Ecology Ecology is the study of relationships between all organisms and their environment.
Biosphere The largest environment we focus on at one time is the biosphere. The biosphere consists of the thin layer of the earth’s surface where all organisms live.
The biosphere can be divided into various biomes which are the world's major communities, classified according to the predominant vegetation and characterized by adaptations of organisms to that particular environment. Biomes
Biomes Each biome supports certain varieties of organisms that are adapted to that environment such that they are getting their needs met and are successfully reproducing offspring.
Levels of Organization Ecosystem – a self-sustaining collection of organisms and their environment. Community – all organisms that live in a particular place Population – all members of a particular species that live in a particular place. Organism – one member of a particular species that lives in a particular place.
Habitat vs. Niche A habitat is the place in which an organism lives (this can be big like the desert or small like your backyard) ◦ for example – a frog lives near a pond-like habitat. A niche is the job or function of an organism within its ecosystem ◦ for example – the frog eats insects and is eaten by small animals and birds.
Components of an Ecosystem Nonliving components of an ecosystem are called abiotic factors. ◦ Examples: sunlight, rocks, slope of the land, temperature Living components of an ecosystem are called biotic factors. ◦ Examples: all living organisms – plants, animals, protists, bacteria, etc.
Describing Biotic Factors There are many ways to describe living things. Be sure you are familiar with the following terms: ◦ Producer ◦ Consumer ◦ Herbivore ◦ Carnivore ◦ Autotroph ◦ Heterotroph
Interactions of Biotic Factors One example of interactions of biotic factors is predation. An organism that consumes others is called a predator and the organism that it consumes is called its prey.
Interactions of Biotic Factors Another example of interactions of biotic factors is symbiosis which is a close, often long-term, interaction between two different biological species. This includes: ◦ Mutualism – both organisms benefit ◦ Commensalism – one benefits and the other derives neither benefit nor harm ◦ Parasitism – one benefits at the expense of the other.
Biodiversity refers to the number and variety of species in a given area and it is always changing! The number of known species on Earth, for instance, is about 1.6 million, most of which are insects. (This differs from the actual number of species on Earth, which may be closer to 13 million!) Biodiversity
The greater the biodiversity (both in different types of species and species numbers), the more sustainable the ecosystem. Biodiversity = Sustainability Diverse, thus Sustainable NOT Diverse, thus Difficult to Sustain
Each species has a role or niche to play in its ecosystem so when an ecosystem changes, hopefully there will be some organisms that possess adaptations or genetic variations (from sexual reproduction) enabling their species, or at least some of their species, to survive. Otherwise, the ecosystem may be in jeopardy! Biodiversity = Sustainability
Sexual vs. Asexual Reproduction Variety within a species is the result of sexual reproduction. Having species richness and species numbers is a good thing for sustainability. Asexual reproduction does NOT promote biodiversity.
Example of Biodiversity Mt. St. Helens’ Gopher. When Mt. St. Helens volcano erupted in 1980, it devastated an entire mountain of life; however, there was one mammal that survived. A small furry gopher species had tunneled underground and eventually found its way to the surface, after the lava cooled. Because this small gopher has adaptations such as fast burrowing claws, and did not require much food, it was able to survive. Hundreds of other gophers died in the devastation, but this particular type survived.
Danger of Limited Biodiversity The tundra is a very fragile environment. It can only support a limited number of consumers because its cold climate limits the growing and reproduction cycles of plants (the producers); therefore, there is very LIMITED biodiversity. Should a disaster arise (like melting of glaciers, etc.), it could damage this fragile ecosystem forever!