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!