5. Place the appropriate word from the list in each of the blanks below:

endangered, web, niche, diversity, disrupted, populations, affect ,interact, biome

1. Development in tropical areas causes more extinctions due to the great … found in tropical rain forests (half of all species on Earth).

2. Within all species, individuals … with each other - feeding together, mating together, and living together.

3. Animals eat other animals through their interactions in a food …

4. Within an ecosystem, all aspects of the environment (both living things and their non-living settings) interact and … one another.

5. A … is a large unit that is home to many different ecosystems.

6. Each organism has its own …, or role to play.

7. We have … the food net, the carbon cycle, the nitrogen cycle, and the water cycle.

8. Two different … can not occupy the same niche at the same time.

9. A species becomes … when there is not enough habitat available to support all members of the population.

Reading for Speaking and Discussing

Read the text and choose the title to each part.

1. Ecosystem dynamics

2. Ecological niche

3. Definition of the ecosystem

4. Ecosystem ecology

Ecosystem

1.An ecosystem is a group of living things in one environment, all interacting together and depending on each other. For example, if a forest disappears then all the plants, mammals, birds, insects, reptiles and perhaps even fish are affected in some way because their shelter, food, protection, nests etc have gone.

The term ecosystem refers to the combined physical and biological components of an environment. An ecosystem is generally an area within the natural environment in which physical (abiotic) factors of the environment, such as rocks and soil, function together along with living organisms, such as plants and animals, within the same habitat to create a stable system. Ecosystems can be permanent or temporary. Ecosystems usually form a number of food webs.

Ecosystem is a functional unit consisting of living things in a given area, non-living chemical and physical factors of their environment, linked together through nutrient cycle and energy flow.

Central to the ecosystem concept is the idea that living organisms interact with every other element in their local environment.

The term ecosystem was coined in 1930 by Roy Clapham to mean the combined physical and biological components of an environment.

2.Loch Lomond in Scotland forms a relatively isolated ecosystem. The fish community of this lake has remained unchanged over a very long period of time.

Introduction of new elements, whether biotic or abiotic, into an ecosystem tends to have a disruptive effect. In some cases, this can lead to ecological collapse and the death of many species within the ecosystem. Often, however, ecosystems have the ability to rebound from a disruptive agent. The difference between collapse and a gentle rebound is determined by two factors—the toxicity of the introduced element and the resiliency of the original ecosystem.

Ecosystems are primarily governed by stochastic (chance) events, the reactions these events provoke on non-living materials and the responses by organisms to the conditions surrounding them. The presence or absence of populations merely depends on reproductive and dispersal success, and population levels fluctuate in response to stochastic events. As the number of species in an ecosystem is higher, the number of stimuli is also higher. Through natural selection the planet's species have continuously adapted to change through variation in their biological composition and distribution.

Given the great diversity among organisms on earth, most ecosystems only changed very gradually, as some species would disappear while others would move in. Feedback mechanisms at the species level regulate population levels, most notably through territorial behavior.

3.Ecosystem ecology is the integrated study of biotic and abiotic components of ecosystems and their interactions within an ecosystem framework. This science examines how ecosystems work and relates to their components such as chemicals, bedrock, soil, plants, and animals. Ecosystem ecology examines physical and biological structure and how these ecosystem characteristics interact.

4.The ecological niche is a central concept in the ecology of organisms. There are many definitions of the niche dating back to 1917, but George Evelyn Hutchinson made conceptual advances in 1957 and introduced the most widely accepted definition: "The niche is the set of biotic and abiotic conditions in which a species is able to persist and maintain stable population sizes." Organisms have functional traits that are uniquely adapted to the ecological niche. A trait is a measurable property of an organism that strongly influences its behavior. Biogeographical patterns and range distributions are explained or predicted through knowledge and understanding of a species niche requirements. Important to the concept of niche is habitat. The habitat describes the environment over which a species is known to occur and the type of community that is formed as a result.