Ecology: Organism and Its Environment: Definition, Characteristics, Classification, Characteristics, Types

What Is Ecology?

Ecology is a branch of biology that deals with the assessment of the relations of living things with each other and with their surroundings, in other words, both biotic and abiotic components. Ecology is a vital subject in society because it helps to determine the interactions between living organisms and their surroundings, as well as the consequences that arise from human interference with the environment.

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It is the academic discipline concerned with nature’s balance and resilience as well as the efficient and environmentally friendly use of the earth’s natural resources. Ecologists want to understand how organisms interact with the world around them to learn about the factors affecting the mechanics of population, the community of organisms, and the processes of ecosystems to further enable the preservation of habitats.

Levels Of Organisation In Ecology

The organisational level is listed below:

Individual Organism

Definition and characteristics

A population is a set of individual organisms that are living and possess the properties of life, for instance, metabolism, growth, reproduction, and differentiated response to stimuli. Thus, the organism is the cell of the biological hierarchy acting independently to sustain its equilibriums and reproduce.

Adaptations and survival strategies

In this way, it is in the ability to maintain proper functioning and some characteristics necessary for the organisms’ existence in the environments they cope with. Such modifications may be morphological, mechanical, or chemical, enabling the organisms to optimise resources, escape from predators, and accommodate environmental stresses.

Example: Desert plants and water conservation

Some of the plant adaptations that are likely to be seen include those commonly found in plants growing in the desert, examples being the cactus and the succulents. It either has thick fleshy stems or leaves which hold water, a small number of leaves to reduce the rate of evaporation, have deep or spread roots to increase the area for water absorption. Some, for instance, the creosotes bush, has leaves that are covered by a waxy film to minimize their rate of transpiration. These changes allow them to live and reproduce in conditions that limit the availability of water in deserts.

Population

Definition and characteristics

Population is the total of humans animals plants or any such living organisms of similar species which are living in a specific geographical area and have a certain amount of intercourses among themselves. Population contains certain attributes like its magnitude, distribution as counted by geographical area per head, and age composition.

Population growth models

Exponential: This model portrays a population that continues to grow without bounds and in this case, the curve is of a ‘J’ shape. This is experienced when there are easily available resources and rationed constraints or factors.

Logistic: This model is characterised by a rapid increase in the population growth rate later slowing down as the population endogenously reaches the carrying capacity of the environment and results in an S-shaped curve.

Factors affecting population size

• Biotic Factors: These are contact with other living beings in aspects such as predator-prey relationships, competition for resources and diseases.

• Abiotic Factors: These are the living elements of the surroundings which are mainly the climatic conditions, availability of water and the space in the environment where the organism is to exist.

• Density-Dependent Factors: Features, in which density impacts the given population, like availability of food and disease.

• Density-Independent Factors: Mechanisms of regulation that also influence the population density but do it independently, such as the effects of natural disasters and seriously low/high temperatures.

Example: Population dynamics of rabbits in a forest

The major factors that affect the population of rabbits in a forest include food factors (plants), foxes/owls, disease, or conditions of the habitat. Such change in circumstances may lead to the rabbit population rapidly increasing in the short term, such as during situations characterized by food abundance and low predatory pressure. Nevertheless, as the population rises competition for food improves and predators may intensify which causes development to be logistic. Other factors that can lead to changes in population number are; environmental hazards; for Example; harsh winters that can lead to loss of lives.

Community

Definition and characteristics

A community is said to be a group of species living within the same geographical region. The extent of species and the relations between them are its main features.

Species interactions

• Competition: Closely related to conflict, the struggle for food and territory determines that within a given population there are winners and losers – all species fight for the chances to get the opportunities for existence in the given territory.

• Predation: Consumers eat producers, and predators consume consumers, which in the process affects their amounts.

• Mutualism: Each gets something out of the deal; courtesies make calls for speculum shaped like avian croppers while avian croppers are made to make calls shaped like contests.

• Commensalism: This species gains, while this species does not.

• Parasitism: One species is parasitic on the other- it gets a resource out of the other without giving anything in return.

Keystone species and their role

It becomes evident that the species in question influences the community structure disproportionately to biomass. This acts as proof that they still exist to ensure that ecosystems are diverse and stable.

Example: Coral reef community interactions

Based on the type of ecosystem, various interactions take place in coral reefs. In general, corals serve as supporter habitats of the fish and other organizational forms. Some of them are mutual successions like coral and alga, and parasitic relationships between fish and invertebrates. Coral and other reef organisms compete and hence the competition affects the community structure and function.

Ecosystem

Definition and characteristics

An ecosystem is a population with interactions between the organisms and their environment. They are the biotic or the living and the abiotic or the non-living factors.

Trophic Levels: These organisms are arranged in tiers according to their location in the food chain ranging from producers to primary, secondary, and tertiary consumers. Energy value gradually declines with the increase in the trophic level.

Energy Pyramid: Explains how energy moves from one trophic level to another with the producers forming the lowest level while the top consumers, or the predators, form the highest level.

Examples include:

• Pollination: Both the plants and bees have a benefit where plants are on the receiving end of pollination and the other extreme bees have a benefit in that they get to feed on nectar as well as get a chance to collect pollen.

• Nitrogen Fixation: It is agreed in mutualism because there are nutritive benefits for the leguminous plants and nitrogen-fixing bacteria whereby the bacteria benefit from organic nitrogen in reciprocation to the plants.

Nutrient cycling

• Carbon Cycle: This is the process that has to do more with the transfer of carbon within the organisms, the air, the seas, and the soil.

• Nitrogen Cycle: Closely associated with nitrogen fixation, plant nutrients, absorption of nitrogen compounds and their cycle.

Example: Tropical rainforest ecosystem

High levels of interactions are even experienced in tropical rainforests due to their recorded high levels of biodiversity. Photosynthesizers such as plants cover the producers who trap the light energy and, thus, enable the existence of herbivores, meat-eating animals, and detritivores. Vegetation rates of nutrient cycling and carbon storage are critical to global climate management.

Components Of The Environment

The components of the environment are listed below-

Biotic Factors

Definition and examples

These are living organisms such as plants, and animals and microorganisms such as bacteria and fungi that influence Biomes.

Trophic levels and energy transfer

However, entities inhabiting a given environment are categorized in trophic levels depending on their position in the food web through the feeding hierarchy.

Example: Decomposer role in nutrient cycling

They feed on dead organisms and recycle nutrients such as nitrogen and phosphorus back to the environment to be purchased by plants.

Abiotic Factors

Definition and examples

This encompasses any nonliving component of the organism and ecosystems for instance heat, water, light, and soil and among others.

Influence on organisms and communities

The following factors describe the habitats of various organisms in terms of their physical and their observable characteristics and locations.

Example: Desert adaptation to high temperatures

Some of the characteristics that desert plants and animals have are mechanisms of conserving water that do well in the hot environment.

Ecological Interactions

The ecological interactions are listed below-

Competition

Types

• Intraspecific: This can be defined as an affair whereby the members of the same species tend to struggle for optimal access to useful factors such as food, shelter or even females or males depending on the species.

• Interspecific: It refers to the act of struggle where two or more people fight for available resources perhaps due to their self-assertiveness of power or dominance rather than species.

Competitive exclusion principle

Says that when two species engage in a competitive relationship through a given limiting resource, they cannot persist simultaneously in the same ecological site. One species will drive the other to the local exclusion or they will partition resources and their ranges.

Example: Lions and hyenas competing for prey

For instance, lions and hyenas, two carnivorous animals are bitter enemies mainly because of the struggle for food in the savannahs where animals such as zebras and antelopes can easily be hunted Lions view these hyenas as potential rivals seeing that the Lions used to hunt for the same prey exclusively. Because of the similarity in diet and the instances of geographical overlapping, the relations involve frequent attacks and competition for the intake of leftovers.

Predation

Predator-prey dynamics

Predation is the process in which one species which is called the predator, pursues and kills another species known as the prey, to feed on it. As such, it possesses a contiguous impact on population density and dispersion and also community structure.

Adaptations

Carnivores have also developed strategies such that they include the ability to hide, sharp vision, and the ability to run very fast to hunt prey. Evidence that prey species may evolve defence responses includes; camouflage, warning colouration, and physical defence like; spines, shells etc.

Example: Arctic fox and lemming predator-prey relationship

Lemmings are reported to be the prime diet of the Arctic foxes, especially in the Arctic tundra region. The food distribution of lemmings, their population and scarcity define the cycles of Arctic foxes and in fact, show the predator-prey relations naturally.

Mutualism

Definition and examples

Interdependence interactions involve two species and this particular type of relationship benefits the two species in question, and the kind of relationship they have is called mutualism.

Examples include:

• Pollination: Both the plants and bees have a benefit where plants are on the receiving end of pollination and the other extreme bees have a benefit in that they get to feed on nectar as well as get a chance to collect pollen.

• Nitrogen Fixation: It is agreed in mutualism because there are nutritive benefits for the leguminous plants and nitrogen-fixing bacteria whereby the bacteria benefit from organic nitrogen in reciprocation to the plants.

Symbiotic relationships

The effects may be obligate where the two species require each other to survive and facultative where there is a need for benefit but it is not very crucial.

Example: Bee and flower mutualism

They provide honey for their food and at the same time they help in the process of pollination of flowers throughout the process of nectar and pollen collection. They are mutualistic organisms, which means that bees and flowers will only benefit from one another’s existence and subsequent production of offspring.

Commensalism And Parasitism

Definitions and examples

• Commensalism: The latter is for one species to benefit with the other being unimpaired in any way. For instance, barnacles cling themselves to the body of the whale to get close to nutrient-rich water currents without causing harm to the mammal.

Parasitism: One organism gains something by living off another organism, which could be clipped or killed. These include, for instance, ticks drawing blood from mammals or tapeworms taking nutrients from the host’s intestine.

Ecological Interactions