<< Chapter < Page Chapter >> Page >
By the end of this section, you will be able to:
  • Describe the basic types of ecosystems on Earth
  • Explain the methods that ecologists use to study ecosystem structure and dynamics
  • Identify the different methods of ecosystem modeling
  • Differentiate between food chains and food webs and recognize the importance of each

Life in an ecosystem is often about competition for limited resources, a characteristic of the theory of natural selection. Competition in communities (all living things within specific habitats) is observed both within species and among different species. The resources for which organisms compete include organic material from living or previously living organisms, sunlight, and mineral nutrients, which provide the energy for living processes and the matter to make up organisms’ physical structures. Other critical factors influencing community dynamics are the components of its physical and geographic environment: a habitat’s latitude, amount of rainfall, topography (elevation), and available species. These are all important environmental variables that determine which organisms can exist within a particular area.

An ecosystem    is a community of living organisms and their interactions with their abiotic (non-living) environment. Ecosystems can be small, such as the tide pools found near the rocky shores of many oceans, or large, such as the Amazon Rainforest in Brazil ( [link] ).

Left photo shows a rocky tide pool with seaweed and snails. Right photo shows the Amazon Rainforest.
A (a) tidal pool ecosystem in Matinicus Island in Maine is a small ecosystem, while the (b) Amazon Rainforest in Brazil is a large ecosystem. (credit a: modification of work by “takomabibelot”/Flickr; credit b: modification of work by Ivan Mlinaric)

There are three broad categories of ecosystems based on their general environment: freshwater, ocean water, and terrestrial. Within these broad categories are individual ecosystem types based on the organisms present and the type of environmental habitat.

Ocean ecosystems are the most common, comprising 75 percent of the Earth's surface and consisting of three basic types: shallow ocean, deep ocean water, and deep ocean surfaces (the low depth areas of the deep oceans). The shallow ocean ecosystems include extremely biodiverse coral reef ecosystems, and the deep ocean surface is known for its large numbers of plankton and krill (small crustaceans) that support it. These two environments are especially important to aerobic respirators worldwide as the phytoplankton perform 40 percent of all photosynthesis on Earth. Although not as diverse as the other two, deep ocean ecosystems contain a wide variety of marine organisms. Such ecosystems exist even at the bottom of the ocean where light is unable to penetrate through the water.

Freshwater ecosystems are the rarest, occurring on only 1.8 percent of the Earth's surface. Lakes, rivers, streams, and springs comprise these systems; they are quite diverse, and they support a variety of fish, amphibians, reptiles, insects, phytoplankton, fungi, and bacteria.

Terrestrial ecosystems, also known for their diversity, are grouped into large categories called biomes, such as tropical rain forests, savannas, deserts, coniferous forests, deciduous forests, and tundra. Grouping these ecosystems into just a few biome categories obscures the great diversity of the individual ecosystems within them. For example, there is great variation in desert vegetation: the saguaro cacti and other plant life in the Sonoran Desert, in the United States, are relatively abundant compared to the desolate rocky desert of Boa Vista, an island off the coast of Western Africa ( [link] ).

Questions & Answers

the study of living organisms
Dorcas Reply
what is body symmetry
Elizabeth Reply
What is the instrument used for measuring water potential?
Agyeiwaa Reply
tensiometers
osometer
MP
difference between food chain and food web
tunz Reply
is the study of living
Cabdi Reply
ohh ok..
HAMIDAH
hys
Cabdi
tro or right
Cabdi
yeah u re right, study of living
HAMIDAH
ok dear
Cabdi
aha
HAMIDAH
hee maxaa kwda hee
Cabdi
what is biology
Sandra Reply
Biology is the natural science that studies life n living organisms which include physical structures, chemical processes, molecular interaction, physiological mechanisms, evolution n development
HAMIDAH
biology is d study of living things
tunz
tru
Cabdi
brnch of biology
Cabdi
biology is the study of living things
tunz
hy hamidah
Cabdi
biology is the study of living things
Nikolas
main branch re botany, zoology n micro biology
HAMIDAH
1.Biochemistry 2.Biophysics 3.Biotechnology 4.Botany 5.Cell biology 6.Ecology
Peace
Main branch of biology are,zoology, botany and microbiology
Agyeiwaa
the period of cell growth between nuclear division
AAYAT Reply
what is synapsis
Edward Reply
the fusion of chromosomes at yhe the beginning of meiosis
Hassan
what do we mean by the team genetic
Regina Reply
is the inheritance of the living organisms
Sarah
am I right?
Sarah
is the variation and inheritance of living organism
Raymond
genetic is define as the scientific study of heredity and variation in living things
HAMIDAH
give all the characteristics of an enzyme
Davies Reply
it alters the rate of chemical reaction
tunz
-some require coenzymes -they re inhibited by inhibitors -they re required in minute amount -they speed up the rate of chemical reaction
HAMIDAH
hi Hamida, may I ask how do you study bio?
al
thanks
al
what is the difference between meiosi and
Glory Reply
TCRs. in full. and was it all about .Tell me about all of immunity.
KIIZA Reply
why is it that, when using light microscope for viewing the red blood cell is not distinguishable
Samuel Reply
Hello guy what is happening
Glory Reply
what is a cell
Innocent Reply
basic unit of life
Adoma
smallest unit of living things
Nicholas
cell is a basic unit of life
Senamile
the fundamental and structural unit of a living organism
angelina

Get the best Biology course in your pocket!





Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Biology' conversation and receive update notifications?

Ask