Ideas About Evolution

Theories of geologic change set the stage for Darwin’s evolutionary theory.

Earth’s age – hotly debated• Common view – Earth was 6000 years old• Calculated by biblical reference

• Common belief that since the Earth was created

• Earth had not changed• Creatures on Earth had not

changed• No extinctions

Learning Target: Early Ideas About Evolution

Theories of geologic change set the stage for Darwin’s evolutionary theory.

Georges Cuvier – French Zoologist• Proposed that species could become extinct• Fossil evidence in Earth’s strata showed

different organisms at different layers.• Fossil – trace of organisms that

existed in the past. Something (such as a leaf, skeleton, or footprint) that is from a plant or animal which lived in ancient times and that you can see in some rocks (Merriam Webster.com)

Learning Target: Early Ideas About Evolution

Theories of geologic change set the stage for Darwin’s evolutionary theory.

Catastrophism- (Cuvier)• Natural disasters occurred often in Earth’s

past• Shaped landforms• Caused extinctions

• Other species moved into areas after extinction events• Explains different fossils in

layers of same area

Learning Target: Early Ideas About Evolution

Theories of geologic change set the stage for Darwin’s evolutionary theory.

Gradualism- (Hutton / 1700s Scottish Geologist)• Proposed slow changes over a long period of time

altered Earth’s structures.

Uniformitarianism – (Lyell / 1800s English Geologist)• Expanded gradualism

• Geologic processes are not only slow, but uniform through time

• Present processes occurred in past

Learning Target: Early Ideas About Evolution

Theories of geologic change set the stage for Darwin’s evolutionary theory.

Catastrophism Gradualism

Learning Target: Early Ideas About Evolution

Theories of geologic change set the stage for Darwin’s evolutionary theory.

Gradualism

Uniformitarianism

Learning Target: Early Ideas About Evolution

Darwin was influenced by both naturalists and geologists of the 1700 and 1800s.• Rejecting some ideas• Expanding other ideas

Think: Why was uniformitarianism stating that the Earth has gone through continuous gradual changes over billions of years important to Darwin’s Theory of Evolution by Natural Selection?