Ch 52 Bio

thermocline

-A narrow stratum of abrupt temperature change in the ocean and in many temperate-zone lakes. -separates the more uniformly warm upper layer from more uniformly cold deeper waters -Lakes tend to be particularly layered with respect to temperature, especially during summer and winter, but many temperate lakes undergo a semiannual mixing of their waters as a result of changing temperature profiles

disturbance

-A natural or human-caused event that changes a biological community and usually removes organisms from it. Disturbances, such as fires and storms, play a pivotal role in structuring many communities -changes a community, removing organisms from it and altering resource availability -frequent fires can kill woody plants and maintain the characteristic vegetation of a savanna; fires and outbreaks of pests create gaps in forest that allow different species to grow -Hurricanes and other storms create openings for new species in many tropical and temperate forests and can alter forest composition

abiotic factors

-Abiotic factors affecting distribution of organisms include: Temperature, Water, Sunlight, Wind, Rocks and soil -Most abiotic factors vary in space and time

reciprocal effects of ecological and evolutionary change (reciprocal eco-evolutionary effects)

-An ecological change, such as the expansion of a predator's range, can alter the selective pressures faced by prey populations. This could cause evolutionary change, such as an increase in the frequency of a new defensive mechanism in a prey population; that change, in turn, could alter the outcome of ecological interactions -ex: the evolutionary origin of plants altered the chemical cycling of carbon, leading to the removal of large quantities of carbon dioxide from the atmosphere. As the adaptive radiation of plants continued over time, the appearance of new plant species provided new habitats and new sources of food for insects and other animals; the availability of new habitats and new food sources stimulated bursts of speciation in animals, leading to further ecological changes

how do oceans and lakes moderate the climate?

-Because of the high specific heat of water, oceans and large lakes tend to moderate the climate of nearby land -During a hot day, when land is warmer than the water, air over the land heats up and rises, drawing a cool breeze from the water across the land -because temperatures drop more quickly over land than over water at night, air over the now warmer water rises, drawing cooler air from the land back out over the water and replacing it with warmer air from offshore

biotic factors

-Biotic factors that affect the distribution of organisms may include: Predation, Herbivory, Competition -ex: sea urchins can limit the distribution of seaweeds (inverse relationship between number of sea urchins and abundance of seaweeds) -In addition to predation and herbivory, the presence or absence of pollinators, food resources, parasites, pathogens, and competing organisms can act as a biotic limitation on species distribution. Such biotic limitations are common in nature

seasonality

-In middle to high latitudes, Earth's tilted axis of rotation and its annual passage around the sun cause strong seasonal cycles in day length, solar radiation, and temperature. The changing angle of the sun over the course of the year also affects local environments -Seasonal variations of light and temperature increase steadily toward the poles, and the variation is the smallest in the tropics -Belts of wet and dry air straddling the equator shift throughout the year with the changing angle of the sun; this produces marked wet and dry seasons around 20° north and 20° south latitude, where many tropical deciduous forests grow -seasonal changes in wind patterns alter ocean currents, sometimes causing the upwelling of cold water from deep ocean layers. This nutrient-rich water stimulates the growth of surface-dwelling phytoplankton and the organisms that feed on them. Though these upwelling zones make up only a few percent of the ocean's area, they are the source of more than a quarter of all fish caught globally

marine biome

-Marine biomes have salt concentrations of about 3%; The largest marine biome (oceans) cover about 75% of Earth's surface and have an enormous impact on the biosphere -Water evaporated from the oceans provides most of the planet's rainfall -Marine algae and photosynthetic bacteria supply much of the world's oxygen and consume large amounts of atmospheric carbon dioxide -Ocean temperatures have a major effect on global climate and wind patterns -along with large lakes, oceans tend to moderate the climate of nearby land

abiotic

-Nonliving; referring to the physical and chemical properties of an environment -influence the distribution and abundance of organisms

how do bodies of water affect climate?

-Oceans, their currents, and large lakes moderate the climate of nearby terrestrial environments -by heating or cooling overlying air masses that pass across the land -Water is warmed at the equator and flows north and south toward the poles, where it cools -ex: Coastal regions are also generally wetter than inland areas at the same latitude. The cool, misty climate produced by the cold California Current that flows southward along western North America supports a coniferous rain forest ecosystem along much of the continent's Pacific coast and large redwood groves farther south -ex: the west coast of northern Europe has a mild climate because the Gulf Stream carries warm water from the equator to the North Atlantic; northwestern Europe is warmer during winter than southeastern Canada, which is farther south but is cooled by the Labrador Current flowing south from the coast of Greenland

biotic

-Pertaining to the living factors—the organisms—in an environment -influence the distribution and abundance of organisms

streams and rivers

-Physical Environment: Currents; Headwater streams are cold/clear/turbulent/swift; Downstream water is warmer and more turbid because of suspended sediment; rivers/streams are stratified into vertical zones -Chemical Environment: Salt and nutrient content increases from the headwaters to the mouth; Headwaters rich in oxygen; Organic matter consists of dissolved material that is carried by the current -Geologic Features: Headwater stream channels are narrow, have a rocky bottom and alternate between shallow and deep; Downstream stretches are wide and meandering; Bottoms are silty from sediments -Photosynthetic Organisms: Headwater streams may be rich in phytoplankton or rooted aquatic plants -Heterotrophs: Great diversity and fish and invertebrates in unpolluted rivers; Organic matter from terrestrial vegetation is primary source of food for aquatic consumers -Human: Municipal, agricultural, and industrial pollution degrade water quality and kill organisms/Damming impairs the natural functioning

marine benthic zone

-Physical Environment: Seafloor below the surface waters of the coastal (neritic) zone and the offshore pelagic zone; Receives no sunlight; Water temp declines with depth while the pressure increases -Chemical Environment: Oxygen is usually present at sufficient concentrations to support diverse animal life -Geologic Features: Soft sediments cover most of it; Areas of rocky substrate on reefs, submarine mountains, and new oceanic crust -Autotrophs: Seaweeds and filamentous algae limited to shallow areas with sufficient light; deep-sea hydrothermal vents on mid-ocean ridges (dark, hot environments) have chemoautotrophic prokaryotes that obtain energy by oxidizing H2S formed by a reaction of the hot water with dissolved sulfate -Heterotrophs: Neritic benthic include numerous invertebrates and fishes; most consumers depend on organic matter raining down from above -Human: Overfishing has decimated important fish populations; Dumping of organic wastes has created oxygen-deprived areas

oceanic pelagic zone

-Physical Environment: Vast realm of open blue water, constantly mixed by oceanic currents; Higher water clarity=photic zone extends to greater depths than in coastal marine waters -Chemical Environment: High oxygen levels; Low nutrient concentrations; Turnover between fall and spring renews nutrients in photic zones of temperate and high-latitude ocean areas -Geologic Features: Covers 70% of earth's surface -Photosynthetic Organisms: Phytoplankton that drift with the currents; Spring produces surge of phytoplankton growth bc of turnover -Heterotrophs: Zooplankton (protists/worms/copepods/shrimp-like krill/jellies/small larvae of invertebrates and fishes eat phytoplankton); Free-swimming animals and marine mammals -Human: Overfishing has depleted fish stocks; marine life harmed by pollution, ocean acidification, and global warming

effect of global climate change on distribution of organisms

-Predictions for change can be based on previous changes -Glacier retreat 16,000 years ago caused tree distribution patterns to change: As the climate warmed and the glaciers retreated, tree species distributions expanded northward; fossilized pollen data show that while some species moved northward rapidly, others moved more slowly. For species that moved more slowly, the expansion of their ranges lagged several thousand years behind the shift in suitable habitat -other species may not be able to keep up with the climate change/warming: American beech, Fagus grandifolia- ecological models predict that the northern limit of the beech's range may move 700-900 km northward in the next century, and its southern range limit will shift even more. If these predictions are even approximately correct, the beech's range must shift 7-9 km northward per year to keep pace with the warming climate, but since the end of the last ice age, the beech has moved at a rate of only 0.2 km per year -Without human help in moving to new habitats, species such as the American beech may have much smaller ranges or even become extinct

convergent evolution

-Process by which unrelated organisms independently evolve similarities when adapting to similar environments -Similar characteristics can arise in distant biomes through convergent evolution -ex: cacti in North America and euphorbs in African deserts appear similar but are from different evolutionary lineages

water and oxygen

-Species living at the seashore or in tidal wetlands can desiccate (dry out) as the tide recedes. Terrestrial organisms face a nearly constant threat of desiccation, and the distribution of terrestrial species reflects their ability to obtain and conserve water. Many amphibians, such as the tiny frog, are particularly vulnerable to drying because they use their moist, delicate skin for gas exchange -Water affects oxygen availability in aquatic environments and in flooded soils, where the slow diffusion of oxygen in water can limit cellular respiration and other physiological processes -Oxygen concentrations can be particularly low in deep ocean and deep lake waters as well as in sediments where organic matter is abundant -Mangroves and other trees have specialized roots that project above the water and help the root system obtain oxygen; the surface waters of streams and rivers tend to be well oxygenated because of rapid exchange of gases with the atmosphere

general features of terrestrial biomes

-Terrestrial biomes are often named for major physical or climatic factors and for vegetation -Terrestrial biomes usually grade into each other, without sharp boundaries -The area of intergradation, called an ecotone, may be wide or narrow -Vertical layering is an important feature of terrestrial biomes, and in a forest it might consist of an upper canopy, low-tree layer, shrub understory, ground layer of herbaceous plants, forest floor, and root layer; Nonforest biomes have similar, though usually less pronounced, layers -Layering of vegetation provides many different habitats for animals, which sometimes exist in well-defined feeding groups, from the insectivorous birds and bats that feed above canopies to the small mammals, numerous worms, and arthropods that search for food in the litter and root layers below -Biomes are dynamic and usually exhibit extensive patchiness; species composition of each kind of biome varies from one location to another

benthic zone

-The bottom surface of an aquatic environment -Made up of sand and organic and inorganic sediments, the benthic zone is occupied by communities of organisms collectively called the benthos -A major source of food for many benthic species is dead organic matter called detritus, which "rains" down from the productive surface waters of the photic zone

turnover

-The mixing of waters as a result of changing water-temperature profiles in a lake -sends oxygenated water from the lake surface to the bottom -brings nutrient-rich water from the bottom to the surface -Seasonal turnover causes the lake waters to be well oxygenated at all depths in spring and autumn; in winter and summer, when the lake is stratified by temperature, the oxygen concentration decreases with depth -winter: the coldest water in the lake (0℃) lies just below the surface ice; water is progressively warmer at deeper levels of the lake, typically 4℃ at the bottom -spring: surface water warms to 4℃ and mixes with layers below, eliminating thermal stratification; spring winds help mix water, bringing oxygen to the bottom and nutrients to the surface -summer: lake regains thermal profile, with warm surface water separated by cold bottom water by a thermocline -autumn: as surface water cools rapidly, it sinks beneath the underlying layers, remixing the water until the surface begins to freeze and the winter temp profile is reestablished

photic zone

-The narrow top layer of an ocean or lake, where light penetrates sufficiently for photosynthesis to occur -The photic and aphotic zones together make up the pelagic zone

pelagic zone

-The open-water component of aquatic biomes -made up of the photic and aphotic zones

aphotic zone

-The part of an ocean or lake beneath the photic zone, where light does not penetrate sufficiently for photosynthesis to occur -little light penetrates -The photic and aphotic zones together make up the pelagic zone

ecology

-The study of how organisms interact with each other and their environment -the term environment refers to other organisms as well as the physical aspects of an organism's surroundings -interactions studied by ecologists can be organized into a hierarchy that ranges in scale from single organisms to the planet

ecotone

-The transition from one type of habitat or ecosystem to another, such as the transition from a forest to a grassland

what happens on the windward and leeward sides of a mountain?

-When warm, moist air approaches a mountain, the 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." Such leeward rain shadows determine where many deserts are found, including the Mojave Desert of western North America and the Gobi Desert of Asia

Mediterranean climate

-a climate marked by warm, dry summers and cool, rainy winters -local moderation of climate by bodies of water can be limited to the coast itself. In southern California and southwestern Australia, cool, dry ocean breezes in summer are warmed when they contact the land, absorbing moisture and creating a hot, arid climate just a few kilometers inland. This climate pattern also occurs around the Mediterranean Sea, which gives it the name Mediterranean climate

community ecology

-a community is a group of populations of different species in an area -deals with the whole array of interacting species in a community and examines how interactions between species, such as predation and competition, affect community structure and organization

climate change

-a directional change to the global climate that lasts for three decades or more, as opposed to short-term weather changes -Earth has warmed an average of 0.9°C (1.6°F) since 1900 and is projected to warm 1-6°C (2-11°F) more by the year 2100 -Wind and precipitation patterns are shifting, and extreme weather events (such as droughts and storms) are occurring more frequently

landscape ecology

-a landscape (or seascape) is a mosaic of connected ecosystems -focuses on factors controlling exchanges of energy, materials, and organisms across multiple ecosystems

climograph

-a plot of the temperature and precipitation in a particular region -it is based on annual averages. Often, however, the pattern of climatic variation is as important as the average climate. For example, some areas may receive regular precipitation throughout the year, whereas other areas may have distinct wet and dry seasons

population ecology

-a population is a group of individuals of the same species living in an area -analyzes factors that affect population size and how and why it changes through time

ecosystem ecology

-an ecosystem is the community of organisms in an area and the physical factors with which those organisms interact -emphasizes energy flow and chemical cycling among the various biotic and abiotic components

examples of how climate change has already affected species

-as the climate has warmed, 22 of 35 European butterfly species studied have shifted their ranges farther north by 35-240 km in recent decades -In western North America, nearly 200 plant species have moved to lower elevations, most likely in response to decreased rain and snow at higher elevations -Neodenticula seminae recently colonized the Atlantic Ocean for the first time in 800,000 years -when climate change enables or causes a species to expand its range into a new geographic area, other organisms living there may be harmed -as the climate changes, some species are facing a shortage of suitable replacement habitat, while others cannot migrate quickly enough- the geographic ranges of 67 bumblebee species in the Northern Hemisphere were shrinking: The bumblebees were retreating from the southern edges of their distributions, but failing to expand their ranges to the north. -Overall, climate change is causing the populations of many species to decrease in size or even disappear

zonation in a lake

-classified based on 3 physical criteria: light penetration (photic and aphotic zones), distance from shore and water depth (littoral and limnetic zones), and whether the environment is open water (pelagic zone) or on the bottom (benthic zone)

marine zonation

-classified based on light penetration (photic, aphotic zones), distance from shore and water depth (intertidal, neritic, oceanic zones), and whether the environment is open water (pelagic zone) or on the bottom (benthic and abyssal zones) -Marine communities, in particular, illustrate the limitations on species distribution that result from these abiotic factors; ex: Plankton and many fish species live in the relatively shallow photic zone. Because water absorbs light so well and the ocean is so deep, most of the ocean volume is dark (the aphotic zone) and harbors relatively little life.

freshwater biomes

-closely linked to the soils and biotic components of the surrounding terrestrial biome -The particular characteristics of a freshwater biome are also influenced by the patterns and speed of water flow and the climate to which the biome is exposed -have salt concentrations of less than 0.1%

global climate pattern

-determined largely by the input of solar energy and Earth's movement in space -The sun warms the atmosphere, land, and water. This warming establishes the temperature variations, movements of air and water, and evaporation of water that cause dramatic latitudinal variations in climate

tundra

-distr: Arctic; Alpine tundra exists on high mountaintops at all latitudes -precip: Precipitation is low in arctic tundra, and higher in alpine tundra -temp: Winters are long and cold (below -30°C) while summers are relatively cool (less than 10°C) -plants: herbaceous- mosses, grasses, forbs, dwarf shrubs, trees, lichens; permafrost restricts growth of plant roots -animals: Reindeer and caribou (migratory), musk oxen (resident); predators- bears, wolves, foxes; birds migrate to tundra for summer nesting -human impact: sparsely settled but has become the focus of significant mineral and oil extraction in recent years

savanna

-distr: equatorial and subequatorial regions -precip: seasonal -temp: warm year-round (24-29°C) but more seasonally variable than the tropics -plants: Fire adapted plants and tolerant to seasonal drought; Grasses and forbs tolerant of grazing by large mammals and herbivores; thorny trees with small leaves (adaptation to relatively dry conditions) -animals: Zebras, wildebeests, lions, hyena; large plant-eating mammals and predators; dominant herbivores are insects, esp termites; during seasonal droughts, grazing mammals migrate to parts of the savanna with more forage and scattered watering holes -human impact: earliest human may have lived in savannas; fires set may help maintain this biome, but too many reduce tree regeneration by killing seedlings/saplings; cattle ranching/overhunting led to declines in large-mammal populations

chaparral

-distr: midlatitude coastal regions on several continents -precip: rainy winters and dry summers -temp: Summer hot (30°C+) while fall, winter, and spring are cool (10-12°C) -plants: Shrubs, grasses, herbs (fire-resistant); plant diversity is high, with many species confined to a specific, relatively small geographic area; tough evergreen leaves reduce water loss; some shrubs produce seeds that only germinate after a hot fire -animals: Insects and small mammals (browsers like goats, deer) -human impact: have been heavily settled and reduced thru conversion to agriculture and urbanization; humans contribute to fires that sweep across the chaparral

temperate broadleaf forest

-distr: midlatitudes in the Northern Hemisphere, with smaller areas in Chile, South Africa, Australia, and New Zealand -precip: Large amount of precip in all seasons -temp: Winters average 0°C, while summers are hot and humid (near 35°C) -plants: Vertical layering; Deciduous trees (dominant plants in northern hemisphere- drop leaves before winter when low temps reduce photosynthesis and make water uptake hard b/c of frozen soil); few epiphytes; evergreen eucalyptus forests dominate in Australia -animals: Mammals (hibernate in winter), birds (migrate to warmer climates), insects; use all vertical layers of the forest -human impact: heavily settled; logging/land clearing for ag and urban development cleared virtually all original deciduous forests in N. America, but these forests are returning over much of their former range

temperate grassland

-distribution: found on many continents -precip: highly seasonal, relatively dry winters/wet summers; 30-100 cm; periodic drought common -temp: winters are cold with avg temp below -10°C; hot summers with temps close to 30°C -plants: Grasses and forbs adapted to fire and drought; grazing by large animals helps prevents development of woody shrubs/trees -animals: bison and wild horses; burrowing animals (prairie dogs) -human impact: deep, fertile soils make temperate grasslands great for agriculture (esp grains), so most grassland has been converted into farmland; in drier grasslands, cattle and other grazers have turned parts of the biome into desert

desert

-distribution: occur in bands near 30°C north and south and in the interior of continents -precipitation: low and highly variable; generally less than 30 cm per year -temp: variable seasonally and daily; max air temp may exceed 50°C; in cold deserts, air temp may drop below -30°C -plants: low, widely scattered vegetation; high proportion of bare ground; succulents (cacti/euphorbs), deeply rooted shrubs, herbs that grow during infrequent moist periods; plant adaptations include tolerance of heat/dessication, water storage, and reduced leaf surface area; physical defenses (spines) and chemical defenses (toxins in leaves) are common; many exhibit C4 or CAM photosynthesis -animals: snakes, lizards, scorpions, ants, beetles, migratory/resident birds, seed-eating rodents; many species are nocturnal; water conservation- important adaptation, with some species surviving solely on water obtained from breaking down carbohydrates in seeds -human impact: long-distance water transport and deep groundwater wells have allowed humans to maintain substantial populations in deserts; urbanization and conversion to irrigated agriculture have reduced the natural biodiversity of some deserts

tropical forest

-distribution: occur in equatorial and subequatorial regions -precipitation: in tropical rain forests, rainfall is relatively constant, and in tropical dry forests, rainfall is highly seasonal (6-7 mo dry period) -temp: high year round, 25-29 C, with little seasonal variation -plants: tropical rain forests are vertically layered, and competition for sunlight is intense; layers include trees that grow above the canopy, the canopy trees, 1-2 layers of subcanopy trees, and layers of shrubs/herbs (small, nonwoody plants); generally less layers in tropical dry forests; broadleaf evergreen trees dominant in tropical rain forests, but many tropical dry forest trees drop leaves during the dry season; epiphytes (bromeliads/orchids) cover tropical forest trees but less abundant in dry forests; thorny shrubs/succulents common in tropical dry forests -animals: animal diversity is higher in tropical forests than in any other terrestrial biome; the amphibians, birds/ other reptiles, mammals, arthropods are adapted to vertically layered environment and are often inconspicuous -human impact: tropical forests are now being cut down/converted to farmland, urban areas, and other types of land use

northern coniferous forest

-distribution: taiga, spans northern North America and Eurasia and is the largest terrestrial biome on Earth -precip: varies -temp: Winters are cold and long while summers may be hot (e.g., Siberia ranges from -50°C to 20°C) -plants: Pine, spruce, fir & hemlock- cone-bearing trees; conical shapes prevents too much snow from accumulating and breaking their branches & needle/scale-like leaves reduce water loss -animals: Moose, brown bear, migratory birds, Siberian tigers; periodic outbursts of insects that feed on dominant trees can kill vast tracts of trees -human impact: being logged at an alarming rate; old-growth stands of trees may soon disappear

Latitudinal variation in sunlight intensity

-earth's curved shape causes latitudinal variation in the intensity of sunlight -because sunlight strikes the tropics most directly, more heat and light per unit of surface area are delivered there -at higher latitudes, sunlight strikes earth at a an oblique angle, and thus the light energy is more diffuse on earths surface

Are joint effects between ecological and evolutionary change common over shorter periods of time?

-ecological change can cause evolutionary change over the course of a few years to decades; examples include beak length evolution in soapberry bugs and the formation of new sunflower species -Rapid evolution can also cause ecological change -ex: Trinidadian guppy (Poecilia reticulata) populations evolve rapidly when predators are removed: guppy color patterns change and guppies produce fewer but larger offspring. Larger fish excrete more nitrogen than do smaller fish, and nitrogenous wastes contribute to the growth of primary producers such as algae. -Overall, this and other studies show that ecological change and evolution have the potential to exert rapid feedback effects on each other

temperature

-important factor in the distribution of organisms because of its effect on biological processes -Cells may rupture if the water they contain freezes (at temperatures below 0°C), and the proteins of most organisms denature at temperatures above 45°C -Organisms typically function best within a specific range of environmental temperature. Temperatures outside that range may force some animals to expend energy regulating their internal temperature, as mammals and birds do -ex: climate change has already caused hundreds of species to alter their geographic ranges. A shift in the range of one species can also have profound effects on the distribution of other species. Consider how rising sea temperatures have affected the geographic range of the sea urchin C. rodgersii; water temps have increased from 11.5°C to 12.5°C, which has enabled C. rodgersii— whose larvae fail to develop properly if temperatures drop below 12°C—to expand its range to the south. The urchin is a voracious consumer of kelp and other algae, so algal communities that once harbored a rich diversity of other species have been completely destroyed in regions where the urchin has become well established

organismal ecology

-includes physiological, evolutionary, and behavioral ecology -concerned with how an organism's structure, psychology, and behavior meet the challenges posed by its environment

global air circulation and precipitation patterns

-initiated by intense solar radiation near the equator -Rising air masses release water and cause high precipitation, especially in the tropics -Dry, descending air masses create arid climates, especially near 30° -Air flowing close to Earth's surface creates predictable global wind patterns -Cooling trade winds blow from east to west in the tropics; prevailing westerlies blow from west to east in the temperate zones (regions between Tropic of Cancer and Arctic Circle and between Tropic of Capricorn and the Antarctic Circle

evolutionary history and ecological factors influencing species distribution example

-kangaroos are only in Australia and not found anywhere else in the world b/c the lineage originated there at a point in time when the continent was geographically isolated; Australia was already isolated from the other continents when kangaroos originated 5 mil yrs ago -ecological factors (abiotic and biotic factors): kangaroos have not dispersed (on their own) to other continents; hence, they are restricted to the continent on which they originated. And within Australia, kangaroos are found in some habitats but not in others -ex: red kangaroos live in arid grasslands but not in tall open forests; this is similar to all species: all species are found in some habitats but not in others -abiotic/biotic factors affect distribution of the saguaro cactus: found almost exclusively in the Sonoran Desert of the southwestern United States and northwestern Mexico. To the north, their range is limited by temperature. Saguaros tolerate freezing temperatures only briefly, typically for less than a day, and generally cannot survive at temperatures below -4°C (25°F). For the same reason, saguaros are rarely found at elevations above 1,200 m (4,000 feet) -Water availability is critical because seedling survival typically requires consecutive years of moist conditions -Biotic factors almost certainly influence their distribution as well. Mice and grazers such as goats eat the seedlings, and bats pollinate the large, white flowers that open at night. Saguaros are also vulnerable to a deadly bacterial disease

aquatic biomes

-largest part of the biosphere in terms of area -They show less latitudinal variation than terrestrial biomes -Many aquatic biomes are physically and chemically stratified (layered), vertically and horizontally

microclimate affected by other factors

-microclimate is characterized by differences in abiotic and biotic factors -Many features in the environment influence microclimate by casting shade, altering evaporation from soil, or changing wind patterns -ex: forest trees often moderate the microclimate below them. Cleared areas therefore typically experience greater temperature extremes than the forest interior because of greater solar radiation and wind currents that arise from the rapid heating and cooling of open land -Within a forest, low-lying ground is usually wetter than higher ground and tends to be occupied by different tree species -A log or large stone can shelter organisms such as salamanders, worms, and insects, buffering them from the extremes of temperature and moisture

species transplant

-organisms that are intentionally or accidentally relocated from their original distribution/to areas where they're originally absent -For a transplant to be successful, some of the organisms must not only survive in the new area but also reproduce there sustainably -If a transplant is successful, then the potential range of the species is larger than its actual range; the species could live in certain areas where it currently does not -Species introduced to new geographic locations can disrupt the communities and ecosystems to which they have been introduced, so ecologists rarely move species to new regions -Instead, they document the outcome when a species has been transplanted for other purposes, as when a predator is introduced to control a pest species, or when a species has been moved accidentally to a new region

rocks and soil

-pH, mineral composition, and physical structure of rocks and soil limit the distribution of plants and thus of the animals that feed on them -pH of soil can limit the distribution of organisms directly, through extreme acidic or basic conditions, or indirectly, by affecting the solubility of toxins and nutrients -ex: Soil phosphorus, for instance, is relatively insoluble in basic soils and precipitates into forms unavailable to plants -In a river, the composition of rocks and soil that make up the substrate (riverbed) can affect water chemistry, which in turn influences the resident organisms -In freshwater and marine environments, the structure of the substrate determines the organisms that can attach to it or burrow into it

wetlands

-physical environ: a habitat that is inundated by water at least some of the time and that supports plants adapted to water-saturated soil; some are constantly inundated while others flood infrequently -chemical environ: have high organic production and decomposition, which leads to periodically low 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/forth b/c of rising lake levels/tidal action--fringe wetlands include freshwater and marine biomes -photosynthetic organisms: most productive biomes on Earth; lilies, cattails, sedges, tamarack, and black spruce; adaptations enabling them to grow in water or in soil that's periodically anaerobic -heterotrophs: invertebrates and birds, as well as otters, frogs, and alligators; herbivores eat algae, detritus, and plants -human impact: Humans have destroyed up to 90% of wetlands; wetlands purify water and reduce flooding

coral reefs

-physical environ: calcium carbonate skeletons of corals; shallow reef-building corals live in the photic zone -chem environ: high oxygen levels and are excluded by high inputs of freshwater and nutrients -geologic features: corals require a solid substrate for attachment; begins as a fringing reef on a young, high island, forming an offshore barrier reef later in the history of the island and becoming a coral atoll as the older island submerges -photosynthetic organisms: unicellular algae live in the tissues of the coral- mutualistic relationship; multicellular red/green algae photosynthesize -heterotrophs: corals, a diverse group of cnidarians, are themselves the predominant animals of coral reefs; fish/invertebrate diversity is high -human impact: collecting of coral skeletons/overfishing have reduced populations of corals and reef fishes; global warming/pollution- large scale coral death; development of coastal mangroves for aquaculture reduced spawning grounds for many reef fishes

estuaries

-physical environ: transition area between river and sea; high-density sea water occupies the bottom of the channel and mixes little with low-density river water at the surface -chem environ: Salinity varies spatially and with the rise and fall of the tides; nutrient rich and highly productive -geologic features: complex network of tidal channels, islands, natural levees, and mudflats -photosynthetic organisms: Saltmarsh grasses and algae are the major producers -heterotrophs: worms, oysters, crabs, fish; An abundant supply of food attracts marine invertebrates, fish, waterfowl, and marine mammals -human impact: filling, dredging, and pollution from upstream disrupt estuaries worldwide

intertidal zones

-physical environment: periodically submerged and exposed by the tides; organisms are challenged by variations in temperature and salinity and by the mechanical forces of wave action -chem environ: Oxygen and nutrient levels are high -geologic features: Substrate varies from rocky to sandy -photosynthetic organisms: attached marine algae in rocky intertidal zones, esp lower zone; sandy intertidal zones exposed to vigorous waves lack attached plants/algae, but sandy intertidal zones in protected bays/lagoons support rich beds of seagrass/algae -heterotrophs: animals have structural adaptations that enable them to stick to the hard substrate; many animals in sandy/muddy intertidal zones (worms, clams, predatory crustaceans) bury themselves and feed as tides bring in food; also sponges, sea anemones, echinoderms, small fishes -human impact: oil pollution; construction of rock walls/barriers to reduce erosion from waves has disrupted this zone in some locations

lakes

-physical environment: stratification b/c of light decreasing w/ depth; temperate lakes may have a seasonal thermocline, while tropical lowland lakes have a year-round thermocline -chemical environ: oligotrophic lakes are nutrient-poor and generally oxygen-rich; are nutrient-rich and often depleted of oxygen in the deepest zone in the summer and if ice covered in winter; the amount of decomposable organic matter in bottom sediments is low in oligotrophic and high in eutrophic lakes; high rates of decomposition in deeper layers of eutrophic lakes cause temporary depletions of oxygen -geologic features: oligotrophic lakes have less surface area to depth compared to eutrophic lakes and can become more eutrophic over time as runoff adds sediments and nutrients -photosynthetic organisms: rooted/floating plants in the littoral zone and variety of phytoplankton (including cyanobacteria) in the limnetic zone -heterotrophs: small drifting heterotrophs (zooplankton) graze on phytoplankton in limnetic zone; invertebrates whose species composition depends on oxygen levels in the benthic zone; fishes in all zones with enough oxygen -human impact: runoff from fertilized land and dumping wastes lead to nutrient enrichment, which produces algal blooms, oxygen depletion, and fish kills

salinity

-salt concentration of water in the environment affects the water balance of organisms through osmosis -Most aquatic organisms are restricted to either freshwater or saltwater habitats by their limited ability to osmoregulate -most terrestrial organisms can excrete excess salts from specialized glands or in feces or urine, but still few terrestrial organisms are adapted to high-salinity habitats -ex: Salmon that migrate between freshwater streams and the ocean use both behavioral and physiological mechanisms to osmoregulate. They balance their salt content by adjusting the amount of water they drink and by switching their gills from taking up salt in fresh water to excreting salt in the ocean

global ecology

-the biosphere is the global ecosystem, the sum of all the planet's ecosystems -Global ecology examines the influence of energy and materials on organisms across the biosphere

climate

-the long-term prevailing weather conditions in an area: temperature, precipitation, sunlight, wind -most significant influence on the distribution of organisms on land -Macroclimate - global, regional, and landscape level -Microclimate -small, very fine, localized climatic patterns (community of organisms underneath a fallen log) -varies seasonally and can be modified by other factors, such as large bodies of water and mountain ranges

dispersal

-the movement of individuals or gametes away from their parent location; this movement sometimes expands the geographic range of a population or species -movement away from their area of origin or from centers of high population density -ex: while land-bound kangaroos have not reached Africa under their own power, other organisms that disperse more readily, such as some birds, have

abyssal zone

-the part of the ocean's benthic zone between 2000 and 6000 meters deep -deep in the aphotic zone

adaptive radiation

-the rapid evolution of an ancestral species into new species that fill many ecological niches -in rare cases, long-distance dispersal can result in adaptive radiation

how do mountains affect temperature and rainfall?

-they affect the amount of sunlight that reaches a certain area -South-facing slopes in the Northern Hemisphere receive more sunlight than north-facing slopes and are therefore warmer and drier, which influence species distributions locally -in western North America, spruce and other conifers grow on the cooler north-facing slopes, but shrubby, drought-resistant plants inhabit the south-facing slopes -every 1,000-m increase in elevation produces an average temperature drop of 6°C, equivalent to that produced by an 880-km increase in latitude. This is one reason that high-elevation communities near the equator, for example, can be similar to lower-elevation communities that are far from the equator

sunlight

-too little sunlight can limit the distribution of photosynthetic species -shading by leaves makes competition for light especially intense, particularly for seedlings growing on the forest floor -every meter of water depth absorbs about 45% of the red light and about 2% of the blue light passing through it, so most photosynthesis occurs relatively near the water surface -high light levels can increase temperature stress if animals and plants are unable to avoid the light or to cool themselves through evaporation -At high elevations, the sun's rays are more likely to damage DNA and proteins because the atmosphere is thinner, absorbing less ultraviolet (UV) radiation. Damage from UV radiation, combined with other abiotic stresses, prevents trees from surviving above a certain elevation, causing a tree line on mountain slopes

range expansion

-when organisms reach an area where they did not exist previously -Natural range expansions clearly show the influence of dispersal on distribution. However, opportunities to observe such dispersal directly are rare, so ecologists often turn to experimental methods to better understand the role of dispersal in limiting the distribution of species -in the late 1800s, egrets managed to cross the Atlantic Ocean and colonize northeastern South America. From there, cattle egrets gradually spread southward and also northward through Central America and into North America, reaching Florida by 1960. Today they have breeding populations as far west as the Pacific coast of the United States and as far north as southern Canada

do dominant plants depend on periodic disturbance in some biomes?

-yes, In many biomes, even the dominant plants depend on periodic disturbance -Natural wildfires are an integral component of grasslands, savannas, chaparral, and many coniferous forests -Before agricultural and urban development, much of the southeastern United States was dominated by a single conifer species, the longleaf pine -Without periodic burning, broadleaf trees tended to replace the pines. Forest managers now use fire as a tool to help maintain many coniferous forests -Fire suppression has changed the vegetation of the Great Plains

How large bodies of water and mountains affect climate

1- cool air flows inland from the water, moderating temperatures near the shore 2- air that encounters mountains flows upward, cools at higher altitudes, and releases water as precipitation 3- less moisture is left in the air reaching the leeward side, which therefore has little precipitation; this rain shadow can create a desert on the back side of the mountain range

Which of the following causes Earth's seasons?

Earth's tilt on its axis -Earth's tilt toward or away from the sun allows for direct and indirect solar collection, respectively. When the Northern Hemisphere is tilted toward the sun, it is summer because of the increased duration and intensity of insolation

Which would be a consequence of the removal of predators from a population such as the Trinidadian guppy population?

Guppy color patterns would change; guppies would produce fewer but larger offspring; the nitrogen excretion rate would increase and the rate of growth of primary producers such as algae would increase. -these represent the reciprocal effects of ecological and evolutionary change

What is a biome?

a major type of ecosystem -A biome is a type of community with certain abiotic environmental conditions -any of the world's major ecosystem types, often classified according to the predominant vegetation for terrestrial biomes and the physical environment for aquatic biomes and characterized by adaptations of organisms to that particular environment -affected not just by average temperature and precipitation, but also by the pattern of temperature and precipitation through the year; Some areas in North America with a particular combination of temperature and precipitation support a temperate broadleaf forest, but other areas with similar values for these variables support a coniferous forest

Which of the following investigations is an example of the study of an abiotic factor?

investigating how the amount of annual precipitation affects the distribution of a tree species -Annual precipitation is not a biotic factor of an environment; it is an abiotic factor

Which of the biomes—tundra, coniferous forest, temperate broadleaf forest, temperate grassland, savanna, chaparral, desert, tropical rainforest—require periodic fires to maintain their existence?

savanna, chaparral, temperate grassland, and coniferous forest

In most cases, the two major climatic factors affecting the distribution of organisms in terrestrial ecosystems are _____

water and temperature -These are the two most important climatic factors affecting the distribution of organisms

What are the most abundant animals found in the pelagic zone?

zooplankton -Zooplankton that graze on phytoplankton are the most abundant life-forms in the open ocean of the pelagic zone