ESS Topic 2

Question 1

Niche

Answer 1

particular set of abiotic and biotic conditions and resources to which an organism or population responds

Question 2

Carrying capacity

Answer 2

max no. of species or ‘load’ that can be sustainably supported by a given area,
resource becomes scarce as it nears it,
depends on limiting factors

Question 3

Limiting Factors

Answer 3

slow down growth of a population as it reaches its carrying capacity

Question 4

Biotic Factors

Answer 4

living components of an ecosystem that directly or indirectly affect another organisms

Question 5

Abiotic Factors

Answer 5

non-living physical factors that influence organism and ecosystem

Question 6

Niche Overlap

Answer 6

if two organisms establish niche in the same area and competition occurs - in mating food and resources

Question 7

how to avoid niche overlap

Answer 7

different organisms go for different resources - increases survival

Question 8

Fundamental niche

Answer 8

potential occupied niche

Question 9

realised niche

Answer 9

portion of fundamental niche a species actually occupies based on other factors impacting where the species actually occupies

Question 10

S curve

Answer 10

starts with exponential growth - no limiting factors affect growth at first –> however after certain population size growth (carrying capacity) rate slows down resulting in constant population

Question 11

J Curve

Answer 11

show a ‘boom and bust’ pattern - population grows exponentially at first and then suddenly collapses - often exceeds carrying capacity on a long-term or continuing basis before collapse occurs

Question 12

diebacks

Answer 12

sudden collapses in J curve

Question 13

overshoot

Answer 13

when population exceeds carrying capacity on a long-term or continuing basis before the collapse occurs

Question 14

Competition

Answer 14

interaction between organisms over a resource

Question 15

Interspecific competition results

Answer 15

balance (shared resource)
or competitive exclusion

Question 16

Parasitism

Answer 16

relationship between two species in which one species lives in or on another - gaming its food from it

Question 17

Mutualism

Answer 17

relationship between two or more species in which all benefit and none suffer

Question 18

Commensalism

Answer 18

a relationship between two species where one benefits and the other is not affected

Question 19

Respiration

Answer 19

increases entropy of a system while organisms maintains high level of organisation aka low entropy

Question 20

Primary Producer

Answer 20

makes own food,
provides energy requirements of all other trophic levels,
habitat for tother organisms,
supply nutrients to the soil

Question 21

Primary Consumer

Answer 21

consumes PP,
keep each other in check through negative feedback loops,
disperse seeds

Question 22

Decomposer

Answer 22

obtain energy from dead organisms by secreting enzymes that break down the organic matter

Question 23

Ecological Pyramids

Answer 23

include number, biomass, productivity (energy),
quantative models,
uses - easy examination of energy transfer and losses,
given an idea of what organisms exist at different trophic levels,
help demonstrate that ecosystems that are in balance

Question 24

Pyramids of numbers

Answer 24

advantages:
simple method of giving overview and good for comparing changes in population numbers over time

disadvantages:
all organisms included regardless of size,
does not allow for juveniles or immature forms,
number can be too great to represent accurately

Question 25

Pyramids of Biomass

Answer 25

advantages:
overcomes problems of pyramids of no.

disadvantages:
only uses samples - impossible to measure exactly,
organisms must be killed to measure dry mass

Question 26

Pyramid of Productivity

Answer 26

advantages:
most accurate,
allows for comparison based on relative energy flows,
not inverted pyramids,
solar radiation added

disadvantages:
very difficult to collect data
problem of assigning species to a particular trophic level

Question 27

Earth’s energy budget

Answer 27

as solar radiation (insolation) enters earth’s atmosphere some energy becomes unavailable as its absorbed by inorganic matter or reflected back into atmosphere

Question 28

Productivity

Answer 28

conversion of energy into biomass over given period of time,
rate of growth or biomass increase in plants and animals

Question 29

Net Productivtiy

Answer 29

they are deductions in energy organisms use in respiration instead of growing

Question 30

Primary Productivity

Answer 30

autotrophs are base unit of all stored energy
light energy converted into chemical energy through photosynthesis

Question 31

Net Primary/Secondary Productivity

Answer 31

GPP (gross) or GSP - Respiration

Question 32

Nitrates

Answer 32

formed from decay of dead oganisms - N2 in air and nitrates in soil
formed by nitrogen fixing bacteria - transformed into soil

Question 33

Gross Secondary Productivity

Answer 33

food eaten - fecal loss

Question 34

Nitrogen Fixation

Answer 34

nitrogen in air combines with other elements

Question 35

Ammonification

Answer 35

nitrogen transformed in ammonia

Question 36

Assimilation

Answer 36

when plants and animal take ammonia and nitrates as food for energy

Question 37

Denitrification

Answer 37

nitrate is converted into nitrogen gas and put back into atmosphere

Question 38

Bioaccumulation

Answer 38

non-biodegradable chemicals taken in by animals and plants which they do not excrete causing concentration of chemcials in an ecosystem to increase over time

Question 39

biomagnification

Answer 39

chemical’s concentration magnified from one trophic level to another

Question 40

Biomes

Answer 40

aquatic, forest, grassland, desert and tundra

Question 41

Factors governing distribution of biomes

Answer 41

insolation, precipitation, temperature

Question 42

zonation

Answer 42

change in community along environmental gradient due to spaital and static factors

Question 43

factors influencing zonation

Answer 43

temperature - decreases with increasing latitude,

precipitation - on mountains most rainfall is at middle so forests grows - higher up too dry for trees,

solar insolation - more intense at higher altitudes - plants adapts,

soil type - in warmer zones decompositon is fast so soils deeper and more fertile,

interactions between species - competition may crow out some species and grazing may alter plant composition

Question 44

Succession

Answer 44

change in species composition over time

Question 45

primary succession

Answer 45

on bare inorganic surface - colonisation of newly created organisms

Question 46

stages in primary sucession

Answer 46

colonisation - establishment - competition - stabilisation - climax community

Question 47

secondary succession

Answer 47

already established community is suddenly destroyed an abridged version of succession occurs –> because occurs on soils already developed and ready to accept seeds carried by wind

Question 48

Methods for estimating biomass and energy of trophic levels in a community

Answer 48

measurement of dry mass, controlled combustion, extrapolation from samples

done to construct ecological pyramids

Question 49

Methods for estamiting abundance of non-motile organisms

Answer 49

quadrats, measuring population density, percentage cover, percentage frequency

should repeat measurements for realiability

Question 50

Estimating abundance of motile organisms

Answer 50

direct - actual counts and sampling
indirect - capture mark recapture and application of licoln index