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Biology Ch. 34

Organisms are WHAT by the environment, but also change it. Ex.) Plants alter environment by extracting CO2 and trading O2.
Ecologists examine how one kind of organism meets the challenges of its environment. Ex.) An ecologist working at this level might study the adaptations of clams to the extreme temperatures around hydrothermal vents
a group of individuals of the same species living in a particular geographic area. An ecologist might study what factors limit their population size.
consists of all the populations of different species
levels of ecology
organism, population, community, ecosystem
includes all the forms of life in a certain area and all the nonliving factors as well
abiotic components
This includes temperature, forms of energy, water, inorganic nutrients, and other chemicals
biotic components
A living component of a biological community; an organism, or a factor pertaining to one or more organisms
scientific study of the interactions of organisms with their environment
elements of the scientific process
Ecological researchers use this: posing of hypotheses and the use of observations and experiments to test those hypothesis.
The global ecosystem- sum of all the planet's ecosystems
feature of biosphere
patchiness. Ex.) Mixture of forrest, small lakes and a river. Moving in closer, each lakes have different habitats.
specific environments in which organisms live. Each habitat has characteristic abiotic factors- such as water depth, temperature, and dissolved O2 in a lake habitat- that largely determine the kinds of organisms that live in that habitat.
rachel carson
One of the first to perceive the global dangers of pesticide abuse. Pesticides, herbicides, agricultural waste, etc. Her warnings were underscored when scientists reported that DDT was threatening the survival of predatory birds and was showing up in human milk.
solar energy
WHAT powers nearly all terrestrial and shallow-water ecosystems
inorganic chemicals
Other ecosystems, such as the hydrothermal vents and ecosystems in dark caves and in groundwater deep beneath Earth's surface, are powered by energy that bacteria extra from WHAT
Because water itself and the microorganism in it absorb light and keep it from penetrating very far, most photosynthesis occurs near the WHAT of a body of water?
a second abiotic factor that is essential to all life. For a terrestrial organism, the main water problem is the threat of drying out.
fresh water (bursts)
marine (shrivals)
An important abiotic factor because of its effect on metabolism. 0 to 45 degrees celsius optimal for life.
An important abiotic factor. Local wind damage often creates opening in forests, contributing to patchiness in ecosystems. Wind also increases an organism's rate of water loss by evaporation.
nitrogen and phosphorus
inorganic nutrients
aquatic factors
dissolved oxygen, salinity, tides
goal of ecology
Fundamental WHAT is to explain the distribution of organisms
two ways:
The presence of a species in a particular place can come about in two ways: 1. Species may evolve in that location 2. May disperse to that location
natural selection
heritable variations are exposed to environmental factors that favor the reproductive success of some individuals over others
terrestrial communities
climate influences WHAT?
temperature and rainfall
What determines whether a particular organism or community of organisms lives in a certain area, the climate of the region- especially WHAT?
solar energy
Earth's global climate patterns are largely determined by the input of WHAT and the planet's movement in space.
the region between latitudes 23.5 north and 23.5 south. Region surrounding the equator. It experiences the greatest annual input and least seasonal variation in solar radiation. warm, lots of rain.
high temperatures in the tropics evaporate water from Earth's surface. Heated by the direct rays of the sun, moist air at the equator rises, creating an area of calm or of very light winds known as WHAT? As warm equatorial air rises, it cools and releases much of its water content, creating the abundant precipitation typical of most tropical regions. High temperatures throughout the year and ample rainfall largely explain why rain forests are concentrated near the equator.
trade winds
After losing their moisture over equatorial zones, high altitude air masses spread away from the equator until they cool and descend again at the latitudes of about 30 degrees north and south. This descending dry air absorbs moisture from the land. Thus, many deserts are centered at these latitudes. As the dry air descends, some of it spreads back toward the equator. This movement creates the cooling WHAT, which dominate the tropics (As dry air descends, some spreads back toward the equator (cooling) mostly around the equator)
temperate zones
The latitudes between the tropics and the Article Circle in the north and the Antarctic Circle in the south are called WHAT? Generally, these regions have seasonal variations in climate and more moderate temperatures than the tropics or the polar zones. (latitudes between the tropics and arctic circle- largest zone)
prevailing winds
major global air movements results from the combined effects of the rising and falling of a air masses and Earth's rotation. Because Earth is spherical, its surface moves faster at the equator. (E to W)- created from rising/lowering air masses and earth's rotation
In temperate zones, the slower-moving surface produces WHAT, wind that blows from W to E
ocean currents
A combination of the prevailing winds, the planet's rotation, unequal heating of surface waters, and the locations and shapes of the continents creates WHAT?, riverlike flow patterns in the oceans.
WHAT can also affect local climate? Air temperature declines about 6 degrees C with every 1,000-m increase in elevation.
A terrestrial ecosystem, largely determined by climate, usually classified according to the predominant vegetation and characterized by organisms adapted to the particular environments.
Covering about 75% of the planet's surface, oceans have an enormous impact on the biosphere. Their evaporation provides most of Earth's rainfall, and ocean temperatures have a major effect on climate and wind patterns.
amount of light and distance from shore
Abiotic factors such as AMOUNT OF LIGHT AND DISTANCE FROM SHORE influence the distribution of aquatic biomes
intertidal zone
The area of the shore where land meets ocean is called WHAT? This area is often pounded by waves during high tide and exposed to the sun during low tide.
how much salt in the water
less than 1% salt concentration
marine water
more than 1% salt concentration
tide pool
a small body of water that remains in a rock or sand depression during low tide.
pelagic zone
The open ocean itself. This supports communities dominated by highly motile animals such as fishes, squids, and marine mammals, including whales and dolphins. (Surface of the water)
microscopic algae and cyanobacteria drift passively in the pelagic zone. Phytoplankton are the ocean's main photosynthesizers.
zoo plankton
small, drifting animals that usually have morphological features that keep them afloat. They eat phytoplankton and in turn are consumed by larger animals.
benthic zone
seafloor. This community consists of attached algae, fungi, bacteria, sponges, burrowing worms, clams, sea anemones, crabs and fishes.
photic zone
benthic and pelagic communities together. It is a relatively small portion of ocean water and bottom into which light penetrates and in which photosynthesis occurs. (aquatic level where light penetrates the water column- max 200 m.)
aphotic zone
Most extensive part of the biosphere. No light, no photosynthesis. Below 1,000 m. Completely dark.
continental shelves
The submerged part of a continent. The benthic communities usually receive some light, and nutrients from the seafloor circulate in the shallow water.
coral reefs
a visually spectacular and biologically diverse ecosystem, are found in warm tropical waters above the continental shelf. The reef is built up slowly by successive generations of coral animals- a diverse group of cnidarians that secrete a hard external skeleton- and by multicellular algae encrusted with limestone.
an area where a freshwater stream or river merges with the ocean. With their waters enriched by nutrients from the river, estuaries are among the most productive biomes on Earth. Oysters, crabs, and many fishes live in estuaries or reproduce in them. Estuaries are also crucial in nesting and feeding areas for waterfowl.
an area that is transitional between an aquatic ecosystem and a terrestrial one
Large populations of microorganisms in the benthic community WHAT dead organisms that sink to the bottom.
Respiration by microbes also removes WHAT from water near the bottom, and in some lakes, benthic areas are unsuitable for any organisms except anaerobic microbes.
freshwater biomes
includes lakes, streams, rivers and wetlands
nitrogen and phosphorus
these nutrients usually limit the amount of phytoplankton growth in a lake or pond. Ex.) When there are temperature layers in a lake, nutrients released by decomposers can become trapped near the bottom, out of reach of the phytoplankton. During the summer months, this may limit the growth of algae in the photic zone.
algal blooms
Today, many lakes and ponds are affected by large inputs of nitrogen and phosphorus from sewage and from runoff from fertilized lawns and agricultural fields. These nutrients often produce WHAT, or population explosions of algae. Heavy algal growth reduces light penetration into the water, and when the algae die and decompose, a pond or lake can suffer serious oxygen depletion.
rivers and streams
WHAT changes greatly between its source and the point at which it empties into a lake or the ocean. Near the source, the water is usually cool, low in nutrients and clear.
WHAT also inhibits the growth of phytoplankton; most of the organisms found here are supported by the photosynthesis of algae attached to rocks or by organic material carried into the stream from the surrounding land
The most abundant benthic animals are usually WHAT such as small crustaceans and insect larvae that have physical and behavioral adaptations that enable them to resist being swept away.
A river or stream generally wides and slows WHERE? The water is usually warmer and may be murkier because of sediments and phytoplankton suspended in it.
Range from swamps to marshes and bogs. They may form in shallow basins or along the banks of rivers or lakes. Wetlands are among the richest of biomes in terms of species diversity. They provide water storage areas that reduce flooding and improve water quality by filtering pollutants.
Why does sewage cause algal blooms in lakes?
Why does sewage cause algal blooms in lakes?: The sewage adds nutrients, such as nitrates and phosphates, that stimulate growth of the algae
how many types of terrestrial biomes?
predominant vegetation
Many of the biomes are named for climatic features and for their WHAT, but each is also characterized by microorganisms, fungi, and animals adapted to that particular environment.
climate, temperature, and rainfall
the distribution of the biomes largely depends on CLIMATE, with TEMPERATURE, and RAINFALL often the key factors determining the kind of biome that exists in a particular region.
Each biome type occurs on at least how many continents?
Each biome is characterized by a WHAT of biological community, not a specific assemblage of species. Ex.) The groups of species living in the deserts of the American Southwest and in the Sahara Desert of Africa are different, but the species in both are adapted to desert conditions.
local variation
Within each biome there is WHAT, giving the vegetation a patchy, rather than a uniform, appearance. For ex.) in northern coniferous forests, snowfall may break branches and small trees, causing openings where broadleaf trees such as aspen and birch can grow. Local storms and fires also create openings in many biomes
WHAT has a very important effect in some biomes? Without periodic burning, many grasslands would be replaced by forests. Most grasses survive burning because the growing points of their shoots and below-grown and not killed
tropical forests
occur in equatorial areas where the temperature is warm and days are 11-12 hours long year-round.
tropical dry forest
In areas where rainfall is scarce or there is prolonged dry season, tropical dry forests predominate. The plants found there are a mixture of thorny shrubs and deciduous trees and succulents. Tropical rain forests are found in very humid equatorial areas where rainfall is abundant (200-400 cm per year)
tropical rain forest
Tropical rain forest is among the most complex of all biomes, harboring enormous numbers of different species. Up to 300 species of trees can be found in a single hectare.
tropical rainforests soil
soil is typically poor, because high temperatures and rainfall lead to rapid decomposition and recycling rather than to a buildup of organic material.
poor soil in tropical rain forests
poor soil in tropical rain forests: Why are the soils in most tropical rain forests so poor in nutrients that they can only support farming for a few years after the forest is cleared? -The tropical conditions favor rapid decomposition of organic litter in the forest soil, and most of the ecosystem's nutrients are tied up in the vegetation that is cleared away before farming.
a biome dominated by grasses and scattered trees. Rainfall averages 30-50 cm per year and the temperature is warm year-round. It is simple in structure compared with tropical forests.
savanna fires
frequent fires, caused by lightning or human activity, and grazing animals inhibit further invasion by trees. The dominant plants are fire adapt.
savanna animals
The dominant herbivores in savannas are actually insects, especially ants and termites. Also common are many burrowing animals like mice, moles, ground squirrels. Many of the world's large herbivores and their predators inhabit savannas. African savannas are home to giraffes, zebras, and many species of antelopes as well as to lions and cheetahs.
how do fires help maintain savannas as grassland ecosystems?
how do fires help maintain savannas as grassland ecosystems?: By repeatedly preventing the spread of trees and other woody plants
the driest of all terrestrial biomes, characterized by low and unpredictable rainfall (less than 30 cm per year).
desert temperature
Some deserts can be very hair with day time soil surface above 60 degrees C. Air temp in cold deserts may fall below -30 degrees C.
growth and reproduction
The cycles of WHAT and WHAT in the desert are keyed to rainfall.
Desert plants typically produce a great number of WHAT, which many remain dormant until a heavy rain triggers germination.
desert animals
Like desert plants, desert animals are adapted to drought and extreme temperatures. Many live in burrows and are active only during the cooler nights, and most have special adaptations that conserve water. Seed-eaters such as ants, many birds, and rodents are common in deserts. Lizards, snakes and hawks eat the seed-eaters.
the conversion of semiarid regions to desert. This is a significant environmental problem. Ex.) In central Africa, a burgeoning human population, overgrazing, and dry land farming are converting large areas of savanna to desert.
a region of dense, spiny shrubs with tough, evergreen leaves. Occurring in midlatitude coastal areas, (mediterranean region and california) the chaparral climate results mainly from cool ocean currents circulating offshore, which tends to produce mild, rainy winters and long, hot, dry summers.
Chaparral vegetation is adapted to periodic fires, most often caused by WHAT; in fact, the vegetation requires occasional fires for long-term maintance.
chaparral plants
Shrubs usually regenerate quickly from their fire-resistant roots, using stored food reserves and mineral nutrients released by the fires. In addition, many chaparral plant species produce seeds t hat will germinate only after a hot fire.
Animal characteristics of the chaparral are WHAT such as deer, fruit-eating birds, and seed-eating rodents, as well as lizards and snakes.
temperate grasslands
This biome has some of the characteristics of tropical savannas, but they are mostly treeless, except along rivers or streams, and are found in regions of relatively cold winter temperatures. Most grasslands persist because of periodic drought, fires, and grazing by large mammals, all of which inhibit growth of woody plants but do not harm the below-ground grass shoots.
large grazing mammals
Grasslands expanded in range following the retreat of the glaciers after the last ice age. Coupled with this expansion was the proliferation of WHAT. The bison and pronghorn of North America, the gazelles and zebras of the African veldt, and the wild horses and sheep.
grassland soil
Enriched by glacial deposits and mulch from decaying plant material, the soil of this biome supports a great diversity of microorganisms and small animals, especially annelids, anthropods, and burrowing mammals.
grassland rainfall
the amount of annual rainfall influences the height of vegetation. Moderate rainfall 25-27 cm. More than chaparral and desert, but less than savannas.
temperate broadleaf forests
grow throughout midlatitude regions, where there is sufficient moisture to support the growth of large trees. This includes eastern U.S., central Europe, and east Asia
deciduous trees
In the Northern Hemisphere, WHAT characterize the temperate broadleaf forests? Some of the dominant trees include species of oak, hickory, birch, beech, and maple.
broadleaf forest temperature
temperature range from very cold in the winter to hot in the summer (-30 degrees C to + degrees C)
broadleaf forest rainfall
Precipitation is relatively high and usually evenly distributed throughout the year. These forests typically have a growing season of 5 to 6 months. The loss of leaves in winter prevents evaporation of water from the tree at a time when freezing reduces the available water.
Temperate broadleaf forests are more WHAT than tropical rainforests, but are not as tall or diverse
broadleaf forest soil
Soil is rich in inorganic and organic nutrients. Rates of decomposition are lower in temperate forests than in tropics, and a thick layer of leaf little accumulates on forest floors, which conserves many of the biome's nutrients.
How does the soil of a temperate broadleaf forest differ from that of a tropical rainforest?
How does the soil of a temperate broadleaf forest differ from that of a tropical rainforest?: the soil in temperate broadleaf forests is rich in inorganic and organic nutrients
coniferous forests
cone-bearing evergreen trees, such as spruce, pine, fir, and hemlock dominate this biome. The northern coniferous forest, or taiga, is the largest terrestrial biome on Earth, stretching in broad band across North America to the souther border of the artic tundra.
coniferous forest temperature
Characterized by long, cold winters and short, wet summers that are sometimes warm
coniferous forest soil
The soil is nutrient poor, thin, and acidic, forming slowly because of the slow decomposition of conifer needles.
coniferous forest soil
The snow usually falls before the coldest temperatures occur, and it insulates the soil, keeping it from freezing to such depths that it would never thaw out during the short summers
coniferous forest animals
Animals include moose, elk, hares, bears, wolves, grouse, and migratory birds
How does the soil of the northern coniferous forest differ from that of a broadleaf forest?
The soil is thinner, nutrient-poor, and acidic because conifer needles decompose slowly in the low temperatures
At the northernmost limits of plant growth and at high altitudes is WHAT biome?
tundra temperature
climate is often extremely cold, with little light for long periods of time. During the brief, warm summers, when there is nearly constant daylight, plants grow quickly and flower in a rapid burst.
continuously frozen subsoil. Only the upper part of tundra soil thaws in the summer. The permafrost prevents the roots of plants from penetrating very far into the soil. Extremely cold winter air temperatures, high winds, and permafrost explain the absence of trees
tundra soil
The arctic tundra may receive as little precipitation as some deserts. But poor drainage, due to the permafrost, and slow evaporation, because of the low temp., keep the soil continually saturated.
tundra animals
Animals withstand the cold by having good insulation that retains heat. Large herbivores of the tundra include musk oxen and caribou. The principal smaller animals are rodents called lemmings and a few predators such as foxes and owls. mosquitos, and birds
What three abiotic factors account for the rarity of trees in arctic tundra?
What three abiotic factors account for the rarity of trees in arctic tundra?: Long, very cold winters (short growing season), high winds and permafrost