Download The following Lecture Notes were taken directly from

The following Lecture Notes were taken directly from: Biology: The Dynamics of Life by Glencoe.
Chapters 3 and 4 pages 53 – 108.
Ecology is the scientific study of interactions between organisms and their environments. Ecological
study reveals interrelationships between living and nonliving parts of the world.
The biosphere is the portion of Earth that supports life. It extends from high in the atmosphere to the
bottom of the oceans. Living things can be found in the air, on land, and in both fresh wanted and salt
water.
Each environment includes both living and nonliving factors that affect the organisms living there. All
living things that inhabit an environment are Biotic Factors
All nonliving things that inhabit an environment are Abiotic Factors.
Abiotic Factors examples: air currents, temperature, moisture, light and soil.
Abiotic factors can determine which species can survive in a particular environment.
Lack of Rainfall---Grasses grow less quickly, wildflowers would not produce as many seeds and the
animals that depend on plants for food would find it harder to survive.
The Hierarchy of Life
All organisms depend on others for food, shelter, reproduction of protection. Scientists study individual
organisms, interactions between organisms of the same species and interactions between organisms of
different species along with how abiotic factors affect groups of interacting species.
A population a group of organisms of one species living in the same place at the same time that
interbreed.
A community is a collection of several interacting populations. A change in one population in a
community will cause changes in the other populations.
An ecosystem is made up of the interaction among the populations in a community and the community’s
physical surroundings, or abiotic factors.
Types of Ecosystem’s
1- Terrestrial ecosystem are those located on land.
2-Aquatic ecosystems are either fresh water or saltwater

Fresh water includes ponds, lakes and streams

Saltwater AKA--marine ecosystem oceans occupies approximately 75 % of Earth’s surface
Niche- the role a species plays in a community. The space, food and other conditions an organism needs
to survive and reproduce are part of its niche.
Autotrophs- self feeder--they use energy from the sun or energy stored in chemical compounds to
manufacture their food. Also known as producers
Hetertrophs-eats other things--organisms that depend on autotrophs as their source of nutrients and
energy. Also known as consumers. A consumer that only feeds on plants is called an herbivore, and a
consumer that feeds on other animal is called a carnivore. A consumer that eats both plants and animals
is called an omnivore.
Scavengers such as black vultures are animals that feed on carrion, refuse, and similar dead organisms.
Organisms that break down and absorb nutrients from dead organisms are called decomposers.
Symbiosis--living together--the relationship in which there is a close and permanent association between
organisms of different species.
Ch 4 --- Biomes
Components of Ecology:
1) energy flow
2) nutrient cycles
3) interactions of life forms
Ecosystems are always changing. Sometimes they change quickly and dramatically as with fire or flood.
A limiting factor is any biotic or abiotic factor that restricts the existence, numbers, reproduction or
distribution of organisms.
EX----The timberline is how limiting factors affect the plant life of an ecosystem. At high elevations,
temperatures are too low, winds too strong, and the soil too thin to support the growth of large trees.
Vegetation is limited to small, shallow-rooted plants, mosses, ferns, and lichens.
Ecologists refer to orderly, natural changes that take place in the communities of an ecosystem as
succession. The colonization of new sites by communities of organisms is called primary succession. A
stable, mature community that undergoes little or no succession is called a Climax community. A sere is
the beginning of a new community which will lead to a climax community.
Ex--lichens, mosses, ferns shrubs and grasses, pines, beeches and maples.
Secondary succession is the sequence of community changes that takes place when a community is
disrupted by natural disasters or human actions. During secondary succession the community of
organisms inhabiting an area gradually changes. But the species involved in secondary succession are
different. Pioneer species, are not the same because the area has not reverted back to the original
conditions. Secondary succession also takes less time to reach a climax community than primary
succession.
Aquatic Biomes
A biome is a large group of ecosystems that share the same type of climax community.
Marine Biomes
To study marine biomes ecologists separate them into shallow, sunlit zones and deeper, unlighted
zones. The portion of the marine biome that is shallow enough for sunlight to penetrate is called the
photic zone. Deeper water that never receives sunlight makes up the aphotic zone. Different parts of the
ocean differ in physical factors and in the organisms found there. An estuary is a coastal body of water,
partially surrounded by land, in which fresh water and salt water mix. Salinity ranges between that of
seawater and of fresh water, and depends on how much fresh water the river brings into the estuary.
Salinity in the estuary also changes with the tide. Estuaries contain salt marsh ecosystems, which an
dominated by grasses. Twice a day, the gravitational pull of the sun and moon causes the rise and fall of
ocean tides. Tides vary in height, depending on the season and the slope of the land. The portion of the
shoreline that lies between high and low tide lines is called the intertidal zone.
ecotone- transition areas i.e.--palmtrees characteristics of a transition of end of marshes to the forest
Freshwater Biomes
The shallow waters on which these plants grow are highly productive and include fish, algae, protists,
mosquito larvae, tadpoles and crayfish. The temperature variations within a lake are an abiotic factor that
limits the kinds of organisms that can survive in deep lakes.
Water--most dense at 4 degrees C.
South Pacific--warmest ocean water on earth at 84 degrees F
Ocean Currents-- based on: 1) rotation of earth
2) surface winds
3) configuration of land masses
Terrestrial Biomes
Three factors determine which biome will be dominant in a terrestrial location--latitude, altitude and
precipitation.
The first of two biomes are near the poles. This community is the tundra, a treeless land with long
summer days and short periods of winter sunlight. Underneath this topsoil is a layer of permanently
frozen ground called Permafrost.
Just south of tundra lies another community that circles the north pole. The taiga, also called the
northern coniferous forest, is a land of mixed pine, fir, hemlock and spruce trees.
Taiga communities are usually somewhat warmer and wetter than tundra, but the prevailing climatic
conditions are still harsh, with long, severe winters and short mild summers.
The driest of the biomes south of the taiga is the desert biome. A desert is an arid region with sparse to
almost nonexistent plant life. Deserts are formed by Rain shadows---the production of deserts through
mountain range blocking causing drought. ex---Rockies
Grasslands are large communities covered with grasses and similar small plants. They experience a dry
season, with insufficient water exists to support forests. This biome occupies more area than any other
terrestrial biome, and it has a higher biodiversity than deserts, often with more than 100 species per acre.
Temperate Forests are dominated by broad-leaved hardwood trees that lose their foliage annually.
The most biologically diverse of terrestrial biomes, the tropical rain forest is a region of uniformly
warm, wet weather dominated by lush plant growth. Butterflies and other insects are by far the most
numerous animals in the rain forest. Biologists estimate that there may be as many as 3 million species of
insects in the tropical rain forest.