BRAINCAKE

Biodiversity

OCR AS-level BiologyTopic 11 of 1233 lessons

Revision notes for Biodiversity in OCR Biology A (H020). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.

  1. Importance of BiodiversityBiodiversity is essential in maintaining a balanced ecosystem for all the organisms living in the ecosystem.
  2. Measuring BiodiversityGenerally, the closer the region is to the Equator, the greater the biodiversity.
  3. Habitat BiodiversityA habitat is the place where a particular species lives.
  4. Species BiodiversitySpecies diversity depends on both species richness and species evenness.
  5. Genetic BiodiversityGenetic biodiversity refers to the variety of genes that make up a particular species.
  6. SamplingIt is not always possible to count every individual in a population because the large number of organisms would make it time-consuming.
  7. Random SamplingIn random sampling, each individual in the population has an equal chance of being selected.
  8. Non-Random SamplingThe sample may not be chosen at random.
  9. ReliabilityIn statistics, reliability is the consistency of a measurement.
  10. Sampling AnimalsLiving animals can be collected for later study.
  11. Sampling PlantsPlants are sampled using a quadrat.
  12. Species RichnessSpecies richness is a measure of the number of different species living in a specific area.
  13. Species EvennessSpecies evenness refers to how close in numbers the populations of each species in an environment are.
  14. Frame QuadratsA frame quadrat can be used to sample populations living in a habitat.
  15. Estimating Population SizeAnimals tend to move around so it is harder to estimate the population size.
  16. Measuring Abiotic FactorsAbiotic factors are the non-living components of the habitat.
  17. Simpson's Index of DiversityThe combination of species richness and species evenness give an indication of biodiversity.
  18. The Importance of Genetic DiversityThe difference between the DNA of individuals within a species is much less than the difference between DNA of different species.
  19. Factors Affecting Genetic BiodiversityMutation of the DNA creates new alleles.
  20. Measuring Genetic BiodiversityGenetic biodiversity can be measured by measuring polymorphism.
  21. Human Influence on BiodiversityThe human population is growing exponentially.
  22. DeforestationDeforestation can occur naturally.
  23. AgricultureFarmers tend to grow a few species of crop plant and rear only a few species of animals.
  24. Climate ChangeGlobal warming is the rise in the Earth's mean surface temperature.
  25. Reasons for Maintaining BiodiversityThere are three main reasons for maintaining biodiversity.
  26. Aesthetic ReasonsThe aesthetics of plants and animals in the environment enriches our lives.
  27. Economic ReasonsSoil erosion and desertification may occur as a result of deforestation.
  28. Ecological ReasonsAll organisms are interdependent.
  29. Human Activity and BiodiversityHuman activity alters ecosystems, depletes resources, and changes the climate.
  30. Maintaining BiodiversityConservation is the practice of carefully managing the environment and natural resources to increase the chances of survival of an organism.
  31. In Situ ConservationIn situ conservation maintains the genetic diversity inside an organisms natural habitat.
  32. Ex Situ ConservationBotanic gardens Plant species can be provided with the best nutrients, water, light and the best conditions to grow.
  33. Conservation AgreementsLocal and international conservation agreements ensure species and habitats are preserved.

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