THE TERRESTRIAL HABITAT

THE TERRESTRIAL HABITAT ECOLOGY

Terrestrial EcosystemsTerrestrial ecosystems are ecosystems on land.

They can be as big as a continent, or as small as an island!

They make up about 28% of the entire Worlds ecosystems.

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Six primary terrestrial ecosystems exist: tundra, taiga, temperate deciduous forest, tropical forest, grassland and desertTerrestrial ecosystems are distinguished from aquatic ecosystems by the lower availability of water and the consequent importance of water as a limiting factor.

Terrestrial ecosystems are characterized by greater temperature fluctuations on both a diurnal and seasonal basis than occur in aquatic ecosystems in similar climates.

The availability of light is greater in terrestrial ecosystems than in aquatic ecosystems because the atmosphere is more transparent than water.

Gases are more available in terrestrial ecosystems than in aquatic ecosystems.

Those gases include carbon dioxide that serves as a substrate for photosynthesis, oxygen that serves as a substrate in aerobic respiration, and nitrogen that serves as a substrate for nitrogen fixation

Terrestrial ecosystems occupy 28.2%, of Earth's surface. Although they occupy a much smaller portion of Earth's surface than marine ecosystems, terrestrial ecosystems have been a major site of adaptive radiation of both plants and animals. Major plant taxa in terrestrial ecosystems are members of the division Magnoliophyta (flowering plants), of which there are about 275,000 species, and the division Pinophyta (conifers), of which there are about 500 species.

Members of the division Bryophyta (mosses and liverworts), of which there are about 24,000 species, are also important in some terrestrial ecosystems. Major animal taxa in terrestrial ecosystems include the classes Insecta (insects) with about 900,000 species, Aves (birds) with 8500 species, and Mammalia (mammals) with approximately 4100 species

What Animals Live There?Many different animals call terrestrial ecosystems home.

The most common are:BirdsMammals of all shapes and sizesinsects

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What Plants Live There?Many plants also call terrestrial ecosystems their home also, we see many of them everyday!Common plants are:

Flowering plants, like rosesMosses, like moss that grows on rocksConifers, which are pine trees

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Abiotic ComponentsAbiotic components are the non-living components of an ecosystem, affecting the life of organisms.Abiotic components can be harmful to the ecosystemAbiotic components are:Temperature, light, water, soil, rocks, sulphur, nitrogen, phosphorous, proteins, lipids, carbohydrates ,humic substances etc

These specific abiotic factors represent the geological, geographical, hydrological and climatological features of a particular ecosystem

TEMPERATUREMost life exists within a fairly narrow range of temperatures, from about 0 C to about 50 C. Few organisms can maintain an active metabolism below 0 C for long, and most organisms enzymes are denatured (they lose their shape and stop working) above 50 C. However, extraordinary adaptations enable certain species to live at extreme temperatures

It influences organisms in distinct ways :Animals have clear distinction between being cold blooded or warm blooded.Migration is seen in some animals.Rate of respiration increases with increase in temperature.Water absorption decreases at low temperature.Stimulated the growth of seedlings.

TYPES OF VEGETATIONMEGATHERMS: vegetation where temperature remain high throughout the year. E.g. dominant vegetation of tropical rain forest.MESOTHERMS: vegetation where there is an alteration of low and high temperature season. E.g. vegetation of tropical deciduous forest.MICROTHERMS: region where temperature always remain comparatively lower. E.g. mixed coniferous forest.HEKISTOTHERMS: vegetation where temperature remains low throughout the year. E.g. alpine vegetation.

SUNLIGHTThe sun provides light and warmth and it is the energy source for almost all ecosystems on Earth. Sunlight powers photosynthesis by plants, the main producer in most terrestrial ecosystems

2. Light Influence on organisms:Enabling the organisms to seen or to be seen.Essential for growth of green plants.In mammals, it plays vita role in formation of substances such as vitamin D : regulates quantities of calcium and phosphorous.

Depending upon the relative light requirements, plants have been placed in 2 groups:PHOTOPHILOUS: (heliophilous or sun loving): these plants grow in high intensities of sunlight.SCIOPHILOUS or shade loving: these plants are best suited to diffuse or low light intensity.

PHOTOPERIODISM: the duration of light affects the flowering in plants. This is known as photoperiodism. on the basis of this plants have been grouped into following:SHORTDAY PLANTS: plants flower when photoperiod is less than the critical limit. E.g. tobacco, soya bean, Xanthium.LONGDAY PLANTS: plants flower when photoperiod is more than the critical limit. E.g. beat root, radish.DAY NEUTRAL PLANTS: not affected by the photoperiod. E.g. cotton, sunflower, tomato.

WINDMany plants use the help of the wind to disperse seeds over long distances. Organisms disperse to find new habitats rich in needed resources. Strong winds can be very destructive

WATERWater is one of natures most important thing Essential for life of an organisms survival. Water is necessary for digestion and absorption of food; helps maintain proper muscle tone-, supplies oxygen and nutrients to the cells; rids the body of water; and serves as a natural air conditioning system

Effect of water:Affects all the vital functions of an organisms.Controls the structure and distribution of communities.Influences morphology and physiology of organisms.Minerals in the soil get dissolved in water and are than absorbed by plant.

Humidity :In the atmosphere water is present in the form of water vapours, called atmospheric humidity.Clouds and fog are the visible form of humidity.Major source: evaporation of water and transpiration.Humidity is expressed in different terms.:Specific humidity: amount of water vapour present per unit weight of air.Absolute humidity: amount of water vapours present per unit volume of air at saturation.Relative humidity: amount of water vapours actually present in air and expressed as % of the amount which the air can hold at saturation at existing temperature.

Relative humidity is measured by an instrument called psychrometer.Effect of humidity on plant life:Affects structure, form and transpiration.Plants like orchids, mosses and lichens depends on atmospheric humidity for their requirement of moisture.Evaporation of water, its condensation and precipitation depends upon relative humidity.

BIOTIC COMPONENTThe biotic components ranges from extremely small bacteria, which live in the air, water and soil, algae which live in fresh and salt water, to the terrestrial plants which range from grasses and herbs that grow after the monsoon of every year to the giant long lived trees of the forestThe living component of the animal world ranges from microscopic animals to small insects and larger animals such as fish, amphibians , reptiles, birds and mammals

Biotic component is distinguished into autotrophs , heterotrophs and saprotrophs

Autotrophs are also called producersThese are photosynthetic plants, generally chlorophyll bearing, which synthesize high-energy complex organic compounds (food) from inorganic raw materials with the help of sunlight, and the process is referred as photosynthesis. Autotrophs form the basis of any biotic system.

In terrestrial ecosystems, the autotrophs are mainly the rooted plants.

HeterotrophsHeterotrophs are called consumers, which are generally animals feeding on other organisms

Consumer's also referred as phagotrophs (phago - to ingest or swallow) or macroconsumers are mainly herbivores and carnivores

Herbivores are referred as First order consumers or primary consumers, as they feed directly on plants . For e.g., Terrestrial ecosystem consumers like cattle, deer, rabbit, grass hopper, etc..

Carnivores are animals, which feed or prey upon other animalsPrimary carnivores or Second order consumers include the animals which feed on the herbivorous animals. For e.g., fox, frog, predatory birds, smaller fishes, snakes, etc.Secondary carnivores or Third order consumers include the animals, which feed on the primary carnivores. For e.g., wolf, peacock, owl, etc.

Saprotrophs are also called decomposers or reducers. They break down the complex organic compounds of dead matter (of plants and animals). Decomposers do not ingest their food. Instead they secrete digestive enzymes into the dead and decaying plant and animal remains to digest the organic material. Enzymes act upon the complex organic compounds of the dead matter.

Classification of terrestrial communities on the basis of habitatTerrestrial organisms are found living on the surface of earth, below it or in the sky. therefore, on the basis of habitat, they are divided into 3 categories:Subterranean communitiesSurface communitiesAerial communities

Subterranean communities:Animals which live about 5 to 6 inches deep inside the earth.These animals are adapted to various modes of life living inside earth. These adaptations depend upon the nature and type of soil they live in.

On the basis of the size, the subterranean communities are further classified as follows:

Microbiota subterranean communities It includes algae, bacteria and fungi.

ii. Mesobiota subterranean communities: It includes nematodes, oligochaetes, small insect larvae and some arthropods.

iii. Macrobiota subterranean communities: It includes roots of some plants, large insects, earthworms, moles, ground squirrel and pocket gophers.

b). Surface communities: communities which live on earth. on the basis of climatic factors it can be divided into following: Tropical : temperature : 48 degree Celsius or more ; rainfall: 200-400 cm per year. Climate is warm.Temperate: temperature: 40 degree Celsius or more; rainfall: 76 cms. Summers are warm and winters are cold.Alpine: snowfall takes place, avg rainfall is 25cm or less.

c). Aerial communities: organisms which fly in the sky.They come on land, trees or rocks for feeding, breeding and resting.Insects, moths, birds and bats are main sky fliers.

Examples of Terrestrial Ecosystems

Forests

Deserts

Grasslands

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