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Ecology is the study of the living world and the interactions among organisms and where they live; it is the study of interactions between living (animals, plants) and nonliving (earth, air, sun water) components in the environment. 2
An animal s environment is everything in its surroundings. The environment is made up of living (biotic) and non-living (abiotic) components. Biotic components are the living parts such as plants and animals. Abiotic components are non-living parts which include air, water, rocks and minerals, and sunlight. 3
Ecologist look at the interactions between plants and animals and their environments. An ecosystem is a community of living organisms and their environment working together and in a natural balance. To clarify the difference between an ecosystem and an environment: An ecosystem includes the interactions between the environment and the organisms that dwell within it. The term environment does not include these relationships. 4
A habitat is the specific environment in which any given organism or any given population lives. It is the address of the organism. A habitat contains everything that an animal needs to survive, including air, food, water, shelter, sun, space and other animals of its own kind so that it can reproduce. 5
Habitats can vary from aquatic (freshwater or marine) to terrestrial (forest, desert, tundra, grassland, etc.) Biomes are a specific kind of habitat and are defined by climate and dominate plants; the climate is mainly determined by the temperature and rainfall. Each biome consists of many ecosystems whose communities have adapted to the small differences in climate and the environment inside the biome. A biome supports a characteristic fauna, which are adapted to that particular environment. There are five principal biomes that you should be aware of: The aquatic biome includes freshwater habitats (ponds, lakes, streams, wetlands) as well as marine habitats (ocean, coastal waters, estuaries, coral reefs). The desert biome includes areas where rainfall is less than 10 inches/year. Desert habitat types include hot and dry, semiarid, coastal, and cold. The forest biome includes areas that are dominated by trees and other woody vegetation. The grassland biome includes habitats dominated by grasses (not trees and shrubs). Grasslands include tropical savannas and temperate grasslands (prairies). The tundra biome includes cold habitats with low biotic diversity and simple vegetation structure. The tundra and desert biomes occupy the most extreme environments, with little or no moisture and extremes of temperature. These two biomes have the fewest numbers of species due to the stringent environmental conditions. Factors that determine whether an organism can live in a specific biome include climate (temperature, rainfall, light, and altitude), available food sources, available plant life (provides food and shelter), other species it interacts with and predators (presence or absence of). We 6
The niche refers to the role or job a species plays in its environment; it describes the way of life of that species and how they use resources and respond to their competitors. Each species is thought to have a separate, unique niche; no two species can occupy exactly the same niche. Species may share the same habitat, but their roles (or jobs) are different. If two species are competing for the same niche, the one that is best adapted to the range of conditions present will survive by having the higher birth rate and/or lower death rate. In natural situations, species that might compete have evolved ways to reduce competition and divide resources. In describing a niche, you want to ask where it lives, when it is active and what it eats. For example, the niche of a two-toed sloth would be a herbivorous, nocturnal species of the understory and canopy of rainforest trees. One of the natural ways species avoid competition is to hunt or forage for food at different times of the day. Those who forage at night are nocturnal. Those who hunt during the day are diurnal and those who hunt during the twilight (either dawn or dusk) hours are considered crepuscular. 7
Photosynthesis is a process used by plants to convert light energy from the sun into chemical energy that can be later released to fuel the plant s activities. The sun s energy is captured by chlorophyll in the plant s leaves. This energy fuels a chemical reaction between with carbon dioxide and water to produce glucose, the main fuel that powers life. Oxygen is a by-product of this reaction and is released into the air. The oxygen released during photosynthesis can be used during respiration by both plants and animals. Plants must breathe just as animals do; they take in oxygen and give off carbon dioxide. Their photosynthetic activity is however greater than their respiratory activity resulting in an increase in atmospheric oxygen levels. Through photosynthesis, plants make their own nutrients; they are producers. Anything that eats a plant is considered a consumer. 8
Interdependence is the idea that everything in nature is connected to everything else; what happens to one plant or animal also affects other plants and animals. An example of interdependence is a food chain. A simple food chain is based on who eats who; plants are the producer, and make their own energy by photosynthesis. All other living things are consumers; they get energy from the food they eat; they survive by eating a producer, or another consumer that ate a producer, gaining the chemical energy from the original process of the producer. A primary consumer or herbivore, eats plants whereas a secondary consumer eats a primary consumer and is a carnivore. An omnivore may eat both meat and vegetation. Decomposers break down dead plant and animal matter at any level and help recycle nutrients back into the soil so that they can be used again. In this way nutrients are cycled through the food chain. Nutrients are inorganic compounds such as phosphorous which is in your teeth, bones, and cellular membranes, nitrogen which is part of your amino acids, the building blocks of protein and the iron in your blood. A food web is several food chains put together. A food web shows the more complex relationships present in ecosystems. 9
Species have special characteristics which allow them to be successful in their habitat, these are termed adaptations. There are both physical and behavioral adaptations. Camouflage is an excellent example of a external physical characteristic. Coloring helps an animal blend into its environment and avoid detection. A dry, savanna animal will be tan or brown, a wet, rainforest animal will be glossy green, and so forth. Coloring may also have a physiological benefit; lighter colors reflect more of the sun s radiation than a darker one and thus helps them to remain cool. A behavioral adaptation would be a kangaroo seeking shade and resting in the hottest part of the day. 10
Carl Linnaeus in the 18th Century put forth a classification system giving unique names to every plant and animal both extinct and extant. Linnaeus proposed a binomial nomenclature which turned out to be an important turning point in how we give formal names to organisms. By using a two part, or binomial name, unique to each organism, confusion could be eliminated. The scientific names that Linnaeus proposed allowed scientists from across the world to discuss the same animal (or plant) that might be called by different common names in each region they existed. Kingdom as the broadest category. Animalia and Plantae are two Kingdoms. These Kingdoms are subdivided into smaller and smaller groups: Phylum (traditionally in botany the term Division is used in plant and fungi classification and is equivalent to the rank of phylum) Class, Family, Genus, and finally Species. [A simple mnemonic for remembering is Kings Play Chess On Fine Gold Sets will help you remember the order.] A species is defined as a group of organisms having common characteristics and are capable of mating with one another to produce fertile offspring. You may have subspecies that have differences but are still capable of interbreeding. A species scientific name combines its genus and species. The genus is always capitalized, and underlined or in italics. Humans scientific name is Homo sapiens. You may also see an abbreviation of this name as H. sapiens where the genus is only represented by the first letter. The species is never capitalized, but is underlined or in italics. Species are similar organisms that are able to interbreed in the wild; they are a group of organisms that can potentially breed with one another. 11
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Definition: Ecology: the study of the relationships between living organisms and their physical environment. Environment: An animal s environment is everything in its surroundings. The environment is made up of living (biotic) and non-living (abiotic) components. Ecosystem: a community of living (biotic) and non-living (abiotic) things that work together. Niche: The ecological role and space that an organism fills in an ecosystem. An animal s niche includes its usage of resources, its unique way of life and its relationship to other biotic and abiotic factors. An animal s job. Habitat: the specific environment in which any given organism or any given population lives. It is the address of the organism. A habitat contains everything that an animal needs to survive, including air, food, water, shelter, sun, space and other animals. Biome: the specific environment in which any given organism or any given population lives; biomes are defined by their climate and dominant vegetation. Nocturnal: of or relating to activity occurring during the night hours. Diurnal: of or relating to activity occurring during the daylight hours. Crepuscular: of or relating to activity occurring during the twilight hours, of dawn or dusk. Photosynthesis: process used by plants and other organisms to convert light energy, normally from the sun, into chemical energy that can be later released to fuel the organisms' activities. Food chain: the linear sequence of who eats whom in an ecosystem to obtain nutrition. Food web: depicts feeding connections in an ecological community. Producer: organisms in an ecosystem that produce biomass from inorganic compounds; they are plants. Consumer: organisms of an food chain that receive energy by consuming other organisms. Decomposer: organisms that break down dead or decaying organisms. Herbivore: an animal that gets its energy from eating plants, and only plants. Carnivore: an animal that gets its energy from eating other animals. Omnivore: an animal that eats both plants and animals. Binomial nomenclature: a formal system of naming species by giving each a name composed of two parts; one indicating the genus and one indicating the species. Each binomial name is unique to a specific species. Species: an individual belonging to a group of organisms having common characteristics and are capable of mating with one another to produce fertile offspring. 13