Download Dustin D`Andrea THE LIVING WORLD Ecosystem Structure

Dustin D`Andrea
THE LIVING WORLD
Ecosystem Structure
• Ecology – the study of how organisms interact with one another and their nonliving
environment;
• Realm of ecology
1) organisms – any form of life;
2) populations – a group of interacting individuals of the same species that occupy a
specific are at the same time;
3) communities – populations of different species occupying a particular place;
4) ecosystems – a community of different species interacting with one another and
with their nonliving environment of matter and energy;
5) biosphere – the portion of the earth in which living organisms exist and interact
with one another and with their nonliving environment;
• Ecotone – a region containing a mixture of species from adjacent ecosystems and
often species not found in either of the bordering ecosystems;
• Major abiotic components of ecosystems
- terrestrial ecosystems
1) sunlight, temperature, precipitation, wind, latitude, altitude, fire frequency, soil
- aquatic life zones
2) light penetration, water currents, dissolved nutrients, suspended solids,
salinity
• Evolution – change in a population’s genetic makeup through successive
generations;
- microevolution – small genetic changes that occur in a population;
- macroevolution – long-term, large-scale evolutionary changes;
• Ecological Niche – a species’ way of life or functional role in an ecosystem;
- Involves everything that affects its survival and reproduction
1) Range of tolerance for various physical and chemical conditions
2) Types and amounts of resources it uses
3) How it interacts with other living and nonliving components of the ecosystems
it lives in
4) The role it plays in energy flow and matter cycling
- Fundamental Niche – the full potential range of physical, chemical, and biological
condition and resources it could theoretically use if there were no direct
competition from other species;
- Realized Niche – the part of the fundamental niche a species occupies;
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Generalist species have broad niches
1) Live in many different places
2) Eat variety of foods
3) Tolerate wide range of environmental conditions
Specialist species have narrow niches
1) Live in only one type of habitat
2) Use only one or a few types of food
3) Tolerate only a narrow range of climatic and other environmental conditions
Type of species
- native species – normally live and thrive in a particular ecosystem;
nonnative species – migrate into an ecosystem;
indicator species – serve as early warning of damage to a community or an
ecosystem;
- keystone species – species in a ecosystem that play a large role in the
interactions of that ecosystem;
1) affect the health and survival of others
2) process material out of proportion to their numbers
3) pollinate flowering plants
4) disperse seeds
5) habitat modification
6) predation by top carnivores helps control population
7) improve ability of a plant species to obtain nutrients
8) efficient recycling of animal waste
Species interactions
- five basic types: interspecific competition, predation, parasitism, mutualism, and
commensalism
- intraspecific competition – competition between members of the same species
for resources;
1) territoriality – organisms patrol or mark an are around their home and defend
it against members of their own species;
- interspecific competition – competition between member of two or more different
species for food, space, or any other limited resource;
- interference competition – one species may limit another’s access to some
resource, regardless of its abundance;
- exploitation competition – competing species have roughly equal access to a
specific resource but differ in how fast or efficiently they exploit it;
- competitive exclusion principle – the niches of two species cannot overlap
completely or significantly for very long;
- predation – one species feed directly on all or part of a living organism of another
species;
1) predators have two main options of pursuit or ambush
2) prey may have special characteristics to help avoid predators
- symbiosis – relationship in which species live together in an intimate association
1) parasitism – one species feeds on part of another organism by living on the
host, parasite benefits and host is harmed;
2) mutualism – two species involved in a symbiotic relationship interact in ways
that benefit both;
3) commensalism – symbiotic interaction that benefits one species but neither
harms nor helps the other species much, if at all;
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Terrestrial biomes
- desert – area where evaporation exceeds precipitation, plants live with waxcoated leaves, plants have deep roots for ground water;
- grasslands – regions with enough average annual precipitation to allow grass to
prosper but with precipitation so erratic that drought and fire prevent large stands
of trees from growing;
- tundra - tree growth is hindered by low temperatures and short growing seasons
- chaparral – occurs along coastal area with mediterranean climate, winters are
mild and moderately rainy, summers long and hot;
- forest – undisturbed areas with moderate to high average annual precipitation
mountain – places where dramatic changes in altitude, climate, soil, and
vegetation take place over a very short distance;
Aquatic biomes
- saltwater life zones
1) coastal zone – warm, nutrient rich, shallow water that extends from the hightide mark on land tot the gently sloping, shallow edge of the continental shelf;
2) estuary – partially enclosed area of coastal water where seawater mixes with
fresh water and nutrients from rivers, streams, and runoff;
3) coastal wetlands – include river mouths, inlets, bays, sounds, mangrove
forest swamps, salt marshes;
4) intertidal zone – area of shoreline between low and high tides;
5) barrier islands – long, thin, low offshore islands of sediment that generally run
parallel of the shore;
6) coral reefs – form in clear, warm coastal waters of the tropics, contain high
biodiversity;
7) open sea – contains euphotic zone: lighted upper zone, bathyal zone: dimly lit
middle zone, and abyssal zone: dark lower zone;
- freshwater life zones
1) lakes – large natural bodies of standing fresh water formed when
precipitation, runoff, or groundwater seepage fills depressions in the earth’s
surface;
2) streams – precipitation that does into sink into the ground and becomes
runoff; land area around it is called drainage basin;
3) inland wetlands – lands covered with fresh water all or part of the time and
located away from coastal areas; include marshes swamps, prairie potholes,
floodplains, bogs, and wet arctic tundra;
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