Ecology

• Ecosystem


  all the organisms living in a habitat and the non-living parts of the habitat.
• Habitat


  the area or natural environment in which an organism or population normally lives.
• Community


  made up of many populations living together
• Population


  groups of individuals of the same species
• Competition


  the contest between organisms for resources such as food and shelter
• Interdependence


  all the organisms in a community depend upon each other and, because of this, changes to them or their environment can cause unforeseen damage.
• Invasive species


  an organism that is not native and causes negative effects.
• Abiotic factors


  Non-living conditions that affect the distribution of an organism.
• Biotic factors


  caused by living organisms affecting their environment.
• Abiotic


  the non-living parts of the environment.
• Biotic


  the living parts of the environment.
• Extreme environment


  a location in which it is challenging for most organisms to live.
• Extremophile


  an organism that can survive in a very extreme environment, including:

  • very high or low temperatures
  • high salt concentrations
  • high pressures
• Structural adaptations


  an advantage to an organism as a result of the way it is formed, like gills in fish.
• Physiological adaptation/Functional adaptation


  an advantage to an organism as a result of a process, such as the production of poisonous venom or camels not sweating.
• Behavioural adaptations


  an advantage to an organism as a result of behaviour, such as a mating ritual or hibernation.
• Examples of abiotic factors:

  • Temperature
  • Light intensity
  • carbon dioxide levels for plants
  • oxygen levels for animals that live in water
  • moisture levels
  • wind intensity and direction
  • soil pH and content for plants.
• Examples of biotic factors:

  • Food availability
  • new pathogens
  • new predators
  • competition between species
• Surface area to volume ratio:

  • The smaller the sa:vol, the less efficient it is at losing heat.
  • The larger the sa:vol, the more efficient it is at losing heat.

  
• Animal adaptations-camel:

  • Thick fur to keep the sun's heat away during the day and provide warmth at night.
  • Hump to store fat as food to provide energy for long periods of time.
• Animal adaptations-camel:

  • Very long intestines to reabsorb as much water from foods eaten as possible.
  • Long, muscular legs to allow them to walk for miles across the desert.
• Animal adaptations-camel:

  • Long eyelashes to keep sand out of eyes.
  • Thin nostrils that can be closed to prevent sand from blowing in.
• Animal adaptations-camel:

  • Leathery knees to help prevent burning when kneeling on hot sand.
  • Wide feet help to spread camel's weight so it is easier to walk on sand.
  • Leathery pads on feet to protect them from heat and to stop the camel from sinking into sand.
• Animal adaptations-polar bear:

  • Large animal so small sa:vol to prevent heat loss.
  • Small eyes and ears to prevent heat loss.
  • Thin nostrils to prevent snow blowing in.
• Animal adaptations-polar bear:

  • Sharp teeth and claws for hunting.
  • Wide feet and thick skin on feet to spread weight on the snow and to keep them warm.
• Animal adaptations-polar bear:

  • White fur to camouflage into the environment when hunting.
  • Thick fur to prevent heat loss.
  • Thick layer of blubber (fat) to conserve heat and prevent heat loss.
• Synchronised birth - behavioural feature


  Animals such as wildebeest try to give birth at the same time, reducing the chance of all of the calves being eaten by predators.
• Extremophiles can survive in conditions that would kill most species. Some bacteria live in hot springs or around deep-sea vents. Others live in extreme cold.

  Examples: water bears, Loricifera, Grylloblattidae, Giant Tube Worms, Snottites.
• Plant adaptations-cactus:

  • Waxy cuticle covering fleshy leaves to help store water and protect it from the sun. Also prevents evaporation.
  • Can have long vertical roots growing deep into the soil to reach the water table.
• Plant adaptations-cactus:

  • Prickles and spikes on stem to protect against thirsty animals.
  • Can have roots growing horizontally in the top layers of the soil to collect surface water and to provide stability.
  • Some have a small sa:vol by not having leaves to reduce water loss.
• Plant adaptations-cactus:

  • No leaves to prevent water loss through transpiration.
  • Some store water in special tubers or bulbs.
  • green chlorophyll in stem, chloroplasts for photosynthesis.
• Plant adaptations:

  • Flowers open petals everyday in daylight but close them at night, flowers need to be open for pollination but closing them at night protects the flowers.
  • Deciduous trees lose leaves in the Winter to protect the leaves from frost.
  • Pine trees have needle shaped leaves to reduce surface area for water loss.
• Plant adaptations-Arctic plants:

  • small leaves to prevent water loss
  • grow very close to the ground to stay sheltered.
• Mimicry


  When an animal has adapted to look like another more poisonous or venomous animal for protection.
• Examples of mimicry:

  An advantage for the dangerous animal is safety in number and prey may not always run away from it.

  • Hoverflies look like wasps.
  • Coral snake (venomous), Kingsnake (copies)
• Food chain:

  Producer -> Primary consumer -> Secondary consumer

  • The arrows show the direction of energy flow.
  • They are in trophic levels ("up a trophic level"). Not all energy from a producer will go up a trophic level
• Predator-prey relationship


  All species in a community depend upon each other. This is known as interdependence. The size of each population is dependent on the other.
• Mutually beneficial relationship e.gs:

  • Cleaner fish eat dead skin and parasites off of larger fish. They get food and avoid being eaten.
  • Burdock fruits have hooks. They attach to the fur of passing animals for dispersal.
• Parasitism:

  when one organism benefits but the other is harmed by the relationship.

  • Lice feed on your blood. This makes you tired as the body tries to replace the red blood cells.
  • Tape worms live in the intestines and eat your food, making you malnourished.
• The water cycle:

  1. Evaporation- water evaporates as it is heated by the sun's energy. Water vapour is carried upwards in convection currents.
  2. Condensation- water vapour rises, cools, and condenses back into water droplets that form clouds.