Biology module 3

• species diversity refers to the number of different species and the abundance of each species in an ecosystem.
• An ecosystem is any area that contains a community of living things that interact with each other and their environment.
• Diversity and distribution is due to the variation in abiotic and biotic factors.
• The diversity that is seen is developed over time is due to survival of the fittest and reproduction.
• Ecosystems provide nutrients, shelter and opportunities to mate.
• what is distribution?


  Where a species is found
• What is abundance?


  how many individuals of that species live throughout the ecosystem.
• Rainfall, temperature and landform patterns affect distribution and abundance.
• Measuring with quadrats is easy as plants are not mobile.
• examining population trends leads to inferences about species and what environment they are most suited.
• Adaptations are caused by DNA mutations/ natural selection (anything that helps survival and therefore reproduction)
• Temperature, water availability, salinity are main selection pressures.
• Adaptations occur as a result of a change or variation that arises.
• Plants that live in hot/dry environments must achieve a balance between photosynthesis and how much water the plant can afford to lose for cooling purposes without risking dehydration.
• Hard leaves minimise water loss with a waxy or hairy surface.
• Sunken stomata are lower than the surface of the leaf, allowing moist air to be trapped in the pit.
• Hairs in the pit of plants trap water vapour.
• The main survival issues for animals are gaining enough water and food, keeping cool or warm, finding space to live, reproducing and deterring predators.
• Behavioural adaptations refer to actions performed by organisms in response to a stimulus.
• Physiological adaptations refer to all the processes involved in an organism carrying out its function.
• What is genetic diversity?


  The total number of genetic characteristics in the genetic makeup of a species (this can change due to selection pressures)
• What is species diversity?


  The measure of the diversity of different species in an ecological community.
• What is ecosystem diversity?

  Variations of different ecosystems that are found in a region.
• Microevolution refers to the evolution changes on a small scale within a single population, a change in gene frequency over a short period.
• Macroevolution refers to evolution on a large scale that takes place over millions of years and results in new species.
• Speciation is the process that produces two or more species, often because of geological isolation.
• Diversification of species and branching into two or more species occurs as groups adapt to different environments.
• Isolation occurs when a species may form into distinct breeding populations as selection pressures are often not the same when the population are in different environments.
• The evolution of a species involves a change in the characteristics (genetic makeup) of a population over time.
• Evolution can be seen through fossil records which show how organisms have changed over time.
• Natural selection can result in changes within a species if a population is isolated in two different environments.
• A species could split fairly equally into two populations that evolve differently until they eventually become separate species.
• Divergent evolution occurs when different species arise from a common ancestor due to isolation from one another and adaptation to different environemnts.
• Convergent evolution is a pattem of evolution whereby unrelated species evolve similar traits.
• Punctuated equilibrium is a model of evolution that is backed by sufficient fossil evidence which shows that some species remained essentially the same way for millions of years and then underwent short periods of very rapid major change.
• Gradualism is Darwin's long-held view that evolutionary change occurred gradually over a long period of time.
• Evolution is the process by which new species are formed through natural selection acting on genetic variation.
• Natural selection is the mechanism by which organisms best adapted to their environment survive and reproduce, passing on advantageous genes to offspring.
• Adaptation is an inherited characteristic that increases an individual’s chance of survival and reproduction in its current environment.
• A mutation is any permanent alteration in DNA sequence