Ecology

Question 1

Modified populations

Answer 1

Populations humans interfere with - through hunting, harvesting, translocation

Question 2

Density of population

Answer 2

Not static - births, deaths, migration

Question 3

Demography

Answer 3

Key characteristics of a population
Quantifying pattens - who stays/goes/lives/dies

Question 4

Survivorship curves

Answer 4

How many individuals alive at each age
Type one - humans (low offspring high survival)
Type 2 - squirrels (decrease steadily)
Type 3 - tree (lots of young, reduce quick)
Stepped curves - death rate higher at certain life stages

Question 5

K selection life history

Answer 5

Population living near limits imposed by resources ; at or near carrying capacity
Eg mature trees in old growth forest

Question 6

R selection life history

Answer 6

Populations have unlimited resources
Eg weeds in disturbed gardens

Question 7

Density independent factors

Answer 7

Forces that affect size of population regardless of birth/death rate eg cyclone

Question 8

Density dependant

Answer 8

Births / Deaths dependant on population growth. Usually halts growth
Eg disease

Question 9

Dispersion

Answer 9

Pattern of spacing among individuals within the boundaries of a population
Clumped, - water, food
Uniform - territories, burrows
Random - resting animals, weed dispersal

Question 10

Dispersal

Answer 10

Process involving the movement of individuals away from the population they were born in to another to settle and reproduce

Question 11

Active dispersal

Answer 11

Fly, swim, walk, run

Question 12

Passive dispersal

Answer 12

Float, raft, transported

Question 13

Dispersal barriers

Answer 13

Barriers that limit physical movement
Anthropogenic, physical, behavioural

Question 14

Range expansion

Answer 14

Expansion of an area a species is found in - natural or human influenced
Eg cane toads

Question 15

Metapopulations

Answer 15

A number of local populations that
are linked - occupy discrete patches of suitable habitat surrounded by unsuitable habitat
- spatially discrete (migration limited)
- extinction risk
- not static

Question 16

Possible meta population structures

Answer 16

Classical (uniform/natural)
Patchy (random)
Mainland-island
Non-equilibrium (highly isolated, low interaction between pop)

Question 17

Attributes of habitat patches

Answer 17

Size appropriate
Quality
Isolation
Within dispersal distance
Ability for organisms to establish

Question 18

Ways of tracking movement

Answer 18

Tagging (bands, gps or satellite)
Genotyping (sex, relatedness, tissue, scat, hair, eDNA)
Photo id (natural markings, drones, ai, videos)
Rates of movement (individual/generational)

Question 19

Physical plant defences

Answer 19

• thorns
• trichromes (hairy insect deterrents)
• waxy surface
• leaf structure (thick cell walls)

Question 20

Aquatic plant defences

Answer 20

Thinner structures to maximise light and carbon
More likely to have chemical defences

Question 21

Herbivore offense

Answer 21

Toxins for own defences
Food choice
Eat tissues with high nutritional value and low toxins
Morphological evolution around digestion