Prediction and succession

Question 1

How have predator and prey evolved?

Answer 1

both = faster movement and more effective camouflage  
predator= better means of detecting prey 
prey= better protective features

Question 2

What is predation?

Answer 2

when one’s organism is consumed by another

Question 3

Describe the prey-predator graphs

Answer 3

cyclic fluctuations

Question 4

Describe the relationship between predators and prey

Answer 4

predator eats prey so pop. of prey decreases
decreases prey = increase competition for predators
decrease pop. of predators as some are unable to survive ad reproduce due to lack of prey
fewer prey eaten so more can survive and reproduce
increases the prey population which in turn increases the predator population

Question 5

What other factors can play a part in population size other than prey/predator pop.

Answer 5

disease and climate factors

Question 6

What should you always mention when the environment changes

Answer 6

selection pressure

species evolve to be better adapted

Question 7

Define conservation

Answer 7

management of the earth natural resources by humans for max. us in the future.

Question 8

what are the reasons for conservation?

Answer 8

personal
ethical
economic
cultural
 aesthetic

Question 9

What can conservation look like?

Answer 9

preventing succession to preserve habitats by burning to destroy young tree spellings

Question 10

Define succession

Answer 10

term used to describe the changes in an ecosystem

Question 11

At each stage, the species may alter the environment to ….

Answer 11

make it less suitable for the existing species
make it more suitable for other species with different adaptations

this alters the abiotic environment to make it less hostile

Question 12

What is the first stage of succession?

Answer 12

the colonisation of an inhospitable environment by pioneer species

Question 13

what features of the pioneer pieces help them colonise?

6

Answer 13

asexual reproduction
production of vast quantities of wind dispersing seeds/spores
rapid germination of seeds on arrival so no dormancy period
the ability to photosynthesis
the ability to fix nitrogen from the atmosphere as soil as little to no nutrients
tolerance to extreme conditions

Question 14

What is the ultimate community in the UK?

Answer 14

Deciduous Oak woodland

Question 15

Define the Climax Community

Answer 15

When the species are balanced and in equilibrium so are stable

Question 16

Name the 5 common features of succession

Answer 16

abiotic environment = less hostile 
greater number and variety of habitats and niches
increased biodiversity
more complex food webs
increased biomass

Question 17

Describe secondary succession

Answer 17

more rapid as land has been altered to prevent climax community from being reached

Question 18

One farmer stated that the increase in the use of Bt crop plants had caused a
mutation in one of the insect species and that this mutation had spread to other
species of insect. Was he correct?

Answer 18

1. Mutations are spontaneous / random;
2. Only the rate of mutation is affected by environment;
3. Different species do not interbreed / do not produce fertile offspring;
4. So mutation

Question 19

There was a time lag between the introduction of Bt crops and the appearance of
the first insect species that was resistant to the Bt toxin.
Explain why there was a time lag.

Answer 19

1. Initially one / few insects with favourable mutation / allele;
2. Individuals with (favourable) mutation / allele will have more offspring;
3. Takes many generations for (favourable) mutation / allele to become the
   most common allele (of this gene).