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Allogenic Succession, Allogenic Factors
Factors causing community change originate outside the community; usually large-scale environmental factors like climate chagne, large-scale disterbances
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Autogenic Succession, Autogenic Factors
Factors causing community change originate within the community, from inter-specific interactions (compeition, predation, mutualism) and the different physiologies of species
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Biodiversity Hotspot
A region with a very high number of endemic species
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Biome, Ecoregion
Broad areas of more of less uniform life form of vegetation, with associated animal cmmunities, examples- tundra, taiga, temperate forest, tropical rain forest, savanna, grassland, desert, chaparral (shrublands)
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Community
The group of species that co-exist and interact in a particular place and time
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Disturbance
Any sudden or abrupt removal or destruction of live biomass. Disturbances can range from small events to very large events
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Disturbance return interval or frequency
The average amount of time between disturbance events of a defined size (flood depth and duration)
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Diversity
A combination of the number of species and their relative abundance (evenness)
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Species Richness
A simple count of the number of species in an area
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Evenness and Dominance
The relative numbners of individuals of each species in total number of indiciuals in a sample. In a community with high evenness, all species are equally represented amount the indiciduals. In a community with low evenness (-high dominance), one or a few species account for most of the indicuals and all other species have only a few indivuals present.
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Shannon-Weiner Index
A mathematical formula that incorporates both richness and evenness into a single measure of diversity;l it describes the uncertainty of identifying of identifying any randomly chosen indicual from a community (the high the divevrsity, the higher the uncertainty).
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Shannon Diversity Index equation
![Image Upload 2](/flashcards/images/image_placeholder.png)
- s = total number of species
- pi = fraction of individuals that are in species i
- = ni / N
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Ecotone
An area over which one community grades into another, with species characteristic of each of the two comunities may be found together, and the physical environment typically has characteristics intermediate between those of the two different communities. An example is the vegetation at the boundary between a forest and a field.
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Endemic
A species that is found only in a single restricted area.
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Facilation
The presence of one species enhances the growth and/or survival of another species.
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F.E. Clements
Discovered 'superorganism' concept of the community.
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H.A. Gleason
'individualistic' concepts of the community
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R. H. Wittaker
Data collected along gradients supports the individualistic idea (gradient approach)
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G.E. Hutchinson
Asked the big question-why are there so many species?
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R. MacArthur
collaborator in developing island biogeography theory
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E.O. Wilson
collaborator in developing island biogeography theory
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D. Simberloff
Experimental test of island biogeography
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E. Odum
Change in ecosystem function during sucession
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Gradient
A regualrly changing environmental property (elevation, moisture, temperature)
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Guild
A group of organisms within a community that all use a suite of resources in the same way (insects whose larvae grow within seeds; bottom feeding fish; ground-nesting birds; annual plants growing in gaps in the forest canopy)
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Individualistic Community
The concept put forward by Henry Gleason to describe the concept of the community as a group of speices that happen to live in the same place because they have similar responses to environmental factors, but are not particularly related to or dependent on each other.
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Net Primary productivity
The total amount of new biomass produced by plants during a defined period of time, usually a year or a growing season; usually measured as "grams of biomass per unit area per unit time (grams/hectare/year)
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Paleoecology
The use of pollen and plant fossils to study communities an climate in the past
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Pioneer
A species capable of establishing and growing on bear surface
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Sucession
Sequential change in species composition of communites over time
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Primary Succession
Sequence of communities that occur on a substrate that never had a biotic commmunity on it
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Secondary succession
Sequence of communities that occur on a substrate that was previously occupied by a biotic community
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Sere
A set of intermediate stages in the sequence of communities changing over time
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Climax
The final stage of a sere; the community that persists for a long period of time (a concept not often used today)
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Mosaic
A set of concurrently eisting patches of different successional stages
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Superorganism
The concept put foward by Frederic Clements to descrube the concept of the community as a group of tightly connected organisms that all depend on each other, and that respond to environmental factors as coordinated group
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Intraspecific competition
Form of competition in which members of the same species vie for the same resource in an ecosystem (e.g. food, light, nutrients, space).
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Interspecific Competition
Interspecific competition, in ecology, is a form of competition in which individuals of different species vie for the same resource in an ecosystem (e.g. food or living space).
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Co-existance
When species grow together without causeing harm to one another (defeating survival rates)
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Parasitoid
- Kills prey
- Consume part of prey individual
- Consumes part of one individual
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Competitive exclusion
The concept that two species cannot long coexist if they have identical niches
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Niche
An n-dimensional hypervolume which defines the limits within which a given species can survive and reproduce
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True Predators
- Kill prey
- Often consume prey in entirety
- Consume many individuals
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Grazers
- Rarely lethal
- Consume part of prey individual
- Consume part of many individuals
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Parasites
- Rarely lethal
- Consume part of prey
- Consume one or very few individuals
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Prey Defenses
- Chemical Defense
- Armor and Weapons (turtle shells)
- Warning Coloration and mimicry
- Cryptic or confusing coloration
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Predator Adaptations
- Cryptic Coloration
- Mimcry
- Evolutionary Specialization ( Owls- specialized beaks, eye sight, Bats- ecolocation, Angler Fish-trap)
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Types of Herbivory
- Leaf-Biting
- Sap-Sucking
- Leaf-Mining
- Flower damage
- Fruit damage
- Root damage
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How does Herbivory effect plant fitness?
- Herbivory can change the set of plants that co-exist by reducing fitness of some species but not others.
- Compensation: grazing of older leaves off of some plants (like grasses) stimulates new growth and/or flowering
- Seed dispersal by fruit predators (scarification)
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Plant Defenses Against Herbivory
- Chemical (ferulic acid, scopoletin, morphine)
- Structural Defenses (spines and thornes)
- Mimicry
- Predator Satiation (prey occur at high population densities, reducing the probability of an individual organism being eaten)
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Predator Satiation
- Disperse seeds UNEVENLY ACROSS SPACE so that some places have LOTS of seeds and some places have only a few -- counting on attracting and satiating seed predators in only one spot.
- Disperse seeds unevenly THROUGH A SEASON so that there are LOTS and LOTS of seeds for only a few days -- counting on attracting and satiating seed predators in a short time.
- Disperse seeds UNEVENLY ACROSS YEARS so that there are only seeds available in random years -- counting on predators not keying in on a single spot as a seed source year after year.
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Herbavore Defenses
- Detoxification (metabolize or eat around chemical defenses)
- Accumulation
- Stem Cutting
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Trophic Levels
Energy transfer is inefficent which may limit the length of food chains (each degree raised only gets 10% of orginial energy)
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Keystone species
a species whose activities have a significant role in determining community structure
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Community Interations
- Predation
- Parasitism
- Herbivory
- Mutalism
- Competition
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Lotka-Volterra Model
- A Model of Inter-specific Competition
![Image Upload 4](/flashcards/images/image_placeholder.png) - α = negative competitive impact, per individual, of species 2 on species 1
- β = negative competitive impact, per individual, of species 1 on species 2
- K: carrying capacity
- t: time
- r: per capita growth rate
- d: change
- N: population size
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The four outcomes of the Lotka-Volterra Model
- 1. Species 1 outcompetes species 2
- strong interspecific competition
- 2. Species 2 outcompetes species 1
- strong interspecific competition
- 3. Unstable equilibrium
- 4. interspecific competition more important than intraspecific → outcome depends on initial
- conditions (Priority Effects)
- Stable equilibrium (coexistence)
- when intraspecific competition is more important than interspecific
![Image Upload 6](/flashcards/images/image_placeholder.png)
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Fundamental Niche
Absence of competitors
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Realized Niche
Determined by Competitiors
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Apparent Competition
Occurs indirectly between two species which are both preyed upon by the same predator. For example, species A and species B are both preys for predator C
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Mutalism
A reciprocal relationship between two species where the survival, growth and reproduction of individuals from each species is enhanced. (+,+)
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Mutualistic Benefits
- ENERGETIC
- NUTRITIONAL
- PROTECTIVE
- TRANSPORT
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Types of Mutalism
- Facultative
- Obligate Symbiotic (lichens, myciorrhizae)
- Obligate Non-symbiotic
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Generalist mutualisms
Opportunistic for at least one species
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Benefits of dispersal of seeds
- Predator escape
- Colonization
- Directed dispersal
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Benefits of Pollination Mutualisms
- Male Euglossine bees collect fragrant chemicals from orchids for use in mating
- Orchids are pollinated through transfer of pollinia Pollinia of different orchid species attach to different parts of pollinators
- Pollinators get nectar (food), and flower gets pollen transfer and (hopefully) reproduction
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Parasitism
- An intimate relationship between two organisms in which one (the parasite) lives on, off or at the expense of the other (host).
- *additionally, parasites have at least one life stage that is dependent upon ONE host for the duration of that stage.
- (+,-)
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Social parasitism (Brood Parasitism)
host raises young of parasite Co-evolution between breed parasites and hosts (nest abandonment and/or raising parasitic young)
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Kleptoparasitism
Parasite gains a substantial portion of its food by stealing it from hosts
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Types of Parasitism
- Social
- Klepto
- Direct
- Indirect
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Arctic Tundra
- Cold temperatures, strong winds, and permanently frozen soil (permafrost).
- Dominant vegetation types are grasses, mosses, and lichens.
- Treeless land
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Boreal Forest (taiga)
Forests of pine, spruce, fir, and larch
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Grasslands and Savannas
- containing many grasses but few trees and having low to moderate rainfall
- dominated by grammanoid or herbaceous vegetation, generally greater than 80 percent of the total vegetation
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Deserts
A dry, barren area of land, that is characteristically desolate, waterless, and without vegetation
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Tropical Rain Forest
- lush vegetation, abundant rainfall, and plentiful sunlight
- hot and wet all year
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Factors Driving Diversity Among Biomes
- Habitat area
- Evolutionary age
- Speciation rates
- Environmental heterogentity
- Climate and variability
- Net primary productivity
- Environmental stress
- Disturbance
- Latitude
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Factors driving diversity within biomes
- Habitat area
- Environmental heterogenetiy
- Net primary productivity
- Distrubance
- Immigration and extinction
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Evenness equation
H'/ln S
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Values of Diversity
- Ethical considerations
- Ecosystem stability
- Breeding sources
- Disease prevention
- Bioprospecting
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Primary Succession
- No prior community (non-soil substrate)
- Pioneer species start the process
- Soil development is critical
- Often 100s of years before climax
- Animals can influence strongly
- Each seral community changes environment
- Examples: volcanos, coastal dunes, mine spoil, glacial moraines, sand mines, libersty state park, Warren Grove Gunnery Range
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Secondary succession
- Prior community (soil substrate)
- a process started by an event (e.g. forest fire, harvesting, hurricane) that reduces an already established ecosystem
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Autogentic species traits
- Seeds and Dispersal
- Environmental alteration and tolerances
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Autogenic species interactions
- Facilitation
- Competition
- Herbivory
- Indiferct effects
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Distrubance
- Changes the availability of envioronmental resources in an ecosystem
- Characterized by frequency and intensity
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Allogenic mechanisms
- Distrubance
- Climate change
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Facilitation
A type of species interaction that benefit at least one of the participants and causes harm to neither.
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Resource ratio hypothesis
- A hypothesis that assumes that species can coexist in a community by using resources the same resources but in different proportions.
- (light vs nutrients and water)
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Biotic Interactions and Invasion
- Resistance (-)
- Faciliataion (+)
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Ecological Restoration
The process of assisting the recoverry of an ecosystem that has been degraded, damaged or destroyed
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Two factors of Ecological Restoration
- Directing ecological succession
- --Disturbance
- – Community assembly and dynamics
- – Successional trajectories
- Land management applications
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How is restoration implimented?
- Degradation
- Damage
- Destruction
- Conversion
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Ecosystem Services
- Provisioning services
- Regulating services
- Supporting services
- Cultural services
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Attributes of restored systems
- Characteristic species
- Community structure
- Native species
- Function
- Physical conditions
- Landscape matrix
- Threats
- Resilience
- Self-sustaining
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Habitat islands experiment
Introduction of an invasive species to see how fast the species will invade
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Goals and moving targets of Restoration
- Reference systems
- Stochasticity
- History
- Heterogeneity
- Biological legacies
- Climate change
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Ecological Constraints of restoration
- Dispersal
- Propagules: A vegetative structure that can become detached from a plant and give rise to a new plant
- Interactions - missing and new
- Soil quality and biota
- Changed disturbance regimes
- Invasive species
- Genotypes of planting material
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Ecological Opportunities of Restoration
- Restore natural heritage of the land
- Restore ecological functions
- Minimize, but not eliminate, management needs and costs
- Improve biodiversity in surrounding areas
- Add ecological resiliency for the future
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Species-Area Curve
- A relationship between the area of a habitat, or of part of a habitat, and the number of species found within that area.
- Larger areas tend to contain larger numbers of species, and empirically, the relative numbers seem to follow systematic mathematical relationships
- These factors include the relative balance between immigration and extinction, rate and magnitude of disturbance on small vs. large areas, predator-prey dynamics, and clustering of individuals of the same species as a result of dispersal limitation or habitat heterogeneity.
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Net Primary Production
- Net primary production is the rate at which all the plants in an ecosystem produce net useful chemical energy.
- It is equal to the difference between the rate at which the plants in an ecosystem produce useful chemical energy (GPP) and the rate at which they use some of that energy during respiration.
- Some net primary production goes toward growth and reproduction of primary producers, while some is consumed by herbivores.
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Intermediate Disturance Hypothesis
- The Intermediate Disturbance Hypothesis (IDH) states that local species diversity is maximized when ecological disturbance is neither too rare nor too frequent.
- At low levels of disturbance, more competitive organisms will push subordinate species to extinction and dominate the ecosystem.
- At high levels of disturbance, due to frequent forest fires or human impacts like deforestation, all species are at risk of going extinct.
- According to IDH theory, at intermediate levels of disturbance, diversity is thus maximized because both competitive K-selected and opportunistic r-selected species can coexist.
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Major Events in Earth History
- Archean Chronometric Eon (3000 mya): Photosynthetic cyanobacteria; production of molecular O2
- Precambrian Eon (2500 mya): Great Oxidation Event
- Phanerozoic Eon (580-540 mya): Sufficient atmospheric O2 for formation of O3, Colonization of land
- Phanerozoic Eon (570-530 mya): Cambrian Explosion, evolutionary burst of life
- Phanerozoic Eon (424 mya): Primitive plants move onto land
- Phanerozoic Eon (251.4 mya): Permian Extinction Event
- Phanerozoic Eon (65.5 mya): C-T Extiniction Event
- Phanerozoic Eon (60 mya): Earliest primates
- Tertiary Period (6.5 mya): Earliest Hominin
- 50,000 ya: Early colonization of Europe and ASia by modern humans
- 200 ya: Beginning of Anthropocene
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How is the Earth Warming?
- A layer of greenhouse gases – mainly H2O vapor and
- including much smaller amounts of CO2,CH4 &N2O–act as a thermal blanket for the Earth, absorbing heat and warming the surface to a life-supporting average of 59 °F (15 °C).
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Evidence of climate change
- Sea level rising (about 17 cm in last centur)
- Declining Arctic Sea Ice: both extent and thickness
- Extreme Events: extreme high and low temeprtures as well as intese rainfall
- Ocean Acidification: Increase in CO2 increases the ocean acidity (30% since 1750).
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Each organism has a specific thermal range. When temperatures exceed the thermal range of an organism, it's probability of lethal heat stress increases.
- Warming in the tropics, although relatively small in magnitude, is likely to have the most deleterious consequences because tropical insects are relatively sensitive to temperature change and are currently living very close to their optimal temperature.
- In contrast, species at higher latitudes have broader thermal tolerance and are living in climates that are currently cooler than their physiological optima, so that warming may even enhance their fitness.
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