Ecology

• Species


  A group of organisms that can reproduce to procure fertile offspring
• Species

  • Can be classified into groups by the features they share e.g. all mammals have bodies covered in hair, feed young from mammary glands and have external ears (pinnas)
• Classification


  The organisation of living things into groups depending on their structure and characteristics
• Classification system


  • Allows us to make sense of the living world (members have features in common e.g. anatomy / fossils/ DNA)
  • Helps us understand how living things are related (evolutionary history)
  • Gives scientists a common language in which to talk about it
• Binomial system


  Linnaeus' system for classifying organisms, where each name has 2 parts - the genus and species
• Levels of classification

  • Species
  • Genus
  • Family
  • Order
  • Class
  • Phylum
  • Kingdom
• Developments in biochemistry

  • As evidence of internal structures became more developed due to improvements in microscopes, and the understanding of biochemical processes progressed, new models of classification were proposed
• Closely related species

  May have fewer differences in their DNA
• Three domain system

  Carl Woese's system for classifying all living organisms based on DNA/chemical analysis, with the domains Archaea, Bacteria, and Eukaryota
• Evolutionary trees


  A method used by scientists to represent the relationships between a set of organisms, where the tips represent different species and where two branches join represents a common ancestor
• Population


  The total number of a single species that live in the same geographical area
• Community


  The populations of different species living in the same habitat
• Habitat


  The environment in which an organism lives
• Ecosystem


  The interaction of a community of living organisms with non-living parts of their environment
• Trophic levels

  • Producer
  • Primary consumer
  • Secondary consumer
  • Tertiary consumer
• Herbivore


  Animals that eat plants
• Carnivore


  Animals that eat other animals
• Omnivore


  Animals that eat both plants and animals
• A stable community is one where all the species and environmental factors are in balance so that population sizes remain fairly constant
• Things plants and animals compete for

  • Light
  • Water
  • Space
  • Mineral nutrients
  • Food
  • Mates
  • Territory
  • Mates
• Interspecific competition


  Competition between organisms of different species
• Intraspecific competition


  Competition between organisms within the same species
• Without predators (foxes) in this food chain


  The numbers of rabbits will increase and the amount of grass will decrease
• Without rabbits in this food chain


  The number of foxes will decrease and the amount of grass will increase
• Abiotic factors

  • Temperature
  • Soil pH and mineral content
  • Moisture levels
  • Light intensity
  • Carbon dioxide levels for plants
  • Oxygen levels for aquatic animals
  • Wind intensity and direction
• Biotic factors

  • New pathogens
  • Competition between species
  • Availability of food
  • New predators arriving
• When the red fox was introduced to Australia

  It caused concern over its effect on native birds & small mammals, ruining established predator-prey relationships and causing a rapid decline in prey, reducing food supply for existing predators
• When a new pathogen emerges

  Organisms have no resistance to the disease, which can wipe out populations in a community
• When a new species outcompetes a native species

  It can reduce the numbers and places where the native species lives
• Adaptations of arctic animals (polar bears)


  • Insulation from a layer of blubber
  • Small surface area to volume ratio to maintain body heat
  • Grow to a large size to maintain body heat
  • Camouflaged white fur
  • Small ears to reduce heat loss
• Adaptations of desert animals (camels)

  • Little insulation to allow heat loss
  • Thin layer of blubber and fur coat
  • Active at night (nocturnal) to reduce heat loss
  • Do not sweat to reduce water loss
• Adaptations of plants (cacti) to warm environments

  • Waxy layer/thicker cuticle to prevent water loss
  • Long roots to reach deep water
  • Prickles to protect against prey
  • No leaves (thorns), fewer stomata to prevent water loss through transpiration
• Structural adaptations


  Physical features of an organism that make it adapted to its environment
• Functional adaptations


  Processes that take place in an organism that make it adapted to its environment
• Behavioral adaptations


  Behaviors of an organism that make it adapted to its environment
• Extremophiles


  Organisms that can survive in very extreme environments, such as extreme temperatures or pressures, or in high salt concentration
• Individual


  Part of a species, lives in its habitat within a population
• Population


  Many different populations interact in the same habitat, creating a community
• Community


  The interaction of a population with non-living (abiotic) parts of the environment
• Ecosystem


  The interaction of a community with non-living (abiotic) parts of the environment