SKILLS:
- classifying species as autotrophs, consumers, detritivores or saprotrophs from a knowledge of their mode of nutrition
- testing for association between two species using the chi-squared test with data obtained by quadrate sampling
- recognizing and interpreting statistical significance
- setting up sealed mesocosms to try to establish sustainability.
SPECIES
Species are groups of organisms that can potentially interbreed to produce fertile offspring.
Birds of paradise inhabit Papua New Guinea and other Australasian islands. There are forty-one different types of bird of paradise. Each of these usually only reproduces with other of its type and hybrids between the different types are rarely produced. For this reason each of the forty-one types of bird of paradise remains distinct, with characters that are different to those other types. Biologists call types of organisms such as these species.
When two members of the same species mate and produce offspring, they are interbreeding. Occasionally members of different species breed together, and this is called cross-breeding.
The reproductive separation between species is the reason for each species being a recognizable type of organism with characters that distinguish it from even the most closely related other species.
POPULATIONS
Members of a species may be reproductively isolated in separate populations.
A population is a group of organisms of the same species who live in the same area at the same time. If tow populations live in different areas they are unlikely to interbreed with each other. If two populations of a species never interbreed then they may gradually develop differences in their characters.
AUTOTROPHIC AND HETEROTROPHIC NUTRITION
Species have either an autotrophic or heterotrophic method of nutrition ( a few have both methods)
All organisms need a supply of organic nutrients, such as glucose and amino acid. They are needed for growth and reproduction. Methods of obtaining these carbon compounds can be divided into two types:
- some organisms make their own carbon compounds from carbon dioxide and other simple substances- they are autotrophic, which means self-feeding.
- some organisms obtain their carbon compounds from other organisms - they are heterotrophic, which means feeding on others.
CONSUMERS
Consumers are heterotrophs that feed on living organisms by ingestion.
Heterotrophs are divided into groups by ecologists according to the source of organic molecules that they use and the method of taking them in. One group of heterotrophs is called consumers.
Consumers feed off other organisms. These other organisms are either still alive or have only been dead for a relatively short time.
Consumers ingest their food. This means that they take in undigested material from other organisms. They digest it and absorb the products of digestion.
Consumers are sometimes divided up into trophic groups according to what other organisms they consume. Primary consumers feed on autotrophs; secondary consumers feed on primary consumers and so on.
DETRITIVORES
They are heterotrophs that obtain organic nutrients from detritus by internal digestion.
Organisms discard large quantities of organic matter, for example:
- dead leaves and other parts of plants
- feathers, hairs and other dead parts of animal bodies
- feces from animals
This dead organic matter rarely accumulates in ecosystems and instead is used as a source of nutrition by two groups of heterotroph-detritivores and saprotrophs.
Detritivores ingest dead organic matter and then digest it internally and absorb the products of digestion.
SAPROTROPHS
Saprotrophs are heterotrophs that obtain organic nutrients from dead organic matter by external digestion.
Saprotrophs secrete digestive enzymes into the dead organic matter and digest it externally. They then absorb the products of digestion. Many types of bacteria and fungi are saprotrophic. They are also known as decomposers because they break down carbon compounds in dead organic matter
COMMUNITIES
A community is formed by populations of different species living together and interacting with each other.
An important part of ecology is research inter relationships between organisms. These relationships are complex and varied. In some cases the interaction between two species is of benefit to one species and harms the other, like a parasite and its host. In other cases both species benefit, as when a hummingbird feeds on nectar from a flower and helps the plant by pollinating it.
ECOSYSTEMS
A community forms an ecosystem by its interactions with the abiotic environment
A community is composed of all organisms living in an area. These organisms could not live in isolation- they depend on there non-living surroundings of air, water, soil or rock. Ecologists refer to these surroundings as the abiotic environment.
In some cases the abiotic environment exerts a powerful influence over the organisms, for example, the wave action on a rocky shore creates a very specialized habitat and only organisms adapted to it can survive. But, there are also many cases where living organisms influence the abiotic environment, sand dunes are an example of this; they develop along the coasts where sand is blown up the shore and specialized plants grow in those loose wind-blown sand.
INORGANIC NUTRIENT
Autotrophs and heterotrophs obtain inorganic nutrients from the abiotic environment.
Living organisms need a supply of chemical elements:
- Carbon, hydrogen and oxygen are needed to make carbohydrates, lipid and other carbon compounds on which life is based.
- Nitrogen and phosphorus are also needed to make many of these compounds
- Approximately fifteen other elements are needed by living organisms. Some of them are used in minute traces only, but they are nonetheless essential.
Autotrophs obtain all of the elements that they need as inorganic nutrients from the abiotic environment. Heterotrophs on the other hand obtain these two elements and several others as part of the carbon compounds in their food. They do however obtain other elements as inorganic nutrients from the abiotic environment, including sodium, potassium and calcium
NUTRIENT CYCLES
The supply of inorganic nutrients is maintained by nutrient cycling.
There are limited supplies on Earth of chemical elements. Although living organisms have been using the supplies for three billion years, they have not run out. This is because chemical elements can be endlessly recycled. Organisms absorb the elements that they require as inorganic nutrients from the abiotic environment, use them and then return them to the environment with the atoms unchanged.
SUSTAINABILITY OF ECOSYSTEMS
Ecosystems have the potential to be sustainable over long periods of time.
The concept of sustainability has risen to prominence recently because it is clear that some current human uses of resources are unsustainable. Something is sustainable if it can continue indefinitely.
Natural ecosystems can teach us how to live in a sustainable way, so that our children and grandchildren can live as we do. There are three requirements for sustainability in ecosystems:
- nutrient availability
- detoxification of waste products
- energy availability
Nutrients can be recycled indefinitely and if this is done there should not a be a lack of the chemical elements on which life is based. The waste products of one species are usually exploited as a resource by another species.
Energy cannot be recycled, so sustainability depends on continued energy supply to ecosystems. Most energy is supplied to ecosystems as light from the sun.
- classifying species as autotrophs, consumers, detritivores or saprotrophs from a knowledge of their mode of nutrition
- testing for association between two species using the chi-squared test with data obtained by quadrate sampling
- recognizing and interpreting statistical significance
- setting up sealed mesocosms to try to establish sustainability.
SPECIES
Species are groups of organisms that can potentially interbreed to produce fertile offspring.
Birds of paradise inhabit Papua New Guinea and other Australasian islands. There are forty-one different types of bird of paradise. Each of these usually only reproduces with other of its type and hybrids between the different types are rarely produced. For this reason each of the forty-one types of bird of paradise remains distinct, with characters that are different to those other types. Biologists call types of organisms such as these species.
When two members of the same species mate and produce offspring, they are interbreeding. Occasionally members of different species breed together, and this is called cross-breeding.
The reproductive separation between species is the reason for each species being a recognizable type of organism with characters that distinguish it from even the most closely related other species.
POPULATIONS
Members of a species may be reproductively isolated in separate populations.
A population is a group of organisms of the same species who live in the same area at the same time. If tow populations live in different areas they are unlikely to interbreed with each other. If two populations of a species never interbreed then they may gradually develop differences in their characters.
AUTOTROPHIC AND HETEROTROPHIC NUTRITION
Species have either an autotrophic or heterotrophic method of nutrition ( a few have both methods)
All organisms need a supply of organic nutrients, such as glucose and amino acid. They are needed for growth and reproduction. Methods of obtaining these carbon compounds can be divided into two types:
- some organisms make their own carbon compounds from carbon dioxide and other simple substances- they are autotrophic, which means self-feeding.
- some organisms obtain their carbon compounds from other organisms - they are heterotrophic, which means feeding on others.
CONSUMERS
Consumers are heterotrophs that feed on living organisms by ingestion.
Heterotrophs are divided into groups by ecologists according to the source of organic molecules that they use and the method of taking them in. One group of heterotrophs is called consumers.
Consumers feed off other organisms. These other organisms are either still alive or have only been dead for a relatively short time.
Consumers ingest their food. This means that they take in undigested material from other organisms. They digest it and absorb the products of digestion.
Consumers are sometimes divided up into trophic groups according to what other organisms they consume. Primary consumers feed on autotrophs; secondary consumers feed on primary consumers and so on.
DETRITIVORES
They are heterotrophs that obtain organic nutrients from detritus by internal digestion.
Organisms discard large quantities of organic matter, for example:
- dead leaves and other parts of plants
- feathers, hairs and other dead parts of animal bodies
- feces from animals
This dead organic matter rarely accumulates in ecosystems and instead is used as a source of nutrition by two groups of heterotroph-detritivores and saprotrophs.
Detritivores ingest dead organic matter and then digest it internally and absorb the products of digestion.
SAPROTROPHS
Saprotrophs are heterotrophs that obtain organic nutrients from dead organic matter by external digestion.
Saprotrophs secrete digestive enzymes into the dead organic matter and digest it externally. They then absorb the products of digestion. Many types of bacteria and fungi are saprotrophic. They are also known as decomposers because they break down carbon compounds in dead organic matter
COMMUNITIES
A community is formed by populations of different species living together and interacting with each other.
An important part of ecology is research inter relationships between organisms. These relationships are complex and varied. In some cases the interaction between two species is of benefit to one species and harms the other, like a parasite and its host. In other cases both species benefit, as when a hummingbird feeds on nectar from a flower and helps the plant by pollinating it.
ECOSYSTEMS
A community forms an ecosystem by its interactions with the abiotic environment
A community is composed of all organisms living in an area. These organisms could not live in isolation- they depend on there non-living surroundings of air, water, soil or rock. Ecologists refer to these surroundings as the abiotic environment.
In some cases the abiotic environment exerts a powerful influence over the organisms, for example, the wave action on a rocky shore creates a very specialized habitat and only organisms adapted to it can survive. But, there are also many cases where living organisms influence the abiotic environment, sand dunes are an example of this; they develop along the coasts where sand is blown up the shore and specialized plants grow in those loose wind-blown sand.
INORGANIC NUTRIENT
Autotrophs and heterotrophs obtain inorganic nutrients from the abiotic environment.
Living organisms need a supply of chemical elements:
- Carbon, hydrogen and oxygen are needed to make carbohydrates, lipid and other carbon compounds on which life is based.
- Nitrogen and phosphorus are also needed to make many of these compounds
- Approximately fifteen other elements are needed by living organisms. Some of them are used in minute traces only, but they are nonetheless essential.
Autotrophs obtain all of the elements that they need as inorganic nutrients from the abiotic environment. Heterotrophs on the other hand obtain these two elements and several others as part of the carbon compounds in their food. They do however obtain other elements as inorganic nutrients from the abiotic environment, including sodium, potassium and calcium
NUTRIENT CYCLES
The supply of inorganic nutrients is maintained by nutrient cycling.
There are limited supplies on Earth of chemical elements. Although living organisms have been using the supplies for three billion years, they have not run out. This is because chemical elements can be endlessly recycled. Organisms absorb the elements that they require as inorganic nutrients from the abiotic environment, use them and then return them to the environment with the atoms unchanged.
SUSTAINABILITY OF ECOSYSTEMS
Ecosystems have the potential to be sustainable over long periods of time.
The concept of sustainability has risen to prominence recently because it is clear that some current human uses of resources are unsustainable. Something is sustainable if it can continue indefinitely.
Natural ecosystems can teach us how to live in a sustainable way, so that our children and grandchildren can live as we do. There are three requirements for sustainability in ecosystems:
- nutrient availability
- detoxification of waste products
- energy availability
Nutrients can be recycled indefinitely and if this is done there should not a be a lack of the chemical elements on which life is based. The waste products of one species are usually exploited as a resource by another species.
Energy cannot be recycled, so sustainability depends on continued energy supply to ecosystems. Most energy is supplied to ecosystems as light from the sun.
FACTORS WHICH AFFECT THE DISTRIBUTION OF ANIMALS
•Temperature: all animals are adapted to survive in narrow range of temperatures
–E.g. Coral reefs, ectotherms (cold-blooded) rely on external temperatures for metabolism
•Water: animals vary in amount of water that they need
–As habitat, drinking, heating/cooling, a place to lay eggs. etc.
•Breeding sites: some animals require specific type of site.
–E.g. mosquitoes need water for egg laying
•Food supply: some species adapted to feed on specific foods
–E.g. pandas and bamboos
•Territory: some species establish and defend certain territories
–E.g. Coyotes mark territories with scent
FACTORS WHICH AFFECT THE DISTRIBUTION OF PLANTS
•Temperature: all animals are adapted to survive in narrow range of temperatures
–E.g. Coral reefs, ectotherms (cold-blooded) rely on external temperatures for metabolism
•Water: animals vary in amount of water that they need
–As habitat, drinking, heating/cooling, a place to lay eggs. etc.
•Breeding sites: some animals require specific type of site.
–E.g. mosquitoes need water for egg laying
•Food supply: some species adapted to feed on specific foods
–E.g. pandas and bamboos
•Territory: some species establish and defend certain territories
–E.g. Coyotes mark territories with scent
FACTORS WHICH AFFECT THE DISTRIBUTION OF PLANTS