EVOLUTION

Evolution• Change over time• Occurs to species, not individual

• Explains diversity on Earth today

Diversity• Great variety of types of living

things• Between species

– 10 – 100 million species on earth• Within a species• Result of evolution

Diversity

Diversitybacteria

phytoplankton

zooplankton

Diversity

sponges

mollusks

Diversityechinoderms

Diversity

Evolutionary Tree

How Evolution Works• Explained by Charles Darwin

and Alfred Russell Wallace• Darwin wrote On

the Origin of Species

How Evolution Works• Darwin visited Galapagos

Islands on HMS Beagle

How Evolution Works1. Overpopulation• more individuals born than

can survive

How Evolution Works2. Competition• for limited resources• some will survive, some will

not

How Evolution Works3. Variation• differences among individuals• a result of geneticmutation – changes inDNA

How Evolution Works4. Adaptation• some variation gives some

individuals a slight survival advantage

• these are favorable traits

How Evolution Works5. Natural Selection• those with best traits survive,

reproduce and pass favorable traits on to their offspring

• the mechanism of evolution

natural selectionresulting inreduced armor insticklebacks

How Evolution Works6. Speciation• changes build up and the

species changes over time

Adaptations• traits or characteristics that help an organism survive in its ecosystem

• three types:

Adaptations1. Structural- physical structure thathelps organism survive

Adaptations2. chemical

- chemical that helps organism survive

Adaptations

3. behavioral- behavior that helpsorganism survive

Adaptations

Camouflage• Allows an organism to

blend with its environment

AdaptationsWarning Coloration• bright colors make an

organism easily recognized

AdaptationsMimicry• one species is protected by

resembling another species or part of an organism

flatworm (right)mimicing atoxic nudibranch(left)

Isolation• if one part of a population is separated or

isolated from another, speciation is more likely

Isolation

Through the process of evolution by natural selection we have the great diversity of organisms that inhabit the Earth today.

For the rest of the school year we will be examining the results of evolution. We will study the adaptations of marine organisms and how they evolved over the 3.7 billion years that there has been life on Earth.