Populations

Question 1

Habitat vs. Niche

Answer 1

Habitat - an area where an organism lives

Niche - exact role an organism plays in its habitat, including all the abiotic and biotic conditions required for the organism to survive and reproduce

Question 2

Fundamental niche

Answer 2

• aka -> potential niche
• where it is possible for an organism to survive
• determined by abiotic factors

Question 3

Realised niche

Answer 3

• aka -> actual niche
• where an organism actually survives
• reduces volume than the fundamental niche due to competition
• determined by abiotic and biotic factors

Question 4

Competitive exclusion principle

Answer 4

• no two organism of different species can occupy the same niche indefinitely
• complété competitors cannot exist
• results in niche separation, to avoid competitive advantages

Question 5

MRR

Answer 5

• allocate an area with a defined boundary
• capture a group of individuals and tag with a non-invasive, non-toxic market that would not result in any disadvantage to the organism
• reintroduce into population and allow enough time for even distribution
• capture another sample and count the number of tagged organisms
• déterminé population using Lincoln-Peterson Index

Question 6

Lincoln-Peterson index

Answer 6

• multiply samples 1 and 2
• divide by the number of tagged individuals recaptured
• population estimate

Question 7

Abiotic limiting factors on population

Answer 7

• temperature
• pH
• light
• humidity
• wind speed
• tidal range
• wave/water speed
• viral infection

Question 8

Biotic limiting factors on population

Answer 8

• intraspecific competition
• interspecific competition
• predation
• bacterial disease

Question 9

Sampling

Answer 9

• representation (proved accurate by statistical testing)

* affected by change (REPEAT) and bias (RANDOM)

Question 10

Use systematic sampling for

Answer 10

Gradual change in conditions

Question 11

Picking a quadrat

Answer 11

• species size
• evenness of distribution
• rarity of species

Question 12

How does temperature affect carrying capacity?

Answer 12

• optimum for enzymes
• réduction in plant metabolic rate
• dénaturation
• higher homeostatic energy expenses; less energy for growth, maturation and reproduction

Question 13

How does light affect carrying capacity?

Answer 13

• ultimate energy source for most ecosystems; basic necessity of life
• rate of photosynthesis increases with light intensity
• rate of growth and spore production increases with rate of photosynthesis
• increases plant and plant-eating carrying capacities

Question 14

How does pH affect carrying capacity?

Answer 14

• any deviation from optimum means carrying capacity is tiny

Question 15

How does water affect carrying capacity?

Answer 15

• lack of aquatic creatures

* only organisms adapted to dry conditions can survive

Question 16

How does humidity affect carrying capacity?

Answer 16

• transpiration and evaporation affected

Question 17

When abiotic conditions shift from optimum

Answer 17

Population sizes decrease- species without suitable adaptations become extinct (barring evolution through advantageous alleles)

Question 18

Human population

Answer 18

• affected by natality, mortality, immigration and emigration

Question 19

Population pyramids

Answer 19

• a series of stacked bars representing percentages of males and female in each age group
• useful because population growth depends on females of child-bearing age
• product future trends for populations
• show demographic transitions

Question 20

Increasing populations

Answer 20

• base of population pyramid is higher than the apex

* typical of less economically developed countries

Question 21

Competition

Answer 21

Arises from insufficient resources to fully satisfy the requirements of two individuals sharing

Question 22

Availability of resources

Answer 22

Determines population size

Question 23

Predation

Answer 23

• interspecific relationship

* consumption of one consumer with another

Question 24

Predator

Answer 24

• a consumer that feeds on another (prey)

* evolved speed and camouflage

Question 25

Prey

Answer 25

* a consumer consumed by another | * evolves canouflage, protective features and concealment behaviour

Question 26

Predators and prey....

Answer 26

Evolve alongside each other, otherwise extinction would occur, which is rare

Question 27

Prey escape due to

Answer 27

* greater area for travel * potential refugee * not being the only predated species

Question 28

Describe the predator-prey graph

Answer 28

* predators consume prey, reducing their population * greater intraspecitic competition between predators * predators population decreases due to inability to survive and reproduce * there are cyclic fluctuations in populations * periodic population crashes influence evolution by creating selective pressures

Question 29

Succession

Answer 29

Changes experiences by dynamic ecosystems due to population fluctuations

Question 30

Succession stages

Answer 30

* colonisation of différent species, changing the abiotic conditions * results in out-competition due to adaptations * forms new community, altering biodiversity

Question 31

Pioneer species

Answer 31

* colonise an inhospitable environment * forma pioneer community * use photosynthesis * have wind-dispersed seeds or spores that undergo rapid germination without dormancy * fix nitrogen * xérophytic

Question 32

Climax community

Answer 32

* many species flourish - relatively high biodiversity | * stable over long periods

Question 33

Ramifications of stages of succession

Answer 33

* decrease is hostility of abiotic conditions * proliferation of habitat and niche number * increases biodiversity (decreases slightly with climax community with out competition of pioneer species) * more complex food we’ve * higher biomass

Question 34

Secondary succession

Answer 34

* disruption of climax community by abiotic factors * succession stages begin again * faster due to established hospitality