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Ecology Unit

Michaela Matos

Michaela Matos

on 15 August 2010

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Transcript of Ecology Unit

Ecology and the Biosphere Behavioral Ecology Population Ecology Community Ecology Ecosystems Conservation Biology
and Restoration
Ecology Introduction to Ecology
and the Biosphere Behavior is everything an
animal does and how
it does it. Proximate questions of behavior
are the "how" questions. They are
environmental stimuli, if any, that
trigger a behavior, as well as the
genetic, physiological, and anatomical
mechanisms underlying a behavioral act. Ultimate questions of behavior
are the "why" questions, and
address the evolutionary
significance of a behavior. Ethology is the scientific study
of how animals behave, especially
in their natural environments The Fixed Action Pattern is
the sequence of unlearned
behavioral acts that is
essentially unchangeable
and, once initiated, is usually
carried to completion Sign stimulus is the
external sensory stimulus Imprinting is a type of
behavior that includes
both learning and innate
components and is
generally irreversible The Sensitive Period is a limited
phase in an animals
development that is the only
time when certain behaviors
can be learned Innate behavior is a behavior
that is developmentally fixed Kinesis and Taxis are both animal movements.
Kinesis is a simple change in activivty or turning
rate in response to a stimulus, where as taxis is a
more or less automatic, oriented movement toward
(positive) or away(negative) from some stimulus. Kinesis increases the chance that a sow bug will encounter and stay in a moist environment and a positive rheotaxis keeps trout facing into the current, the direction from which most food comes. Example Migratory Restlessness is under
genetic control and follows a
polygenic inheritance pattern Communication is multiple Signals
back and forth between the animals Example Territorial fish erect their fins and that drives off the other fish. Most terrestrial mammals use olfactory and auditory signals to communicate with each other. Birds communicate mostly with visual and auditory signals, as do humans. Arginine-Vasopressin and V1a receptors combine, and these genes influence mating and parental behaviors by making the male form a strong pair and stay with his mate. It also makes him engage in more parenting behaviors. Learning is a modification of behavior based on specific experiences. Habituation is a loss of responsiveness to stimuli that convey little or no information. Spatial learning is the modification of behavior based on experience with the spatial structure of the environment, including the locations of nest sites, hazards, food, and prospective mates. A Cognitive Map is an internal representation, or code, of the spatial relationships between objects in an animals surroundings. Associative learning is the ability of many animals to associate one feature of the environment (a stimulus, such as color) with another (bad taste). Classical conditioning is an arbitrary stimulus is associated with a reward or punishment. Operant conditioning is trial and error learning. There is a relationship between behavioral traits and natural selection because behaviors change over time to help the species survive, and doing something that kills them won’t be passed on. There are risks and benefits to everything. The optimal foraging theory relates to this. If an animal goes out to forage, there is a chance or a risk that they will be prey, and a chance that they have the benefit of being the predator. The needs of the young is the most important factor in the evolution of mating systems because they want their young to survive. If they need more than one adult to feed them, the parents will likely stay together, but if they can handle themselves, the parents have no real need to stay together, and may mate multiple times. Agonistic behavior is a ritualized contest that determines which competitor gains access to a resource, such as food or mates. Altruism is like selflessness. It is behaving in ways that reduces indiviual fitness but increases the fitness of other individuals in the population. Inclusive fitness is the total effect an individual has on proliferating its genes by producing its own offspring and and by providing aid that enables other close relatives, who share many of those genes, to produce offspring. Coefficient of Relatedness equals the probability that if two individuals share a common parent or ancestor, a particular gene present in one individual will also be present in the other. Kin selection is the natual selection that favors altruistic behavior by enhancing reproductive success of relatives. Reciproical Altruism is not common in animals unless they are a species with a social group stable enough that individuals have many chances to exchange aid. Culture is based off of social learning. Abiotic- nonliving components – chemical and physical factors such as temp, light, water, and nutrients. Biotic- living components- all the organisms, or biota that are part of the individuals environment. Biota-all the organisms that are part of the individuals environment. Organismal ecology-may be subdivided into the disciplines of physiological ecology, evolutionary ecology, and behavioral ecology, concerns how an organisms structure, physiology, and (for animals) behavior meet the challenges posed by the environment. Population ecology – include the definition of population- a group of individuals of the same species living in a particular geographic area. Population ecology concentrates mainly on factors that affect how many individuals of a particular species live in an area. Community ecology – include the definition of community- consists of all the organisms of all the species that inhabit a particular area; it is an assemblage of populations of many different species. Ecosystem ecology – include the definition of ecosystem- consists of all the antibiotic factors in addition to the entire community of species that exist in a certain area. In ecosystem ecology, the emphasis is on energy flow and the chemical cycling among the various biotic and abiotic components. Landscape ecology- deals with arrays of ecosystems and how they are arranged in a geographic region. Every landscape or seascape consists of a mosaic of different types of “patches,” an environmental characteristic ecologists refer to as patchiness. Factors that affect dispersal of organisms. Behavior and habitat selection – avoiding certain habitats, only ovipositing in certain conditions Biotic factors- or other species, like predators, transplanted to a new area, parasitism, disease, competition, lack of other need species, herbivore limitation Abiotic- special heterogeneity and temporal heterogeneity Impact of abiotic factors on the distribution of organism Temperature- cells may rupture in freezing temps, few organisms can maintain an appropriately active metabolism in extreme temps, internal temp affected. Water- freshwater and marine organisms live submerged in aquatic environments, but most are restricted to either freshwater or saltwater for osmoregulation. Variety of conservation and desiccating environment. Sunlight- provides energy, light intensity, photosynthetic aquatic environments towards surface, photoperiod. Wind- increases heat loss due to evaporation and convection, contributes to water loss, inhibits growth of limbs on plants. Rocks and soil- contributes to patchiness, can affect water chemistry in streams and rivers. Macroclimate- Global regional and local level Microclimate- very fine patterns Sunlight strikes the equater perpendicularly, most heat and light per surface . higher latitudes sunlight strikes earth at oblique angle (more diffuse) Seasons are caused by the Earth's tilt. When moist air approaches mountain, air rises and cools, releasing moisture on the windward side of the peak. On the leeward side, cooler dry air descends, absorbing moisture and producing a “rain shadow”. Seasonal turnover in lakes brings oxygenated water from the surface to the bottom, and nutrient rich water from the bottom to the surface, in both spring and autumn. It is essential for survival and growth of organisms at all levels within this ecosystem. littoral
zone limnetic
zone photic
zone benthic
zone aphotic
zone pelagic
zone Aquatic Marine Intertidal zone Neritic zone oceanic zone 2,500-6,000 m 0 200 m photic zone pelagic
zone Aphotic
zone Continental
shelf Abyssal zone
(deepest regions of ocean floor) Benthic
zone Lakes Phys. Environment- standing bodies of water . light decreases with depth creating stratification. Temperate lakes may have seasonal thermocline, tropical lowland lakes have a thermocline year-round.
chemical environment- salinity, oxygen content, and nutrient content differ greatly, oligotrophic lakes are nutrient poor and usually oxygen rich, eutrophic lakes are nutrient rich and often oxygen depleted in winter and deepest zone during summer, the amount of decomposable organic matter in bottom sedimenets is low in oligotrophic lakes and high in eutrophic lakes
geologic features-oligotrophic lakes tend to have less surface area relative to their depth than eutrophic lakes(over long periods of time, oligotrophic can become more eutrophic as runoff adds sediments and nutrients to a lake. Photosynthetic organisms- photosynthesis higher in eutrophic lakes than oligotrophic, rooted and floating aquatic plants live in the littoral zone, (shallow, well lighted waters close to shore) the limnetic zone, where water is too deep to support rooted plants, is inhabited by a variety of phytoplankton and cyanobacteria animals- in limnetic zone, small drifting animals or zooplankton graze on phytoplankton. The benthic zone is inhabited by a variety of invertebrate animals (species composition depending partly on oxygen levels
human impact- pollution by runoff from fertilized land and dumping of municipal wastes leads to nutrient enrichment which can produce algal blooms, oxygen depletion, and fish kills Wetlands P.E.- wetland is an area covered with water for a long enough period to support aquatic plants-range from permanently inundated to those that flood infrequently C.E.- high organic production and decomposition, both water and soils are low in dissolved oxygen, high capacity to filter dissolved nutrients and chemical pollutants
geological features- basin wetlands develop in shallow basins ranging from upland depressions to filled-in lakes and ponds. Riverine wetlands develop along shallow and periodically flooded banks of rivers and streams. Fringe wetlands occur along the coasts of large lakes and seas where water flows back and forth because of rising lake levels or tides(include both freshwater and marine biomes)
photosynthetic organisms- wetlands among most productive biomes, water saturated soils favor growth of plants(floating pond lilies, emergent cattails, sedges, tamarack, black spruce) that have adaptions enabling them to grow in water or soilthat is periodically anaerobic owing to the presence of unaerated water. Woody plants dominate swamps, sphagnum dominates bogs animals-home to diverse community of invertebates, w;hic;h supports wide variety of birds. Herbivores, (crustaceans and aquatic insect larvae to muskrats) consume algae, detritus, and plants. Carnivores also vary and may include dragonflies, otters, alligators, and owls
human impact- draining and filling have destroyed up to 90% of wetlands in some regions
Streams and Rivers P.E.- currents. Headwaters usually cold clear turbulent and swift. farther downstream, warmer, more turbid, more sediment. stratified into vertical zones, from surface water to groud water
C.E.- salt and nutrient content increases from headwaters to mouth. Headwaters rich in oxygen. Geologic features- headwater stream channels often narrow, rocky bottom, riffles and pools. Downstream, wide and meandering, river bottoms often silty from sediments
photosynthetic organisms- headwater streams that flow through grasslamd or desert may be rich in algae or rooted aquatic plants; but in streams flowing through temperate or tropical forests, leaves and other organic matter produced by terrestrial vegetation are the primary source of food for aquatic consumers. In rivers, a large fraction of the organic matter consists of dissolved and high fragmented material that is carried by the current from forested headwater streams
animals- a great diversity of fishes and invertebrates inhabit unpopulated rivers and streams, distributed to, and throughout, the vertical zones
Estuaries P.E.- a transition area between river and sea. Very complex flow patterns.during rising tide, seawater flows up the estuary channel, flowing down again during falling tide. Higher density seawater occupies bottom of estuary channel, lower density river water forms a surface layer that mixes little with salty bottom layer C.E.- salinity varies spatially within estuaries, and with rise and fall of the tides, one of most productive biomes geologic features- estuarine flow patterns combined with sediments create complex network of tidal channels, islands, natural levees, and mudflats. Photosynthetic organisms- saltmarsh, grasses and algae, including phytoplankton are the major producers in estuaries
animals- support an abundance of worms, oysters, crabs, and many fish species, many marine invertebrates and fishes use them as a breeding ground, others migrate through. They are crucial feeding areas for many semi-aquatic vertebrates, particularly waterfowl
human impact-pollution from upstream, filling, and dredging, have disrupted estuaries
Intertidal zones P.E.- periodically submerged and exposed by the tides, twice daily, upper zones=longer exposures to air and greater variations in phy. Environment, variations in temp, salinity, and mechanical forces of wave action C.E.- oxygen and nutrient levels are usually high geologic features- substrates of intertidal zones, which are either rocky or sandy , select for particular behavior and anatomy. Photosynthetic organisms- high diversity and biomass of attached marine algae inhabit rocky intertidal zones, especially in lower zones. Because of instability of the substrate, sandy intertidal zones exposed to vigorous wave action generally lack attached plants or algae, while sandy intertidal zones, protected in bays or lagoons often support rich beds of sea grass and algae animals- composition, density, and diversity of intertidal animals change markedly from upper to lower zones.many bury themselves in mud (suspension feeding worms, clams, predatory crustaceans). Other common animals are sponges, sea anemones, mollusks, echinoderms, and small fishes human impact- oil pollution has disrupted many intertidal areas, recreational use has caused severe decline in numbers of beach nesting birds and sea turtles Oceanic Pelagic Biome vast calm open blue water, C.E.- high oxygen levels, nutrient levels a little lower, geologic features- vast and deep covers 70% of earths surface photosynthetic organisms- phytoplankton, animals-zooplankton, protozoans, worms, copepods, shrimp-like krill, jellies, and small larvae of invertebrates and fishes graze on photosynthetic plankton, free swimming animals like large squids, fishes sea turtles, and marine mammals human impact- overfishing has depleted fish stocks in all earth’s oceans which have also been polluted by waste dumping and oil spills Coral Reefs high water clarity, temps between 20 and 30 degrees C C.E.- require high oxygen levels and are excluded by high inputs of fresh water and nutrients geologic features- corals require solid substance for attachment (formed by calcium carbonate skeletons of corals) developes over a long time on oceanic islands photosynthetic organisms- Dinoflagellate algae live within the tissues of the corals, forming a mutualistic , symbiotic relationship that provides the corals with organic molecules. Diverse red and green marine algae also contribute substantial amounts of photosynthesis on coral reefs. Marine Benthic zone Sea floor below the surface waters of the nertic or coastal zone, and the offshore pelagic zone. abyssal zone adapted to continuous cold (about 3 degrees C) and extremely high water pressure C.E.- oxygen is present to support diversity of animals geologic features- soft sediments, rocky substrate on reefs, submarine mountains, and oceanic crust created by seafloor volcanoes food-producing organisms- associated with deep sea hydrothermal vents. Oxygen deficient animals- numerous invertebrates and fishes. Giant tube dwelling worms, anthropods and echinoderms human impact- overfishing, dumping of organic wastes has created oxygen deprived benthic areas. Because there are latitudinal patterns of climate over Earth’s surface, there are also latitudinal patterns of biome distribution. Population- group of individuals of a single species living in the same general area. Density-number of individuals per unit area of volume. Dispersion- the pattern of spacing among individuals within the boundaries of the population. Mark-recapture method- sampling technique used to estimate wildlife populations by using traps and marking animals. Immigration- influx of new individuals from other areas Emigration- the movement of individuals out of a population. Territoriality- defense of a bounded physical space against encroachment by other individuals. Patterns of Dispersion Clumped-being in groups increases effectiveness of hunting and spreads out the work. Uniform-maintained by aggressive interactions between neighbors. Random- windblown seeds that land at random. Demography- study of vital statistics of populations and how they change over time. Life tables- age specific summaries of the survival pattern of a population. Survivorship curves- a plot of the proportion or numbers in a cohort still alive at each age. Reproductive table- fertility schedule, age specific summary of the reproductive rates in a population. Life history- traits that affect an organisms schedule of reproduction and survival Tropical Forest Desert Savana Chaparral Temperate grassland Coniferous Forest Temperate broadleaf forest Tundra Number of survivors (log scale) Percentage of maximum life span 1 10 100 1,000 50 100 0 Semelparity is having a single reproductive opportunity, and Iteroparity is having repeated reproductive opportunity. Semelparity has a higher chance of some offspring surviving because there are a lot of them, and iteroparity has a higher chance of them surviving because a few relatively large, well provisioned offspring will have a better chance of surviving to reproductive age. Zero population growth occurs when the per capta birth and death rates are equal Exponential population growth, or geometric population growth, is population increase at a constant rate. You would see a J shaped graph. Some density dependent factors in population regulation are birth and death rates, competition for resources, territoriality, health, predation, toxic wastes, and intrinsic factors. Population dynamics focuses on the complex interactions between biotic and abiotic factors that cause variation in population size. Human population growth has skyrocketed since the industrial revolution but has slowed down quite a bit in recent decades because of decreased birth rates. Age structure pyramids show the relative number of individuals of each age. Ecological footprints are used to estimate the carrying capacity of Earthand they recognize that humans have multiple contstraints. Some key relationships in the life of an organism are its interactions with other species in the community. Ecologists refer to these relationships as interspecific interactions. In interspecific competition, two species compete for the same resource. The Competitive Exclusion Principle comes into play when one species uses the resource more efficiently and thus reproduce more rapidly. This reproductive advantage will eventually wipe out the other competitor. Ecological niche- sum of a species’ use of the biotic and abiotic resources in its environment
Fundamental niche- the niche potentially occupied by that species
-(may be different from its)
Realized niche- the niche it actually occupies
Resource partitioning- the differentiation of niches that enables similar species to coexist in a community
Cryptic coloration- camoflauge, makes prey difficult to spot Aposematic coloring- animals with effective chemical defenses often exhibit bright warning coloration Batesian Mimicry- palatable or harmless species mimics an unplatable or harmful animal Müllerian mimicry- two or more unplatable species resemble each other Mutualism- interspecific interaction that benefits both species (+/+). Commensalism- is an interaction between species that benefits one of the species but neither helps nor harms the other (+/0). Dominant species in a community are the most abundant, or have the highest biomass. Keystone species aren't neccesarily abundant in a community but they have strong control on community by pivotal ecological roles. Evapotranspiration is the evaporation of water from soil plus the transpiration of water from plants. The Island Equilibrium Model is identifies the key determinants of species diversity of an island with a given set of physical characteristics. The Integrated hypothesis describes a community as an assemblage of closely linked species, locked into association by mandatory biotic interactions that cause the community to function as an integrated unit.
Individualistic describes a community of species found in the same area simply because they happen to have similar abiotic requirements. An ecosystem consists of all the organisms living in a community as well as the abiotic factors with which they interact. Microorganisms and other detrtivores Detritus Key Chemical cycling Energy flow Sun heat Primary consumers Primary producers Secondary consumers Tertiary consumers Detrivores are essential to an ecosystem because they decompose organic material in an ecosystem and transfer the chemical elements in inorganic forms to abiotic reservoirs such as soil water, and air. Gross primary production- the amount of light energy that is converted to chemical energy by photosynthesis per unit time. Net primary production- is equal to gross primary production minus the energy used by the primary producers for respiration. Without nutrients and light for photosynthesis, there isn’t very much production because both are necessary for in creating primary producers. Eutrophication has a wide range of ecological impacts, including the eventual loss of all but the most tolerant fish species from the lakes. Secondary production is the amount of chemical energy in consumers’ food that is converted to their own new biomass during a given time period. According to the Green World hypothesis, terrestrial herbivores consume relatively little plant biomass because they are held in check by a variety of factors, including predators, parasites, and disease. Reservoir a Reservoir b Fossilization Burning
of fossil fuels Assimilation, photosynthesis Respiration, decomposition, excretion Weathering, erosion Organic materials available as nutrients Organic materials unavailable as nutrients Formation of sedimentary rock Coal, oil, peat Living organisms, detritus Reservoir d Reservoir c Inorganic materials available as nutrients Inorganic materials unavailable as nutrients Atmosphere, soil, water Minerals in rocks Water cycle Carbon cycle Nitrogen cycle Phosphorus cycle Conservation biology integrates ecology, physiology, molecular biology, genetics, and evolutionary biology to conserve biological diversity at all levels. Restoration ecology applies ecological principles in an effort to return degraded ecosystems to conditions as similar as possible to their natural, predegraded state. Three levels of biodiversity- Genetic diversity-compromises not only the individual genetic variation within a population, but also the genetic variation between populations that is often associated with adaptions to local conditions.
Species diversity- the variety of species in an ecosystem or throughout the entire biosphere. (species richness)
Ecosystem diversity- the variety of the biosphere's ecosystems Ecosystem services Encompass all the processes through which natural ecosystems and the species they contain help sustain life on earth. Purification of air and water
Reduction of the severity of droughts and floods
Generation and preservation of fertile soils
Detoxification and decomposition of wastes
Pollination of crops and natural vegetation
Dispersal of seeds
Cycling of nutrients
Control of many agricultural pests by natural enemies
Protection of shorelines from erosion
Protection from ultraviolet rays
Moderation of weather extremes
Provision of beauty and recreational opportunities Four major threats to biodiversity are habitat destruction, introduced species, overexploitation, and disruption of "interaction networks" such as food webs. Extinction Vortex Small population Genetic Drift Inbreeding Loss of genetic variability Reduction in individual fitness and population adaptability Lower reproduction Higher mortality Smaller population A biodiversity hotspot is a relatively small area with an exceptional concentration of endemic species and a large number of endangered and threatened species. Bioremedation is the use of living organisms, usually prokaryotes, fungi, or plants, to detoxify polluted ecosystems. In contrast to bioremedation, which is a strategy for removing harmful substances, biological augmentation uses organisms to add essential materials to a degraded ecosystem. Sustainable developement is the long-term prosperity of human societies and the ecosystems that support them.
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