ecology - abiotic + biotic factors

Question 1

what is availability of food?

Answer 1

• biotic factor
  all animals eat other living organisms eg lions eat other animals where as zebras eat plants

Question 2

what happens if availability of food falls?

Answer 2

the number of organisms in that community will also fall

Question 3

what is the arrival of a new predator?

Answer 3

• biotic factor
  cause population of prey species to fall. can affect existing predators for example if they are competing for the same prey

Question 4

what is competition between species?

Answer 4

• biotic factor
  if a species is outcompeted then its population can fall so much that numbers are no longer sufficient to breed and may become extinct

Question 5

what is new pathogens?

Answer 5

• biotic factor
  if an infectious disease emerges and then spreads it can wipe out a pollution of species

Question 6

what are the 4 biotic factors

Answer 6

availability of food, new predators, new pathogens, competition between species

Question 7

what is light intensity?

Answer 7

• abiotic factor
  all plants need light to carry out photosynthesis. if light intensity too low, rate of photosynthesis falls and plants will grow more slowly

Question 8

what happens if plants grow more slowly?

Answer 8

then animals which feeds on plants may not have enough food

Question 9

what is temperature?
what could temperature of environment change cause?

Answer 9

• abiotic factor
  cause distribution of species to change. eg animals could migrate and plants species disappear

Question 10

what is water?

Answer 10

• abiotic factor. very important as plants + animals need it to survive
  many species adapted to deal with low levels of water

Question 11

what is the pH + mineral content of soil?

Answer 11

• abiotic factor for plants
  many plants cannot grow on soil that is too acidic or alkaline. they need certain minerals in the soil for example nitrate which makes amino acids for proteins

Question 12

what is wind intensity + direction?

Answer 12

• abiotic factor for plants
  for example strong winds blowing inland from the sea can cause plants to lose water. so plants growing in plant dunes are adapted to low level of water/water loss

Question 13

what are the gases carbon dioxide and oxygen?

Answer 13

• abiotic factors
  CO2 needed for plants to photosynthesise + if levels of it fall then rate of photosynthesis can also decrease. oxygen needed for aerobic respiration. level of oxygen in the air stays fairly constant. however, level of dissolved oxygen in water can fall eg on hot days. can be harmful to aquatic organisms

Question 14

what are the abiotic factors

Answer 14

carbon dioxide + oxygen, wind intensity + direction, temperature, water, light intensity, pH + mineral content in the soil