Evolution part 1 Made just for You by: The Biology 1 Science Team International School Bangkok

Biological Evolution= The accumulation of genetic (inheritable) changes in populations over generations Note: populations can evolve, NOT individuals

Do you have what it takes?

Adaptation (noun) versus Adapt (verb) Physical versus Behavioral Organisms cannot adapt! Only Generations can!! Careful…

Examples of Camouflage Physical Adaptations:

Examples of Warning Coloration Physical Adaptations:

Behavioral Adaptations: migration cooperation

Charles Robert Darwin ( )  Born to a wealthy family he studied medicine at Edinburgh University but later switched to divinity at Cambridge.  His 5-year travels aboard the HMS Beagle led him to develop a theory of evolution through natural selection.  Knowing his work would be controversial he didn’t publish for nearly 20 years.

Influences on Darwin… 1.) Voyage of the HMS Beagle Witnessed a great diversity of living things around the world!

2) Finches of the Galapagos Islands Birds on the different islands had different adaptations, but all shared features with a bird relative on the main land.

3.) Charles Lyell’s Uniformitarianism The key to the past is the present! Things we see happening today must have been happening in the past.

4.) Thomas Malthus’s Populations Organisms tend to overproduce their offspring. But in nature, they don’t all survive to reproduce!

5.) Selective breeding (Artificial Selection) Certain favorable traits are passed down to future generations.

6.) Earlier Theories of Evolutuion Jean Baptiste Lamarck One of the first to propose biological evolution Studied similarities of living things Noticed fossil record and saw change over time Came up with some mechanisms for change, but based on false assumptions

Lammark’s (wrong) explanation of the Giraffe’s Neck “Use and Disuse” Acquired traits (within a lifetime) versus inherited traits (geneticaly inherited)

6.) Similar Theories Alfred Russell Wallace Alfred Russell Wallace “Father of Biogeography” (where organisms are found in the world) Came up with evolutiontheories around the same time as Darwin Published a book on evolution which prompted Darwin to get off his butt and publish his own book

 A man of many talents - an explorer, collector, naturalist, geographer, anthropologist and political commentator  He had the revolutionary idea of evolution by natural selection at the same time as Charles Darwin, but entirely independently  Wallace's remarkable accomplishments are not as appreciated today as they were in his own lifetime Alfred Russel Wallace ( )

Theory of NATURAL SELECTION Survival AND reproduction of the fittest!

1. Genetic variation exists within a population / species – Ex.White cheeked Roseola – Brazilian Drosophila poly.

Wow, look at all the variety! Restate Key Point #1 in your own words.

For natural selection to work… …variation must be heritable! Hair texture Hair color X Hair length

2. More offspring are born than can survive to reproduce Salmon ~25,000 eggs / female Very few (~2) survive to reproduce – Others: eaten, die of disease, don’t mate, etc.

Restate key point #2 in your own words. “Wow, look at all those babies!”

3. Resources are limited Food, water, shelter, mates, etc.

Restate key point #3 in your own words. “Uh oh, there’s not enough for everyone!”

4. Individuals in a population compete for resources Population - individuals of the same species in the same place and time have the SAME NEEDS Therefore they compete for the SAME things

Restate key point #4 in your own words. There’s going to be a fight!

5. Some variations will be more useful in the competition for survival and reproduction.

Restate key point #5 in your own words. Survival of the fittest!

6. Individuals with beneficial variations will survive longer / reproduce more frequently ?????

Conclusion: “Better adapted individuals tend to survive and reproduce at higher rates.” This is NATURAL SELECTION.

7. Over time, beneficial variations become more common and the population changes; this is evolution

Conclusion: “The changes add up and over time the species changes.” This is EVOLUTION.

Darwin-Wallace theory of evolution by NATURAL SELECTION (1858) 1.Genetic variation exists within a population / species 2.More offspring are born than can survive to reproduce 3.Resources are limited (food, mates, shelter, etc.) 4.Because of over-reproduction, individuals of the same species must compete for resources 5.Some variations in the population will be more (or less) useful in the competition for resources / survival / reproduction. 6.Individuals with beneficial variations will survive longer and/or reproduce more frequently 7.The beneficial variations become more common; thus the population / species changes over time

Natural Selection Which key points can you find illustrated here?

Natural Selection

Evolution Made Easy!