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3.7.4 Populations in Ecosystems - Coggle Diagram
3.7.4 Populations in Ecosystems
Key Terms
Ecology
The study of interactions between organisms and their environment
Species
A group of similar organisms that can interbreed to produce fertile, living offspring
Population
All of the individuals of one species that occupy the same habitat at the same time
Community
All of the individuals of all of the different species living and interacting in a particular place at the same time
Habitiat
The place where an organism normally lives
Microhabitat
Smaller units within a habitat with their own microclimate. E.g. lichen growing in the crevice (microhabitat) of an oak tree (habitat)
Environment
All of the living and non-living factors that organisms interact with
Abiotic factor
Non-living factors E.g. temperature, soil pH, Rainfall, light availability
Biotic factors
Living factors E.g. Competition, prey availability, predication, disease outbreaks
Ecosystem
Dynamic system made up of the community and all the non-living factors in a given location
Ecological Niche
This refers to both where an organism lives and its role in the environment
Carrying Capacity
Maximum population an ecosystem can support. Determined by abiotic and biotic factors
Biomes
Major groups of eceosystems
Limiting Factor
A variable that limits the rate of a reaction/growth of a population
Competition
Individual organisms are in a struggle against each other organisms for the means of survival
Intraspecific competion
All are in one competition with each other (member of the same species)
Interspecific competition
Between members of different species, if they have an overlapping niche
Predator
Organism that relies on hunting and eats another organism
Prey
Organism that is hunted and eaten by another organism
Abundance
How many individuals are found in the habitat
Distribution
Where the organisms are found in this habitat
Effect of Abiotic Factors
High light intensity
Effect on Plants: Rate of photosynthesis increases so more glucose for respiration and ATP production, more energy for growth and reproduction.
Effect on animals: Larger population of plants so more food sources and more habitats
Reduced water levels
Effects on Plants: Humidity effects transpiration
Effect on Animals: Humidity effects evaporation from bodies
pH
At Optimum: Enzyme activity is highest so more reactions occur e.g. Photosynthesis so more growth of plants
Outside optimum: Any change to pH disrupts hydrogen and ionic bonds in the tertiary structure of enzymes. Denaturation occurs so the organism can no longer carry out metabolic process and is unable to survive.
Temperature
Effect on plants and cold blooded animals: They rely on the environment temperature to regulate their internal body temperature. So if the environmental temperature decreases, their enzymes work more slowly and their metabolic rate slows down.
Effect on Warm blooded animals: They can maintain their own internal temperature through homeostasis. But low temperatures do still affect the carrying capacity of their populations because organisms have to expend lots of energy so they have less energy to expend on growth.
Population Growth Curves
Lag phase
Slow increase in graph: population is very small, so increase in numbers are small
Log phase
Rapid increase in graph: population growth at maximum as limiting factors are all abundant
Stationary phase
Constant on graph: population is at carrying capacity, limiting factors prevent further growth. There will be some fluctuations due to variations in limiting factors
Death phase
Rapid decrease in graph: Environment unable to support population