19 Competition and Predation

  • Created by: lee8444
  • Created on: 07-02-20 10:04

Intraspecific competition

  • Intraspecific competition is between individuals of the same species
  • Compete for food, water, mates etc
  • The availability of resources determines the size of the population
  • Limpets compete for algae as this is their main source of food, more algae reults in a bigger population
  • Oak trees compete for light and water from the soil. Over tie, there will be just a few large, dominant oak trees
  • Robins compete for breeding territory as females are only attracted to males with established territories as this will hold space for food and a suitable nest
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Interspecific competition

  • Interspecific competition is between individuals of different species
  • Compete for the same resources, other than mates
  • One species normally has a competitive advantage over the other species which will increase this species' poluation whilst decreasing the other
  • If conditions remain constant the less competitive species will become extinct
  • This is the competitive exclusion principle
  • 'The one that uses the resources the most effectively will ultimately eliminate the other'
  • No two species can operate within the same niche
  • Birth rate and death rate need to be linked to look at how polualtions change over time. This can be affected by a change in food supply or a new predator can impact the biirth and death rates of a species
  • This effect may take long periods of time to see a change in population
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  • When predator prey relationships are investigated in labs, the prey is usually exterminated quite quickly due to the range of the habitat being limited by the lab conditions
  • In nature the variety of environments is much larger so prey can adapt and use their surroundings more to their advantage
  • Therefore, prey populations are varely rarely completeley diminished
  • Often hard to obtain accurate predation data as habitats are endless and it can be hard to calculate numbers
  • Sizes can only be estimated by sampling
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Predator-prey relationship cycle

  • Preators eat prey reducing the number of prey
  • With fewer prey, the predators are left in greater competition with eachother
  • Predator population is reduced as there isn't enough food for some to survive and reproduce
  • With fewer predators, more prey can survive and reproduce
  • This increases the population of prey
  • With more prey, more predators can survive and reproduce
  • This increases the popualtion of predators

This causes the population of predators to lag behind te popualtion of prey on a population graph

  • Disease and climatic factors also play a part in chnaging the fluctuations on a graphy of a predator-prey cycle
  • This creates selection pressure as at each cycle only the best adapted are going to survive and reproduce accelerating natural selection
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