EVOLUTION Who is Charles Darwin? Where were the founding ideas of Evolution? What is evolution? Where are the Galapagos Islands?

EVOLUTION  “change over time”

THEORY  Well tested and supported idea  You do not have to agree with a theory  Evidence to support

CHARLES DARWIN  Born Feb 12 th, 1809  England  After college visited many continents as a part of the crew on the HMS Beagle  Naturalist  Observed diversity in organisms

GALAPAGOS ISLANDS “characteristics of many animals and plants varied from one island to the next.” – Charles Darwin

PEOPLE DIDN’T BELIEVE THAT THINGS CHANGED…

WHAT DOES THIS HAVE TO DO WITH CHARLES DARWIN AND EVOLUTION?

CHARLES LYELL JAMES HUTTON 1795  Two geologists who recognized that the Earth changes  Rocks form/change slowly (rock cycle)  Many forces at work  Proposed that the Earth had to be older than previously thought

CHARLES LYELL JAMES HUTTON 1795  Present events help to explain past events  Processes are ongoing  Change does occur

DARWIN CONSIDERS THIS…  Can living organisms change as well?  If so…they would change slowly…over time

LAMARCK  Early theory of evolution  Species descend from others  Living things change over time “selective use or disuse of organs, organisms acquired or lost traits in a lifetime. Traits can be passed to offspring…over time this leads to a change in a species.”

LAMARCK’S PRINCIPLES  1) Tendency towards perfection (birds want to fly)  2) Use/Disuse (front legs to wings)  3) Inheritance of acquired traits

LAMARCK’S PRINCIPLES  There were issues with Lamarck’s principles…but it was a start.  Adaptation  Inheritance

NATURAL VARIATION  Individual differences among species…

ARTIFICIAL SELECTION  Nature’s own variations.  Darwin considered this and decided that species naturally have genetic differences.

FITNESS ADAPTATION  Fitness- ability of an individual to survive and reproduce  Adaptation- inherited (behavior or physical) trait that increases an organisms chance of survival.

NATURAL SELECTION  “Survival of the fittest”- individuals that are better suited for the environment are more likely to survive and therefore reproduce passing off genetic variances to their offspring.

EVIDENCE FOR EVOLUTION  Vestigial organs  Fossil record  Homologous body structures  Geographic distribution of species

BIRD ADAPTATIONS  Galapagos finches  Individual traits suggest specific niches for birds and give indicators of feeding habits and habitats.

GENES AND VARIATION  Gene Pool- Combined genetic combination of an entire population.  -combinations of alleles (A,B,O,AB blood types), (eye colors etc.)  How often do you see those traits?- Relative frequency Blood Type and Rh United States Frequency % of U.S. Population O+1 in 337.4% O-1 in 156.6% A+1 in 335.7% A-1 in 66.3% B+1 in 128.5% B-1 in 671.5% AB+1 in 293.4% AB-1 in %

HOW DOES A POPULATION GAIN GENETIC VARIATION?  1) Genetic shuffling- random draw of genetic traits during meiosis. Crossing over. 8.4 million combos of genes in 23 chromosomes.  2) Mutations

SINGLE GENE VS. POLY GENE TRAITS  Review-  Single gene (controlled by a gene with two alleles) Widows Peak  Poly gene (controlled by two or more genes with multiple geno/phenotype possibilities) Height, eye color, skin color.

16-2 NATURAL SELECTION AND POPULATIONS  Nat selection acts on phenotypes not so much genotypes  Evolution acts on populations not individuals  What factors can change the frequency of alleles in a population?

FACTORS THAT AFFECT ALLELE FREQUENCY  Adding cards to the deck  Removing cards from the deck  (AKA- deaths without reproducing, individuals producing an abundance of offspring)

SINGLE GENE FREQUENCY  Simpler to calculate and understand  Coloration in an organism…  Allele could altogether disappear  Adaptations that enhance traits will survive

POLY GENE FREQUENCY  More complicated to predict  Ex. height

DIRECTIONAL SELECTION  Selection at one end of the curve increases due to higher fitness.

STABILIZING SELECTION  Individuals at the center (norm) of curve have a higher fitness than the ends of the curve.  Ex. Baby weight

DISRUPTIVE SELECTION  Individuals at high/low extreme of curve have a higher fitness that in the middle (norm)

GENETIC DRIFT  Random change in allele frequency  Can cause an allele to become more or less common over time

GENETIC EQUILIBRIUM  Allele frequency is constant  Population is not evolving

HARDY-WEINBERG PRINCIPLE  In order to have genetic equilibrium…  1- No mutations  2- No natural selection  3-Random mating  4-Large population  5-No movement into or out of population

SPECIATION  Formation of a new species  Organisms that breed with one another and produce fertile offspring.  Common gene pool

REPRODUCTIVE ISOLATION  As new species evolve populations become reproductively isolated from one another

BEHAVIORAL ISOLATION  Species have different behavioral practices such as mating song, and technique so they don’t reproduce together.

GEOGRAPHIC ISOLATION  Reproduction is isolated due to a physical barrier such as water, a landform (mountains) etc.

TEMPORAL ISOLATION  Reproduction is isolated due to different reproduction dates/times. (spring/fall)