Ecology - 2.1 Individuals, populations, communities and ecosystems Flashcards
Biosphere
An ecological system composed of individuals, populations, communities and ecosystems
Components of the biosphere
- biome
- ecosystem
- community
- population
- individual
- gene
Species
A group of organisms that can interbreed and produce fertile offspring (biological species concept)
Classification
The systematic arrangement of organisms into groups based on shared characteristics or evolutionary relationships
Stages of classification
- domain
- kingdom
- phylum
- class
- order
- family
- genus
- species
(Do keep penis clean or fanny gets spots)
Genus
A taxonomic category ranking below family and above species, containing related species
Taxonomist
A scientist who identifies, names and classifies organisms into groups based on shared charactristics
Dichotomous key
A tool for identifying organisms using a series of paired, mutually exclusive choices
* series of yes or no questions that divide groups of organisms into smaller and smaller groups
DNA Survey
Method of identidying organisms by analysing genetic material
DNA Survey stages (6)
- collection
- extraction
- amplification
- sequencing
- analysis
- interpretation
Population
A group of organisms of the same species living in the same area at the same time and which are capable of interbreeding
Abiotic factor
Non-living physical factors that may influence organisms
Abiotic factor examples (name 2)
- Air/water temp.
- Ambient light levels
- Water salinity or turbidity (clarity)
- Soil characteristics
Biotic factors
Living components of an ecosystem
Biotic factor examples (name 2)
- Food sources
- Predators
- Competitors for the same resources
pH
A measure of how acidic or basic a substance is, from 0 to 14
Salinity
The concentration of dissolved salts in water, often expressed in parts per thousand
Dissolved oxygen
The amount of oxygen gas present in water, crucial for aquatic life
* higher DO = better water quality
Soil texture
The relative proportions of sand, silt and clay particles in soil
* affects drainage, fertility and productivity of soils
Insolation
The amount of light entering an ecosystem, affecting its temperature and evaporation rate
Niche
Particular set of abiotic and biotic conditions upon which an organisation or population depends
Ecological niche
The role of a species in an ecosystem
Herbivory
The consumption of plant material by animals
Predation
An interaction where one organism (predator) kills and eats another (prey)
Parasitism
Where one organism benefits at the expense of another typically living on or in it
Mutualism
An interaction between two species where both benefit from the relationship
Carrying capacity
The maximum population size an environment can sustain indefinitely with available sources
Density-dependent factor (2 examples)
An influence on population growth that varies with population density
* competition for food becomes more intense as population increases
* disease transmission is faster in dense populations because pathogens can spread more easily between individuals
Density-independent factor (1 example)
An influence on population growth that is unaffected by population size
* natural disasters
Two types of carrying capacity graphs
- Exponential growth - J curve
- Logistic growth - S curve
J curve explained
If there are no limiting factors, the population will continue growing until one is reached
S curve explained
When density-dependent limiting factors start to operate, population growth begins to slow
4 sections of the S curve
- Lag phase (low birth rates)
- Exponential growth phase (growth faster and faster)
- Transitional phase (growth rate slowes)
- Stationary phase (growth rate stabilises)
Limiting factor
Any resource or condition that restricts the growth, abundance or distribution of an organism or population
What has increased our carrying capacity? (2 examples)
- Elimination of natural predators
- Technological advances (modern medicine and agriculture)
Random sampling
A method of selecting individuals from a population where each has an equal chance of being chosen
Systematic sampling
A method of sampling using a fixed, periodic interval to select individuals from a population
Transect sampling
A technique for studying organism distribution along a line across an environmental gradient
Quadrat sampling
A method using square frames to count organisms in a small representative area
Lincoln index
A method for estimating population size using capture-mark-recapture data
Pop. size = (MxN)/R
Community
A collection of interacting populations within the ecosystem
Habitat (how to describe)
The location in which a community species, population or organism lives
(description: geographical and physical locations, type of ecosystem)
Ecosystem
A community and the physical environment with which it interacts
Steady-state ecosystem
A system where inputs and outputs of energy and matter are balanced
Keystone species
An organism with a disproportionately large effect on its ecosystem relative to its abundance
Biosphere integrity
The functional and genetic diversity of Earth’s ecological systems
