Introduction to Evolution

What is evolution? Monkeys to man? Survival of the fittest? Fish sprouting legs?

Evolution is not an “idea” that was made up by scientists!!!!!

What is natural selection? Who survives in the wild, the white or the purple polar bear? Why?

What is evolution? The basic definition: “A change in a population’s traits over time.” Genetic change can lead to phenotypic change

Why isn’t this evolution?

You do not evolve!!!!! If this isn’t evolution, what is it?

Charles Darwin 1809 - 1882 Studied medicine, but he did not like surgery on people without anesthesia. Then began studies in the clergy Set sail on a five-year trip (December 27, 1831) Wrote on the origin of the species

Voyage of the Beagle 1831 to 1836

Darwin considered puzzling questions during his voyage: Why do simple organisms appear in lower geographic layers? Why do more complicated fossils appear in upper layers?

Why do “unrelated” species resemble one another?

Darwin took detailed notes during the voyage. Geologic formations Mountains Islands River systems Strange organisms Flightless birds Finches One month visit to Galapagos islands. The most famous “stop” on the trip.

The Galapagos Finches- animals that are similar but have different looking beaks

Ok, so how does evolution work? Individuals get mutations 

Wait! How do you get mutations?

You CANNOT wish or hope for a trait! Otherwise….

Different phenotypes in population 

Those with good phenotype more likely to survive (wait!!!! What is a ‘good phenotype?’)

Those with better adaptations are more likely to pass mutated genes on when they….

As a result, more babies are made with that phenotype  population changes

Evolution Part 2

Have we actually seen evolution? English peppered moth Antibiotic resistance

There are two types of evolution: Microevolution: change within a species Macroevolution: change within a species that leads to formation of a new species

What examples do we have of microevolution?

http://evolution.berkeley.edu/evolibrary/home.php Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

What is some evidence for evolution? There are 5 big pieces of evidence…

1. Fossil Record

How it supports For the most part, the older the fossil, the less they are like the organisms today.

Extra Knowledge There are huge gaps in the fossil records

2. Vestigial Structures Sometimes organisms have structures that they do not use This shows us the structures may be left from a previous ancestor

3. Similar Skeleton Similar organisms have a similar skeleton, which shows they may have come from a common ancestor.

4. Similar DNA Similar organisms have similar DNA which shows they may have come from a similar organism

Extra Knowledge If organisms need to perform similar functions, then they will need to have similar DNA. Similar DNA will cause similar development of similar structures.

5. Embryology Similar organisms have similar development which shows they may have come from a common ancestor.