evolution. slide 1 - evolution change in species over
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Evolution
Slide 1 - EvolutionChange in species over.
Slide 2People used to believe:
•Species are designed by a divine creator (aka god) and are fixed/unchanging and perfect.
•False belief Earth is only 6000 years old.
•Earth is actually 4.5 Billion Years Old.
Slide 3Charles Darwin and
Evolutions
.
1809 -1882
Slide 4 - Darwin’s Voyage
1831 at age 22 Darwin took a
job as a naturalist on
the English ship HMS Beagle.
Slide 5 - Darwin’s voyage on the Beagle
Slide 6 - Galapagos IslandsSpecies were unique but similar to species elsewhere.
Slide 7 - Galapagos Tortoise
Slide 8 - Galapagos Iguana
Slide 9 - Galapagos Finches
Slide 10 - SpeciesSimilar traits and can mate and produce fertile offspring.But species within a population are different in some way.
Slide 11Natural SelectionWhat causes evolution!
Slide 12 - Peppered MothsBirds eat peppered moths!
What moth has the advantage?What moth population will be larger?
Slide 13 - Industrial Revolution
Covered trees and buildings with soot making them dark. Now which population
is favorable? Dark or white?
Slide 14 - Evidence of Evolution
Fossils
Adaptations
Anatomy
Embryology
Biochemistry
Slide 15 - FossilsShowed that whale ancestors once lived on
land.
Slide 16 - AdaptationsAny variation that aids an organisms chances for survival.
Structural Physiological
Evolves very SLOWLY Evolves RAPIDLY
Slide 17 - Structural Adaptations
Mimicry
Camouflage
Slide 18 - MimicryMimic = to copy someone
When one species resembles another species.
Slide 19 - CamouflageMatching in color with surroundings!
Slide 20 - Anatomy
Homologous Structures
Analogous Structures
Vestigial Structures
Slide 21 - Homologous StructuresHomo = Same
Same structures between species. Come from common ancestor!
Slide 22 - Analogous StructuresSimilar in function but not from common ancestor (e.g. Do bugs’ wings have bones like birds? No).
Slide 23Homology Versus Analogy
Slide 24 - Vestigial Structure
A body structure in a present-day organism that no longer serves its original purpose, but was probably
useful to an ancestor.
Slide 25 - Stop and Think!What’s a vestigial organ in humans?
Slide 26Vestigial Structure
Examples:Mole Rat Ostrich
Slide 27 - Embryo
Slide 28 - EmbryologyEmbryos have same structure among different species.
Slide 29 - Can you tell which will become a chicken? Cat? Bat?
Snake? Human? Possum?
Slide 30 - How about now?
Slide 31 - Now??
Slide 33 - BiochemistrySome organisms have similar DNA sequences.
Slide 34 - For Example:
Versus
Chimpanzee Gorilla
Slide 35 - For Example:
Versus
Chimpanzee Rose Bush
History of Earth
Slide 38 - Geologic Time ScaleSequence of events from Earth’s birth to present-day
(now).
Four main eras:
1. Precambrian (Earth Born) – First life evolved
2. Paleozoic – Plants evolved.
3. Mesozoic – Dinosaurs evolved
4. Cenozoic (Present – day) – Humans evolved
Slide 39 - When Earth was born No life existed.
Surface So hot all of Earth was melted rock!
Atmosphere No O2 because no plants existed yet! Only gasses from outgassing (Volcanoes erupting).
Oceans No liquid water. Too hot! Everything was Water vapor.
Slide 40 -Where did O2 come from?Photosynthesis from plants!
Slide 41 - RocksWhere fossils are found!
Slide 42 - FossilAnything left from a living organism.
Slide 43 - Types of fossils
Petrified Fossil
Casts
Imprint
Amber-Preserved
Ice - Preserved
Slide 45 - Fast Fact!About 99% of species that
have lived on Earth are extinct.
Slide 46 - How old are fossils? Relative Dating
Fossils found in layers closer to the surface are younger than the deeper layers.
Radiometric Dating
Measuring how much of an element is still present in a fossil, using the half life.
Slide 47 - Half LifeAmount of time it takes for a radioactive
element to decrease by half.
Slide 48 - PaleontologistPerson who studies fossils.
Size of Animal
How they moved
What they ate.
What climate they lived in.
When organisms lived.
Slide 49 - Plate Tectonics
Crust floats on the mantle which is
composed of molten (melted) rock.
Crust is divided into plates! Constantly
moving (1-10 cm/year)
Slide 50 - Pangaea “All Land”
All continents were once joined together.
Slide 51 - Pangaea SeparatedLaurasia and Gondwana
Slide 52 - Earth Today
As continents moved species became isolated and started to evolve differently.
Slide 53 - Stop and ThinkSomeone find a fossil of a polar bear that
lived a billion years ago in Hawaii.What was the latitude of Hawaii a billion
years ago?
Slide 54 - AustraliaSince it is so isolated from any other land,
it has very unique species.
Slide 55 - Fossil RecordOrdered levels of fossils in rock.
Indicates that organism have evolved in sequence.
History of Life
Slide 57 - Overview
Small Organisms = Bacteria (microscopic)
Large Organisms = Non-microscopic (flies, humans, etc.)
Slide 58Spontaneous Generation (SG)
False idea that non-living things can produce life. Life “spontaneously” appears.
Slide 59 - Francisco RediProved Spontaneous Generation was
wrong with a fly experiment.
Slide 60 – Redi’s Fly Experiment
Slide 61 - Louis Pasteur
Disapproved microscopic organisms spontaneously
appear.
Slide 62 - Before the Microscope
People believed that bacteria was generated from a “vital” force in the air.
Slide 63 - Pasteur’s Experiment
Bacteria create bacteria!
Slide 64 - BiogenesisLiving organisms come from other living
organisms.
Slide 65 - So where did the first life come from?
Slide 66 - BiomoleculesBio = Life
Molecules made by living things!
Proteins (Muscles and Bone)
Carbohydrates (Sugar)
Nucleic Acids (DNA and RNA)
Lipids (Fat)
Slide 67 - Alexander Oparin’s Hypothesis
How Biomolecules formed.
Lightning hit the atmosphere of early earth (ammonia, water vapor, methane, hydrogen gas) and caused amino acids to form.
Slide 68 - Stanley Miller and Harold Urey
Tested Oparin’s Hypothesis and found that it worked!
Speciation
Slide 70 - Speciation: When a species changes so much it
evolves into a new species.
Slide 71 - Gene Pool:All the alleles in a population.
Slide 72 - Allelic FrequencyThe Percentage of any specific
allele in the gene pool.
Allele # of Alleles in
Population
Allelic Frequency
R 5 5/20 = ¼ = 25%
r 15 15/20 = ¾ = 75%Total Alleles in population = 20
Slide 73 - Genetic Equilibrium
When % of alleles does not change.Population is NOT evolving!
Allele 2000 2005 Evolving?
R 25% 27%r 75% 73%
Slide 74 - What Changes Genetic Equilibrium?
Mutation Genetic Drift Migration
Slide 75 - MutationChanges in DNA sequence.
DNA Sequence: A-T-T-G-A-G-C
Mutated DNA Sequence: A-A-T-G-A-G-C
Slide 76 - Genetic Drift:Change in gene pool by chance events.
Affects small populations!
Slide 77 - Gene FlowMovement of genes In and out of a Population.
Slide 78 - SpeciesOrganisms that can can mate and produce fertile
offspring.
Slide 79 - What can prevent mating?
•Geographic Isolation
•Reproductive Isolation
•Polyploidy
Slide 80 - Geographic Isolation:When a physical barrier divides a
population.
Slide 81 - Example:
Marsupials in Australia
Slide 82 - Reproductive Isolation
Slide 83 - PolyploidAbnormal Chromosomes
E.g. Down Syndrome
Reproductive Cell
Gametes
Zygote
Slide 84 - Rates of Speciation
Gradualism
Punctuated Equilibrium
Slide 85 - Gradualism:Species evolve gradually.
Slide 86 - Punctuated Equilibrium:
Species evolve in quick bursts followed by stable periods!
Slide 87 - Patterns of EvolutionDivergent Evolution
Convergent Evolution
Slide 88 - Divergent Evolution: Evolution in which species diverge from an
ancestor.
Slide 89 - Convergent Evolution:When organisms evolve similar traits but did not
come from the same ancestor.
Slide 90 - Natural Selection
Mechanism for change in populations!
Slide – 91 Natural Selection Cont.
Traits vary in populations!
Slide 92 - 3 Types of Natural Selection
Stabilizing Selection
Directional Selection
Disruptive Selection
Slide 93 - Stabilizing Selection:Individuals with average traits tend to survive.
X-AxisBody Size
Pop. SizeY-Axis
Slide 94 - Directional SelectionIndividuals with one of the extreme variations of
a trait tend to survive.
Beak Size
Slide 95 - Disruptive Selection: Individuals with either extreme of a trait’s
variation tend to survive.
Limpet Color
Slide 96 - PopulationMembers of the same species that
live in the same area.
Populations not individuals evolve!
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