PRINCIPLES OF ECOLOGY CH 34

examples of animals

Large grazing mammals, such as the bison and pronghorn of North America and the wild horses and sheep of the Asian steppes, are characteristic of grasslands

freshwater biomes typically have salt concentrations less than...

1%

Freshwater biomes cover less than ____ of Earth's surface and contain a mere _____ of its water

1%, 0.01%

silent spring

1962 book by Rachel Carson that started the environmental movement

marine biomes (oceans, intertidal zones, coral reefs, estuaries) have salt concentrations around...

3%

large tracts of desert occur in two regions of descending dry air centered around the _________. At higher latitudes, large deserts may occur in the __________ of mountains

30° north and 30° south latitudes, rain shadows

Few organisms can maintain a sufficiently active metabolism at temperatures close to 0°C, and temperatures above _________ destroy the enzymes of most organisms

45°C (113°F)

But they harbor a disproportionate share of biodiversity—an estimated ______- of all described species.

6%

Annual precipitation is relatively high at ____________ and is usually evenly distributed throughout the year as either rain or snow.

75-150 cm (30-60 inches)

what creates ocean currents

A combination of the prevailing winds, the planet's rotation, unequal heating of surface waters, and the locations and shapes of the continent

Why are birds and mammals found in Himalayan alpine meadows, but non-bird reptiles and amphibians are not?

As ectotherms (see Module 25.1), reptiles other than birds and amphibians do not have adaptations that enable them to withstand the cold temperatures of the alpine habitat.

But not all desert air is dry.

Coastal sections of the Atacama and of the Namib Desert in Africa are often shrouded in fog, although the ground remains extremely dry.

common animals in deep sea

Crustaceans, annelid worms, sea anemones, and echinoderms such as sea cucumbers, sea stars, and sea urchins are common

taiga soil and precipitation notes

soil is thin and acidic, and the slow decomposition of conifer needles makes few nutrients available for plant growth ; most precip is in form of snow

what powers most ecosystems?

solar energy from sunlight captured by photosynthesis

aquatic organisms concern in water

solute concentration - need to maintain fluid balance

what happens as the dry air descends?

some of it spreads back towards the equator, causing cooling trade winds; as it moves back, it warms and picks up moisture until it ascends again

why are the north and south temperate zones, especially lats around 60 degrees, tend to be wet?

some of the descending air heads into the latitudes above 30° north and south. At first these air masses pick up moisture, but they tend to drop it as they cool at higher latitudes

A river or a stream changes greatly between its ______ and the _______

source (perhaps a spring or snowmelt), point at which it empties into a lake or the ocean

freshwater wetlands are high in

species diversity

habitat

specific environment an organism lives in, including biotic and abiotic factors

The rocky intertidal zone is home to many sedentary organisms, such as...

algae, barnacles, and mussels, which attach to rocks and thus resist being washed away when the tide comes in

biosphere

all of earth that is inhabited by life - extends from the atmosphere several km above earth to the depths of oceans

example of tilt affecting seasons

the Northern Hemisphere tilts toward the sun in June, resulting in the long days of summer in that hemisphere. But during this time, days are short in the Southern Hemisphere and it is winter there. Conversely, the Southern Hemisphere tilts toward the sun in December, causing summer there and winter in the Northern Hemisphere

what do the seasons result from?

the permanent tilt of the planet on its axis as it orbits the sun

aphotic zone

the region of an aquatic ecosystem beneath the photic zone, where light does not penetrate enough for photosynthesis to take place ; AKA twilight zone

photic zone

the region of an aquatic ecosystem into which light penetrates and where photosynthesis occurs - maximum depth of light penetration is 200m (656 feet)

pelagic realm of ocean

the region of an ocean occupied by seawater - all open water

The sun's rays strike equatorial areas most directly (perpendicularly). Away from the equator, the rays strike Earth's surface at a slant. As a result...

the same amount of solar energy is spread over a larger area. Thus, any particular area of land or ocean near the equator absorbs more heat than comparable areas in the more northern or southern latitudes.

what happens if the climate in two geographically separate areas is similar

the same type of biome may occur in both places

ecology

the scientific study of interactions between organisms and the environment - complexity = can be affected by multiple variables

Each biome is characterized by a type of biological community, rather than an assemblage of particular species. For example...

the species living in the deserts of the American Southwest and in the Sahara Desert of Africa are different, but all are adapted to desert conditions

what would happen if the pronghorn's environment changed drastically?

their adaptations may not be as advantageous

Because these biomes are embedded in terrestrial landscapes....

their characteristics are intimately connected with the soils and organisms of the ecosystems that surround them.

why are many of the world's deserts centered around lats of 30 degrees north and south

there, after losing their moisture over equatorial zones, high-altitude air masses spread away until they cool and descend again, absorbing moisture from the land

Mudflats and salt marshes are coastal wetlands that often border estuaries and experience what?

tidal fluctuations

In the tropics, Earth's rapidly moving surface deflects vertically circulating air, making the_________ blow from east to west. In temperate zones, the slower-moving surface produces the __________, winds that blow from west to east.

trade winds, westerlies

what is one of the most complex biomes, where up to 300 species of tree can be found in 2.5 acres

tropical rain forest

what provides a reef food

unicellular algae

Terrestrial ecosystems are grouped into nine major types of biomes, which are distinguished primarily by their predominant ________.

vegetation

The biotic environment, which includes what the animal eats and any predators that threaten it, is also a factor in determining which members of a population survive and reproduce - example of this?

ver time, characteristics that enabled the ancestors of the pronghorn to exploit these food sources more efficiently became established through natural selection. As a result, the teeth of a pronghorn are specialized for biting and chewing tough plant material. Like the stomach of a cow, the pronghorn's stomach contains cellulose-digesting bacteria.

what is a river like near the source?

water is usually clear, cold, and oxygen-rich, with a swift current that inhibits the growth of phytoplankton - most orgs supported by the photosynthesis of algae attached to rocks or by organic material from surrounding land - arthropods and trout dominant in benthic

what adaptation was key to success of plants and verts on land?

watertight coverings to prevent dehydration

what adaptation on leaves prevents water loss

waxy coating

what do the adaptations of pronghorns to survive in cold temps tell us?

we can infer that many of the adaptations that contribute to the success of present-day pronghorns must also have contributed to the success of their ancestors

What factors prevent woody plants from growing in temperate grasslands?

Low rainfall, fires, and grazing by large mammals

result of light not being uniformly available in aquatic environments

Microorganisms and suspended particles, as well as the water itself, absorb light and prevent it from penetrating beyond certain depths. As a result, most photosynthesis occurs near the water's surface.

deposit feeders

animals that consume dead organic matter (detritus) on the substrate

zooplankton

animals that drift in aquatic environments

If a lake or pond is deep enough or murky enough, it has an ______ where light levels are too low to support photosynthesis

aphotic zone

community

assemblage of all the populations of organisms living close enough for potential interaction - all of the biotic factors in the environment

what powers dark environments?

bacteria that extract energy from chemicals, such as sulfur bacteria in hydrothermal vents

tundra

biome at northernmost limits of plant growth and at high altitudes, characterized by dwarf woody shrubs, grasses, mosses, and lichens - extremely cold, little light for much of autumn and winter

savanna

biome dominated by grasses and scattered trees and maintained by occasional fires and drought

estuary

biome where freshwater stream or river emerges with the ocean - saltiness ranges, across their length, from nearly that of freshwater to that of the ocean - among mostly productive biomes on earth due to nutrients from the river

temperate rain forests are also...

coniferous forests ; warm, moist air from Pacific supports this biome

permafrost

continuously frozen subsoil

Widely separated biomes may look alike because of _______, the appearance of similar traits in independently evolved species living in similar environments

convergent evolution

desertification

conversion of semi-arid regions to desert

As global temperatures continue to rise, which biome will most likely replace arctic tundra?

Northern coniferous forest

examples of animals in estuaries

Oysters, crabs, and many fishes live in estuaries or reproduce in them. Estuaries are also crucial nesting and feeding areas for waterfowl.

What is the main way that living organisms contribute to the water cycle?

Plants move water from the ground to the atmosphere via transpiration.

rain shadow effect

Precipitation falls on the windward side of a mountain range, resulting in lush vegetation & a warm, moist climate on one side, but a desert area on the leeward side.

why are the soils richer in inorganic and organic nutrients than a tropical rain forest?

Rates of decomposition are lower in temperate forests than in the tropics, and a thick layer of leaf litter on forest floors conserves many of the biome's nutrients.

animal examples

Some vertebrates, such as mice, shrews, and ground squirrels, burrow for shelter and food, while others, including many species of birds, live in the trees. Predators include bobcats, foxes, black bears, and mountain lions.

examples of animals inhabiting benthic realm of the photic zone

Sponges, burrowing worms, clams, sea anemones, crabs, and echinoderms

T or F - deserts can be hot or cold, and can have daily fluctuations

T

These forests typically have a growing season of five to six months and a distinct annual rhythm :

Trees drop their leaves and become dormant in late autumn, preventing the loss of water from the tree at a time when frozen soil makes water less available. The trees produce new leaves in the spring.

coniferous forests

a biome characterized by conifers, cone-bearing evergreen trees

temperate grasslands

a biome dominated bt grasses and other non-woody plants and maintained by seasonal drought, occasional fires, and grazing by large mammals ; differ from tropical savannas as are mostly treeless except along rivers and streams and are found in regions w relatively cold winter temps

temperate broadleaf forests

a biome located throughout midlatitude regions, where there is sufficient moisture to support the growth of large, broadleaf deciduous trees

wetlands

a biome that is transitional between an aquatic ecosystem - either marine or fresh - and a terrestrial one ; covered with water either permanently or periodically

benthic realm

a seafloor or the bottom of a freshwater lake, pond, river, or stream - the substrate

intertidal zone

a shallow zone where the waters of an estuary or ocean meet land - waves on shore during high tide and exposed to sun and drying winds during low tide

tropical forests

a terrestrial biome characterized by high levels of precipitation and warm temps year-round ; occur in equatorial areas, days 11-12 hrs long

polar ice

a terrestrial biome that includes regions of extremely cold temperature and low precipitation located at high latitudes north of the arctic tundra and in Antarctica

In lakes and large ponds, as in the oceans, the communities of plants, algae, and animals are distributed how?

according to the depth of the water and its distance from shore

what allows some organisms to live outside this temp range?

adaptations, such as the enzymes in archaeans in hot springs that work better at high temps

important abiotic factors in freshwater biomes include...

current, sunlight, and nutrients

why does Earth receive an uneven distribution of energy

curvature

Many trees and shrubs are ________, dropping their leaves during the dry season, an adaptation that helps conserve water.

deciduous

The driest deserts have no perennial vegetation at all, but less arid regions have scattered __________, often interspersed with water-storing _________ such as cacti.

deep-rooted shrubs, succulents

deserts

driest of all terrestrial biomes, characterized by low and unpredictible rainfall (less than 30 cm / 12 in a year)

The forest structure consists of distinct layers that provide many different habitats

emergent trees growing above a closed upper canopy, one or two layers of lower trees, a shrub understory, and a sparse ground layer of herbaceous plants.

photosynthesis by phytoplankton and multicellular algae provide what in sunlit regions?

energy and organic carbon for a diverse community of animals

The science of ecology can provide the understanding needed to resolve what?

environmental problems

Ecological subdivisions such as biomes are not self-contained units. Rather, all parts of the biosphere are linked by the global water cycle and by nutrient cycles. Consequently...

events in one biome may reverberate throughout the biosphere

Soil structure, pH, and nutrient content often play major roles in determining the distribution of plants

ex - in many aquatic ecosystems, low levels of nitrogen and phosphorus limit the growth of algae and photosynthetic bacteria.

Coniferous forests are often dominated by a....

few species of trees

what provides sustenance for small fishes and crustaceans living in the aphotic zone

food sinking from the photic zone, some migrate to surface at night to feed

The amount of annual precipitation influences the ______ of grassland vegetation

height

Temperatures in temperate broadleaf forests vary seasonally over a wide range, with ________ summers and ____ winters

hot, cold

density of animals in dark is low except for where? why?

hydrothermal vents, where chemoautotrophic bacteria support an abundance of lif

where are tropical rainforests found

in very humid equatorial areas where rainfall is abundant (200-400 cm ; 79-157 in /year)

ecosystem

includes biotic and abiotic components of the environment

what makes wind an important abiotic factor?

increases an organism's rate of water loss by evaporation - evaporative cooling is positive, but can cause wind chill = dangerous in winter

what are earth's global climate patterns largely determined by?

input of radiant energy from the sun and the planet's movement in space

what do ecologists study as several levels?

interactions

why is temperature an important abiotic factor?

its effect on metabolism

example of abiotic factors effecting only aquatic animals

land have access to plentiful O2, but aquatic rely on dissolved O2 which varies in dif types of water

adaptations for animals living in dark (below 1,000 m) include...

large mouths, inwardly angled teeth, bioluminesents

In the benthic realm ...

large populations of microorganisms decompose dead organisms that sink to the bottom. Respiration by microbes removes oxygen from water near the bottom, and in some lakes, benthic areas are unsuitable for any organisms except anaerobic microbes.

taiga

largest terrestrial biome - the northern coniferous forest, characterized by long, snowy winters and short, wet summer - extends across NA and Eurasia to arctic tundra

plants and animals here include

lichens and small plants, such as mosses, manage to survive, and invertebrates such as nematodes, mites, and wingless insects called springtails inhabit the frigid soil

result of climate of chaparral

limited to small coastal areas - incl Cali

biotic factors

living components

prevailing winds

major global air movements, winds that result from the combined effects of Earth's rotation and the rising/falling of air masses

biome

major types of ecological association that occupies a broad geographic region of land or water and is characterized by organisms adapted to the particular environment

examples of animals in savanna

mice, moles, gophers, snakes, ground squirrels, worms, and numerous arthropods, giraffes, zebras, and many species of antelope, as well as to lions and cheetahs

phytoplankton

microscopic algae and cyanobacteria

Taiga is also found at cool, high elevations in more temperate latitudes, as in...

much of the mountainous region of western North America.

Organisms are adapted to abiotic and biotic factors through _________.

natural selection

The distribution and abundance of photosynthetic organisms, including plants, algae, and photosynthetic bacteria, depend on the availability of inorganic nutrients such as _________ ; plants often obtain these from ______

nitrogen and phosphorus, the soil

abiotic factors

nonliving components; ex - temperature, water, nutrients available

why is tropical rain forest soil poor if high temps and rainfall lead to rapid decomposition and release of nutrients?

nutrients are quickly taken up by the vegetation or washed away by rain

examples of dominant trees

oak, hickory, birch, beech, and maple

High winds and cold temperatures create plant communities called alpine tundra on very high mountaintops at all latitudes, including the tropics. Although these communities are similar to arctic tundra, there is no _______ beneath alpine tundra.

permafrost

what explains the absence of trees in the tundra

permafrost prevents roots penetrating deeply, and very cold temps/high winds

where are coral reefs found

photic zone of warm tropical waters above continental shelves

what abiotic factors influence life in the biosphere

physical and chemical

what keeps the soil continually saturated despite rain levels that can be as low as deserts

poor drainage due to permafrost and slow evaporation

what limits invasion of trees in a savanna

poor soil, lack of moisture, grazing animals, frequent fires

example of pronghorn adaptation

pronghorn has a thick coat made of hollow hairs that trap air, insulating the animal in cold weather ; In hot weather, the pronghorn can raise patches of this stiff hair to release body heat.

what variability generally determines the vegetation that grows in a particular tropical forest

rainfall

They provide water storage areas that _______ and ______ by filtering pollutants

reduce flooding, improve water quality

what influences the distribution of terrestrial communities?

regional climate change

deciduous trees

(drop their leaves seasonally)

how is a coral reef formed?

A 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 calcium carbonate

Chaparral vegetation is adapted to periodic fires, most often caused by ________. Examples -

After a fire, shrubs use food reserves stored in the surviving roots to support rapid shoot regeneration. Some chaparral plant species produce seeds that will germinate only after exposure to a hot fire. The ashes of burned vegetation fertilize the soil with mineral nutrients, promoting regrowth of the plant community

example of landforms affecting local climate

Air temperature declines by about 6°C with every 1,000-m increase in elevation

Why isn't "cold desert" an oxymoron?

Because deserts are defined by low precipitation and dry soil, not by temperature

What causes summer in the Northern Hemisphere?

Because of the fixed angle of Earth's axis relative to the plane of its orbit around the sun, the Northern Hemisphere is tilted toward the sun during the portion of the annual orbit that corresponds to the summer months.

why does the soil of grasslands support a great diversity of microorganisms and small animals, including annelids and arthropods.

Enriched by glacial deposits and mulch from decaying plant material

Because Earth is spherical, its surface moves ______ at the equator, where diameter is greatest, than other latitudes

FASTER

example of above effect

For instance, the Gulf Stream circulates warm water northward from the Gulf of Mexico and makes the climate on the west coast of Great Britain warmer during winter than the coast of New England, which is actually farther south but is cooled by the Labrador Current flowing south from the coast of Greenland.

why are rain forests are concentrated near the equator?

High temperatures throughout the year and ample rainfall largely explain this

adaptations of desert animals

Many live in burrows and are active only at night, when temperatures drop, and most have special adaptations that conserve water. Seed-eaters such as ants, many birds, and rodents are common in deserts.

Oil from the 2010 Deepwater Horizon disaster in the Gulf of Mexico has polluted estuaries in Louisiana. Why does this pollution affect other animals in addition to those that live permanently in the estuaries?

Many species, including fishes and waterfowl, visit estuaries to feed or reproduce.

How does the vegetation found in polar ice regions compare with tundra vegetation?

Neither biome is hospitable to plants because of the cold temperatures. However, tundra supports the growth of small shrubs, while polar ice vegetation is limited to mosses and lichens.

how is the terrestrial polar biome closely interconnected with the neighboring marine biome?

Seals and marine birds, such as penguins, gulls, and skuas, feed in the ocean and visit the land or sea ice to rest and to breed. In the Northern Hemisphere, sea ice provides a feeding platform for polar bears

List the biotic and abiotic factors shown in Figure 34.1D.

The biotic factors include the animals and plants (blue poppies and grass). Abiotic factors include the soil, temperature, and precipitation.

What is the role of the environment in adaptive evolution?

The individuals whose phenotypes are best suited to the environment (including both abiotic and biotic factors) will pass their alleles to the next generation. But individuals with other phenotypes may not. For example, if the biotic environment includes wolves, a pronghorn that is not able to run at top speed for as long as the rest of the herd will probably not survive to reproduce.

Climate and other abiotic factors of the environment control the global distribution of organisms....

The influence of these abiotic factors results in biomes

In areas where rainfall is scarce or there is a prolonged dry season, tropical dry forests predominate.

The plants found there are a mixture of thorny shrubs and deciduous trees and succulents.

One of the fundamental goals of ecology is to explain the distribution of organism

The presence of a species in a particular place has two possible explanations: The species may have evolved from ancestors living in that location, or it may have dispersed to that location and been able to survive once it arrived

Why can't ecologists alone solve environmental problems?

The science of ecology can inform the decision-making process, but solving environmental problems involves making ethical, economic, and political judgments that are outside the realm of science.

Why does sewage cause algal blooms in lakes?

The sewage adds nutrients, such as nitrates and phosphates, that stimulate growth of algae.

How and why does the soil of the northern coniferous forests differ from that of a broadleaf forest?

The soil is thinner, nutrient-poor, and acidic because conifer needles decompose slowly in the low temperatures.

High temperatures in the tropics evaporate water from Earth's surface and cause warm, moist air masses to rise and flow toward the poles. As the rising air cools, its ability to hold moisture diminishes, so...

The water vapor condenses into clouds and rain falls.

Many lakes and ponds receive large inputs of nitrogen and phosphorus from sewage and runoff from fertilized lawns and farms. As a result...

These nutrients may produce a heavy growth ("bloom") of algae, which reduces light penetration. When the algae die and decompose, a pond or lake can suffer severe oxygen depletion, killing fish that are adapted to high-oxygen conditions.

What is one way that homeowners in chaparral areas can protect their neighborhoods from fire?

They can keep the area clear of dead brush, which is highly flammable.

Animals characteristic of the chaparral include...

browsers such as deer, fruit-eating birds, and seed-eating rodents, as well as lizards and snakes.

chaparral

characterized by dense, spiny shrubs with tough, evergreen leaves - climate that supports chaparral veg results from cool ocean currents circulating offshore which produce mild, rainy winters and hot,dry summers

terrestrial biomes reflect regional variations in what?

climate

what does the mix of trees depend on

climate at different latitudes, topography, and local soil conditions

downstream of river is...

generally wider and slower, usually warmer water w less O2 and murkier due to sediment and phytoplankton suspended ; Worms and insects that burrow into mud are often abundant, as are waterfowl, frogs, and catfish and other fishes that find food more by scent and taste than by sight.

The _________ connects aquatic and terrestrial biomes

global water cycle

Desert plants typically produce _______ numbers of seeds, which may remain _______ until a heavy rain triggers germination.

great, dormant

population

group of individuals of the same species living in a particular geographic area

why do grasses in savanna survive burning

growing points of their shoots below soil

how do animals of tundra withstand cold

have good insulation

ocean currents

river-like flow patterns at the ocean's surface that have a profound effect on REGIONAL CLIMATES

what is the primary distinction in aquatic biomes?

salinity

effect of climate change on vegetation patterns

scientists are documenting shifts in latitudes of biome borders, changes in snow and ice coverage, and changes in length of the growing season

disturbing spread of DDT

scientists found that small amounts of pesticides had accumulated in the fatty tissues of vertebrates thousands of miles from where pesticides were used. DDT was even detected in human milk ; Scientists also found that DDT remained in the soil or water long after application of the pesticide

landscapes

several different ecosystems linked by exchanges of energy, materials, and organisms

Freshwater biomes fall into two broad categories:

standing water, which includes lakes and ponds, and flowing water, such as rivers and streams

continental shelves

submerged parts of continents - in shallow areas such as these, the photic zones include both pelagic and benthic realms

what are the two key factors in the distribution of marine organisms?

sunlight and substrate

because pronghorns new predators cannot keep up with their speed (that they developed due to fast cheetahs in the past), what do their new predators, wolves, do?

take young or sick/elderly adults

The canopy of a temperate broadleaf forest is more open than that of a tropical rain forest, and the trees are not as __________.

tall or as diverse

where do distinct seasonal variations occur

temperate zones - the latitudes between the tropics and the Arctic Circle in the north/ Antarctic Circle in the south

The geographic distribution of plants, and thus of terrestrial biomes, largely depends on climate, with ________ often the key factors determining the kind of biome that exists in a particular region.

temperature and precipitation

climate includes

temperature and precipitation

Terrestrial biomes are determined primarily by what?

temperature and precipitation—similar assemblages of plant and animal types are found in areas that have similar climates

tropics (region surrounding the equator bw 23.5 degrees north and 23.5 degrees south) experience...

the greatest annual input and least seasonal variation in solar radiation

what typically determines the amount of phytoplankton growth in a lake or pond?

the mineral nutrients nitrogen and phosphorous

examples of animals abundant in the pelagic photic zone

zooplankton, fish, marine mammals