SPEC FOR SOME ECO BITZ X

Question 1

lag phase

Answer 1

slow population growth
nutrient assimilation- activate genes to produce enzymes to eg metabolise food
few reproducing organism

Question 2

exponential phase

Answer 2

fast population growth not limited by food or other resources
birth rate / death rate
large no of reproducing organism

Question 3

stationary phases

Answer 3

population levels off = carrying capacity
br = dr
interspecific completion, predation and disease increase

Question 4

decline phase

Answer 4

population may fall or even die out due to food shortages or disease
dr / br
waste accumulation

Question 5

What influences exponential / stationary phase

Answer 5

competition for resources

waste accumulation

Question 6

What influence stationary / decline phase

Answer 6

availability of resources (R and NR)

Question 7

features of r-selected species

Answer 7

eg algae, bacteria, mice, grass
small body size
short lived
reproduce rapidly 
disperse rapidly 
pioneer species
population density variable 
evolve rapidly

Question 8

features of k selected species

Answer 8

eg humans, trees
large body size
long lived
reproduce slowly 
disperse slowly 
climax species
population density constant- stay at carrying capacity  
evolve slowly

Question 9

competition

Answer 9

• /- interaction which generally leads to the elimination of one species
• two or more organism are competing for a resource which is in short supply.
• interspecific/ interspecific
• neither species can grow as fast as they’d like
• one is better competitor
• competition exclusion

Question 10

mutualism

Answer 10

+/+ interaction
both species benefit from living together
NFB and plant

Question 11

parasitism

Answer 11

-/+

parasitism live on/in host and benefits and the host is harmed but stays alive.

Question 12

grazing

Answer 12

-/ +

Question 13

predator / prey

Answer 13

- / +
prey always higher no- energy diagram 
no prey increase as few predators 
no predators will increase more food available 
prey will decrease due to predation. 
no predators fall.
- oscillations fairly reg
-time lag

Question 14

ideal natural predator

Answer 14

• reduce pest no quickly
• only attack pest
• does not cause harm or interfere with other species
• thrive in habitat
• does not need reapplied

Question 15

adv biological control

Answer 15

• cost effective
• no bioaccumulation of chemical through the food chain
• very specific to pest- sprays may kill useful organism too
• no resistance developed
• constantly keep pest at low level

Question 16

disadvantage biological control

Answer 16

• pest not completely irradiated
• spread into other ecosystems
• must be able to thrive

Question 17

Factors that influence population size

Answer 17

birth
death
immigration
emigration

Question 18

ecological community

Answer 18

biotic component of an ecosystem and involving interaction between autotrophic and heterotopic population

Question 19

secondary succession

Answer 19

predictable, faster, repeatable process of community development in an area where the climax community was destroyed by fire, flooding, wind, human activity

Question 20

primary produces

Answer 20

1st trophic level

Question 21

features of a succession

Answer 21

no soil, few minerals -/ deep fertile soil
low biomass -/ high biomass
low biodiversity -/ high biodiversity
small animals -/ large animals

Question 22

pyramid of numbers

Answer 22

• large carnivore small parasites

- large plant and many wee herbivores

Question 23

pyramid of biomass

Answer 23

• seasonal change
• difficulty obtaining mass of eg plant
• kj/ area

Question 24

pyramid of energy

Answer 24

• always a pyramid
• kj/ unit area/ year
• kill organism obtain energy

Question 25

agriculture probs

Answer 25

• extra energy cost of producing animal products
• fertiliser to increase primary productivity
• confinement to improve respiration/ production ratio
• high energy food eg silage or protein