EvolutionEvolution

Chapters 15/16Chapters 15/16

Intro VideoIntro Video

• https://youtu.be/FpfAZaVhx3k?list=PLISBHwlJXpn2bmLjfiShKcIHpBPcov24O

• https://youtu.be/FpfAZaVhx3k?list=PLISBHwlJXpn2bmLjfiShKcIHpBPcov24O

EvolutionEvolution

• A change over time

• A process by which modern organisms have descended from ancient organisms

• Theory- a broad, well tested explanation that unifies a broad range of observations

• A change over time

• A process by which modern organisms have descended from ancient organisms

• Theory- a broad, well tested explanation that unifies a broad range of observations

Earth’s HistoryEarth’s History

• More than 4 Billion years old

• Fossils- preserved remains of ancient organisms

• Many modern life forms appear to be modifications of fossil forms

• More than 4 Billion years old

• Fossils- preserved remains of ancient organisms

• Many modern life forms appear to be modifications of fossil forms

Theories of EvolutionTheories of Evolution

• Three Scientists

• Lamarck• Malthus• Darwin

• Three Scientists

• Lamarck• Malthus• Darwin

LamarckLamarck

• French Scientist

• Proposed that acquired traits were passed on to offspring

• French Scientist

• Proposed that acquired traits were passed on to offspring

• Acquired Trait- one that is not determined by genes, instead arises over time by experience or behavior– Example- developing large muscles

• Disproved by current knowledge of genetics

• Acquired Trait- one that is not determined by genes, instead arises over time by experience or behavior– Example- developing large muscles

• Disproved by current knowledge of genetics

MalthusMalthus

• Stated that if the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone

• Stated that if the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone

Charles DarwinCharles Darwin

• British Scientist

• Sailed on ship HMS Beagle on trip to explore S. America

• Was the Naturalist on board, collecting plant and animal samples

• British Scientist

• Sailed on ship HMS Beagle on trip to explore S. America

• Was the Naturalist on board, collecting plant and animal samples

Darwin’s WorkDarwin’s Work

• While on the Beagle, Darwin collected and recorded information about all types of living species

• Back in Britain he analyzed his observation and published The Origin of Species

• While on the Beagle, Darwin collected and recorded information about all types of living species

• Back in Britain he analyzed his observation and published The Origin of Species

Darwin’s TheoriesDarwin’s Theories

• Descent with Modification- newer forms of life are modified descendents of older species

• Modification by Natural Selection- states how evolution is occurring

• Descent with Modification- newer forms of life are modified descendents of older species

• Modification by Natural Selection- states how evolution is occurring

Theory Part 2 ConceptsTheory Part 2 Concepts

• Natural Selection- organisms best suited to their environment will reproduce more successfully

• Adapt- a change in a population in response to the environment

• Natural Selection- organisms best suited to their environment will reproduce more successfully

• Adapt- a change in a population in response to the environment

• Fitness- an individual’s genetic contribution to the next generation– High fitness= more offspring

• Survival of the fittest- competition for food and living space will only allow for those best suited to environment to reproduce

• Fitness- an individual’s genetic contribution to the next generation– High fitness= more offspring

• Survival of the fittest- competition for food and living space will only allow for those best suited to environment to reproduce

Evidence of EvolutionEvidence of Evolution

• Homologous Features• Analogous Features• Vestigial Structures• Conserved Genes• Similarities in Embryos• Macromolecules

• Homologous Features• Analogous Features• Vestigial Structures• Conserved Genes• Similarities in Embryos• Macromolecules

Homologous FeaturesHomologous Features

• Similar features that have slightly different mature forms but originated from a common ancestor– Example- forearm

of mammals

• Similar features that have slightly different mature forms but originated from a common ancestor– Example- forearm

of mammals

Analogous FeatureAnalogous Feature

• Have same function, but have different development– Example: Wings

on bird and insect

• Have same function, but have different development– Example: Wings

on bird and insect

Vestigial StructuresVestigial Structures

• Organ that serves no current purpose in organism, but is believed to have one in ancestor– Examples:

• Tailbone in humans• Appendix in humans• Pelvic bones in

whales

• Organ that serves no current purpose in organism, but is believed to have one in ancestor– Examples:

• Tailbone in humans• Appendix in humans• Pelvic bones in

whales

Conserved GenesConserved Genes

• A gene that remains unchanged within DNA, but is turned off and not used– Example: hind

legs in whales

• A gene that remains unchanged within DNA, but is turned off and not used– Example: hind

legs in whales

Similar EmbryosSimilar Embryos

• During early fetal development, vertebrates all appear the same

• During early fetal development, vertebrates all appear the same

MacromoleculesMacromolecules

• All have DNA as basis

• Similar amino acid sequence that make up proteins– More similarities

the closer related the two organisms are

• All have DNA as basis

• Similar amino acid sequence that make up proteins– More similarities

the closer related the two organisms are

Patterns of EvolutionPatterns of Evolution

• Co-evolution

• Convergent

• Divergent

• Co-evolution

• Convergent

• Divergent

CoevolutionCoevolution

• Changes in two or more species in close association with each other– Example- plant

and animal pollinators

• Changes in two or more species in close association with each other– Example- plant

and animal pollinators

ConvergentConvergent

• Occurs when the environment selects for similar phenotype, even though ancestry is very different– Example- body

shape of dolphins and sharks

• Occurs when the environment selects for similar phenotype, even though ancestry is very different– Example- body

shape of dolphins and sharks

DivergentDivergent

• Two related species becoming different from one another

• Two Types– Adaptive– Artificial

• Two related species becoming different from one another

• Two Types– Adaptive– Artificial

• Divergent Adaptive- change is in response to habitat

– Example: Galapagos finches

• Divergent Adaptive- change is in response to habitat

– Example: Galapagos finches

• Divergent Artificial- other interference speeds up differences (breeding)

– Example: Dog breeding

• Divergent Artificial- other interference speeds up differences (breeding)

– Example: Dog breeding

Genetic EquilibriumGenetic Equilibrium

• Population Genetics- looking at evolution from a genetic point of view

• Population- members of a species that live in the same area and make up a breeding group

• Population Genetics- looking at evolution from a genetic point of view

• Population- members of a species that live in the same area and make up a breeding group

• In normal circumstances the percentages of a particular trait remain constant– Equilibrium

• In normal circumstances the percentages of a particular trait remain constant– Equilibrium

Disruption of EquilibriumDisruption of Equilibrium

• Mutation• Genetic Drift• Migration• Non-random Mating• Natural Selection

• Mutation• Genetic Drift• Migration• Non-random Mating• Natural Selection

• Mutation- any change to DNA

– Can affect the protein made which can affect the individual and their offspring

• Mutation- any change to DNA

– Can affect the protein made which can affect the individual and their offspring

• Genetic Drift- allele frequencies (%) change due to chance or random events

– Example- Natural disasters

• Genetic Drift- allele frequencies (%) change due to chance or random events

– Example- Natural disasters

• Migration- net movement in or out of a population

– Immigration- moving into a population

– Emigration- movement out of a population

• Migration- net movement in or out of a population

– Immigration- moving into a population

– Emigration- movement out of a population

• Migration creates gene flow

• Gene Flow- movement of genes from one population to another

• Migration creates gene flow

• Gene Flow- movement of genes from one population to another

• Non-random Mating- mating in small populations– Leads to higher

occurrences of disorders

– Example- Amish

• Non-random Mating- mating in small populations– Leads to higher

occurrences of disorders

– Example- Amish

Natural SelectionNatural Selection

• Traits being selected for or against

• Three Types– Stabilization– Directional– Disruptive

• Traits being selected for or against

• Three Types– Stabilization– Directional– Disruptive

Stabilization SelectionStabilization Selection

• Type of natural selection in which the average form is being selected for

• Type of natural selection in which the average form is being selected for

Directional SelectionDirectional Selection

• Type of natural selection in which one extreme is being selected for, creating movement in one direction

• Type of natural selection in which one extreme is being selected for, creating movement in one direction

Disruptive SelectionDisruptive Selection

• Type of natural selection in which the average is being selected against and both extremes are being selected for

• Type of natural selection in which the average is being selected against and both extremes are being selected for

Formation of SpeciesFormation of Species

• Speciation- process of forming new species

• Morphology- internal and external structure and appearance– Scientists use this as basis for

classifying species

• Speciation- process of forming new species

• Morphology- internal and external structure and appearance– Scientists use this as basis for

classifying species

• Biological Species Concept- A species is a population that can interbreed, but not breed with other groups

• Biological Species Concept- A species is a population that can interbreed, but not breed with other groups

Isolating MechanismsIsolating Mechanisms

• Mechanisms that can cause new species to form

• Two Types– Geographic

– Reproductive

• Mechanisms that can cause new species to form

• Two Types– Geographic

– Reproductive

• Geographic Isolation- having a physical barrier between groups– Example: river,

canyon, mountain

• Geographic Isolation- having a physical barrier between groups– Example: river,

canyon, mountain

• Reproductive Isolation- barrier to successful breeding

• Examples: different mating calls, different mating seasons

• Reproductive Isolation- barrier to successful breeding

• Examples: different mating calls, different mating seasons

Rates of SpeciationRates of Speciation

• Gradual- slow change over time– Lots of intermediates in fossil record

• Punctuated- sudden shift in fossil record– Could be caused by natural disaster

or other sudden change to environment

• Gradual- slow change over time– Lots of intermediates in fossil record

• Punctuated- sudden shift in fossil record– Could be caused by natural disaster

or other sudden change to environment