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Objectives To make the students aware of different types of abiotic components, significance of abiotic factors, influence on Keywords , ,

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<1 Introduction > < 2 Significance of abiotic factors>, < 3 Topography>, < 4 Biotic and abiotic influence on ecosystem>, < 5 Influence of Abiotic factors>, < 6 Biome> ,

Habitat and Niche Types and overlapping of Niche, character displacement

1. Introduction All consist of two major components—biotic and abiotic. The represents all the living and the abiotic component includes the non-living (physical) environment. Both of these components interact closely to exhibit a definite structural organization. In any ecosystem both of these components are interdependent on each other for various kinds of changes. (Source:http://www.yourarticlelibrary.com/essay/environment-essay/components-of- ecosystem-biotic-components-and-abiotic-components-with-info-graphics/41923/)

ABIOTIC COMPONENTS BIOTIC COMPONENTS Sunlight Primary producers Temperature Precipitation Water (in all forms) (Edaphic factor) Elements and Molecules

(Source:http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/ecosystem/ ec system.html)

i. Abiotic Components: The abiotic factors are the governing forces of environment having an impact on the life cycle of . Initially, organisms try to adapt to the surrounding environment. They later look for modifying environment so as to enable abiotic components more suitable for their own living. The abiotic factors of the environment impact the well-being and distribution of organisms and the functions of the ecosystem. For example, temperature and moisture acting together determine in large measure the climate of a region and the distribution of plant and animal life. Light is essential to plants, without it, ecosystems could not function. Light also influences circadian rhythms of plants and animals. Soil, functioning as edaphic factor regulates plant growth through nutrient supply, soil microbial activity, water holding.

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

2. Significance of Abiotic Factors

a. Light: It is the primary source of energy for biological processes. It is the energy that is used by green plants for . Factors such as quality of light, intensity of light and the length of the light period (day length) play an important part in regulating these processes. Light energy (specifically UV radiation) acts as a catalyst for genetic mutation. It also drive Hydrological cycle. Light regulates photoperiodism, circadian rhythms.

i. Quality of light: Plants absorb blue and red light during photosynthesis. In terrestrial ecosystems the quality of light does not change much. In aquatic ecosystems, the quality of light is a . Both blue and red light are absorbed and as a result do not penetrate deeply into the water. To compensate, by water, some algae have additional pigments which are able to absorb other colors wavelengths of light.

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

ii. Light intensity The intensity of the light that reaches the earth varies according to the latitude and season of the year. The southern hemisphere receives less than 12 hours of sunlight during the period between the 21st March and the 23rd of September, but receives more than 12 hours of sunlight during the following six months. iii. Day length: Relative lengths of daylight and darkness that effect the physiology and behavior of an organism. Certain plants flower only during certain times of the year. One of the reasons for this is that these plants are able to "measure" the length of the night (dark periods). Relative lengths of daylight and darkness that effect the physiology and behavior of an organism.

b. Temperature Temperature is an indication of the amount of heat energy in a system; the higher the heat content, the higher the temperature. On a worldwide basis, temperature is one of the dominating factors affecting plant and animal distribution. The arctic, the temperate zones, and the tropics are largely delimited by temperature differences. The environmental temperatures experienced by most organisms result directly or indirectly from solar radiation reaching any point on Earth at any time and varying with the time of year, slope, cloud cover, time of day, and other factors. Temperature is one of the most critical factors of the environment and exerts a profound influence on all physiological activities by controlling the rate of chemical reaction. Every physiological function has temperature limits above and below which it ceases and an optimum range of temperature at which reactions proceed at maximum rates. As the temperature deviates from this optimum, the rate of reaction decreases, stopping completely beyond a critical limit. Range of temperature at which organisms normally exist is referred to as its physiological range. It varies in different organisms depending on local adaptations. The thermal limit for the survival of metabolically active vascular plants ranges from about +60 °C to –60 °C in different species. Some blue green algae and other prokaryotic organisms are known to exist from slightly below 0 °C to about 70 °C. Frost damage can be seen in plants as some of them cannot prevent freezing of their tissues. Temperature regulates seed germination. Chilling or other special treatment is required for seed germination. This is referred as Vernalization. Some fruit trees such as the peach require a cold period each year so that it can blossom in the spring. Deciduous trees lose their leaves in winter and enter into a state of dormancy, where the buds are covered for protection against the cold. These

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

adaptive measures assist plants in overcoming the negative impact of wider fluctuations in temperature. Predictive climate change largely because of Green House Gas can have a sizeable impact on ambient temperature.

c. Precipitation: Rainfall is the most common form of precipitation. Other forms of precipitation are in the form of sleet or ice pellets, snowfall, and hail (Eagleman 1985; Miller 2001). The amount and regularity of rainfall vary with location and climate types and affect the of certain types of vegetation as well as crop growth and yield. Most terrestrial plant species are limited by a combination of temperature, precipitation and light.

d. Water Without water, most life forms would be unable to sustain themselves and the Earth would be a barren, -like place. About 97% of Earth’s volume of water is found in the oceans and the remaining 3% is fresh water. More than 75% of fresh water (about 2% of Earth’s total volume) is locked up as ice at the poles and in glaciers leaving less than 1% of the world’s water available as fresh liquid water. Only about 0.003% of Earth’s total volume of water is easily available to us as freshwater in lakes, soil moisture, exploitable ground water, atmospheric water vapour and streams. There are two sources of freshwater, namely surface water and groundwater. (Source: Environmental monitoring- Vol. I- Priority Parameters: Abiotic and Biotic Components- Muoghalu J.I.) Aquatic plants exhibit a wide variety of morphological and physiological adaptations that allow them to survive, compete and diversify in their natural . For example, the roots and stems develop large cellular air spaces to allow for the efficient transportation gases (for example, CO2 and O2) used in respiration and photosynthesis. In aquatic environments, anaerobic soil use nitrate, manganese ions, ferric ions, sulfate, and some organic compounds. The activity of soil microorganisms and the chemistry of the water reduces the oxidation/reduction potentials of the water. Carbon dioxide, for example, is reduced to (CH4) by methanogenic bacteria. Because of these processes, wetlands play a vital role in global nutrient and element cycles.

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

The saltwater environments are physiological in which the concentration of salts outside the body of the organism can osmotically dehydrate the organism. In the deserts, an absolute lack of moisture exists. Human activity has a large effect on both these types of ecosystems; excessively fishing and pollution can drastically affect the salinity and oxygen content of these habits. Aquatic and Sunlight In large bodies of standing water, including the ocean and lakes, the water can be divided into zones based on the amount of sunlight it receives: 1. The photic zone extends to a maximum depth of 200 meters (656 feet) below the surface of the water. This is where enough sunlight penetrates for photosynthesis to occur. Algae and other photosynthetic organisms can make food and support food webs. 2. The aphotic zone is water deeper than 200 meters. This is where too little sunlight penetrates for photosynthesis to occur. As a result, food must be made by or else drift down from the water above. These and other aquatic zones in the ocean are identified in figure:

Figure: 1. The ocean is divided into many different zones, depending on distance from shore and depth of water. (Source:http://greatneck.k12.ny.us/GNPS/SHS/dept/science/krauz/bio_h/images/50_16Aquati cZonation_L.jpg )

e. Soil (edaphic factors) factors include soil texture, soil air, soil temperature, soil water, soil solution and pH, together with soil organisms and decaying matter.

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

Fig: 2. Different types factors affecting soil formation

i. Soil texture The size of soil particles varies from microscopic particles called clay to larger particles called sand. Loam soil is a mixture of sand and clay particles. Sandy are suitable for growing plants because they are well aerated, excess water drains away quickly, they warm up quickly during the day and is easy to cultivate. Sandy soils is unsuitable because they do not retain much water and soon dry out and contain few soil nutrients required for plant growth. Clay soils are suitable for plant growth because they hold large quantities of water and are rich in mineral nutrients. They are unsuitable in that they are badly aerated, soon becomes waterlogged and is difficult to cultivate; it also cold during winter. Loam soils possess desirable properties of both sand and clay - it has a high water retaining capacity, good aeration, good nutrient content and is easily cultivated. ii. Soil aeration Soil air is found in those spaces between the soil particles that are not filled with soil water. The amount of air in a soil depends on how firmly the soil is compacted. In well-aerated soil at least 20% of its volume is made up of air. Compact soils of high bulk density and poor structure are aerated poorly. Pore space is occupied by air and water so the amount of air and water are inversely proportional to the amount of oxygen in the soil. On well drained soils, oxygen content

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

is not likely to be limiting to plant growth. Plants vary widely in their sensitivity to soil oxygen. Paddy rice vs tobacco. Soil water can be classified into three types, namely hygroscopic, capillary and gravitational water. Hygroscopic water occurs as a thin film of water around each soil particle. Capillary water is that water held in the small spaces between the soil particles and gravitational water is the water which drains downwards through the soil. Soil water is essential for soil microorganisms. Without some water, there is no microbial activity. Sandy soils with large diameter particles (coarse texture) can contain less water than clay soils with small diameter particles (fine texture). The formation of primary soil particles into soil aggregates creates an ideal environment for most bacteria. As the amount of available water decreases, the ability to take up water in the soil differs among organisms. Fungal hyphae have the ability to extend through soil pores and obtain water, but bacteria do not share the same advantage. iii. Soil temperature Soil temperature is an important ecological factor. It has been found that the temperature of soil below a depth of about 30cm is almost constant during the day but seasonal temperature differences do occur. At low temperature there is little decay by decay-causing micro-organisms. iv. Soil solution Soil solution is the decaying remains of plants and animals, together with animal excretory products and faeces, form humus. This increases the fertility of the soil. v. Soil pH Acidity or alkalinity of soil (the pH of the soil) influences the biological activity in soil and the availability of certain minerals. Thus the pH of soil has a greater influence on the growth and development of plants. Some plants e.g. azaleas, ericas, ferns and many protea species grow best in acid soils (soils with a pH below 7), while lucerne and many grow better in alkaline soils (soils with a pH above 7). The organisms and the decaying matter in the soil is known as soil solution and it increases the fertility of the soil. Soil Composition Plants obtain inorganic elements from the soil, which aids as a natural medium for land plants. Soil is the outer, loose layer that covers the surface of Earth. Soil quality, a major determinant, along with climate, of plant distribution and growth, depends not only on the chemical composition of the soil, but also the topography (regional surface features) and the presence of living organisms.

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

It consists of these major components:

Components of soil The four major components of soil are shown: inorganic minerals, organic matter, water, and air.

 inorganic mineral matter, about 40 to 45 percent of the soil volume

 organic matter, about 5 percent of the soil volume  water, about 25 percent of the soil volume

 air, about 25 percent of the soil volume The amount of each of the four major components of soil depends on the quantity of vegetation, soil compaction, and water present in the soil. A good, healthy soil has sufficient air, water, minerals, and organic material to promote and sustain plant life. The organic material of soil, called humus, is made up of microorganisms (dead and alive), and dead animals and plants in varying stages of decay. Humus improves soil structure, providing plants with water and minerals. The inorganic material of soil is composed of rock, slowly broken down into smaller particles that vary in size. (Source: Boundless. “Soil Composition.” Boundless . Boundless, 21 Jul.2015. Retrieved 26 Dec. 2015 from

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

https://www.boundless.com/biology/textbooks/boundless-biology-textbook/soil-and-plant- nutrition-31/the-soil-187/soil-composition-712-11936/)

F

Fig:3. Different types of soil water process in soil

f. Element and Molecules In biological systems, we refer to important elements as "conservative". These elements are often nutrients. By "conservative" we mean that an organism can change only slightly the amount of these elements in their tissues if they are to remain in good health. It is easiest to think of these conservative elements in relation to other important elements in the organism. For example, in healthy algae the elements C, N, P, and Fe have the following ratio, called the Redfield ratio after the oceanographer who discovered it: C : N : P : Fe = 106 : 16 : 1 : 0.01 Once we know these ratios, we can compare them to the ratios that we measure in a sample of algae to determine if the algae are lacking in one of these limiting nutrients. The major organic substances e.g. proteins, carbohydrates, lipids, humic substances which are present either in the environment or in .

3.TOPOGRAPHY

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

Topography is the landscape shapes which is determined by the aspects of slopes and elevations. Topography gives a variety to the ecosystems. For example: The grassland topography is varied like hills, prairies, cliffs, low lying areas etc, which gives variability to life forms. The aspect of the direction of the land facing also varies as the land facing towards the south or the sun are hotter and drier than areas in the north, which are away from the sun. Slope of on areas is also important as water may run downhill and may soak in ground which makes it available for plants. The areas in the southern part with slopes will be much be hotter and drier than the northern areas with slopes. Altitude plays a role in vegetation’s zones. Slopes are important when considering the temperature of the soil surface on land with a northern slope, on level and on land with south facing slopes. In South Africa the south-eastern slopes face the rain-bearing winds and in some areas are covered with forest, whilst the slopes on the leeward side are in a rain-shadow and thorn scrub is often found growing on these slopes.

(Source: http://images.tutorvista.com/cms/images/123/topography-abiotic-factors.PNG)

4. Biotic and Abiotic Influences on Ecosystems

Ideal biotic and abiotic conditions allow a species to flourish. Other conditions may lead to a species’ decline or even extinction. Both abiotic and biotic factors determine where a species can live. A limiting factor is any factor that places an upper limit on the size of a population.

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

Limiting factors may be biotic, such as the availability of food, or abiotic, such as access to water. Human influences often act as limiting factors.

5. INFLUENCE OF ABIOTIC FACTORS

Abiotic factors such as temperature, light, and soil can influence a species’ ability to survive. Every species is able to survive within a range of each of these factors. This range is called the species’ tolerance range (Figure 1). Near the upper and lower limits of the tolerance range, individuals experience stress. This will reduce their health and their rate of growth and . Within a species’ tolerance range lies an optimal range, where conditions are ideal for a species. Populations try to keep themselves at optimal range.

Figure: 4. Species can be successful over a range of abiotic conditions. However, they will become stressed and will die out if conditions exceed their tolerance limits.

(Source:http://blogs.mtlakes.org/contemporarybio/files/2015/05/environmental- gradient.jpeg)

Some species have wide tolerance ranges, while others have much narrower ranges. Species with broad tolerance ranges will tend to be widely distributed and may easily spread across

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

ecosystems. For example, buckthorn, a small tree native to Europe, has become widespread over much of southern and central Ontario due to its broad tolerance range. Conversely, the showy lady’s-slipper orchid has a narrow tolerance range. It is found only in specific types of wetlands.

Figure: 5. (a) Cacti can withstand long periods of drought. If overwatered, they may die because their roots cannot survive consistently damp conditions. (b) Aquatic plants, such as water lilies, will perish quickly if the water level drops and the roots are exposed to air. (c) While both cacti and water lilies prefer exposure to full sun, bunchberries are adapted to shade.

6. Biomes

Fig: 6. Biomes determined by temperature and precipitation

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

A biome is known as a major regional or global biotic , such as a grassland or desert, characterized chiefly by the dominant forms of plant life and the prevailing climate. There are a wide variety of biomes, including tundra, tropical, , taiga or boreal forest, temperate forest, grassland, shrubland, savanna, and desert. Biomes are generally created by the interchange of temperature and precipitation in a given region on the earth. A biome is a large geographical area of distinctive plant and animal groups, which are adapted to that particular plant and animal groups, which are adapted to that particular environment. The climate and geography of a region determines what type of biome can exist in that region.

References 1. Barbour M.G, Burk J.H., and Pitts W.D. (1987). Terrestrial . The Benjamin/Commings Publishing Company Inc., Menlo Park. 634 pp. Second Edition 2. Muoghalu J.I. Environmental Monitoring – Vol. I (2003). Priority Parameters: Abiotic and Biotic Components. Encyclopedia of Life Support Systems (EOLSS) 3. Hogan, C. (2011). Abiotic factor. Retrieved from http://www.eoearth.org/view/article/149786

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

Self Assessment

Abbreviation Type of Question

MCQS Multiple Choice Question with single correct option

Correct Q1 The two important abiotic factors influencing Option vegetation distribution across the globe are

√ A Water and Sunlight

B Sunlight and Temperature

C Soil and Water D Soil and humidity

Correct Q2 Option One of these regions of light makes stomata open

A Red B Green √ C Blue D Ultra violet

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

Correct Q3 Option Pore space in soils is filled with

A Water

B Air

√ C Water and Air

D None of the above

Correct Q4 One of the important limiting element for the growth of Option Phytoplankton in oceans is

A Carbon

B Oxygen C Hydrogen

√ D Iron

Correct Q5 Important abiotic factor distinguishing Tropical and Option temperate deciduous forests is

A Rainfall

√ B Temperature

C Sunlight

D Soil

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

2. 2. Development Team

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National Coordinator

Subject Coordinator

Paper Coordinator

Content Writer/Author (CW) < N.S.R. Krishnayya >

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Language Editor (LE)

Habitat and Niche Ecology Types and overlapping of Niche, character displacement

TABLE OF CONTENTS (for textual content)

1 Introduction 2 Significance of Abiotic factors 3 Topography 4 Biotic and Abiotic influence on ecosystem 5 Influence of Abiotic factors 6 Biomes

Habitat and Niche Ecology Types and overlapping of Niche, character displacement