Diversity of Life

EVOLUTION

DEFINITION

•Evolution is the biological change by which a population of organisms over time

species

A group of organisms so similar to one another they can reproduce and have fertile offspring

PRINCIPLES OF GEOLOGIC

CHANGE

Natural disasters such as floods and volcanic eruptions shaped landforms and caused species to become extinct in the process

Gradualism

Slow changes over a long period of time resulted in a gradual change of the species

Uniformitarianism

Geologic processes that shaped the earth are uniformthrough time

“Nothing in biology makes sense EXCEPT in the light of

evolution.” Theodosius Dobzhansky

Evolution

Charles Darwin in later years

James Hutton’s Theory of Geological Change

Described the Geological Forces that have changed Life on Earth over millions of years (erosion, earthquakes,

volcanoes…)

Idea Known as Gradualism

CONTRIBUTOR’S TO THEORIES OF EVOLUTION:

•Charles Lyell –

uniformintarianism (geologic

processes still changing Earth-

supported Hutton)

•John Baptiste Lamarck –

presented evolution as occurring due to environmental change over

long periods of time

:

•Thomas Malthus– related human population growth & the

production of food

•Alfred Russel Wallace – organisms evolved from

common ancestors – in Darwin’s Shadow

•Mendel – genetics - the missing link in evolutionary theory was

found

:

Idea called Law of Use and

Disuse

If a body part were used, it got

stronger

If body part NOT used, it

deteriorated

These traits could then be passed on to their offspring

Over time this led to new species

LAMARCK’S THEORY OF EVOLUTION

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C O P Y R I G H T C M A S S E N G A L E

SCIENTIFIC THEORY FOR

EVOLUTION IS SUPPORTED BY…

Fossil Record

Comparative Anatomy

Comparative Embryology

Biogeography

Molecular Biology

The Fossil Record

Fossils in different layers of rock (sedimentary Rock Strata) showed evidence Of gradual change over time

Comparative anatomy has long served as evidence for evolution

Homologous structures - structures are features that are similar in structure in different species but they have different functions An example is the forelimb structure shared by cats and whales. Analogous structures - structures that perform a similar function – but are not similar in origin. An example is the streamlined torpedo body shape of porpoises and sharks.

Analogous Structures

Homologous Structures

Bird Wing

Fly Wing

similarity among embryos of complex animals such as humans, chickens, frogs, reptiles, and fish

Comparative embryology

the science that seeks to explain the distribution of species How does a species move from area to area

Biogeography

How do climate changes affect geographical distribution

How has continental drift affected geographical distribution?

Similarities in DNA Sequence in different species

Molecular Biology