Biomes

Module 1

Community Ecology - the study of interactions among species

Symbiosis - two species living in a close and long term relationship with one another

The characteristics of any given environment are highly dependent on the climate that exists in that location Ex: ecosystems in the desert of Death Valley, California, where temperatures may reach 50 degrees Celsius/120 degrees Fahrenheit, are very different from those on the continent of Antarctica, where temperatures may drop as low as -85 degrees Celcius

The biotic and abiotic components of an ecosystem provide the boundaries that distinguish one ecosystem from another. Some ecosystems have well-defined boundaries, whereas others do not. A cave, for example, is a well-defined ecosystem. It contains identifiable biotic components, such as animals and microorganisms that are specifically adapted to live in a cave environment, as well as distinctive abiotic components, including temperature, salinity, and water that flows through the cave as an underground stream.

Many aquatic ecosystems, such as lakes, ponds, and streams, are relatively easy to define because the ecosystem’s boundaries correspond to the boundaries between land and water. Knowing the boundaries of an ecosystem makes it easier to identify the system’s biotic and abiotic components and to trace the cycling of energy and matter through the system.

In most cases, however, determining where one ecosystem ends and another begins is difficult. For this reason, ecosystem boundaries are often subjective. Environmental scientists might define a terrestrial ecosystem as the range of a particular species of interest, such as the area where wolves roam, or they might define it by using topographic features, such as two mountain ranges enclosing a valley.

Yellowstone National Park, for example, was once managed as its own ecosystem until scientists began to realize that many species of conservation interest, such as grizzly bears, spent time both inside and outside the park, despite the park’s massive area of 898,000 ha (2.2 million acres). To manage these species effectively, scientists had to think much more broadly; they had to include nearly 20 million ha (50 million acres) of public and private land outside the park

Each ecosystem interacts with surrounding ecosystems through the exchange of energy and matter. Organisms such as bats — which fly in and out of caves — move across ecosystem boundaries, as do chemical elements, such as carbon or nitrogen dissolved in water. As a result, changes in any one ecosystem can ultimately have far-reaching effects on the global environment.

Any plant species influence the distribution and abundance of other plant species

Tragedy of the Commons: degradation of a renewable and free access resource

Main Idea of the Tragedy of the Commons: Everyone is trying to take as much as they can from a public resource because they think if they don’t, someone else will

Carrying Capacity: The number of people, other organisms, or crops that a region can support without environmental degradation

Climate: The average weather that occurs in an area over a given time

Weather: The short-term conditions of the atmosphere in a local area that include temperature, humidity, clouds, precipitation, and wind speed

The characteristics of any given environment depend on the climate that exists in that location of the Earth

The abiotic and biotic components of an ecosystem provide the boundaries that distinguish one ecosystem from another

Well-defined ecosystem: identifiable biological components such as animals, microorganisms that are adapted to live in those specific conditions, as well as abiotic components such as temperature, salinity, and sources of water

The biosphere is the region of our planet where all life resides

Competition is the struggle of individuals, either within or between species, to obtain a shared limited resource

Competitive-exclusion principle: Principle stating that two species competing for the same limiting resource cannot coexist

Under a given set of environmental conditions, when two species have the same realized niche, one species will perform better and will drive the other species to extinction.

Resource partitioning: When two species evolve to divide a resource based on differences of their behavior or morphology

When competition reduces the ability of individuals to survive and reproduce, natural selection will favor individuals of one species that overlap less with individuals of another species in the resources they use

Temporal resource partitioning: a process in which two species utilize the same resource at different times

Spatial resource partitioning: When two species reduce competition by using different habitats

Morphological resource partitioning: the evolution of differences in body shape or size. This morphological resource partitioning allows for reduced competition among the species of finches that live on the Galápagos Islands.