Evolution and Evolution and BiogeograhyBiogeograhyJune 20, 2006June 20, 2006

Lecturer: Meg GranthamLecturer: Meg Grantham

Adaptive Features of Adaptive Features of OrganismsOrganisms

Ancestral descent with modification – Ancestral descent with modification – something arises that makes organism something arises that makes organism better equipped to survive.better equipped to survive.

Natural Selection – features allow Natural Selection – features allow organism to survive to reproduce.organism to survive to reproduce.

Macroevolution: Macroevolution: the origin of new taxonomic groupsthe origin of new taxonomic groups

Speciation: Speciation: the origin of new speciesthe origin of new species 1-1- Anagenesis Anagenesis (phyletic evolution): (phyletic evolution): accumulation accumulation

of heritable changesof heritable changes 2- Cladogenesis (branching evolution):

budding of new species from a parent species that continues to exist (basis of biological diversity)

What is a species?What is a species?

Biological species concept Biological species concept

(Mayr):(Mayr): a population or group of a population or group of populations whose members have the populations whose members have the potential to interbreed and produce viable, potential to interbreed and produce viable, fertile offspring (genetic exchange is fertile offspring (genetic exchange is possible and that is genetically isolated possible and that is genetically isolated from other populations)from other populations)

SpeciationSpeciation

Morphological species – determined by Morphological species – determined by appearanceappearance

Biological species – the largest unit of a Biological species – the largest unit of a population in which gene flow is possible population in which gene flow is possible without artificial meanswithout artificial means

Reproductive Isolation (isolation of gene Reproductive Isolation (isolation of gene pools), Ipools), I

Prezygotic barriers:Prezygotic barriers: impede mating between impede mating between species or hinder the fertilization of the ovaspecies or hinder the fertilization of the ova

Habitat (snakes; water/terrestrial)Habitat (snakes; water/terrestrial) Behavioral (fireflies; mate signaling)Behavioral (fireflies; mate signaling) Temporal (salmon; seasonal mating)Temporal (salmon; seasonal mating) Mechanical (flowers; pollination anatomy)Mechanical (flowers; pollination anatomy) Gametic (frogs; egg coat receptors)Gametic (frogs; egg coat receptors)

Reproductive Isolation, IIReproductive Isolation, II

Postzygotic barriers: Postzygotic barriers: fertilization occurs, but the fertilization occurs, but the hybrid zygote does not develop into a viable, fertile hybrid zygote does not develop into a viable, fertile adultadult

Reduced hybrid viability (frogs; zygotes fail to Reduced hybrid viability (frogs; zygotes fail to develop or reach sexual maturity)develop or reach sexual maturity)

Reduced hybrid fertility (mule; horse x donkey; Reduced hybrid fertility (mule; horse x donkey; cannot backbreed)cannot backbreed)

Hybrid breakdown (cotton; 2nd generation Hybrid breakdown (cotton; 2nd generation hybrids are sterile)hybrids are sterile)

Mechanisms for the Mechanisms for the origin of reproductive origin of reproductive isolationisolation

Geographic BarriersGeographic Barriers Small populations become separatedSmall populations become separated Fringe populations become segregated from Fringe populations become segregated from

smaller populationsmaller population Adaptive radiationsAdaptive radiations Gene pools become segregated by Gene pools become segregated by

adaptations to different habitatsadaptations to different habitats

Mechanisms for the Mechanisms for the origin of reproductive origin of reproductive isolationisolation

Genetic BarriersGenetic Barriers Can be gradual or sudden.Can be gradual or sudden. Speciation by diverengence – isolation is Speciation by diverengence – isolation is

secondary consequence between already secondary consequence between already separated populations.separated populations. Separated populations accumulate mutations Separated populations accumulate mutations

over timeover time Barrier produced by prezygotic or postzygotic Barrier produced by prezygotic or postzygotic

mechanisms.mechanisms.

Resources to investigate Resources to investigate evolutionevolution

List of resource material from PBS.List of resource material from PBS.

http://www.pbs.org/wgbh/nova/link/resourceshttp://www.pbs.org/wgbh/nova/link/resources.html.html

Evidence for assessing Evidence for assessing historical population historical population shiftsshifts

PaleontologyPaleontology Phylogenetic systematicsPhylogenetic systematics Interplay between dispersal and Interplay between dispersal and

continental driftcontinental drift Example: S. America had distinct Example: S. America had distinct

populations until continental collisions about populations until continental collisions about 3 MYA, when Panamanian uplift connected 3 MYA, when Panamanian uplift connected N. and S. America. N. and S. America.

Introduction of Population Introduction of Population Biology:Biology:Biogeographic DistributionsBiogeographic Distributions

Cosmopolitan – everywhereCosmopolitan – everywhere Endemic – restricted to specific regionsEndemic – restricted to specific regions Disjunct – separatedDisjunct – separated

Caused by Caused by DispersalDispersal Vicariance – i. e. continental driftVicariance – i. e. continental drift

Biogeography ResourcesBiogeography Resources

An excellent online textbook to An excellent online textbook to investigate biomes:investigate biomes: http://www.uwsp.edu/geo/faculty/ritter/http://www.uwsp.edu/geo/faculty/ritter/

geog101/textbook/biogeography/outline.htmlgeog101/textbook/biogeography/outline.html

Biogeographical Biogeographical HeirarchyHeirarchy

Realm – Geographical DistinctionRealm – Geographical Distinction Ecoregion – Function of ClimateEcoregion – Function of Climate Biome – Function of RainfallBiome – Function of Rainfall Community – Function of other physical Community – Function of other physical

parametersparameters Ecotone – intermediate plant distribution; Ecotone – intermediate plant distribution;

characteristics of 2 different communitiescharacteristics of 2 different communities

Energy Transfer in the Energy Transfer in the EnvironmentEnvironment

PhotosynthesisPhotosynthesis6CO6CO22+12H+12H22O + (Solar Energy) ---> CO + (Solar Energy) ---> C66HH1212OO66+6O+6O22+6H+6H22OO

RespirationRespiration

CC66HH1212OO66+6O+6O22---> 6CO---> 6CO22+6H+6H22O+2830 kjO+2830 kj

SimplifiedSimplified

COCO22+H+H22O + (Solar Energy) ---> COO + (Solar Energy) ---> CO22+ CH+ CH22OO

BiomesBiomes

Five Principal Biomes – based on unique Five Principal Biomes – based on unique plant and animal communities.plant and animal communities. ForestForest SavannahSavannah GrasslandGrassland DesertDesert TundraTundra

Comparison between a Comparison between a food chain and a food webfood chain and a food web

Ecology – Trophic LevelsEcology – Trophic Levels

Primary Producers – plantsPrimary Producers – plants Consumers – live plants or preyConsumers – live plants or prey Decomposers – use energy stored in Decomposers – use energy stored in

dead plants or animalsdead plants or animals

Ecology – Trophic LevelsEcology – Trophic Levels

First Law of Thermodynamics - First Law of Thermodynamics - states that states that energy cannot be created or destroyed; it can only be energy cannot be created or destroyed; it can only be changed from one form to another. changed from one form to another.

Second Law of Thermodynamics - Second Law of Thermodynamics - states states that whenever energy is transformed, there is a loss that whenever energy is transformed, there is a loss energy through the release of heat. This occurs when energy through the release of heat. This occurs when energy is transferred between trophic levels energy is transferred between trophic levels

Ecology – Trophic LevelsEcology – Trophic Levels

Ecology – Trophic LevelsEcology – Trophic Levels

Pond Ecology ResourcesPond Ecology Resources Microscopic Pond LifeMicroscopic Pond Lifehttp://www.microscopy-uk.org.uk/index.html?http://www.microscopy-uk.org.uk/ponddip/index.htmlhttp://www.microscopy-uk.org.uk/index.html?http://www.microscopy-uk.org.uk/ponddip/index.html

Virtual Pond Virtual Pond http://www.uen.org/utahlink/pond/virtpond2.cgihttp://www.uen.org/utahlink/pond/virtpond2.cgi

Pond Life GamePond Life Gamehttp://www.nalms.org/games/pondgame/plgame.htm#002http://www.nalms.org/games/pondgame/plgame.htm#002

Create a Pond ActivityCreate a Pond Activityhttp://www.geocities.com/sseagraves/createapond.htmhttp://www.geocities.com/sseagraves/createapond.htm

Center for Global Environmental EducationCenter for Global Environmental Educationhttp://cgee.hamline.edu/http://cgee.hamline.edu/

http://cgee.hamline.edu/frogs/teachers/index.htmlhttp://cgee.hamline.edu/frogs/teachers/index.html

Difference between lake Difference between lake and pondand pond

Lakes are statified by temp and oxygenLakes are statified by temp and oxygen

Ponds are not for the most partPonds are not for the most part Can get an estimate by the use of a Secchi Can get an estimate by the use of a Secchi

Disk.Disk.

Other ResourcesOther Resources

Find an activity-Find an activity-

http://www.accessexcellence.org/AE/ATG/http://www.accessexcellence.org/AE/ATG/

Schematic for Virtual Pond