Variation In Population Size Flashcards
What is population size
The number of individuals in a population
What are the abiotic factors that influence the size of a population and explain in
Temp - each species has a different optimum temp at which it’s able to best survive. The further away from this optimum the fewer individuals in a population are able to survive and the smaller is the population that can be supported
Light - source of energy for most ecosystems, light is a basic necessity of life. The rate of photosynthesis increased as light intensity increases. The greater the rate of photosynthesis, therefore plants grow faster and grow more
pH- effects action of enzymes. Each enzyme has an optimum pH
Water and humidity- where there’s no water, populations have to be adapted to living in dry conditions. Humidity affects transpiration rate in plants and the evaporation of water from bodies in animals
What is the carrying capacity
the maximum stable population size of a species that an ecosystem can support
Give examples of how temp affects population size
In plants+cold blood animals - when temps fall below optimum - enzymes work slower and metabolic rate is reduced. Therefore have a smaller carrying capacity. At temps above optimum enzymes may denature, and carrying capacity is reduced
Warm blood animals - the further the temp of the external environment gets from their optimum frequency temperature, the more energy these organisms expend trying to maintain body temp. This leaves less energy for individual growth and so hey mature slowly and reproductive rates slower. Therefore carrying capacity of the population is reduced
Explain why populations never grow indefinitely
Certain factors limit growth e.g. availability of food, accumulation of waste, disease
