biology 2

• what is an ecosystem?


  a community of organisms interacting with the non-living abiotic elements of their environment
• what is a community?


  all the different population of species living in one area
• what is a species?


  group of organisms with similar charactersitics that can interbreed to produce fertile offspring
• what is a population?


  a group of the same species living in one area
• what is a stable community?


  the size of the populations of all species remain relatively constant over time and the different populations are living in a healthy balance with their environment
• when is systematic sampling used?


  to see how an abiotic factor affects a biotic factor as it changes over the length of the transect
• what is an extremophile?


  an organism that lives in an extreme environment that most organisms would find it near impossible to survive
• how is biomass made?

  the sun's light energy is captured and used by green plants and algae during photosynthesis to make new biomass
• what is biomass?


  all biological molecules that make up an organism
• what does a biogas generator do?


  anaerobically decays organic waste to produce biogas containing methane
• forms of farming run-off


  eutrophication and bio accumulation
• what is bio accumulation?

  the build up of toxins within the fatty tissue of an organism. It increases as you move up the food chain
• what are peat bogs made of?

  plant material that cannot decay. It's not fully decomposed as it's waterloogged, there isn't enough oxygen and the soil is very acidic
• how is information passed across a synapse?


  Neurotransmitters (chemical messengers)
• where are neurotransmitters stored?

  Synaptic vesicles
• what does the cerebral cortex do?


  control conscious thoughts
• what does the cerebellum do?


  coordinates muscular activity
• what does the hypothalamus do?


  coordinates homeostatic control
• what does the pituitary gland do? 


  produces and releases hormones
• what does the medulla oblongata do?


  controls unconscious activities
• what does MRI stand for?

  magnetic resonance imaging
• what does the sclera do?


  protects the eye
• what does the retina do?


  senses light
• what does the optic nerve do?


  Transmits impulses to the brain.
• what do the ciliary muscles do?


  Change the shape of the lens
• what does the cornea do?


  protects the eye surface and focuses light rays
• what do the suspensory ligaments do?


  holds lens in place
• what does the lens do?


  focuses light on the retina.
• what does the iris do?


  regulates the amount of light entering the eye
• what does the pupil do?


  lets light into the eye
• what is accomodation?


  changing the shape of the lens so you can see objects near and far clearly
• what angle does light hit the eye from distant objects?


  almost parallel
• what does the eye do to see distant objects clearly?

  the ciliary muscles relax, so the suspensory ligaments are pulled and stretched, and the lens is long and thin so the light doesn't bend as much
• how does light from close objects hit the eye?


  it is more spread out
• what does the eye do to see close objects clearly?

  the ciliary muscles contract, allowing the suspensory ligaments to slacken, and the lens become fatter and more curved to bend the light more
• what is myopia?


  short-sightedness
• what is hyperopia?


  long-sightedness
• what causes myopia?


  the eyeball is too long so the distance between the lens and retina is too great . Or the lens is too thick and curved so the light is focused in front of the retina
• how is myopia corrected?


  glasses with concave lenses to spread light out more before it enters the eyeball
• how is hyperopia caused?


  the eyeball is too short so the distance between the lens and retina is too small. Or there is a loss of elasticity in the lens so it cannot become thick enough to focus