genomes to ecosystems lecture 7- individuals, communities and population

Question 1

what are the three levels of an ecosystem?

Answer 1

community, population and individual

Question 2

is population the same species?

Answer 2

Because we’re discussing organisms at a specific time & place, using ‘population’ is more accurate. Populations are of the same species so they could theoretically interbreed, but don’t for some reason – geographic separation, ecological separation, different times

Question 3

what are key biological processes?

Answer 3

Growth, Metabolism, Activity, Thermoregulation, Reproduction

Question 4

why do they need to reproduce?

Answer 4

Need animals to produce more animals: individual survival & fitness

Reproduction is only process that really affects POPULATION, but as a result of all the survival processes, those reproductive resources only constitute a part of the overall energy available within an individual. They also must be allocated WITHIN reproduction and those differences affect how likely a population is to survive under certain environmental conditions

Question 5

what is succession?

Answer 5

sequence of development of vegetation from a sterile surface

Question 6

what is primary succession?

Answer 6

a new bare surface such as emergence of a new island, a mud volcano - mud, fine sand and a solid rock

Question 7

what is secondary succession?

Answer 7

destruction of existing vegetation such as Deforestation, human-related destruction of habitat, natural destruction

Question 8

what is an example of secondary succession?

Answer 8

History:Cricket field
War
School ground
Football field
Sowed grass
Unmanaged, litter
Series of motivations for green space for the community, now managed by volunteers and show facilitated regrowth (visit during Biol2A lab: Habitat Differences)

Question 9

what is the initiation stage?

Answer 9

bare substrate, no vegetation and 0 adaptations

Question 10

what is the colonisation stage?

Answer 10

low-nutrients, low water, unstable soil. bryophytes and lichens. stress tolerant, small, rapidly growing and reproducing

Question 11

what is the development stage?

Answer 11

stable soil, grasses and seeds. competitive and disturbance tolerant adaptation

Question 12

what is the mature stage?

Answer 12

stable, nutrient and water rich soil. competitive grasses, bushes and small trees. less disturbance tolerant

Question 13

what is the climax stage?

Answer 13

stable, nutrient rich soil. large trees and is now long lived and disturbance intolerant

Question 14

what are density independent processes?

Answer 14

factors that have nothing to do with the size of the population itself, generally abiotic factors such as floods and volcanic eruptions

Question 15

what are types of stressors which affect all individuals regardless of the size of population?

Answer 15

wind-Cold temperatures, High winds, High UV
light- Low PAR (<1% energy above canopy)
salt-High salt toxic to plants, desiccates cells
water-Desiccates cells, Reduces photosynthesis
temperature- Damage due to freezing, water loss
ph-Damage from toxic compounds; change gas exchange

Question 16

how does dispersal affect population

Answer 16

Dispersing individuals leave natal area to find a new location to survive as adults. Often happens early in life (larval, seed, juvenile) to avoid problems of overpopulation (leave territory of parents)

Question 17

what are advantages of dispersal

Answer 17

Finding resources
Finding better conditions
Reducing competition
Avoiding inbreeding depression

Question 18

what are disadvantages of dispersal

Answer 18

Energy cost
Increased risk of predation
Lack of settlement

Question 19

what is competition?

Answer 19

Competition: negative effects by one organism consuming or controlling access to a limited resource

Question 20

what are the outcomes of competition?

Answer 20

Coexistence: Ecological differentiation

Elimination: Dominant species ousts (‘outcompetes’) others

Question 21

what species are good competitors?

Answer 21

Good competitors: Broad distributions, abundant
Influence distribution of other species
Competition based on success of traits and stress/disturbance trade-off

Question 22

what is the result of competition?

Answer 22

dominant get their preferred and subordinate get the suboptimal

Question 23

what does assemblage mean?

Answer 23

Assemblage: collection of interacting populations in the same geographic area

Few organisms occur simply in their own population. Most populations occur in the same place as a range of other species, so have the same resources available. Some assemblages consist of a food web, where some populations require others to survive, whereas others are competing for the same resource.

Question 24

what does fundamental niche mean?

Answer 24

Fundamental Niche: set of resources under which organisms COULD survive

Question 25

what is the realised niche?

Answer 25

set of conditions under which a group of organisms ACTUALLY survive

Question 26

what are invasive species?

Answer 26

Invasive species evolved under a different set of evolutionary pressures and in different communities of predators, so when they arrive in a new location without those, they can outcompete native species, both dominating resources, predating on native species and spreading disease

Question 27

what are examples of invasive species?

Answer 27

giant hogweed, rhododendron, American skunk cabbage, Himalayan bales, killer shrimp, carpet sea squirt, harlequin ladybird, American signal crayfish and American mink

Question 28

what does success require?

Answer 28

Success requires some advantage to access different resources as rest of crowd eg darwins finches

Question 29

what is spatial variation?

Answer 29

Mosaic of stresses & disturbances: ‘patches’
More habitats, niches = higher biodiversity

Question 30

what is temporal variation?

Answer 30

Changes throughout period of time
Predictable variation = predictable response
such as months and seasons

Question 31

how does population of organisms vary?

Answer 31

predation, disease, parasitism, competition