Life processes in the biosphere

• A species is a group of organisms that can breed to produce fertile offspring
• a population is the number of all the individuals of a species in a given area
• Community of species is a group of different interacting species that inhabit an area at the same time
• A habitat is the place where organisms or a population lives
• Ecosystem is a community of interdependent organisms that interact with the abiotic factors of the environment
• Taxon is a group of organisms with similar and shared characteristics, like the pantherea family
• Gene pool is all the different alleles in a population
• Ecological niche is the functional role of a species in its environment
• indigenous species are originally found in a specific habitat
• endemic species are restricted to a certain area or location, typically found on islands
• The biosphere is all the living things that inhabit the earth
• Organisms with a larger gene pool with a larger range of tolerance to environmental changes
• For each abiotic factor a organisms has a range of tolerance for which it can survive
• Abiotic factors

  • temperature
  • pH
  • water
  • light intensity
  • minerals and nutrients
  • species interdependence
• biotic factors

  • feeding
  • vegetation
  • avoiding predators
  • pollination
  • seed dispersal
  • disease resistance
• Closely related species don’t bred in the wild because of different anatomical differences and different mating behaviours
• Taxonomy is the evolutionary relationship between all living things
• A biome is a large zone of distinctive vegetation types and are determined by climate conditions
• The types of biome are

  • aquatic (biggest biome on earth)
  • grassland
  • forest (biggest terrestrial biome)
  • desert
  • Tundra
• Succession is the gradual change in the structure and composition of species of a community in an area overtime as abiotic factors are modified
• A climax community is a species that can’t be competed against
• A pioneer species can tolerate the initial harsh conditions of a new habitat but are bad competitors
• A sere is a sequence of changing communities
• Primary succession hapens in a place without any soil, on bare rock or sand or water in hostile conditions
• Pioneer species can be lichen or algae
• Secondary succession is faster than primary succession it occurs when existing community has been cleared but leaves the soil intact
• Types of seres:

  • lithosere
  • Psammosere
  • hydrosere
• Plagioclimaxes are often caused by humans and stop succession from naturally occurring
• Factors that can effect population

  • food
  • pests
  • endangered species
  • raw materials
  • indicator
• Population change = (births + immigration) - (deaths + emigration)
• Reproductive potential is the amount of offspring that can be born depending on the numbers of available breeding pairs
• R selected species are species that reach sexual maturity quickly. when they have offspring they have a large amount at once. Low degree of parental care
• K selected species reach sexual maturity slower. Have a smaller amount of offspring at the time. Have a high degree of parental core and long gestational period
• Environmental resistance is all the factors that could limit the growth of the population
• Factors that control mortality rate

  • drought
  • Flood
  • volcanic eruption
  • pollution
  • food supply
  • disease
  • predators
  • water supply
  • habitat
• Density dependant environmental factors are factors that are dependent on the size/ density available
• Density independent factors that are not dependent on the size/ density available
• Wildlife migration is a regular cycle where animals follow a seasonal pattern and usually return to there original area
• Stages of population growth

  • colonisation
  • lag phase- wait for organisms to reach sexual maturity, gestation periods
  • log phase- birth rates exceed deaths
  • stabilising
  • stable fluctuating- more food/ shelter competition, disease spreads
• Carrying capacity is the maximum population a habitat can support sustainably