1 Evolution, Biodiversity, and Community Processes La Cañada High School Dr. E

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Evolution, Evolution, Biodiversity, and Biodiversity, and

Community Community Processes Processes La CaLa Cañada High Schoolñada High School

Dr. EDr. E

http://abandoncorporel.ca/medias/evolution.jpg

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What types of Life What types of Life exist on the Earth? exist on the Earth?

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Types of OrganismsTypes of Organisms

• Prokaryotic KingdomProkaryotic Kingdom: : single-single-celled organisms containing no celled organisms containing no internal structures surrounded by internal structures surrounded by membranes (therefore there is no membranes (therefore there is no nucleus) nucleus) – MoneraMonera – bacteria and – bacteria and

cyanobacteriacyanobacteria

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Aerobic bacteria

Ancient Prokaryotes

Ancient Anaerobic Prokaryote

Primitive Aerobic Eukaryote

Primitive Photosynthetic Eukaryote

Chloroplast

Photosynthetic bacteriaNuclear

envelope evolving Mitochondrion

Plants and plantlike protists

Animals, fungi, and non-plantlike protists

Endosymbiotic TheoryEndosymbiotic Theory

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Types of OrganismsTypes of Organisms• Eukaryotic KingdomsEukaryotic Kingdoms: : all organisms consisting of all organisms consisting of

cells which contain membrane-bound nucleicells which contain membrane-bound nuclei– ProtistaProtista - mostly - mostly one-celled organisms – have one-celled organisms – have

characteristics of all three other Eukaryote Kingdomscharacteristics of all three other Eukaryote Kingdoms

– FungiFungi - - organisms which decompose stufforganisms which decompose stuff

– PlantaePlantae - - organisms which use photosynthesis to make organisms which use photosynthesis to make their own food their own food

• AnnualsAnnuals complete complete life cycle in one seasonlife cycle in one season

• PerennialsPerennials live for more than one seasonlive for more than one season

– AnimaliaAnimalia - - organisms which must get organic compounds organisms which must get organic compounds from food they eat - most are able to movefrom food they eat - most are able to move

• InvertebratesInvertebrates – – no backboneno backbone

• VertebratesVertebrates – – Fish, Amphibians, Reptiles, Birds and Fish, Amphibians, Reptiles, Birds and MammalsMammals

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http://www.mun.ca/biology/scarr/Five_Kingdoms_Three_Domains.htm

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Naming Naming SpeciesSpecies

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Naming of SpeciesNaming of SpeciesThe system of naming species was first developed by The system of naming species was first developed by Swedish botanist and physician, Carolus Linnaeus in the Swedish botanist and physician, Carolus Linnaeus in the mid- 1700smid- 1700s•Taxonomy, which seeks to describe, name and classify organismsTaxonomy, which seeks to describe, name and classify organisms•begins with assigning all species a two-part Latin name called a begins with assigning all species a two-part Latin name called a binomialbinomial•first word of the binomial is the genus name of the species, first word of the binomial is the genus name of the species, • second word is the specific epithet for the species. second word is the specific epithet for the species.

– scientific name for the blue crab is scientific name for the blue crab is Callinectes sapidusCallinectes sapidus– CallinectesCallinectes, the genus name, is the collective term which , the genus name, is the collective term which

includes many species of crabs closely related to the blue crabincludes many species of crabs closely related to the blue crab– sapidussapidus, describes exactly which of the , describes exactly which of the CallinectesCallinectes species is species is

being identifiedbeing identified

http://www.falcons.co.uk/mefrg/Falco/13/Species.htm

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http://www.dnr.state.md.us/education/horseshoecrab/lifecycle.html

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http://www.sms.si.edu/irlspec/NamSpecies.htm

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Definition of SpeciesDefinition of Species• Morphological Species Concept (MSC) Morphological Species Concept (MSC)

– traced back to the philosophies of Plato traced back to the philosophies of Plato and Aristotle, and which and Aristotle, and which continued to be continued to be used until the first half of the twentieth used until the first half of the twentieth centurycentury

– defines species purely by their defines species purely by their phenotypic traits rather than their phenotypic traits rather than their genetic complement or potential genetic complement or potential interbreedinginterbreeding

– number of species classified was large number of species classified was large because each group of individuals that because each group of individuals that exhibited a slight phenotypic difference exhibited a slight phenotypic difference were considered a different specieswere considered a different species



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Definition of SpeciesDefinition of Species• Biological Species Concept (BSC) Biological Species Concept (BSC)

– ‘‘a species is a group of interbreeding a species is a group of interbreeding populations that are genetically isolated from populations that are genetically isolated from other groups by reproductive isolating other groups by reproductive isolating mechanisms such as hybrid sterility or mate mechanisms such as hybrid sterility or mate acceptability’acceptability’

• Phylogenetic Species Concept (PSCPhylogenetic Species Concept (PSC– Each population of sexually reproducing Each population of sexually reproducing

organisms that possesses at least one organisms that possesses at least one diagnostic character present in all population diagnostic character present in all population members but absent from all closest relatives members but absent from all closest relatives is considered a speciesis considered a species

– each geographically distinct form is each geographically distinct form is classified as a speciesclassified as a species



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How did Life How did Life Originate?Originate?

OrOrChemical EvolutionChemical Evolution

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EVOLUTIONEVOLUTIONisis

Gradual ChangeGradual Change

EVOLUTIONEVOLUTIONisis

Gradual ChangeGradual Change

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Origin of LifeOrigin of Life• 600 BC Anaximander600 BC Anaximander

– life began in water.life began in water.– early forms were simple.early forms were simple.– simple forms begat more complex forms over timesimple forms begat more complex forms over time

• Aristotle (350 BC)Aristotle (350 BC) – decayingdecaying material could be transformed by the material could be transformed by the

‘Spontaneous Action of Nature' into living animals‘Spontaneous Action of Nature' into living animals

• ArchBishop Usher (early 1600’s)ArchBishop Usher (early 1600’s) and his scholars and his scholars – provided exact dates for all the various occurrences in the provided exact dates for all the various occurrences in the

new Bible being translated for King James new Bible being translated for King James – ‘‘proved’ to the King that the world was created on proved’ to the King that the world was created on

Tuesday, October 8, 4004 BC at 9:30 in the morningTuesday, October 8, 4004 BC at 9:30 in the morning

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Chemical EvolutionChemical EvolutionOparin Hypothesis (early 1930s)Oparin Hypothesis (early 1930s)

1) 1) Formation of the planetFormation of the planet with gases in the with gases in the atmosphere that could serve as the raw atmosphere that could serve as the raw materials for life. materials for life. – most widely accepted astronomical theory for most widely accepted astronomical theory for

the origin of the earth and the rest of the solar the origin of the earth and the rest of the solar system is that the solar system formed about system is that the solar system formed about 4.7 billion years ago from a diffuse dust cloud4.7 billion years ago from a diffuse dust cloud

– central portion probably condensed to form central portion probably condensed to form the sun and areas in the outer parts of the the sun and areas in the outer parts of the cloud condensed to form the planetscloud condensed to form the planets

– beginning of the universe according to the "Big beginning of the universe according to the "Big Bang" theory occurred about 15 billion years Bang" theory occurred about 15 billion years agoago

http://nsm1.nsm.iup.edu/rwinstea/oparin.shtm

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Chemical EvolutionChemical EvolutionOparin HypothesisOparin Hypothesis

2) 2) Random synthesis of simple organic moleculesRandom synthesis of simple organic molecules (such as amino acids that make up proteins) (such as amino acids that make up proteins) from the gases in the surrounding atmosphere.from the gases in the surrounding atmosphere.

3) 3) Formation of larger, more complex moleculesFormation of larger, more complex molecules (Macromolecules) from the simple organic (Macromolecules) from the simple organic molecules, e.g., the formation of simple proteins.molecules, e.g., the formation of simple proteins.

4) 4) Formation of coacervatesFormation of coacervates - unique droplets - unique droplets containing the macromolecules , i.e., a containing the macromolecules , i.e., a coacervates consists of chemicals suspended coacervates consists of chemicals suspended within a liquid surrounded by a membrane, e.g. within a liquid surrounded by a membrane, e.g. a droplet consisting of chemicals in water a droplet consisting of chemicals in water surrounded by an oil layer membrane.surrounded by an oil layer membrane.

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Chemical EvolutionChemical EvolutionOparin HypothesisOparin Hypothesis

5) 5) Development of some type of chemical organizersDevelopment of some type of chemical organizers that function to give these droplets the ability to that function to give these droplets the ability to take in molecules, discharge other molecules, and take in molecules, discharge other molecules, and control and maintain a characteristic chemical control and maintain a characteristic chemical pattern. These chemical organizers would pattern. These chemical organizers would probably be similar to nucleic acids (that make up probably be similar to nucleic acids (that make up chromosomes).chromosomes).

6) 6) Development of controlled reproductionDevelopment of controlled reproduction to insure to insure that resultant daughter cells have the same that resultant daughter cells have the same chemical capabilities. The droplets could now be chemical capabilities. The droplets could now be considered to be primitive cells.considered to be primitive cells.

7) 7) Beginnings of evolutionary developmentsBeginnings of evolutionary developments so that a so that a group of cells could adapt to changes in the group of cells could adapt to changes in the environment over time.environment over time.

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Miller-Urey ExperimentMiller-Urey Experiment• conducted in 1953 by Stanley Miller with conducted in 1953 by Stanley Miller with

Harold UreyHarold Urey• the first experiment to about the evolution of the first experiment to about the evolution of

prebiotic chemicals and the origin of life on prebiotic chemicals and the origin of life on EarthEarth

– mixture of methane, ammonia, mixture of methane, ammonia, hydrogen, and water vapor introduced hydrogen, and water vapor introduced into a 5-liter flask (simulate the into a 5-liter flask (simulate the Earth's primitive, reducing Earth's primitive, reducing atmosphere) atmosphere)

– energized by an electrical discharge energized by an electrical discharge apparatus to represent ultraviolet apparatus to represent ultraviolet radiation from the Sunradiation from the Sun

– products were allowed to condense products were allowed to condense and collect in a lower flask which and collect in a lower flask which modeled a body of water on the modeled a body of water on the Earth's surfaceEarth's surface

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Miller-Urey ExperimentMiller-Urey Experiment– heat supplied to this flask heat supplied to this flask

recycled the water vapor just as recycled the water vapor just as water evaporates from lakes and water evaporates from lakes and seas, before moving into the seas, before moving into the atmosphere and condensing again atmosphere and condensing again as rainas rain

– after a day of continuous after a day of continuous operation operation

• a thin layer of hydrocarbons on the a thin layer of hydrocarbons on the surface of the watersurface of the water

– after about a week of operationafter about a week of operation• a dark brown scum had collected in a dark brown scum had collected in

the lower flask and was found to the lower flask and was found to contain several types of amino contain several types of amino acids, including glycine and acids, including glycine and alanine, together with sugars, tars, alanine, together with sugars, tars, and various other unidentified and various other unidentified organic chemicals organic chemicals

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The Just-Right PlanetThe Just-Right PlanetRead CONNECTIONS on page 139. Read CONNECTIONS on page 139.

http://csep10.phys.utk.edu/astr161/lect/time/eclipses_lunar.html

http://images.google.com/imgres?imgurl=tubes.ominix.com/art/a/landscapes/landscape-ice-mountains-in-water.jpg&imgrefurl=http://tubes.ominix.com/art/a/landscapes/&h=480&w=640&prev=/images%3Fq%3Dwater%2Bice%2B%26start%3D20%26svnum%3D100%26hl%3Den%26lr%3Dlang_en%26ie%3DUTF-8%26oe%3DUTF-8%26sa%3DN

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Evolution of First LifeEvolution of First Life• Formation of the earliest precursors of life Formation of the earliest precursors of life

–must have self-organizedmust have self-organized

–acquired the capabilities needed to survive and reproduceacquired the capabilities needed to survive and reproduce

• Biomolecules of life became enclosed within a lipid Biomolecules of life became enclosed within a lipid membranemembrane–forming rudimentary assemblages that resembled cells or forming rudimentary assemblages that resembled cells or

protocellsprotocells

• Essential protocellular functionsEssential protocellular functions–acquisition of energy from the environment acquisition of energy from the environment

–use of energy to synthesize molecules – use of energy to synthesize molecules – metabolismmetabolism

–information transfer to succeeding generations – information transfer to succeeding generations – geneticsgenetics

http://www.unm.edu/~astro1/ET109/intelligence/coacervate%20photo.gif

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EvidenceEvidence

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FossilsFossils• Oldest fossils are the Oldest fossils are the

approximately 3.465 approximately 3.465 billion-year-old billion-year-old microfossils from the microfossils from the Apex Chert, AustraliaApex Chert, Australia– colonies of colonies of

cyanobacteria cyanobacteria (formerly called blue-(formerly called blue-green algae) which green algae) which

built real reefsbuilt real reefs

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FossilsFossils1600's - Danish scientist Nicholas Steno studied 1600's - Danish scientist Nicholas Steno studied the relative positions of sedimentary rocksthe relative positions of sedimentary rocks

– LayeringLayering is the most obvious feature of sedimentary is the most obvious feature of sedimentary rocksrocks

• formed particle by particle and bed by bed, and the layers formed particle by particle and bed by bed, and the layers are piled one on top of the otherare piled one on top of the other

• any sequence of layered rocks, a given bed must be older any sequence of layered rocks, a given bed must be older than any bed on top of itthan any bed on top of it

– Law of SuperpositionLaw of Superposition is fundamental to the is fundamental to the interpretation of Earth history, because at any one interpretation of Earth history, because at any one location it indicates the relative ages of rock layers location it indicates the relative ages of rock layers and the fossils in them. and the fossils in them.

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Half-life for a given radioisotope is the time for half the Half-life for a given radioisotope is the time for half the radioactive nuclei in any sample to undergo radioactive nuclei in any sample to undergo

radioactive decayradioactive decay

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Half-life for a given radioisotope is the time for half the Half-life for a given radioisotope is the time for half the radioactive nuclei in any sample to undergo radioactive nuclei in any sample to undergo

radioactive decayradioactive decay

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Biological Biological EvolutionEvolution

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(ORGANIC) EVOLUTION: (ORGANIC) EVOLUTION: change in change in gene frequenciesgene frequencies

within populations from within populations from generation to generation.generation to generation.

(ORGANIC) EVOLUTION: (ORGANIC) EVOLUTION: change in change in gene frequenciesgene frequencies

within populations from within populations from generation to generation.generation to generation.

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(ORGANIC) EVOLUTION: (ORGANIC) EVOLUTION:

gene frequencies over timegene frequencies over time

…no concepts of…no concepts of “planning” or “planning” or “progress”“progress” apply. No goals! apply. No goals!

(ORGANIC) EVOLUTION: (ORGANIC) EVOLUTION:

gene frequencies over timegene frequencies over time

…no concepts of…no concepts of “planning” or “planning” or “progress”“progress” apply. No goals! apply. No goals!

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Early Evolutionists’ Early Evolutionists’ Anthropocentric view: Anthropocentric view:

Scala Natura Scala Natura (ladder of life).(ladder of life).



A linear rise A linear rise from from ‘primitive’ to ‘primitive’ to ‘advanced’.‘advanced’.

A linear rise A linear rise from from ‘primitive’ to ‘primitive’ to ‘advanced’.‘advanced’.

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Needless to say, we Needless to say, we are the are the most most ‘advanced’‘advanced’ in this in this scheme…scheme…after all, it’s after all, it’s our ladderour ladder!!!!

Needless to say, we Needless to say, we are the are the most most ‘advanced’‘advanced’ in this in this scheme…scheme…after all, it’s after all, it’s our ladderour ladder!!!!

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Evolutionary BushEvolutionary BushEvolutionary BushEvolutionary BushOne life-form splits into two One life-form splits into two and those branches split and those branches split (independently) to make (independently) to make more.more.

One life-form splits into two One life-form splits into two and those branches split and those branches split (independently) to make (independently) to make more.more.

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Phenotypic Phenotypic ‘distance’‘distance’

Phenotypic Phenotypic ‘distance’‘distance’

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Evolutionary Bush -- Evolutionary Bush -- thousands of earlier and thousands of earlier and later branches.later branches.

Evolutionary Bush -- Evolutionary Bush -- thousands of earlier and thousands of earlier and later branches.later branches.

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At any given moment (e.g. the At any given moment (e.g. the ‘present’), all we see is ‘present’), all we see is current current

diversitydiversity……all all extinctextinct forms are gone (99.9%) forms are gone (99.9%)

At any given moment (e.g. the At any given moment (e.g. the ‘present’), all we see is ‘present’), all we see is current current

diversitydiversity……all all extinctextinct forms are gone (99.9%) forms are gone (99.9%)

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Four causes of evolutionary Four causes of evolutionary change:change:Four causes of evolutionary Four causes of evolutionary change:change:

1.1. MutationMutation:: fundamental origin of fundamental origin of allall genetic genetic (DNA) change.(DNA) change.


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Point mutationPoint mutationPoint mutationPoint mutation

……some at base-pair levelsome at base-pair level……some at base-pair levelsome at base-pair level

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1.1. MutationMutation:: fundamental origin of fundamental origin of allall genetic (DNA) change.genetic (DNA) change.

1.1. MutationMutation:: fundamental origin of fundamental origin of allall genetic (DNA) change.genetic (DNA) change.

Crossing-overCrossing-overCrossing-overCrossing-over

……others at grosser others at grosser chromosome levelchromosome level……others at grosser others at grosser chromosome levelchromosome level

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1.1. MutationMutation: fundamental genetic shifts.: fundamental genetic shifts.

2.2. Genetic DriftGenetic Drift:: isolated populations accumulate isolated populations accumulate different mutations over time.different mutations over time.



In a continuous In a continuous population, genetic population, genetic novelty can spread novelty can spread locally.locally.

In a continuous In a continuous population, genetic population, genetic novelty can spread novelty can spread locally.locally.

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2.2. Genetic DriftGenetic Drift:: isolated populations isolated populations accumulate different mutations over time.accumulate different mutations over time.



Local spreading of allelesLocal spreading of allelesLocal spreading of allelesLocal spreading of alleles

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Local spreading of allelesLocal spreading of allelesLocal spreading of allelesLocal spreading of alleles

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Spreading process Spreading process known as ‘known as ‘gene gene flowflow’.’.

Spreading process Spreading process known as ‘known as ‘gene gene flowflow’.’.

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But in But in discontinuousdiscontinuous populations, populations, gene gene flowflow is blocked. is blocked.

But in But in discontinuousdiscontinuous populations, populations, gene gene flowflow is blocked. is blocked.

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Variations Variations accumulate without accumulate without inter-demicinter-demic exchange exchange

Variations Variations accumulate without accumulate without inter-demicinter-demic exchange exchange

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Of course, this Of course, this works at many works at many loci loci simultaneouslysimultaneously

Of course, this Of course, this works at many works at many loci loci simultaneouslysimultaneously

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Four causes of evolutionary changeFour causes of evolutionary changeFour causes of evolutionary changeFour causes of evolutionary change


2.2. Genetic DriftGenetic Drift: isolation : isolation accumulate accumulate mutations mutations

3.3. Founder EffectFounder Effect:: sampling biassampling bias during during immigration. When a new population is immigration. When a new population is formed, its genetic composition depends formed, its genetic composition depends largely on the gene frequencies within the largely on the gene frequencies within the group of first settlers.group of first settlers.


2.2. Genetic DriftGenetic Drift: isolation : isolation accumulate accumulate mutations mutations

3.3. Founder EffectFounder Effect:: sampling biassampling bias during during immigration. When a new population is immigration. When a new population is formed, its genetic composition depends formed, its genetic composition depends largely on the gene frequencies within the largely on the gene frequencies within the group of first settlers.group of first settlers.

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Founder Effect.--Founder Effect.--

Human example: your tribe had to Human example: your tribe had to live near the Bering land bridge…live near the Bering land bridge…

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Founder Effect.--Founder Effect.--

……to invade & settle the ‘New World’!to invade & settle the ‘New World’!

55Audeskirk & Audeskirk, 1993

Galapagos FinchesGalapagos Finches

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Four causes of evolutionary change:Four causes of evolutionary change:Four causes of evolutionary change:Four causes of evolutionary change:


2.2. Genetic DriftGenetic Drift: isolation : isolation accumulation of accumulation of mutations mutations

3.3. Founder EffectFounder Effect: immigrant sampling bias. : immigrant sampling bias.

4.4. Natural SelectionNatural Selection: differential : differential reproduction of individuals in the same reproduction of individuals in the same population based on genetic differences population based on genetic differences among them.among them.




4.4. Natural SelectionNatural Selection: differential : differential reproduction of individuals in the same reproduction of individuals in the same population based on genetic differences population based on genetic differences among them.among them.

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Four causes of evolutionary Four causes of evolutionary change:change:Four causes of evolutionary Four causes of evolutionary change:change:1.1. MutationMutation: fundamental genetic shifts.: fundamental genetic shifts.



4.4. Natural SelectionNatural Selection: reproductive race: reproductive race

These 4 interact synergisticallyThese 4 interact synergistically




4.4. Natural SelectionNatural Selection: reproductive race: reproductive race

These 4 interact synergisticallyThese 4 interact synergistically

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Evidence of Evidence of EvolutionEvolution

1. Biogeography:1. Biogeography:Geographical distribution of speciesGeographical distribution of species

2. Fossil Record:2. Fossil Record:Fossils and the order in Fossils and the order in

which they appear in layers of which they appear in layers of sedimentary rock (sedimentary rock (strongest strongest

evidenceevidence))

http://images.google.com/imgres?imgurl=www.christiananswers.net/q-eden/fossil-fish.jpg&imgrefurl=http://www.christiananswers.net/q-eden/edn-sciencebias.html&h=152&w=200&prev=/images%3Fq%3Dfossil%2B%26svnum%3D100%26hl%3Den%26lr%3Dlang_en%26ie%3DUTF-8%26oe%3DUTF-8%26output%3Dsearch%26sa%3DG

http://images.google.com/imgres?imgurl=www.nmgw.ac.uk/nmgc/_img/fossil.jpg&imgrefurl=http://www.nmgw.ac.uk/nmgc/&h=158&w=145&prev=/images%3Fq%3Dfossil%2B%26svnum%3D100%26hl%3Den%26lr%3Dlang_en%26ie%3DUTF-8%26oe%3DUTF-8%26output%3Dsearch%26sa%3DG

http://images.google.com/imgres?imgurl=www.highest-tides.com/images/fossil.jpg&imgrefurl=http://www.highest-tides.com/recommended.html&h=242&w=200&prev=/images%3Fq%3Dfossil%2B%26svnum%3D100%26hl%3Den%26lr%3Dlang_en%26ie%3DUTF-8%26oe%3DUTF-8%26output%3Dsearch%26sa%3DG

http://images.google.com/imgres?imgurl=www.dinosaur-farm.co.uk/media/fossil.jpg&imgrefurl=http://www.dinosaur-farm.co.uk/pages/fossils/restoration.html&h=144&w=200&prev=/images%3Fq%3Dfossil%2B%26svnum%3D100%26hl%3Den%26lr%3Dlang_en%26ie%3DUTF-8%26oe%3DUTF-8%26output%3Dsearch%26sa%3DG

http://images.google.com/imgres?imgurl=www.ub.ntnu.no/scorpion-files/a_estephani(fossil).jpg&imgrefurl=http://www.ub.ntnu.no/scorpion-files/gallery.htm&h=682&w=501&prev=/images%3Fq%3Dfossil%2B%26start%3D20%26svnum%3D100%26hl%3Den%26lr%3Dlang_en%26ie%3DUTF-8%26oe%3DUTF-8%26output%3Dsearch%26sa%3DN

http://images.google.com/imgres?imgurl=www.museums.org.za/sam/resource/palaeo/pics/trace_fp.jpg&imgrefurl=http://www.museums.org.za/sam/resource/palaeo/trfossil.htm&h=450&w=322&prev=/images%3Fq%3Dfossil%2Bfootprints%26svnum%3D100%26hl%3Den%26lr%3Dlang_en%26ie%3DUTF-8%26oe%3DUTF-8%26output%3Dsearch

http://images.google.com/imgres?imgurl=www.pbs.org/wgbh/aso/tryit/evolution/images/footprints.jpeg&imgrefurl=http://www.pbs.org/wgbh/aso/tryit/evolution/footprints.html&h=250&w=160&prev=/images%3Fq%3Dfossil%2Bfootprints%26svnum%3D100%26hl%3Den%26lr%3Dlang_en%26ie%3DUTF-8%26oe%3DUTF-8%26output%3Dsearch

3. Taxonomy:3. Taxonomy:

Classification of life Classification of life forms.forms.

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http://www.gpc.peachnet.edu/~ccarter/Millerlec5/Millerlec5.PPT

4. Homologous Structures:4. Homologous Structures:Structures that Structures that are similar are similar because of because of common common ancestry ancestry (comparative (comparative anatomy)anatomy)

Turtle Alligator Bird Mammals

Typical primitive fish

5. Comparative Embryology:5. Comparative Embryology:

Study of Study of structures structures that appear that appear during during embryonic embryonic developmentdevelopment

http://fig.cox.miami.edu/~blase/image044.jpg

6. Molecular Biology:6. Molecular Biology:

DNA and proteins (amino acids)DNA and proteins (amino acids)

http://www.micro.biol.ethz.ch/re/re_thoeny/re_lt_cc_1.gif

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History of History of Theories of Theories of EvolutionEvolution

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Old Theories of EvolutionOld Theories of EvolutionJean Baptiste Lamarck (early 1800’s) Jean Baptiste Lamarck (early 1800’s)

proposed:proposed:

““The inheritance of acquired The inheritance of acquired characteristics”characteristics”

He proposed that by using or not using He proposed that by using or not using its body parts, an individual tends to its body parts, an individual tends to

develop certain characteristics, which it develop certain characteristics, which it passes on to its offspring.passes on to its offspring.

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““The Inheritance of Acquired The Inheritance of Acquired Characteristics”Characteristics”

• Example:Example:

A giraffe acquired its long neck A giraffe acquired its long neck because its ancestor stretched higher because its ancestor stretched higher

and higher into the trees to reach and higher into the trees to reach leaves, and that the animal’s leaves, and that the animal’s

increasingly lengthened neck was increasingly lengthened neck was passed on to its offspring.passed on to its offspring.

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Charles DarwinCharles Darwin• Darwin set sail on the H.M.S. Beagle Darwin set sail on the H.M.S. Beagle

(1831-1836) to survey the south seas (1831-1836) to survey the south seas (mainly South America and the (mainly South America and the Galapagos Islands) to collect plants and Galapagos Islands) to collect plants and animals.animals.

• On the Galapagos Islands, Darwin On the Galapagos Islands, Darwin observed species that lived no where else observed species that lived no where else in the world.in the world.

• These observations led Darwin to write These observations led Darwin to write a booka book

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Pinta IslandIntermediate shell

Pinta

Isabela IslandDome-shaped shell

Hood IslandSaddle-backed shell

HoodFloreana

Santa Fe

Santa Cruz

James

Marchena

Fernandina

Isabela

Tower

Giant Tortoises of the Galápagos Giant Tortoises of the Galápagos IslandsIslands

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http://www.galapagosislands.com

http://www.galapagosislands.com/



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Charles DarwinCharles DarwinWrote in 1859: Wrote in 1859:

““On the Origin of Species by Means of On the Origin of Species by Means of Natural Selection”Natural Selection”

Two main conclusions:Two main conclusions:1.1. Species were not created in their Species were not created in their

present form, but evolved from present form, but evolved from ancestral species.ancestral species.

2.2. Proposed a mechanism for evolution:Proposed a mechanism for evolution: NATURAL SELECTIONNATURAL SELECTION

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Darwin’s ObservationsDarwin’s Observations1.1. Most species produce more offspring Most species produce more offspring

than can be supported by the than can be supported by the environmentenvironment

2.2. Environmental resources are limitedEnvironmental resources are limited3.3. Most populations are stable in sizeMost populations are stable in size4.4. Individuals vary greatly in their Individuals vary greatly in their

characteristics (phenotypes)characteristics (phenotypes)5.5. Variation is heritable (genotypes)Variation is heritable (genotypes)

Natural SelectionNatural Selection• Individuals with favorable traits are Individuals with favorable traits are

more likely to leave more offspring more likely to leave more offspring better suited for their environmentbetter suited for their environment

• Also known as “Differential Also known as “Differential Reproduction”Reproduction”

Example:Example:

English pEnglish peeppppeerreedd

moth moth (Biston betularia)

http://tidepool.st.usm.edu/crswr/peppermoths.html

http://www.uc.edu/info-services/buglady.htm

Modes of ActionModes of Action

• Natural selection has three modes of action:Natural selection has three modes of action:

1.1. Stabilizing selectionStabilizing selection

2.2. Directional selectionDirectional selection

3.3. Diversifying selectionDiversifying selection

Number ofIndividuals

Size of individuals

Small Large

1.1. Stabilizing SelectionStabilizing Selection

Acts upon extremes and favors Acts upon extremes and favors the intermediatethe intermediate


Size of individualsSmall Large

2.2. Directional SelectionDirectional Selection

Favors variants of one extremeFavors variants of one extreme



3.3. Diversifying SelectionDiversifying SelectionFavors variants of opposite Favors variants of opposite

extremesextremes



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SpeciationSpeciation

Evolution of new speciesEvolution of new species

Reproductive BarriersReproductive BarriersAny mechanism that impedes two Any mechanism that impedes two species from producing fertile species from producing fertile and/or viable hybrid offspring.and/or viable hybrid offspring.

Two barriers:Two barriers:1.1. Pre-zygotic barriersPre-zygotic barriers2.2. Post-zygotic barriersPost-zygotic barriers

1.1. Pre-zygotic BarriersPre-zygotic Barriersa. Temporal isolation:a. Temporal isolation:

Breeding occurs at different times Breeding occurs at different times for for different speciesdifferent species

b. Habitat isolation:b. Habitat isolation:Species breed in different habitatsSpecies breed in different habitats

c. Behavioral isolation:c. Behavioral isolation:Little or no sexual attraction Little or no sexual attraction

between between speciesspecies

1.1. Pre-zygotic BarriersPre-zygotic Barriersd. Mechanical isolation:d. Mechanical isolation:

Structural differences prevent gamete Structural differences prevent gamete exchangeexchange

e. Gametic isolation:e. Gametic isolation:

Gametes die before uniting with gametes Gametes die before uniting with gametes of other species, or gametes fail to uniteof other species, or gametes fail to unite

2.2. Post-zygotic BarriersPost-zygotic Barriersa. Hybrid inviability:a. Hybrid inviability:

Hybrid zygotes fail to develop or fail to Hybrid zygotes fail to develop or fail to reach sexual maturityreach sexual maturity

b. Hybrid sterility:b. Hybrid sterility:

Hybrid fails to produce functional gametesHybrid fails to produce functional gametes

c. Hybrid breakdown:c. Hybrid breakdown:

Offspring of hybrids are weak or infertileOffspring of hybrids are weak or infertile

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Evidence for Evidence for

Natural Natural SelectionSelection

Artificial SelectionArtificial SelectionThe selective breeding of The selective breeding of

domesticated plants and animals domesticated plants and animals by manby man

Question: What’s the ancestor of Question: What’s the ancestor of the domesticated dog?the domesticated dog?

Population GeneticsPopulation Genetics

The science of genetic change in The science of genetic change in population – Hardy-Weinbergpopulation – Hardy-Weinberg

PopulationPopulation

A localized group of individuals A localized group of individuals belonging to the same speciesbelonging to the same species

SpeciesSpecies

A group of populations whose A group of populations whose individuals have the potential to individuals have the potential to interbreed and produce viable interbreed and produce viable

offspringoffspring

Gene PoolGene PoolThe total collection of genes in a The total collection of genes in a

population at any one timepopulation at any one time

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BibliographyBibliography1. Miller 11th Edition2. http://abandoncorporel.ca/medias/evolution.jpg3. http://www.ne.jp/asahi/clinic/yfc/fetus.html4. rob.ossifrage.net/images/ 5. http://www.mun.ca/biology/scarr/Five_Kingdoms_Three_Domains.htm6. http://www.gpc.peachnet.edu/~ccarter/Millerlec5/Millerlec5.PPT7. http://www.dnr.state.md.us/education/horseshoecrab/lifecycle.html8. http://www.falcons.co.uk/mefrg/Falco/13/Species.htm9. http://www.sms.si.edu/irlspec/NamSpecies.htm10. http://www.falcons.co.uk/mefrg/Falco/13/Species.htm11. http://www.globalchange.umich.edu/globalchange1/current/lectures/complex_life/complex_life.html12. http://nsm1.nsm.iup.edu/rwinstea/oparin.shtm13. http://www.angelfire.com/on2/daviddarling/MillerUreyexp.htm14. http://exobiology.nasa.gov/ssx/biomod/origin_of_life_slideshow/origin_of_life_slideshow.html15. http://www.geo.cornell.edu/geology/classes/Geo104/HistoryofEarth.html16. http://astrobiology.arc.nasa.gov/roadmap/objectives/o2_cellular_components.html17. http://pubs.usgs.gov/gip/fossils/18. http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/halfli.html19. http://www.accessexcellence.org/AE/AEPC/WWC/1995/teach_rad.html20. http://biology.usgs.gov/s+t/SNT/noframe/pi179.htm21. http://www.npca.org/magazine/2001/march_april/nonnative_species.asp22. http://www.bagheera.com/inthewild/spot_spkey.htm23. Biology, 2003, Prentice Hall24. http://www.nearctica.com/ecology/habitats/island.htm25. http://www.valdosta.edu/~grissino/geog4900/lect_1.htm

http://abandoncorporel.ca/medias/evolution.jpgp

http://www.ne.jp/asahi/clinic/yfc/fetus.html

http://rob.ossifrage.net/images/

http://www.mun.ca/biology/scarr/Five_Kingdoms_Three_Domains.htm

http://www.gpc.peachnet.edu/~ccarter/Millerlec5/Millerlec5.PPT

http://www.dnr.state.md.us/education/horseshoecrab/lifecycle.html


http://www.sms.si.edu/irlspec/NamSpecies.htm


Documents

1 Evolution, Biodiversity, and Community Processes La Cañada High School Dr. E