An ecosystem is a geographic area where plants, animals, and other organisms, as well as weather and landscape, work together to form a bubble of life. Ecosystems contain biotic or living, parts, as well as abiotic factors, or nonliving parts. Biotic factors include plants, animals, and other organisms. Abiotic factors include rocks, temperature, and humidity.

Every factor in an ecosystem depends on every other factor, either directly or indirectly. A change in the temperature of an ecosystem will often affect what plants will grow there, for instance. Animals that depend on plants for food and shelter will have to adapt to the changes, move to another ecosystem, or perish.

Ecosystems can be very large or very small. Tide pools, the ponds left by the ocean as the tide goes out, are complete, tiny ecosystems. Tide pools contain seaweed, a kind of algae, which uses photosynthesis to create food. Herbivores such as abalone eat the seaweed. Carnivores such as sea stars eat other animals in the tide pool, such as clams or mussels. Tide pools depend on the changing level of ocean water. Some organisms, such as seaweed, thrive in an aquatic environment, when the tide is in and the pool is full. Other organisms, such as hermit crabs, cannot live underwater and depend on the shallow pools left by low tides. In this way, the biotic parts of the ecosystem depend on abiotic factors.

The whole surface of Earth is a series of connected ecosystems. Ecosystems are often connected in a larger biome. Biomes are large sections of land, sea, or atmosphere. Forests, ponds, reefs, and tundra are all types of biomes, for example. They're organized very generally, based on the types of plants and animals that live in them. Within each forest, each pond, each reef, or each section of tundra, you'll find many different ecosystems.

The biome of the Sahara Desert, for instance, includes a wide variety of ecosystems. The arid climate and hot weather characterize the biome. Within the Sahara are oasis ecosystems, which have date palm trees, freshwater, and animals such as crocodiles. The Sahara also has dune ecosystems, with the changing landscape determined by the wind. Organisms in these ecosystems, such as snakes or scorpions, must be able to survive in sand dunes for long periods of time. The Sahara even includes a marine environment, where the Atlantic Ocean creates cool fogs on the Northwest African coast. Shrubs and animals that feed on small trees, such as goats, live in this Sahara ecosystem.

Even similar-sounding biomes could have completely different ecosystems. The biome of the Sahara Desert, for instance, is very different from the biome of the Gobi Desert in Mongolia and China. The Gobi is a cold desert, with frequent snowfall and freezing temperatures. Unlike the Sahara, the Gobi has ecosystems based not in sand, but kilometers of bare rock. Some grasses are able to grow in the cold, dry climate. As a result, these Gobi ecosystems have grazing animals such as gazelles and even takhi, an endangered species of wild horse.

Even the cold desert ecosystems of the Gobi are distinct from the freezing desert ecosystems of Antarctica. Antarcticas thick ice sheet covers a continent made almost entirely of dry, bare rock. Only a few mosses grow in this desert ecosystem, supporting only a few birds, such as skuas.

Threats to Ecosystems

For thousands of years, people have interacted with ecosystems. Many cultures developed around nearby ecosystems. Many Native American tribes of North Americas Great Plains developed a complex lifestyle based on the native plants and animals of plains ecosystems, for instance. Bison, a large grazing animal native to the Great Plains, became the most important biotic factor in many Plains Indians cultures, such as the Lakota or Kiowa. Bison are sometimes mistakenly called buffalo. These tribes used buffalo hides for shelter and clothing, buffalo meat for food, and buffalo horn for tools. The tallgrass prairie of the Great Plains supported bison herds, which tribes followed throughout the year.


As human populations have grown, however, people have overtaken many ecosystems. The tallgrass prairie of the Great Plains, for instance, became farmland. As the ecosystem shrunk, fewer bison could survive. Today, a few herds survive in protected ecosystems such as Yellowstone National Park.

In the tropical rain forest ecosystems surrounding the Amazon River in South America, a similar situation is taking place. The Amazon rain forest includes hundreds of ecosystems, including canopies, understories, and forest floors. These ecosystems support vast food webs.

Canopies are ecosystems at the top of the rainforest, where tall, thin trees such as figs grow in search of sunlight. Canopy ecosystems also include other plants, called epiphytes, which grow directly on branches. Understory ecosystems exist under the canopy. They are darker and more humid than canopies. Animals such as monkeys live in understory ecosystems, eating fruits from trees as well as smaller animals like beetles. Forest floor ecosystems support a wide variety of flowers, which are fed on by insects like butterflies. Butterflies, in turn, provide food for animals such as spiders in forest floor ecosystems.

Human activity threatens all these rain forest ecosystems in the Amazon. Thousands of acres of land are cleared for farmland, housing, and industry. Countries of the Amazon rain forest, such as Brazil, Venezuela, and Ecuador, are underdeveloped. Cutting down trees to make room for crops such as soy and corn benefits many poor farmers. These resources give them a reliable source of income and food. Children may be able to attend school, and families are able to afford better health care.

However, the destruction of rain forest ecosystems has its costs. Many modern medicines have been developed from rain forest plants. Curare, a muscle relaxant, and quinine, used to treat malaria, are just two of these medicines. Many scientists worry that destroying the rain forest ecosystem may prevent more medicines from being developed.

The rain forest ecosystems also make poor farmland. Unlike the rich soils of the Great Plains, where people destroyed the tallgrass prairie ecosystem, Amazon rain forest soil is thin and has few nutrients. Only a few seasons of crops may grow before all the nutrients are absorbed. The farmer or agribusiness must move on to the next patch of land, leaving an empty ecosystem behind.

Rebounding Ecosystems

Ecosystems can recover from destruction, however. The delicate coral reef ecosystems in the South Pacific are at risk due to rising ocean temperatures and decreased salinity. Corals bleach, or lose their bright colors, in water that is too warm. They die in water that isnt salty enough. Without the reef structure, the ecosystem collapses. Organisms such as algae, plants such as seagrass, and animals such as fish, snakes, and shrimp disappear.

Most coral reef ecosystems will bounce back from collapse. As ocean temperature cools and retains more salt, the brightly colored corals return. Slowly, they build reefs. Algae, plants, and animals also return.

Individual people, cultures, and governments are working to preserve ecosystems that are important to them. The government of Ecuador, for instance, recognizes ecosystem rights in the countrys constitution. The so-called Rights of Nature says Nature or Pachamama [Earth], where life is reproduced and exists, has the right to exist, persist, maintain and regenerate its vital cycles, structure, functions and its processes in evolution. Every person, people, community or nationality, will be able to demand the recognitions of rights for nature before the public bodies. Ecuador is home not only to rain forest ecosystems, but also river ecosystems and the remarkable ecosystems on the Galapagos Islands.

ecosystem
Tall grasses and Bison bison—must be the tallgrass prairie ecosystem.

Ecocide
The destruction of entire ecosystems by human beings has been called ecocide, or murder of the environment.

Human Ecosystem
"Human ecosystem" is the term scientists use to study the way people interact with their ecosystems. The study of human ecosystems considers geography, ecology, technology, economics, politics, and history. The study of urban ecosystems focuses on cities and suburbs.

Coral Triangle
The most diverse ecosystem in the world is the huge Coral Triangle in Southeast Asia. The Coral Triangle stretches from the Philippines in the north to the Solomon Islands in the east to the islands of Indonesia and Papua in the west.

Bactrian and Dromedary
Different desert ecosystems support different species of camels. The dromedary camel is tall and fast, with long legs. It is native to the hot, dry deserts of North Africa and the Arabian Peninsula. The Bactrian camel has a thicker coat, is shorter, and has more body fat than the dromedary. The Bactrian camel is native to the cold desert steppes of Central Asia.

It is easy to tell the two types of camels apart: Dromedaries have one hump, Bactrians have two.

abiotic
Adjective

lacking or absent of life.

adapt
Verb

to adjust to new surroundings or a new situation.

agribusiness
Noun

the strategy of applying profit-making practices to the operation of farms and ranches.

algae
Plural Noun

(singular: alga) diverse group of aquatic organisms, the largest of which are seaweeds.

animal
Noun

organisms that have a well-defined shape and limited growth, can move voluntarily, acquire food and digest it internally, and can respond rapidly to stimuli.

aquatic
Adjective

having to do with water.

arid
Adjective

dry.

Noun

area of the planet which can be classified according to the plant and animal life in it.

biotic factor
Noun

effect or impact of an organism on its environment.

bison
Noun

large mammal native to North America. Also called American buffalo.

butterfly
Noun

type of flying insect with large, colorful wings.

canopy
Noun

one of the top layers of a forest, formed by the thick leaves of very tall trees.

Noun

organism that eats meat.

characterize
Verb

to describe the characteristics of something.

Noun

all weather conditions for a given location over a period of time.

complex
Adjective

complicated.

constitution
Noun

system of ideas and general laws that guide a nation, state, or other organization.

Noun

one of the seven main land masses on Earth.

coral reef
Noun

rocky ocean features made up of millions of coral skeletons.

corn
noun, adjective

tall cereal plant with large seeds (kernels) cultivated for food and industry. Also called maize.

crocodile
Noun

reptile native to parts of Africa, Asia, and the Americas.

Noun

agricultural produce.

culture
Noun

learned behavior of people, including their languages, belief systems, social structures, institutions, and material goods.

curare
Noun

resin obtained from South American trees, often dried and used as an ingredient in muscle relaxants.

date palm
Noun

type of fruit tree.

delicate
Adjective

fragile or easily damaged.

Noun

area of land that receives no more than 25 centimeters (10 inches) of precipitation a year.

destruction
Noun

ruin.

determine
Verb

to decide.

distinct
Adjective

unique or identifiable.

Noun

a mound or ridge of loose sand that has been deposited by wind.

ecocide
Noun

total destruction of an ecosystem.

Noun

branch of biology that studies the relationship between living organisms and their environment.

economics
Noun

study of monetary systems, or the creation, buying, and selling of goods and services.

Noun

community and interactions of living and nonliving things in an area.

Noun

organism threatened with extinction.

epiphyte
Noun

plant that grows on the branches or trunk of another plant or object.

evolution
Noun

change in heritable traits of a population over time.

farmland
Noun

area used for agriculture.

fig
Noun

fruit and tree native to Asia.

flower
Noun

blossom or reproductive organs of a plant.

Noun

clouds at ground level.

Noun

material, usually of plant or animal origin, that living organisms use to obtain nutrients.

Noun

all related food chains in an ecosystem. Also called a food cycle.

forest
Noun

ecosystem filled with trees and underbrush.

frequent
Adjective

often.

freshwater
Noun

water that is not salty.

Noun

archipelago in the Pacific Ocean, off the coast of Ecuador.

gazelle
Noun

small antelope native to Africa and Asia.

geographic
Adjective

having to do with places and the relationships between people and their environments.

Noun

study of places and the relationships between people and their environments.

goat
Noun

hoofed mammal domesticated for its milk, coat, and flesh.

government
Noun

system or order of a nation, state, or other political unit.

grass
Noun

type of plant with narrow leaves.

grazing animal
Noun

animal that feeds on grasses, trees, and shrubs.

Great Plains
Noun

grassland region of North America, between the Rocky Mountains and the Mississippi River.

health care
Noun

system for addressing the physical health of a population.

Noun

organism that eats mainly plants and other producers.

herd
Noun

group of animals.

hermit crab
Noun

type of marine animal (crustacean) that uses found materials, such as other creatures' shells, as its shell.

hide
Noun

leather skin of an animal.

history
Noun

study of the past.

human ecosystem
Noun

environment constructed or adapted to by people and culture.

Noun

amount of water vapor in the air.

Noun

thick layer of glacial ice that covers a large area of land.

income
Noun

wages, salary, or amount of money earned.

industry
Noun

activity that produces goods and services.

insect
Noun

type of animal that breathes air and has a body divided into three segments, with six legs and usually wings.

Kiowa
Noun

people and culture native to the Great Plains of North America.

Lakota
Noun

people and culture of seven Sioux tribes native to the Great Plains.

Noun

the geographic features of a region.

maintain
Verb

to continue, keep up, or support.

malaria
Noun

infectious disease caused by a parasite carried by mosquitoes.

marine
Adjective

having to do with the ocean.

medicine
Noun

substance used for treating illness or disease.

monkey
Noun

mammal considered to be highly intelligent, with four limbs and, usually, a tail.

moss
Noun

tiny plant usually found in moist, shady areas.

mussel
Noun

aquatic animal with two shells that can open and close for food or defense.

Noun

substance an organism needs for energy, growth, and life.

Noun

area made fertile by a source of fresh water in an otherwise arid region.

Noun

large body of salt water that covers most of the Earth.

organism
Noun

living or once-living thing.

Pachamama
Noun

goddess of the Earth recognized by many cultures of the Andes Mountains.

perish
Verb

to die or be destroyed.

persist
Verb

to endure or continue.

Noun

process by which plants turn water, sunlight, and carbon dioxide into water, oxygen, and simple sugars.

Noun

flat, smooth area at a low elevation.

plant
Noun

organism that produces its own food through photosynthesis and whose cells have walls.

politics
Noun

art and science of public policy.

pond
Noun

small body of water surrounded by land.

preserve
Verb

to maintain and keep safe from damage.

public
Adjective

available to an entire community, not limited to paying members.

quinine
Noun

drug used to treat malaria.

Noun

area of tall, mostly evergreen trees and a high amount of rainfall.

Noun

a ridge of rocks, coral, or sand rising from the ocean floor all the way to or near the ocean's surface.

reliable
Adjective

dependable or consistent.

remarkable
Adjective

unusual and dramatic.

resource
Noun

available supply of materials, goods, or services. Resources can be natural or human.

Noun

large stream of flowing fresh water.

rock
Noun

natural substance composed of solid mineral matter.

Sahara Desert
Noun

world's largest desert, in north Africa.

salinity
Noun

saltiness.

sand
Noun

small, loose grains of disintegrated rocks.

scorpion
Noun

animal related to a spider with a poisonous sting in its tail.

seagrass
Noun

type of plant that grows in the ocean.

sea star
Noun

marine animal (echinoderm) with many arms radiating from its body. Also called a starfish.

seaweed
Noun

marine algae. Seaweed can be composed of brown, green, or red algae, as well as "blue-green algae," which is actually bacteria.

shelter
Noun

structure that protects people or other organisms from weather and other dangers.

shrimp
Noun

animal that lives near the bottom of oceans and lakes.

shrub
Noun

type of plant, smaller than a tree but having woody branches.

skua
Noun

bird related to the seagull.

snake
Noun

reptile with scales and no limbs.

snowfall
Noun

amount of snow at a specific place over a specific period of time.

soil
Noun

top layer of the Earth's surface where plants can grow.

soy
Noun

beans, or fruit, of the soybean plant, native to Asia.

spider
Noun

eight-legged animal (arachnid) that usually spins webs to catch food.

survive
Verb

to live.

takhi
Noun

endangered species of wild horse native to Central Asia. Also called Przewalski's horse.

tallgrass prairie
Noun

plain where grasses grow up to 2 meters (6 feet) tall.

technology
Noun

the science of using tools and complex machines to make human life easier or more profitable.

Noun

degree of hotness or coldness measured by a thermometer with a numerical scale.

Noun

rise and fall of the ocean's waters, caused by the gravitational pull of the moon and sun.

tide pool
Noun

small pond created by an ebb tide and submerged by a high tide.

tropical
Adjective

existing in the tropics, the latitudes between the Tropic of Cancer in the north and the Tropic of Capricorn in the south.

tundra
Noun

cold, treeless region in Arctic and Antarctic climates.

underdeveloped country
Noun

country that has fallen behind on goals of industrialization, infrastructure, and income.

understory
Noun

ecosystem between the canopy and floor of a forest.

urban ecosystem
Noun

environment of cities, towns, and suburbs.

vast
Adjective

huge and spread out.

vital
Adjective

necessary or very important.

Noun

state of the atmosphere, including temperature, atmospheric pressure, wind, humidity, precipitation, and cloudiness.

wind
Noun

movement of air (from a high pressure zone to a low pressure zone) caused by the uneven heating of the Earth by the sun.