energy and ecosystems - topic 5

Question 1

define habitat

Answer 1

the place where an organism lives

Question 2

define population

Answer 2

all of the individuals of one species living in a habitat

Question 3

define community

Answer 3

multiple populations living and interacting in the same area

Question 4

define ecosystem

Answer 4

a community and its interactions with the non-living parts of its habitat

Question 5

define biotic factor and give 3 examples

Answer 5

living factor
- predators
- food availability
- intra/interspecific competition
- disease
- parasitism

Question 6

define abiotic factor and give 3 examples

Answer 6

non-living factor
- humidity
- temperature
- soil/water PH
- O2 / CO2 concentration
- light intensity

Question 7

define niche

Answer 7

the role of a species within its habitat

Question 8

why cant two species occupy the same niche?

Answer 8

species will be in direct competition and one will outcompete the other

Question 9

define abundance

Answer 9

the number of individuals of a particular species living in a habitat

Question 10

what is sampling used for?

Answer 10

investigating the abundance and distribution of species and populations

Question 11

what are the two types of sampling?

Answer 11

random and systematic

Question 12

what does random sampling avoid?

Answer 12

bias

Question 13

describe systematic sampling

Answer 13

sampling points are located at fixed intervals throughout the sampling site.

Question 14

list two methods that can be used to assess distribution and abundance

Answer 14

transect
quadrat

Question 15

what are plants called in an ecosystem?

Answer 15

producers

Question 16

GPP definition

Answer 16

chemical energy store in plant biomass (total energy resulting from photosynthesis).

Question 17

NPP definition

Answer 17

NPP=GPP-R the chemical energy store in plant biomass taking into account the energy lost due to respiration

Question 18

what is NPP used for?

Answer 18

create new biomass that is passed on to the next trophic level

Question 19

Define succession

Answer 19

the change in an ecological community over time

Question 20

what is the first species to colonise an area called? and give an example

Answer 20

pioneer species
- lichen

Question 21

how does lichen change the abiotic factors to become less harsh?

Answer 21

death and decomposition of lichen forms a thin layer of humus and so mosses and smaller plants seeds can now survive
can hold more water
more soil depth

Question 22

what is the final community formed in succession called?

Answer 22

climax community

Question 23

what does primary succession start with

Answer 23

pioneer species

Question 24

describe the process of primary succession

Answer 24

• pioneer species such as lichen colonises bare rock
• decomposition of lichen forms humus
• mosses + smaller plants can survive in the depth and nutrients of the humus
• abiotic factors continue to get less harsh until a climax community is formed with a dominant species

Question 25

what is meant by secondary succession?

Answer 25

succession is disrupted and plants are destroyed, succession restarts but soil is present.

Question 26

what increases as succession occcurs?

Answer 26

biodiversity

Question 27

what happens when succession is managed?

Answer 27

earlier stages are miantained preventing a climax a community. a greater variety of habitats are conserved and therefore a greater range of species.

Question 28

describe and explain how succession occurs (6)

Answer 28

**primary** * pioneer pecies * such as lichen * occupies bare rock * decomposes forming humus * changing abiotic factors **primary succession - intermediate** * seeds can now germinate due to less harsh abiotic conditions * environment becomes more suitable for new species **primary succession - climax** * environment becomes less suitable for previous species * final species to colonise = dominant species * formation of a climax community

Question 29

why would the NPP of a primary consumer be less than a producer?

Answer 29

* some parts of producer not ingested * some parts not digestible * some energy lost as respiritory loss * some energy lost by excretion

Question 30

what is the advantage of two species occupying a different niche?

Answer 30

* they dont have to compete for the same food/water/light * both species can survive