B17: Organising an Ecosystem

Question 1

stages of food chain?

Answer 1

PRODUCER- photosynthetic organisms- USE GLUCOSE made to produce other biological molecules , making up part of their biomass
PRIMARY CONSUMERS- energy is transfered through organisms in an ecosystem, when one is eaten by another
SECONDARY CONSUMERS
TERTIARY CONSUMERS

Question 2

what are quadrats?

Answer 2

square frames made from wod/wire
- measure abundance of plants or slow moving animals
- placed on ground and ogranims within them are recorded

Question 3

how do quadrats measure abundance?

Answer 3

• no. induviduals in a species
• total no. different species
• percentage of land covered by induvidual in a species

Question 4

what are transects and how are they used?

Answer 4

measure how the abundance of a species changes as you move along a changing habitat
1. line called transect set up along changing habitat with tape measure
2. quadrat is placed at regular intervals along transect
3. at each inetrval, quarat can be used to record no. of induviduals in species, no. species and percentage cover

Question 5

population cycles between preadtors and prey?

Answer 5

• if population of prey increases, predators increase
• result in no. prey decreasing bc many predators
• population of predators will decrease bc lack of prey
• prey no. increase again- lack of predators

Question 6

carbon cycle?

Answer 6

CO2 removed from air by PHOTOSYNTHESIS plants and algae - use carbon to make carbs, proteins, fats
- carbon passed to animals when they feed on plants
- CO2 returned when plants, algae and animals RESPIRE (decomposers respire when they return mineral ions to the soil)
- co2 returned to air when wood/fossil fuels burnt

Question 7

water cycle?

Answer 7

• sun’s energy causes water to evaporate from sea/lakes –. water vapour
• transpiration also forms water vapour
• water vapour rises and condenses to form clouds
• precipitation - runs into lakes/ good for plants and animals
• runs into seas

Question 8

factors effecting rate of decomposition?

Answer 8

TEMPERATURE- chemical reaction work well in warm (if too hot, enzymes denature)
WATER- decomposers need it for survival (used for respiration)
- decomposers secrete enzymes on to decaying matter and absorb products of this digestion - need water

OXYGEN - most decomposers respire aerobically

Question 9

uses of decomposition?

Answer 9

COMPOST: produced by decay- used as natural fertiliser for plants and crops
-decomposers break down compost further so minerals are RECYCLED

BIOGAS GENERATORS : large containers in which animal or plant waste is allowed to decay anaerobically, as some decomposers break down substances without O2
- produces methane /Co2
- methane can be burned

Question 10

how does temperature, water availability and gas composition affect distrubution of species ?

Answer 10

TEMPERATURE : climate chnage can lead to insects migrating to hotter places
WATER : populations migrate to find water
GAS : certain pollutants affect distribution of organsims

Question 11

required practical : using random sampling to find population size of plant species

Answer 11

1. Use a random number generator to obtain 2 numbers, which are to be used as coordinates
2. Set down the quadrat at the coordinates.
3. Count and record the number of the required plant species in the quadrat.
4. Repeatsteps 1-3 to take 9 more samples.
5. Estimate the population size using this formula:
   area sampled / total area x number of plant species counted