nonevolutionary responses to environmental change organisms can change to perform better in...
Post on 20-Dec-2015
217 Views
Preview:
TRANSCRIPT
Nonevolutionary Responses to Environmental Change
Organisms can change to perform better in different conditions, without
a change in population genetic makeup
Time scales, mechanisms, flexibility
Regulatory Physiological/behavioral <<1 generation ReversibleAcclimatory Physiological/behavioral <1 generation ReversibleDevelopmental Developmental/behavioral ~1 generation IrreversibleEvolutionary Genetic/ecological >1 generation Reversible
Regulatory Responses
No morphological change required, involves physiology or behavior
Modified activity to maintain favorable body conditions
Examples:
Sweating, panting, shivering, altered kidney filtration, altered heart rate, drinking, basking
Objective: homeostasis-- buffer the internal environment of an individual, or to modify the immediate external environment.
Acclimatory Responses
Change in physiology, behavior, or morphology, in response to environmental changes, especially seasonal changes
Examples:
Fur growthColor changeFoliage lossFloweringMating colorationAntler growthMating ritualsFeeding patterns
Responses to environmental cues (e.g. change in day length)
Developmental Responses (Phenotypic Plasticity)
Differences in body form or behavior depending on environmentalconditions
Induced defenses and cyclomorphosis
Nonevolutionary responsesare not adaptations, but they are
adaptive
Response itself is done without genetic change, butthe ABILITY to make the response has very likely evolvedthrough adaptation (i.e. natural selection)
Success of response
Survival andReproduction
Establishment andMaintenance of population
DistributionsSummarize the locations where a species has been successful
Do not tell us about locations where they could be successful
Do not tell us about places where a species has failed
Understanding distributions relies on knowing what factors prevent species from occupying a particular location or region
Ranges
Geographic-- set of places actually occupied
Ecological-- set of placeswith suitable conditions
Ecological > GeographicReasons why involve most topicsof interest to ecologists
A B C
Explaining an Absence
Species does not occur because:
1) It can’t reach it
2) It doesn’t choose to (habitat selection)
3) Physical or chemical conditions not favorable
4) Other organisms in the area prevent establishment (competition, predation, parasitism) or a key species (food, mutualist) is missing
5) Chance
Transplant experiments
Remove suspected dispersal barrier
Success: transplanted populations growReject: physical/chemical factorsReject: species interactionsSupport: dispersal barrier
Failure: transplanted populations dwindleReject: dispersal barrierConsistent with species interactions or physical/chemical factors
Problem: ethical considerations of transplantation
Solutions:
Compare occupied and unoccupied environmentsWhat major factors differ? --> hypotheses
Duplicate differences in laboratory setting“Transplant” occurs in lab; hypotheses testedlimitation: lab setting
Conduct transplants in field under highly controlled conditions
Catch species in the act of invasion
Lessons from Invasions and Introductions
Starling
Gypsy moth
Aedes albopictus
Rabbits to Australia
Failed introductions:Fish stockingSeeds in wool
Norway maple
Hessian Fly
Dutch Elm Disease
Chestnut Blight
Dispersal BarriersBecome clearest when they are overcome and followed by successful invasions
European Starling:
Chestnut Blight
Gypsy Moth
Gypsy Moth, recent
Gypsy Moth
Antarctic Beech, Nothofagus
Antarctic Beech, Nothofagus
Dispersal Strategies
Water Striders
Desert Locusts
Niche
Tsetse Fly
Temperature and Aedes aegypti
Barnacle life cycle
Temperature and Barnacle dist.
Moisture
Composition of Calif. Forests
Other factors
Fire
Currents
Oxygen
Light, or tolerance to shade
Interactions between factors
Climographs
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
Interactions between factors
Hungarian Partridge:Climograph for home range and for two places where introductions were attempted.
Mediterranean Fruit Fly and TelAviv climates in Two years
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
Interactions between factors
Interactions between factors
Mediterranean Fruit Fly and TelAviv climates in Two years
Georgia climates (A: coastal plain; B: northern mountains)
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
Interactions between factors
Climographs
Mediterranean Fruit Fly and TelAviv climates in Two years
Georgia climates (A: coastal plain; B: northern mountains)
Interspecific Interactionsand distribution
Restriction of a species’ distribution
Some areas may be unfavorable because of:
•Predation in unoccupied areas•Food supply is inadequate in unoccupied sites •Competition with another species in unoccupied sites•Parasitism and disease in unoccupied areas•Commensalism (absence or shortage of host sp.)•Mutualism (absence or shortage of partner sp.)
Parasitoids
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
Pupae of tachinid fly, just lefttheir moth larva host
Ichneumonid wasps and caterpillar host
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
Parasitoids
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
Braconid wasp pupal cocoons on Tobacco Hornworm
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
Predation
Food Supply
Competition
Parasites, Mutualists
Niches
Fundamental Niche: set of physical, chemical and resourceconditions necessary for population maintenance
Realized Niche: set of physical, chemical and resource conditions necessary after taking species interactions into account-- a smaller set and a subset of Fundamental Niche
Niche and DistributionPlacesConditions
Niche and Distribution
Fundamental Niche Ecological Range
PlacesConditions
Niche and Distribution
Fundamental Niche
Realized Niche
Species InteractionsEcological Range
PlacesConditions
Niche and Distribution
Fundamental Niche
Realized Niche
Species InteractionsEcological Range
PlacesConditions
Geographic Range
Niche and Distribution
Fundamental Niche
Realized Niche
Species InteractionsEcological Range
PlacesConditions
Dispersal limitsHabitat selection
Geographic Range
top related