Biology Keypoints: Factors Affecting The Distribution Of Organisms; Ecology is the study of the interactions of living organisms with each other and their environment. One of the fundamental principles of ecology is the distribution of organisms in different ecosystems, which is influenced by various factors. These factors can be broadly classified into two categories: abiotic and biotic factors.

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Biology Keypoints: Factors Affecting The Distribution Of Organisms

I. Abiotic Factors:

Abiotic factors are non-living components of the ecosystem that influence the distribution of organisms. The major abiotic factors include:

1. Temperature: Temperature is one of the most important abiotic factors that affect the distribution of organisms. Different organisms have different temperature preferences, and they will be found in areas where the temperature falls within their tolerance range. For example, organisms that require warm temperatures will be found in tropical regions, while those that prefer cooler temperatures will be found in temperate or polar regions.
2. Light: Light is another important abiotic factor that influences the distribution of organisms. Plants require light for photosynthesis, and the intensity and duration of light determine the distribution of plant species in different ecosystems. Similarly, some animals have adaptations to low light conditions, while others require high light levels for their survival.
3. Water: Water is essential for the survival of all living organisms, and its availability affects the distribution of organisms. Organisms that require a lot of water will be found in areas with high rainfall or near water bodies, while those that can tolerate drought conditions will be found in arid regions.
4. Soil: Soil characteristics such as pH, nutrient availability, and texture can influence the distribution of organisms. For example, plants that require acidic soil will be found in areas with low pH, while those that require nutrient-rich soil will be found in areas with high nutrient availability.
5. Altitude: Altitude affects the distribution of organisms due to changes in temperature, pressure, and oxygen availability. Organisms that require low oxygen levels will be found at lower altitudes, while those that can tolerate high altitudes will be found in mountainous regions.

II. Biotic Factors:

Biotic factors are living components of the ecosystem that influence the distribution of organisms. The major biotic factors include:

1. Predation: Predators can limit the distribution of prey species by preying on them. Prey species will avoid areas with high predator populations, leading to a patchy distribution of organisms.
2. Competition: Competition for resources such as food, water, and habitat can limit the distribution of organisms. Organisms better adapted to compete for resources will have a wider distribution than those less adapted.
3. Symbiosis: Symbiotic relationships between organisms can influence the distribution of both species. For example, a plant species with a mutualistic relationship with a particular pollinator will only be found in areas where the pollinator is present.
4. Disease: Disease can limit the distribution of organisms by reducing their survival and reproductive success. Organisms that are more susceptible to disease will have a restricted distribution.

In conclusion, the distribution of organisms is influenced by both abiotic and biotic factors. Understanding these factors is crucial for predicting the distribution of organisms and managing ecosystems effectively.

A. i. Effects of Abiotic Factors on Organism Distribution:

1. Temperature: Temperature has a direct effect on the metabolism of organisms. The distribution of organisms is affected by their ability to maintain their optimal body temperature. Some organisms have the ability to regulate their body temperature, while others are ectothermic and rely on external sources of heat to regulate their body temperature. The distribution of organisms is influenced by their ability to tolerate and adapt to different temperature ranges.
2. Rainfall: Rainfall is essential for the survival of many organisms. The amount and timing of rainfall affect the distribution of organisms. Organisms that require high levels of water will be found in areas with high rainfall, while those that can tolerate drought conditions will be found in areas with low rainfall.
3. Relative humidity: Relative humidity refers to the amount of moisture in the air. It affects the ability of organisms to regulate their body temperature and water balance. Organisms that require high humidity will be found in areas with high relative humidity, while those that can tolerate low humidity will be found in arid regions.
4. Wind speed and direction: Wind affects the distribution of organisms by influencing the dispersal of seeds, spores, and other propagules. Organisms that have adaptations to wind dispersal will have a wider distribution than those that rely on other dispersal methods.
5. Altitude: Altitude affects the distribution of organisms due to changes in temperature, pressure, and oxygen availability. Organisms that require low oxygen levels will be found at lower altitudes, while those that can tolerate high altitudes will be found in mountainous regions.
6. Salinity: Salinity affects the distribution of aquatic organisms. Organisms that require freshwater will be found in areas with low salinity, while those that can tolerate high salinity will be found in marine environments or areas with high salt concentrations.
7. Turbidity: Turbidity refers to the cloudiness of water. It affects the ability of aquatic organisms to see and find food. Organisms that require clear water will be found in areas with low turbidity, while those that can tolerate cloudy water will be found in areas with high turbidity.
8. pH: pH affects the ability of organisms to maintain their internal chemical balance. Organisms that require acidic or alkaline conditions will be found in areas with low or high pH, respectively.
9. Edaphic (soil) conditions: Soil characteristics such as pH, nutrient availability, and texture can influence the distribution of organisms. For example, plants that require acidic soil will be found in areas with low pH, while those that require nutrient-rich soil will be found in areas with high nutrient availability.

ii. Measuring Abiotic Factors:

To measure abiotic factors, appropriate equipment must be used. Some examples of equipment that can be used to measure abiotic factors include:

1. Secchi disc: A disc used to measure water transparency and turbidity in aquatic environments.
2. Thermometer: A device used to measure temperature.
3. Rain gauge: A device used to measure rainfall.
4. Hygrometer: A device used to measure relative humidity.
5. Anemometer: A device used to measure wind speed.
6. Altimeter: A device used to measure altitude.
7. Conductivity meter: A device used to measure salinity.
8. pH meter: A device used to measure pH.

B. Effects of Plant and Animal Activities on Organism Distribution:

1. Habitat modification: Human activities such as deforestation, urbanization, and agricultural activities can alter the distribution of organisms by modifying their habitats. For example, the destruction of forests can lead to the loss of habitats for many forest-dwelling species.
2. Introduction of non-native species: Human activities such as the introduction of non-native species
3. into new environments can affect the distribution of native organisms. Non-native species can compete with native species for resources, prey on them, or introduce new diseases to which native species are not adapted.
4. Hunting and poaching: Overhunting or poaching of certain species can lead to their decline or extinction in certain areas. This can have ripple effects on the entire ecosystem, as other species may rely on the hunted species for food or other resources.
5. Pollution: Human activities such as industrial processes and waste disposal can introduce pollutants into the environment, which can affect the distribution of organisms. For example, pollution can lead to changes in water quality, affecting aquatic organisms’ distribution.
6. Restoration efforts: Human activities such as habitat restoration and conservation efforts can help restore habitats and protect endangered species. Restoration efforts can involve planting native species, removing invasive species, or restoring degraded habitats.
7. Overall, the activities of plants and animals, particularly humans, can have a significant impact on the distribution of organisms. Understanding these impacts is essential for conserving and managing ecosystems and biodiversity.