Stage 1 Biology Ecology L Notes
Topic One: Introduction to Ecology: Classification
- Study of organisms, decomposers, and their interactions with the environment – both biotic and abiotic
factors.
Levels of organisation
Organism
Species
- A group of organisms that are genetically related and can breed to produce fertile offspring
- They are reproductively isolated
Population
- A group of the same species living in the same area which interbreed with each other. They share a
common gene pool. Gene pool: The sum of all the genes in a population
Community
- A group of various populations that live in the same area and interact
Ecosystem
- All communities in the area and the interaction of these organisms with the abiotic factors of that area
Biome
- A broad area of the world that contains similar biotic and abiotic conditions
Biosphere
- A part of the earth that contains life, primarily made of water, the lithosphere (land), and atmosphere (air).
Classification
Taxa – categories into which related organisms are placed.
Mnemonic Device:
Domain – broadest taxon Dumb
Kingdom: Animalia King
Phylum: Chordata Phillip
Class: Mammalia Came
Order: Carnivora Over
Family: Ursidae For
Genus: Ursus Gooseberry
Species – most specific: Ursus Arctos Soup
Domain Eukarya is Divided into Kingdoms
- Protista (algae)
Fungi (mushrooms)
- Multicellular, except yeast
- Absorptive heterotrophs (digest food outside their body & then absorb it)
Plantae (multicellular plants)
- Autotrophic and use photosynthesis
- Animalia (multicellular animals)
- Ingestive heterotrophs (consume food & digest it inside their body). They feed on plants or animals.
, Stage 1 Biology Ecology L Notes
Topic Two: Trophic Structures & Symbiosis
Trophic Structures
- Producers: Autotrophs which produce the food for the ecosystem e.g. plants
- Consumers: Organisms that feed on the producers (herbivores) and organisms that feed on other animals
(carnivores)
- Decomposers: Organisms that break down dead materials
Species Interaction
- Species living within an area must interact with each other to survive
- Three main interactions:
- Competition
- Predation
- Symbiosis
Competition
- Organisms that compete for the same resource
- Exists between organisms of the same species, and also amongst organisms of different species
- More intense between organisms of the same species, since they have the same requirements
Predation
- Where one organism feeds on another:
- Predation impacts the biodiversity of a community, and also the evolution of a species
Plant Defences
- Chemical:
- Many plants contain a vast array of chemicals to deter herbivores
- Plants can deter herbivores through chemicals which either taste bad or are toxic
- Physical:
- Many plants contain thorns and waxy layers
- Colouration:
- Bright colours: Usually displayed by insects and suggests that they are toxic
- Camouflage: To conceal themselves
- Mimicry: Some non-toxic species have even evolved to mimic the colouration of toxic species
Symbiosis
- A relationship between two different species:
Mutualism: Both species benefit from the interaction
Commensalism: One species benefits and the other is unharmed but does not benefit
Parasitism: One organism benefits and the other organism is harmed but usually not killed.
Type of Relationship Both Benefit One Benefits (none are One benefits (the other
harmed) is harmed)
Parasitism X
Mutualism X
Commensalism X
Topic One: Introduction to Ecology: Classification
- Study of organisms, decomposers, and their interactions with the environment – both biotic and abiotic
factors.
Levels of organisation
Organism
Species
- A group of organisms that are genetically related and can breed to produce fertile offspring
- They are reproductively isolated
Population
- A group of the same species living in the same area which interbreed with each other. They share a
common gene pool. Gene pool: The sum of all the genes in a population
Community
- A group of various populations that live in the same area and interact
Ecosystem
- All communities in the area and the interaction of these organisms with the abiotic factors of that area
Biome
- A broad area of the world that contains similar biotic and abiotic conditions
Biosphere
- A part of the earth that contains life, primarily made of water, the lithosphere (land), and atmosphere (air).
Classification
Taxa – categories into which related organisms are placed.
Mnemonic Device:
Domain – broadest taxon Dumb
Kingdom: Animalia King
Phylum: Chordata Phillip
Class: Mammalia Came
Order: Carnivora Over
Family: Ursidae For
Genus: Ursus Gooseberry
Species – most specific: Ursus Arctos Soup
Domain Eukarya is Divided into Kingdoms
- Protista (algae)
Fungi (mushrooms)
- Multicellular, except yeast
- Absorptive heterotrophs (digest food outside their body & then absorb it)
Plantae (multicellular plants)
- Autotrophic and use photosynthesis
- Animalia (multicellular animals)
- Ingestive heterotrophs (consume food & digest it inside their body). They feed on plants or animals.
, Stage 1 Biology Ecology L Notes
Topic Two: Trophic Structures & Symbiosis
Trophic Structures
- Producers: Autotrophs which produce the food for the ecosystem e.g. plants
- Consumers: Organisms that feed on the producers (herbivores) and organisms that feed on other animals
(carnivores)
- Decomposers: Organisms that break down dead materials
Species Interaction
- Species living within an area must interact with each other to survive
- Three main interactions:
- Competition
- Predation
- Symbiosis
Competition
- Organisms that compete for the same resource
- Exists between organisms of the same species, and also amongst organisms of different species
- More intense between organisms of the same species, since they have the same requirements
Predation
- Where one organism feeds on another:
- Predation impacts the biodiversity of a community, and also the evolution of a species
Plant Defences
- Chemical:
- Many plants contain a vast array of chemicals to deter herbivores
- Plants can deter herbivores through chemicals which either taste bad or are toxic
- Physical:
- Many plants contain thorns and waxy layers
- Colouration:
- Bright colours: Usually displayed by insects and suggests that they are toxic
- Camouflage: To conceal themselves
- Mimicry: Some non-toxic species have even evolved to mimic the colouration of toxic species
Symbiosis
- A relationship between two different species:
Mutualism: Both species benefit from the interaction
Commensalism: One species benefits and the other is unharmed but does not benefit
Parasitism: One organism benefits and the other organism is harmed but usually not killed.
Type of Relationship Both Benefit One Benefits (none are One benefits (the other
harmed) is harmed)
Parasitism X
Mutualism X
Commensalism X
