Charles Darwin and his Finches Turn in your take home quiz to the box. Remember: if its not here today, its half credit only!

Who was Charles Darwin?  Charles Darwin was a naturalist. A naturalist is someone who studies plants and animals (nature)  Darwin served as a naturalist on the HMS Beagle  He went all over the world, but most famously, Charles Darwin went to the Galapagos Islands.

The Galapagos Islands  The Galapagos Islands are found west of S. America  They are an archipelago (a series of many islands)

The Galapagos Islands

 nature-places/coasts-and-islands/ecuador_galapagos/ nature-places/coasts-and-islands/ecuador_galapagos/   Darwin was very observant. He was intrigued by organisms he encountered.  Two organisms that particularly interested him were the finches and tortoises.

The Galapagos Islands  Darwin observed that the finches and tortoises were slightly different on each island.  The finches each had slightly different beaks and the tortoises had slightly different necks

The Galapagos Islands  Darwin saw that the tortoises were all very similar, but their necks were different lengths. Each type of tortoise was adapted specifically for its environment.  Darwin concluded that since these tortoises looked so much alike that they were related.

The Galapagos Islands  Darwin concluded that the tortoises all descended from one tortoise  Over time the tortoises changed and adapted to their specific environment  He concluded similar things about the finches

Darwin’s Finches

Charles Darwin  Charles Darwin looked at all the evidence he saw and came up with the theory of evolution.  Charles Darwin is credited with the theory of evolution.  cators/teachstuds/svideos.html cators/teachstuds/svideos.html

Evolution  Evolution is the change over time in populations of organisms

OMG?! Evolution!?  Evolution is a highly sensitive topic for some people  However, the scientific community recognized the theory of evolution as valid and well-supported  In life science, we will learn about evolution because it is scientifically accepted  “Science investigates; religion interprets. Science gives man knowledge, which is power; religion gives man wisdom, which is control. Science deals mainly with facts; religion deals mainly with values. The two are not rivals.” –Martin Luther King Jr.

Evolution Conflict  Some people feel conflicted between their religious beliefs and the conclusions of science  Many religious people have been able to reconcile the two and accept both  Ultimately, it is a personal journey you must take on your own  on/index.html on/index.html

Evolution: Not “Just A Theory”

 ors/teachstuds/svideos.html ors/teachstuds/svideos.html  What is the difference between a theory and a law?  How much support do scientific theories have?  If someone says something is “just a theory” how would you respond?

Theory vs. Law  In science, a theory is a well-supported explanation for why something in nature occurs  A law is a well-supported explanation of what occurs  Example: the theory of evolution explains why we see the diversity we do today and where organisms came from. Newton’s laws of motion explains that for every force there is an equal but opposite force. It doesn’t explain why.

More on Evolution  Organisms change over time  All organisms have natural variations  Variations have come from random mutations  Natural selection “chooses” the best variations

More on Evolution  Natural selection allows evolution to occur  Evolution eventually produces new species  So… mutation  variations  natural selection  evolution  new species!

Evolution  genes.html genes.html  What makes ice fish unique? How are they able to survive?

More on Evolution  Thus, everything is related to one another  All organisms came from one common ancestor

California Salamanders  n/evolution-action-salamanders.html n/evolution-action-salamanders.html  What are the two strategies used by the salamanders to adapt to their environment?  What is the problem with the hybrid?

Tree of Life   environment/natural-history/tree-life environment/natural-history/tree-life  ctive/ ctive/

Evidence for Evolution  The fossil record shows us organisms have changed over time  Though our fossil record is incomplete, it shows us many examples of organisms changing over time  Why is our fossil record incomplete?

Fossil Evidence  Fossils can show us ancestral or intermediate organisms

Vestigial Structures  Vestigial structures are body parts that have lost their original purpose through evolution  They provide support for evolution

Vestigial Structures

Embryology  Embryology is the study of developing embryos (fertilization to birth). It provides support for evolution.  All vertebrates (animals with backbones) have pouches called pharyngeal pouches during development  Other similarities exist too

Embryology  n/guess-embryo.html n/guess-embryo.html  Can you easily tell vertebrates apart as embryos?  How do these embryos support evolution?

Molecular Biology  Molecular biology is the study of genes and their function. It provides support for evolution.  Scientists can look at how much DNA particular organisms have in common to determine relatedness.

Molecular Biology  Human DNA only varies about 0.1% from individual to individual  Human DNA is only 1.2% different from chimpanzee DNA (This means we share 98.8% of our DNA!)  Humans share about 98.4% of our DNA with gorillas

Evolution game  and-interactives/charles-darwin- game.htm and-interactives/charles-darwin- game.htm