Ecology

Ecology

species ~ population ~ community ~ ecosystem ~ biosphere
Ecology define as , how organisms interact with one another and with their environment
Environment is the biotic (living organisms) and abiotic ( nonliving or physical factors-Heat, Light, Water, Nutrients).

Levels of ecological organization:

Organism/species/individual ecology: the study of individual organisms' behavior, physiology, morphology, etc. in response to environmental challenges.
Population ecology: the study of factors that affect and change the size and genetic composition of populations of organisms.
Community ecology: the study of how community structure and organization are changed by interactions among living organisms
Ecosystem ecology : Includes all of the living things (plants, animals and organisms) in a given area, interacting with each other, and also with their non-living environments (weather, earth, sun, soil, climate, atmosphere).
Biomes: are very large ecological areas on the earth’s surface, with fauna and flora (animals and plants) adapting to their environment. Biomes are often defined by abiotic factors such as climate, relief, geology, soils and vegetation.
Biosphere is the aggregation of all ecosystems (the sum of all of the organisms of the earth and their environment). The living zone of the planet (atmosphere, oceans, soils, and physical and biological cycles that affect them.

Individual ecology

Concerned with how individual organisms deal with their physical environment (abiotic environment) , Includes:
Behavioral adaptations
Physiological adaptations
Morphological adaptations
Ecology of Populations
Population is the group of individuals of the same species occupying a common geographical area.
Population Ecology is the study of how populations interact with their environment.
Habitat mean where a species normally lives.
Population size is the number of individuals making up its gene pool.
Population density is the number of individuals per unit of area or volume, e.g. persons/square mile.
Population distribution is the general pattern in which the population members are dispersed through its habitat, may be:
Clumped (most common).
Uniformly dispersed (rare).
Randomly dispersed.
Age structure defines the relative proportions of individuals of each age: Pre-reproductive, Reproductive, and Post-reproductive
Zero population growth designates a near balance of births and deaths.
Exponential growth: If birth and death rates of a population remain constant.


Ecology of Communities
Community Ecology is the study of how different species interact within communities
Habitat is the physical place where an organism lives, e.g. a pine forest or fresh water lake Some organisms, particularly migratory birds require more than one habitat
Niche is the functional role of an organism in a community, its job or position Each species has a potential niche - what they could do with no competitors or resource limitations but due to competition and/or resource limitations, most organisms occupy a realized niche, the part of the fundamental niche that a species actually occupies in nature
Species interactions
Neutral - two species that don't interact at all.
Commensalism - beneficial to one species but neutral to another, e.g. birds that nest in trees, epiphytes (plants that grow on other plants) such as tropical orchids
Mutualism - an interaction that is beneficial to both species, e.g. plants and their pollinators, plants and animals that disperse their seeds, certain fungi and plant roots
Parasitism - an interaction that benefits one species and is detrimental to another. Note that the host is generally not killed.
Predation - an interaction beneficial to one species and detrimental to another. In this case the prey is killed. Predators are those that kill and eat other animals. Although many organisms eat plants they usually don’t kill them because they are a constant supply of food. Prey are killed and eaten.

Ecosystems

Ecosystem is a community of organisms interacting within a particular physical environment or an ecosystem is a community plus its abiotic factors, e.g. soil, rain, temperatures, etc. Virtually all energy on earth comes from the sun, via photoautotrophs (primarily plants), and it is ultimately distributed throughout ecosystems.
All other organisms are consumers ( herbivores, carnivores, omnivores, Detritivores)

Trophic pyramid

First trophic level - contains the autotrophs which build energy containing molecules . Two types of autotrophs:
Photoautotrophs - plants and some Protista
Chemoautotrophs - bacteria
Second trophic level - contains the primary consumers which eat the primary producers including herbivores, decomposers and detritivores, e.g. insects, grasshoppers, deer and wildebeest
Third trophic level - contains the secondary consumers, primary carnivores which eat the herbivores, e.g. mice, spiders and many birds.
Fourth trophic level - contains the tertiary consumers, secondary carnivores who eat the primary carnivores, e.g. weasel, owl, sharks and wolves.

Biosphere ecology : Concerned with the global ecosystem, deals with:

All the life on the planet
The physical environment (atmosphere, oceans, land, etc.)
The biosphere consists of two primary parts:
Abiotic factors, which influence the distribution of life on Earth.
Biomes, the major types of ecosystems:
Terrestrial biomes:
Tropical forest: high temperature, heavy rainfall, tall trees, epiphytes and vines. Ex. Amazon Rainforest.
Savanna: high temperatures, heavy rainfall for a few months each year, grassland with scattered trees. Ex. savanna is in east Africa.
Desert: low rainfall, high temperature, leathery leaves, reduced leaf size. Ex. Mojave Desert.
Chaparral: Cool rainy winters with hot, dry summers, adapted for periodic fires. Ex. countries surrounding the Mediterranean Sea.
Temperate grassland: hot summers, cold winters. Ex. North American Prairie.
Temperature deciduous forest: warm summers, cold winters, deciduous trees. Ex. forests of the eastern U.S.
Coniferous forest (taiga): long, cold winters, short summers. Ex . forests across Canada
Tundra: long, cold winters, very short summers. Ex. Alaskan tundra.
Aquatic biomes:
Freshwater: Salt concentrations of less than 1 % (not “salty”), Cover 2.5 % of the Earth's surface.
Lakes
Rivers
Marine: Salt concentrations of 3 % (“salty”), Cover 75 % of the Earth's surface.
Estuaries
Coral reefs
Intertidal
Continental shelves
Oceanic pelagic
Abyssal zone
Abiotic biomes
Weather : is the short-term fluctuation of abiotic factors of the atmosphere at any given time (hours) like :
Cloud cover
Humidity
Precipitation
Temperature
Wind


Climate : is the accumulation of weather events over a long period of time from year to year and even century to century in a particular region (temperatures, humidity, wind, cloud cover, rainfall)
Climate is dependent upon several factors:
The earth's daily rotation
The earth's rotation around the sun
The distributions of continents and oceans

Nutrient cycles

Cycling maintains homeostasis (balance) in the environment.

Water cycle

Evaporation, transpiration, condensation, precipitation

The Nitrogen Cycle

Nitrogen is also key in the existence of ecosystems and food chains. Nitrogen forms about 78% of the air on earth. But plants do not use nitrogen directly from the air. This is because nitrogen itself is unreactive, and cannot be used by green plants to make protein. Nitrogen gas therefore, needs to be converted into nitrate compound in the soil by nitrogen-fixing bacteria in soil, root nodules or lightning.

The carbon cycle

The carbon cycle is very important to all ecosystems, and ultimately life on earth. The carbon cycle is critical to the food chain. Living tissue contains carbon, because they contain proteins, fats and carbohydrates. The carbon in these (living or dead) tissues is recycled in various processes. Human activities like heating homes and cars burning fuels (combustion) give off carbon into the atmosphere. During respiration, animals also introduce carbon into the atmosphere in the form of carbon dioxide. The Carbon dioxide in the atmosphere is absorbed by green plants (producers) to make food in photosynthesis. When animals feed on green plants, they pass on carbon compounds unto other animals in the upper levels of their food chains. Animals give off carbon dioxide into the atmosphere during respiration. Carbon dioxide is also given off when plants and animals die. This occurs when decomposers (bacteria and fungi) break down dead plants and animals (decomposition) and release the carbon compounds stored in them. Very often, energy trapped in the dead materials becomes fossil fuels which is used as combustion again at a later time.

Human ecology and health environment

It is a part of the overall ecology was first isolated in 1921 by American sociologists R.Parkom and E. Burgess. It is the branch of sociology that deals with interdisciplinary and trans disciplinary study of the relationship between humans and their natural, social, and built environments.
The term "healthy environment" is a huge one, encompassing many different meanings. To complicate the matter, environments that are healthy for one population aren’t always healthy for another. This makes it hard to agree upon what is needed in order to create a healthy environment, and to determine what has priority in this environment, such as humans, other animals, insects or plants. Usually, when people use this term, they refer to a human environment that would pose few risks for disease or health hazards.
Environment is the sum total of all surrounding living conditions. This would mean all physical things, all growing things, all structures, all objects, and all chemicals. There’s also a sharing aspect to this. People are not only surrounded by their environment but constantly contribute to it with every behavior, including breathing. A person cannot have a smoke, clean a rug, take out the trash, do the dishes, or drive a car without having some effect on the environment.
Obviously smoking improves nothing, threatening the physical health of the smoker and anyone who inhales the smoke. Cleaning the rug may be a bit more complicated. Will rug chemicals have cumulative effects on the health of an environment or will getting rid of dust mites be healthier for asthma sufferers in the home? There’s a growing market for a variety of products that are judged environmentally friendly, but many of these are still sold in plastic bottles, and the manufacture of these can give out chemicals that reduce environmental health.
The issue of a healthy environment goes deeper than this and it’s often pointed out that people forget the structures in which they live and which surround them. Houses, buildings and highways are taken for granted. In creating a healthy environment, though, these cannot simply be ignored while people try to change behavior. Years of research have pointed out problems with things like lead paint in homes or with asbestos, but there are other features in structures that may prove as problematic. For instance, where a structure is built can have a total effect on environment. Schools built near highways could be subject to much higher levels of pollution that contribute to poor human health and higher development of disease.
It’s common to think that simply urban environments are the problem. Studies of farm workers in many parts of the world show this not to be the case. Those who live in areas where pesticides are used frequently may have greater risk of respiratory diseases and development of cancer.
Large structures anywhere tend to affect environment adversely, and they may rely on consumption of fossil fuels, which create greater pollution. They may also, while sheltering people, decimate populations of animals that protect people. There is often much fuss when a protected species is found near a planned building site, and some feel this is overrated. Yet, when that protected species has some positive effect on the human population (the consumption of disease-bearing mosquitoes, for example), effects of removing it could be devastating and hurt people.
Studying the environment helps people understand which issues may be causing the greatest problems. Certainly, understanding that lead paint could harm kids, or that DDT was creating high risk of disease were important findings which have helped eliminate these environmental hazards in certain parts of the world.
Many people devote their lives to finding ways to create a healthy environment for all residents of the planet, and they may focus in different areas. They can examine human behaviors that risk things like lung cancer, diabetes, or perpetuation of abuse. Others study the effects of chemicals, gases, changes in climate, or changes to the total environment. Thus the answer of how to create a healthy environment is not likely to come from a single source, but instead it comes to humans in bits and pieces, like a puzzle. Each human then has the responsibility of deciding how to fit those pieces together to create a healthier world.