Ecosystems are made up of living things (biotic factors) and non-living things (abiotic factors), which are connected to each other in complex interrelationships.
Nutrients are cycled within an ecosystem. producers consumers decomposers producers
Make Yourself a Venn Diagram with the following Terms
The biospheres is the global sum of all ecosystems. It can also be called the zone of life on Earth. From the broadest biophysiological point of view, the biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, hydrosphere, and atmosphere.
Biotic and Abiotic Factors in Ecosystems
An ecosystem is made up of a community of organisms and the non-living environment.
The living components of the ecosystem are called biotic factors , which include plants, fish, invertebrates, and single-celled organisms.
The non-living components, or abiotic factors , include the physical and chemical components in the environment—temperature, wind, water, sunlight, and oxygen.
Biotic and abiotic factors influence each other in an always changing balance called dynamic equilibrium .
2.1 VOCABULARY ecology organism habitat population community ecosystem biosphere biotic factor abiotic factor dynamic equilibrium limiting factor
Limiting factors are environmental influences that constrain the productivity of organisms, populations, or communities and thereby prevent them from achieving their full biological potential which could be realized under optimal conditions. Limiting factors can be single elements or a group of related factors.
Plants harness energy from the sun through photosynthesis
They are the base of every food chain
Source of food for all other animals
Herbivore: eats only plants
Ex. Cows, horses
Carnivore: eats only meat
Ex. Polar bear
Onmivore: eats plants and animals
Ex. Humans, grizzly bears
Scavenger: carnivore that feeds on bodies of dead organisms
Decomposers break down wastes and dead organisms and return the raw materials to the environment
Ex. Bacteria, fungi
Trophic Levels and Energy Flow
Nutrients are cycled back into the ecosystem, but energy only moves in one direction through the community from producers to herbivores to carnivores.
Trophic level describes the position of the organism in relation to the order of nutrient and energy transfers in an ecosystem. Organisms that eat the same type of food belong to the same trophic level.
Food chains show a single pathway taken by nutrients and energy through the trophic levels.
In reality, ecosystems have more complex food webs , showing the different cross-linked food chains.
2.4 VOCABULARY trophic level food chain food web
Interactions in Ecosystems
Energy flows through ecosystems.
This energy comes from an outside source: the Sun.
Ecologists represent food and energy flows in food chain, food web, and pyramid diagrams.
Interactions in Ecosystems Activity Using the food web on the right, predict what might happen if a disease killed all the krill in the ecosystem. Which species would be affected, and how? Try drawing a new food web. 2 CHAPTER
Symbiosis refers to any close relationship between two different species. There are three types of symbiotic relationships:
Mutualism is a relationship in which both species obtain some benefit from the interaction.
Commensalism is an interaction in which one organism benefits while the other is unaffected.
Parasitism occurs when one organism (the parasite ) lives and feeds on, or in, the body of another organism (the host ).
Commensalism usually occurs between a species that is either vulnerable to predation or with an inefficient means of locomotion, and another species with a relatively effective system of defence.
Ex. Of Commensalism
The Anemone crab on its host sea anemone.
One especially amazing example of commensalism occurs between the Pearlfish and a particular species of sea cucumber. The Pearlfish spends the day inside the alimentary tract (‘intestines’) of the sea cucumber, and at night emerges from its anus to feed on small crustaceans! In this manner it gets a safe place to live; and while not appearing to gain any benefit from the relationship, the cucumber is not harmed.
In a parasitic relationship, the host species is always exploited to some degree, although often in such a way that its health is impaired only slowly. This allows the parasite to exploit its host over a longer period. Many parasites only spend a portion of their lives in the relationship, either to reproduce, or during an initial growth stage.
Parasites can be divided into two basic categories, Ectoparasites and Endoparasites , the former referring to external parasites, and the latter internal parasites.
Mutualism is one of the most interesting forms of symbiosis, as it is a benefit to both species involved.
the Boxer crab, carries a pair of small anemones in it s claws . When approached by a predator it waves these around presenting the stinging tentacles so as to deter the marauder. The anemones benefit from the small particles of food dropped by the crab during feeding.
Mimicry is a form of symbiosis where a species may mimic the colours, patterns, or even behaviour of another species for one of two reasons. Either to be able to get closer to unsuspecting prey or in the case of a harmless species; to gain protection by imitating a predator or poisonous species.
One of the most interesting mimic species is the Mimic octopus. It takes on the form of a variety of different animals by bunching up or elongating its arms to mimic anything from a stingray to a Lionfish or even a sea-snake. It could be that this species employs mimicry both as a means of defence and predation
A particular type of mutualistic interrelationship that many divers will have encountered is ‘Cleaning symbiosis ’, The fish being cleaned are often termed ‘client fish’ and the sites they go to to be cleaned are known as ‘Cleaning stations’ ... in tropical waters these areas of the reef are quite clearly defined by the numbers of stationary fish and their attendant cleaner organisms.
Ecologists use three different types of ecological pyramids to illustrate ecosystems:
Pyramid of energy : represents how much energy is available in each trophic level
Pyramid of numbers : represents the actual number of organisms present in each trophic level
Pyramid of biomass : represents the total mass of living things in each trophic level
2.5 VOCABULARY ecological pyramid food pyramid pyramid of energy pyramid of numbers pyramid of biomass
2 nd Law of Thermodynamics: energy is not transferred from one object/organism to the next with 100% efficiency
Some of the energy is lost to the environment
Energy Pyramid shows the amounts of energy that moves from one level to the next
Sample Energy Pyramid
Only about 10% of energy is transferred from one level to the next
The other 90% is used by the organism to carry out its life processes or it is lost to the environment