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Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
Ecological Competition
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Ecological Competition

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more sciencebitz resources on iTunesU and iBooks https://itunesu.itunes.apple.com/enroll/DEZ-HWS-HNJ https://itun.es/gb/ymzI6.n

more sciencebitz resources on iTunesU and iBooks https://itunesu.itunes.apple.com/enroll/DEZ-HWS-HNJ https://itun.es/gb/ymzI6.n

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  • 1. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Competition All the organisms in any ecosystem have some effect on every other organism in that ecosystem. Also any resource in any ecosystem exists only in a limited supply. When these two conditions apply jointly, competition takes place.
  • 2. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Competition Competition between members of the same species: INTRASPECIFIC COMPETITION
  • 3. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Competition In a Gannet colony on an oceanic outcrop, as the population grows, so the pressure for good nesting sites increases This can affect the number of eggs that each female can successfully hatch, and so affects the birth rate of the population as a whole.
  • 4. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Competition Some species deal with intraspecific competition by being territorial.
  • 5. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Competition Or through display
  • 6. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Population growth over time Competition 700 Intraspecific competition leads to 525 Population logistic population growth 350 175 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Time
  • 7. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Competition Competition between members of different species: INTERSPECIFIC COMPETITION
  • 8. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Competition The amount of competition depends on how much each species need for the resource overlaps: Species 1 Species 2 Species 1 Species 2 Resource Overlap Resource Overlap
  • 9. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Intraspecific Competition Greater than Competition 1,000 Interspecific Competition Carrying Capacity -Theoretical Maximum Population Size Interspecific competition may result in a balance, in 800 which both species share Species 1 Species 2 the resource. 600 400 But with the population size of each species 200 reduced compared to without competition 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
  • 10. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Interspecific Competition Greater than Competition 750 Intraspecific Competition Carrying Capacity -Theoretical Maximum Population Size The other outcome is that one species may totally 600 out compete the other. Species 1 Species 2 450 This is the principal of 300 competitive exclusion 150 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
  • 11. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Competition In a woodland plant species compete for light Trees should be able to out compete any smaller plants
  • 12. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Competition In deciduous woodland snowdrops, primroses and bluebells get around this problem They cary out their life cycle when the bigger trees and shrubs have no or few leaves In spring
  • 13. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Competition Interspecific competition is very difficult to show in the wild One example may be Red and Grey Squirrels in Britain
  • 14. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Sciurus vulgaris = Red Squirrel Red Squirrels are redder in the summer, and in Britain they develop a white tail in summer Sometimes the Red Squirrel goes slightly grey in the winter making it difficult to recognise 
  • 15. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Sciurus carolinensis = Grey Squirrel The Grey Squirrel is a native of eastern North America Grey Squirrels sometimes have ginger hair on their faces and hands; they always have white fringes on their tails
  • 16. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Where it all began. In 1870 a small number of Grey Squirrels were brought over to Cheshire (Henbury). They were subsequently released at a further 28 major sites across the UK. Given the numbers of squirrels that were released, the Grey Squirrel did particularly well. They started to spread further over the years, venturing further east, west and north.
  • 17. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Where it all began. In some areas such as a site in Ireland, the squirrels couldn't spread quickly due to the poor quality of woodland. As the Grey Squirrel spread, the Red Squirrel retreated. That retreat has continued. Today, Red Squirrels are very thinly distributed: on the Isle of Wight, in Scotland and the North of England.
  • 18. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Why is the Red Squirrel declining as the Grey extends its range?... • Red-Grey competition? • Loss of woodland?  Not possible as this would cause both to retreat. • A disease exists that is more infective to Reds than Greys?
  • 19. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Red-Grey competition • there could be a direct antagonism between Red and Grey Squirrels • there could be competition for food between Red and Grey Squirrels • Grey Squirrels may have a faster reproduction rate
  • 20. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Reynolds, 1985, Journal of Animal Ecology;56 Records of squirrel sightings in Norfolk between 1960 and 1981 were relied upon to compile this review. At the start there were  Red Squirrels around and no few Greys.
  • 21. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Reynolds, 1985, Journal of Animal Ecology;56 1964 - The first sightings of Grey Squirrels were recorded. 1968 - More Grey Squirrels were recorded as being sighted. 1969 - Grey squirrels began consolidating in the south west corner of Norfolk. 1972 - The first losses of Red Squirrels became apparent. 1976 - Red squirrel decline 1981 - Red Squirrels present in the minority
  • 22. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Reynolds, 1985, Journal of Animal Ecology;56 Over the 20 year period the Red Squirrels were almost all replaced by Greys. There were some squares in the study in which Reds were lost but Greys were never recorded. This suggests there could not have been a direct antagonism. Also it evidently took up to 16 years for the Greys to take over, which implies slow ecological competition, not direct antagonism, at work.
  • 23. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Reynolds, 1985, Journal of Animal Ecology;56 The Parapox Virus... • this virus is similar to myxomatosis, but affects Red Squirrels rather than Rabbits • its records go as far back as 1227 • there is no evidence of a peak in this disease amongst Red Squirrels at the time when the Grey Squirrels spread
  • 24. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Reynolds, 1985, Journal of Animal Ecology;56 Diet... • Grey Squirrels can digest acorns well, Red Squirrels cannot. Fed acorns, Red Squirrels lost weight, and only digested 10% of their polyphenols, while Grey Squirrels maintained weight, and digested 60% of the polyphenols. • Red Squirrels are conifer specialists - Pine cones take two years to mature, so are available in the canopy all year, whereas acorns fall to the ground each autumn, and have to be collected and stored there.
  • 25. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Reynolds, 1985, Journal of Animal Ecology;56 Diet... • Red Squirrels are light, and spend most of their time in the canopy. Grey Squirrels are heavier, and spend much time on the ground.
  • 26. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Reynolds, 1985, Journal of Animal Ecology;56 The Conclusion... It is still unknown exactly how and why the Grey Squirrel 'takes over' the Red. It is thought however to be due to slow competition and ecological differences. There is no evidence to suggest that Grey Squirrels breed faster than Reds. The removal of Grey Squirrels on Anglesey has allowed the Red Squirrels to breed and the young to survive, emphasizing that it is the presence of Grey squirrels that is the real problem for Red Squirrels.
  • 27. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Predator Prey relationships The balance between the population size of a prey species and that of its predator. Populations of predators and prey are linked. Include both carnivore and herbivore relationships.
  • 28. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Predator Prey relationships 80 Number of pelts (1000s) 60 40 Prey population Prey population falls grows 20 More food Less food Less hunting More hunting 0 1900 1905 1910 1915 1920 Predator population Predator population Year falls grows Snowshoe Hare Lynx
  • 29. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Parasitism Special case of predation; the main difference being that the predator (parasite) coexists with the prey (host), rather than killing it.
  • 30. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Parasitism Endoparasite - lives inside the body of the host
  • 31. Topic 2: Ecosystems 2.1.10: Describe and explain population interactions using examples of named species Parasitism Ectoparasite - live on the body of the host.

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