4-1 & 4-2 What Shapes an Ecosystem?

Name: 4-1 & 4-2 What Shapes an Ecosystem?
Uploaded: 2017-10-09T21:57:29+00:00
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Description: 4-1 & 4-2 What Shapes an Ecosystem?

4-1 & 4-2 What Shapes an Ecosystem?
Photo Credit: ©Michael Fogden/DRK PHOTO Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall
The Greenhouse Effect How does the greenhouse effect maintain the biosphere's temperature range? Copyright Pearson Prentice Hall

The Greenhouse Effect The Greenhouse Effect Atmospheric gases that trap the heat energy of sunlight and maintain Earth's temperature range include: carbon dioxide methane water vapor Copyright Pearson Prentice Hall

The Greenhouse Effect Sunlight Some heat escapes into space The natural situation in which heat is retained in Earth’s atmosphere by this layer of gases is called the greenhouse effect. Greenhouse gases trap some heat Greenhouse gases trap some heat Carbon dioxide, water vapor, and several other gases in the atmosphere allow solar radiation to enter the biosphere but slow down the loss of heat to space. These greenhouse gases cause the greenhouse effect, which helps maintain Earth’s temperature range. Atmosphere Earth’s Surface Copyright Pearson Prentice Hall

The Effect of Latitude on Climate
What are Earth's three main climate zones? Copyright Pearson Prentice Hall

The Effect of Latitude on Climate
As a result of differences in latitude and thus the angle of heating, Earth has three main climate zones: polar, temperate, and tropical. Copyright Pearson Prentice Hall

Biotic and Abiotic Factors
Ecosystems are influenced by a combination of biological and physical factors. Copyright Pearson Prentice Hall

Physical, or nonliving, factors that shape ecosystems are called abiotic factors. Abiotic factors include: temperature precipitation humidity wind nutrient availability soil type sunlight Copyright Pearson Prentice Hall

How do biotic and abiotic factors influence an ecosystem? Copyright Pearson Prentice Hall

The area where an organism lives is called its habitat. A habitat includes both biotic and abiotic factors. Copyright Pearson Prentice Hall

The Niche The Niche A niche is the full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions. A plant's or animal's niche, or more correctly, ecological niche, is a way of life that is unique to that species. Niche and habitat are not the same. While many species may share a habitat, this is not true of a niche. Each plant and animal species is a member of a community. The niche describes the species' role or function within this community. For example, the red fox's habitat might include forest edges, meadows and the bank of a river. The niche of the red fox is that of a predator which feeds on the small mammals, amphibians, insects, and fruit found in this habitat. Red foxes are active at night. They provides blood for blackflies and mosquitoes, and are host to numerous diseases. The scraps, or carrion, left behind after a fox's meal provide food for many small scavengers and decomposers. This then is the ecological niche of the red fox. Only the red fox occupies this niche in the meadow-forest edge communities. In other plant communities different species of animal may occupy a similar niche to that of the red fox. For example, in the grassland communities of western Canada and the United States, the coyote occupies a similar niche (to that of the red fox.) The ecological niche includes both the animal's or plant's physical habitat and how it has adapted to life in that habitat. In examining its adaptive strategy, ecologists consider how the plant or animal obtains its energy in order to live. Each organism has made many adaptations to its habitat. The first adaptation concerns where in the habitat the animal or plant has chosen to live. Copyright Pearson Prentice Hall

The Niche The range of temperatures that an organism needs to survive and its place in the food web are part of its niche. The combination of biotic and abiotic factors in an ecosystem often determines the number of different niches in that ecosystem. Copyright Pearson Prentice Hall

The Niche No two species can share the same niche in the same habitat. Different species can occupy niches that are very similar. Copyright Pearson Prentice Hall

Community Interactions
What interactions occur within communities? Copyright Pearson Prentice Hall

When organisms live together in ecological communities, they interact constantly. Community interactions, such as competition, predation, and various forms of symbiosis, can affect an ecosystem. Copyright Pearson Prentice Hall

Competition Competition occurs when organisms of the same or different species attempt to use an ecological resource in the same place at the same time. A resource is any necessity of life, such as water, nutrients, light, food, or space. An example of competition between different species in an ecosystem: Copyright Pearson Prentice Hall

Direct competition in nature often results in a winner and a loser—with the losing organism failing to survive. The competitive exclusion principle states that no two species can occupy the same niche in the same habitat at the same time. Copyright Pearson Prentice Hall

The distribution of these warblers avoids direct competition, because each species feeds in a different part of the tree. 18 12 Feeding height (m) Cape May Warbler Each of these warbler species has a different niche in its spruce tree habitat. By feeding in different areas of the tree, the birds avoid competing with one another for food. Bay-Breasted Warbler 6 Yellow-Rumped Warbler Copyright Pearson Prentice Hall

Predation An interaction in which one organism captures and feeds on another organism is called predation. The organism that does the killing and eating is called the predator, and the food organism is the prey. An example of predator and prey in an ecosystem: Copyright Pearson Prentice Hall

Symbiosis Any relationship in which two species live closely together is called symbiosis. Symbiotic relationships include: mutualism commensalism parasitism \ Copyright Pearson Prentice Hall

Mutualism: both species benefit from the relationship. Commensalism: one member of the association benefits and the other is neither helped nor harmed. Parasitism: one organism lives on or inside another organism and harms it. ADD AN EXAMPLE ON EACH: Copyright Pearson Prentice Hall

Ecological Succession
What is ecological succession? Copyright Pearson Prentice Hall

Ecosystems are constantly changing in response to natural and human disturbances. As an ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further changes in the community. Copyright Pearson Prentice Hall

This series of predictable changes that occurs in a community over time is called ecological succession. Sometimes, an ecosystem changes in response to an abrupt disturbance. At other times, change occurs as a more gradual response to natural fluctuations in the environment. Copyright Pearson Prentice Hall

Primary Succession On land, succession that occurs on surfaces where no soil exists is called primary succession. For example, primary succession occurs on rock surfaces formed after volcanoes erupt. The first species to populate the area are called pioneer species. Copyright Pearson Prentice Hall

In this example, a volcanic eruption has destroyed the previous ecosystem. Primary succession occurs on newly exposed surfaces, such as this newly deposited volcanic rock and ash. Copyright Pearson Prentice Hall

The first organisms to appear are lichens. Primary succession occurs on newly exposed surfaces, such as this newly deposited volcanic rock and ash. Copyright Pearson Prentice Hall

Mosses soon appear, and grasses take root in the thin layer of soil. Primary succession occurs on newly exposed surfaces, such as this newly deposited volcanic rock and ash. Copyright Pearson Prentice Hall

Eventually, tree seedlings and shrubs sprout among the plant community. Primary succession occurs on newly exposed surfaces, such as this newly deposited volcanic rock and ash. AN EXAMPLE OF PIONEER SPECIES: here it could be the “lichens” appearing on the surface as the first species. WHY? (because they were the first ones to appear on the rock surface, and hen they dies they made the soil rich in nutrients so other plants could grow in the ecosystem) Copyright Pearson Prentice Hall

Secondary Succession Components of an ecosystem can be changed by natural events, such as fires. When the disturbance is over, community interactions tend to restore the ecosystem to its original condition through secondary succession. Copyright Pearson Prentice Hall

Healthy ecosystems usually recover from natural disturbances, but may not recover from long-term, human-caused disturbances. Copyright Pearson Prentice Hall

Succession in a Marine Ecosystem Succession can occur in any ecosystem, even in the permanently dark, deep ocean. In 1987, scientists documented an unusual community of organisms living on the remains of a dead whale. The community illustrates the stages in the succession of a whale-fall community. Copyright Pearson Prentice Hall

Succession begins when a whale dies and sinks to the ocean floor. Ecosystems are constantly changing in response to disturbances. In natural environments, succession occurs in stages. A dead whale that falls to the ocean floor is soon covered with scavengers. Copyright Pearson Prentice Hall

Within a year, most of the whale’s tissues have been eaten by scavengers and decomposers. Copyright Pearson Prentice Hall

The decomposition of the whale’s body enriches the surrounding sediments with nutrients. When only the skeleton remains, heterotrophic bacteria decompose oils in the whale bones. This releases compounds that serve as energy sources for chemosynthetic autotrophs. The chemosynthetic bacteria support a diverse community of organisms. Copyright Pearson Prentice Hall

Characteristics of Populations
What characteristics are used to describe a population? Copyright Pearson Prentice Hall

Three important characteristics of a population are its: geographic distribution density growth rate Copyright Pearson Prentice Hall

Geographic distribution, or range, describes the area inhabited by a population. Population density is the number of individuals per unit area. Growth rate is the increase or decrease of the number of individuals in a population over time. Copyright Pearson Prentice Hall

Population Growth What factors affect population size? Copyright Pearson Prentice Hall

Population Growth Population Growth Three factors can affect population size: the number of births the number of deaths the number of individuals that enter or leave the population A population can grow when its birthrate is greater than its death rate. Copyright Pearson Prentice Hall

Population Growth Immigration, the movement of individuals into an area, is another factor that can cause a population to grow. Populations can increase by immigration as animals in search of mates or food arrive from outside. Copyright Pearson Prentice Hall

Population Growth Emigration, the movement of individuals out of an area, can cause a population to decrease in size. Emigration can occur when animals leave to find mates and establish new territories. A shortage of food in one area may also lead to emigration. Copyright Pearson Prentice Hall

Exponential Growth What are exponential growth and logistic growth? Copyright Pearson Prentice Hall

Exponential Growth Exponential Growth Under ideal conditions with unlimited resources, a population will grow exponentially. Exponential growth occurs when the individuals in a population reproduce at a constant rate. The population becomes larger and larger until it approaches an infinitely large size. Copyright Pearson Prentice Hall

Exponential Growth Exponential Growth In the presence of unlimited resources and in the absence of predation and disease, a population will grow exponentially. Both hypothetical graphs show the characteristic J-shape of exponential population growth. Copyright Pearson Prentice Hall

Logistic Growth Logistic Growth In nature, exponential growth does not continue in a population for very long. Copyright Pearson Prentice Hall

Logistic Growth As resources become less available, the growth of a population slows or stops. Logistic growth occurs when a population's growth slows or stops following a period of exponential growth. Copyright Pearson Prentice Hall

Logistic growth is characterized by an S -shaped curve . Logistic Growth This graph shows the S-shaped curve of logistic growth. As resources become less available, the population growth rate slows or stops. The growth of this population has leveled off at its carrying capacity. Copyright Pearson Prentice Hall

Logistic Growth Carrying Capacity The largest number of individuals of a population that a given environment can support is called its carrying capacity. When a population reaches the carrying capacity of its environment, its growth levels off. The average growth rate is zero. This graph shows the S-shaped curve of logistic growth. As resources become less available, the population growth rate slows or stops. The growth of this population has leveled off at its carrying capacity. WHY? This allows for sustaining the current population without depleting resources for future use.. Copyright Pearson Prentice Hall

4-1 & 4-2 What Shapes an Ecosystem?

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