Summary Variation in population size A level Biology

Variation in population size
summary notes
27 June 2023 12:46




Plotting growth curves
- Can plot a graph of numbers in a population
against time where a population grows in size
slowly over a period of time
- If the population grows rapidly over a short
period of time must use logarithmic scale to
represent the number of a population


Carrying capacity- certain size of population that can be
sustained over a long period of time- determined by
limiting factors



Abiotic factors influencing size of a population

Temperature
- Each species has a different optimum
temperature at which it is best able to survive
- Further away from the optimum, the fewer the
individuals in a population are able to survive
- Plants and cold blooded animals- temperatures
fall below the optimum- enzymes work more
slowly- metabolic rate is reduced - populations
have a smaller carrying capacity
- Temperatures above optimum- the enzymes
work less efficiently because they undergo
denaturation- carrying capacity is reduced
- Warm blooded animals can maintain constant
body temperature regardless of external
temperature - further the temperature of the
external environment from optimum, more
energy organisms expend trying to maintain
normal temperature - less energy for individual
growth- mature more slowly- reproductive rate