FOOD CHAINS & FOOD WEBS : FOOD CHAINS & FOOD WEBS
: The source of all food is the activity of autotrophs , mainly photosynthesis by plants. Food chain: A sequence of organisms directly dependent on one another for food. Food web: An interconnection of many food chains Each level of consumption in a food chain is called a trophic level .
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Food Web : Food Web
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Types of Ecosystems : Types of Ecosystems 1.Forest 2.Grassland 3.Desert 4.Aquatic
1.Forest Ecosystems : 1.Forest Ecosystems CONCEPTUAL MODELING DIAGRAM
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Who depends on trees? : Who depends on trees? A whole system of plants, animals, soil, water and air - called an ecosystem - depends on trees for homes and food. And just like you rely on the people around you, trees too rely on each other to stay healthy. they provide homes for many animals and plants
PowerPoint Presentation : Even animals that don't live in the forests rely on trees to survive. Fish and ocean animals depend on the oxygen produced by trees during photosynthesis to keep them alive. Animals that live deep in the deserts rely on the earth's forests to process carbon dioxide and help regulate the temperature of the earth.
PowerPoint Presentation : people depend on the forests. We use forests products every day when we draw a picture on a piece of paper, read the newspaper or sit in a wooden chair. People in the forestry business depend on the forests for their jobs, and with every breath of clean air that we take we can thank a tree. Most importantly, forests provide us with many powerful medicines that can even fight cancer!
2.Grassland Ecosystems : 2.Grassland Ecosystems Over one quarter of the Earth's surface is covered by grasslands. Grasslands are found on every continent except Antarctica, and they make up most of Africa and Asia. There are several types of grassland and each one has its own name. Prairies, plains and savannas are all grasslands. Grasslands develop where there isn't enough rain for forests but too much rain for deserts . Grasslands are filled with - grass. There are many types of grass, though. Fields of wheat are considered grasslands, even though they are often cultivated by people. Grass is special because it grows underneath the ground. During cold periods the grass can stay dormant until it warms up.
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PowerPoint Presentation : Grasslands are considered one of the most biologically diverse habitats on Earth, home to a multitude of insects, reptiles, birds and mammals, many of which depend on one another for their survival . The integrity of grassland ecosystems everywhere has been compromise primarily by the conversion of these ecosystems to agriculture, and more recently, the growth of towns and cities. As a result many species are seeing a rapid decline.
3.Desert Ecosystems : 3.Desert Ecosystems What is a desert? Deserts are very hot and dry places. a desert is defined as having less than an average 25 cm of precipitation per year. deserts have a strong tendency to lose water by evaporation, and this potential for water loss exceeds the annual rainfall . Deserts get very little rain each year. It is made of sand and rocks. Sometimes the sand is red! There aren't a lot of clouds over deserts, so it gets really hot during the day and cold at night.
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PowerPoint Presentation : Deserts provide an excellent climate for observing rock type. Lack of vegetation reveals rock types. In this photograph notice that a streambed meets a rock layer. The streambed is made of loose rock while the dense layer appears white or yellow.
PowerPoint Presentation : Deserts provide an excellent climate for observing rock type. Lack of vegetation reveals rock types. In this photograph notice that several different rock layers exist. Each layer appears as a different color.
This photograph shows several interesting features of a sandy desert. Look at the ripples in the bottom right corner. Ripples form perpendicular to the direction that the wind generally blows. Next, notice that asymmetrical sand dunes. One side is steeper than the other. : This photograph shows several interesting features of a sandy desert. Look at the ripples in the bottom right corner. Ripples form perpendicular to the direction that the wind generally blows. Next, notice that asymmetrical sand dunes. One side is steeper than the other.
PowerPoint Presentation : Camels are very important animals in the desert. People use them instead of a car.
GREAT BASIN DESERT : GREAT BASIN DESERT
SONORAN DESERT : SONORAN DESERT
4.Aquatic Ecosystem : 4.Aquatic Ecosystem An aquatic ecosystem is a group of interacting organisms dependent on one another and their water environment for nutrients (e.g., nitrogen and phosphorus) and shelter. Familiar examples are ponds, lakes and rivers, but aquatic ecosystems also include areas such as floodplains and wetlands, Even a drop of water is an aquatic ecosystem, since it contains or can support living organisms
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Organisms found in aquatic ecosystems : Organisms found in aquatic ecosystems Aquatic ecosystems usually contain a wide variety of life forms including bacteria, fungi, and protozoans; bottom-dwelling organisms such as insect larvae, snails, and worms; free-floating microscopic plants and animals known as plankton; large plants such as cattails, bulrushes, grasses, and reeds; and also fish, amphibians, reptiles, and birds
Aquatic ecosystem health : Aquatic ecosystem health Healthy aquatic ecosystems are those where human disturbances have not impaired the natural functioning (e.g., nutrient cycling) nor appreciably altered the structure (e.g., species composition) of the system. An unhealthy aquatic ecosystem is one where the natural state is out of balance.
PowerPoint Presentation : These disturbances can be physical (e.g., injection of abnormally hot water into a stream), chemical (e.g., introduction of toxic wastes at concentrations harmful to the organisms), or biological (e.g., introduction and propagation of non-native animal or plant species). Symptoms of poor ecosystem health include the following: The loss of species. The accelerated proliferation of organisms. One example is algae blooms caused by an excess of phosphorous and nitrogen compounds in the water. This condition is called "eutrophication". Increased incidences of tumours or deformities in animals. A change in chemical properties. Perhaps one of the most significant has been a reduction of pH in water caused by acid rain. The presence of certain organisms that indicate unsanitary conditions. Coliform bacteria, for example, are a sign that the system may contain organisms that cause a variety of human diseases such as diarrhea, typhoid, and cholera. The loss of traditional Aboriginal culture associated with the ecosystem.
Wetlands : Wetlands Wetlands are areas of standing water that support aquatic plants. Marshes, swamps, and bogs are all considered wetlands.