SPECIES, COMMUNITIES AND ECOSYSTEMS
4.1.1 Species are groups of organisms that can potentially interbreed to produce fertile offspring.
4.1.2 Members of a species may be reproductively isolated in separate populations.
4.1.3 Species have either an autotrophic or heterotrophic method of nutrition (a few species have both methods).
4.1.4 Consumers are heterotrophs that feed on living organisms by ingestion.
4.1.5 Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion.
4.1.6 Saprotrophs are heterotrophs that obtain organic nutrients from dead organisms by external digestion.
4.1.7 A community is formed by populations of different species living together and interacting with each other.
4.1.8 A community forms an ecosystem by its interactions with the abiotic environment.
4.1.9 Autotrophs obtain inorganic nutrients from the abiotic environment.
4.1.10 The supply of inorganic nutrients is maintained by nutrient cycling.
4.1.11 Ecosystems have the potential to be sustainable over long periods of time.
Source: Chapter C and Chapter 4 ecology notes. pdf and Biology: Oxford IB Diploma Programme book.
4.1.2 Members of a species may be reproductively isolated in separate populations.
4.1.3 Species have either an autotrophic or heterotrophic method of nutrition (a few species have both methods).
4.1.4 Consumers are heterotrophs that feed on living organisms by ingestion.
4.1.5 Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion.
4.1.6 Saprotrophs are heterotrophs that obtain organic nutrients from dead organisms by external digestion.
4.1.7 A community is formed by populations of different species living together and interacting with each other.
4.1.8 A community forms an ecosystem by its interactions with the abiotic environment.
4.1.9 Autotrophs obtain inorganic nutrients from the abiotic environment.
4.1.10 The supply of inorganic nutrients is maintained by nutrient cycling.
4.1.11 Ecosystems have the potential to be sustainable over long periods of time.
Source: Chapter C and Chapter 4 ecology notes. pdf and Biology: Oxford IB Diploma Programme book.
ecology
The study of relationships between living organisms and between organisms and their environment.
It is the scientific analysis and study of interactions among organisms and their environment, such as the interactions organisms have with each other and with their abiotic environment.
It is the scientific analysis and study of interactions among organisms and their environment, such as the interactions organisms have with each other and with their abiotic environment.
Ecosystem
A community forms an ecosystem by its interactions with the abiotic environment (non-living).
A community is composed of all organism living in an area. These organism could not live in isolations, they depend on their non-living surrounding of air, water, soil and rock. Ecologist refer to those surrounding as the abiotic environment.
Biotic: living things such as plants, animals, fungi, and bacteria
Abiotic: nonliving things such as moisture, temperature, wind, sunlight and soil.
A community is composed of all organism living in an area. These organism could not live in isolations, they depend on their non-living surrounding of air, water, soil and rock. Ecologist refer to those surrounding as the abiotic environment.
Biotic: living things such as plants, animals, fungi, and bacteria
Abiotic: nonliving things such as moisture, temperature, wind, sunlight and soil.
species
Groups of organisms that can potentially interbreed to produce fertile offspring.
Birds of paradise inhabit Papua New Guinea, there are 41 different types of bird of paradise, each of these usually only reproduces with others of its type and hybrids between the different types are rare;y produced. For this reason eahc of the 41 types of bird remains distinct, with characters that are different to those of other types. Biologist call type of organisms such as these SPECIES.
When 2 members of the same specie mate and produce offspring they are interbreeding.
When members of different types breed together its called cross-breeding
Birds of paradise inhabit Papua New Guinea, there are 41 different types of bird of paradise, each of these usually only reproduces with others of its type and hybrids between the different types are rare;y produced. For this reason eahc of the 41 types of bird remains distinct, with characters that are different to those of other types. Biologist call type of organisms such as these SPECIES.
When 2 members of the same specie mate and produce offspring they are interbreeding.
When members of different types breed together its called cross-breeding
populations
Members of a specie may be reproductively isolated in separate populations.
A population is a group of organisms of the same species living in the same area at the same time
If two populations live in different areas they are unlikely to interbreed with each other.This does not mean that they are different species, if they potentially could interbreed they are still members of the same species.
A population is a group of organisms of the same species living in the same area at the same time
If two populations live in different areas they are unlikely to interbreed with each other.This does not mean that they are different species, if they potentially could interbreed they are still members of the same species.
community
A group of populations living and interacting with each other in an area.
Is the relationship between organisms, these relations are complex and varied. In some cases the interaction between two species is of benefit to one species and harm to the other. In some cases both species benefit, as when a hummingbird feeds on nectar from a flower and helps the plant by pollinating it.
All species are dependent on relationships with other species for their long-term survival. For this reason a population of one specie can never live in isolation. Groups of population live together in an area and interacting with each other is known in ecology as a community. Typical communities consist of hundreds or even thousands of species living together in an area.
Is the relationship between organisms, these relations are complex and varied. In some cases the interaction between two species is of benefit to one species and harm to the other. In some cases both species benefit, as when a hummingbird feeds on nectar from a flower and helps the plant by pollinating it.
All species are dependent on relationships with other species for their long-term survival. For this reason a population of one specie can never live in isolation. Groups of population live together in an area and interacting with each other is known in ecology as a community. Typical communities consist of hundreds or even thousands of species living together in an area.
autotrophic and heterotrophic nutrition
Species have either an autotrophic or heterotrophic method of nutrition:
Autotrophy: self-feeding
Organism which produce their own food from organic molecules
Producers:
-Photo autotrophy: photosynthesis, green plants, phytoplankton and algae
-Chemoautotrophy: chemosynthesis, deep-sea, chemosynthetic bacteria.
Heterotrophy: other source of feeding
-Decomposers: derive energy from non living organic matter
*Detritivores: ingest non-living organic matter (leaves, hairs, dead animals, feces of other animals) .Obtain organic nutrients from detritus by internal digestion. Ex: earthworms ingest the dead matter into their guts.
*Saprotrophs: Lives in or on non-living organic matter, secreting digestive enzymes into it an absorbing digestive products ( bacteria and fungi )They are known as decomposers because they break down carbon compounds in dead organic matter and release elements such as nitrogen into the ecosystem.
-Consumers: ingest organic matter which is living or recently killed. ex: A mosquito sucking blood from a larger animal is a consumer that feed from organism still alive.
*Primary: eat producers (herbivores) feed on autotrophs.
*Secondary: eat other consumers (carnivores, omnivores) feed on primary consumers
Autotrophy: self-feeding
Organism which produce their own food from organic molecules
Producers:
-Photo autotrophy: photosynthesis, green plants, phytoplankton and algae
-Chemoautotrophy: chemosynthesis, deep-sea, chemosynthetic bacteria.
Heterotrophy: other source of feeding
-Decomposers: derive energy from non living organic matter
*Detritivores: ingest non-living organic matter (leaves, hairs, dead animals, feces of other animals) .Obtain organic nutrients from detritus by internal digestion. Ex: earthworms ingest the dead matter into their guts.
*Saprotrophs: Lives in or on non-living organic matter, secreting digestive enzymes into it an absorbing digestive products ( bacteria and fungi )They are known as decomposers because they break down carbon compounds in dead organic matter and release elements such as nitrogen into the ecosystem.
-Consumers: ingest organic matter which is living or recently killed. ex: A mosquito sucking blood from a larger animal is a consumer that feed from organism still alive.
*Primary: eat producers (herbivores) feed on autotrophs.
*Secondary: eat other consumers (carnivores, omnivores) feed on primary consumers
inorganic nutrients
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
-Fifteen other elements are needed by living organisms. Some of them are used in minute traces only, but they are nonetheless essential.
Autotrophs obtain the elements that they need as inorganic nutrients from the abiotic elements.
Heterotrophs obtain the elements as part of the carbon compounds in their food.
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
-Fifteen other elements are needed by living organisms. Some of them are used in minute traces only, but they are nonetheless essential.
Autotrophs obtain the elements that they need as inorganic nutrients from the abiotic elements.
Heterotrophs obtain the elements as part of the carbon compounds in their food.
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.
Recycling of chemical elements is rarely as simple as shown in this diagram and often an element is passed from organism to organism before released back into an abiotic environment.
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.
Recycling of chemical elements is rarely as simple as shown in this diagram and often an element is passed from organism to organism before released back into an abiotic environment.
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. Supplies of fossil fuels is an example of an unsustainable activity given that the supplies of fossil are finite and not currently being renewed.
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.
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. Supplies of fossil fuels is an example of an unsustainable activity given that the supplies of fossil are finite and not currently being renewed.
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.
-Guidance: Mesocosms can be set up in open tanks, but sealed glass vessels are preferable because entry and exit of matter can be prevented but light can enter and heat can leave. Aquatic systems are likely to be more successful than terrestrial ones.
To obtain data for the chi-squared test, an ecosystem should be chosen in which one or more factors affecting the distribution of the chosen speciesaries. Sampling should be based on random numbers. In each quadrat the presence or absence of the chosen species should be recorded.
International-mindedness: The need for sustainability in human activities could be discussed and the methods needed to promote this.
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.