Protective colouration and sucession

Question 1

Aposematic colours

Answer 1

Warning colours to show that they are poisonous

Question 2

Mimicry

Answer 2

Bastian = palatble (not harmful) insects resemble brightly coloured distasteful species

Mullerian = unrelated distasteful species resemble one another

Question 3

Predator-prey co-evolution

Answer 3

predators evolve to overcome prey’s anti-predator defense mechanisms

Question 4

Co-evolution

Answer 4

Parallel developement of adaptions in a population or species that are so constantly interacting with each other that start to exert selective pressure on each other.

Question 5

Interspecific competition forms

Answer 5

Interference - Individuals of one species harm another species directly. Animals fight for resources . Plants release toxins that prevent other plants growing close.

Exploitative - 2 or more populations exploit the same limited resource. Presence of 1 species reduces the resource availability for others.

Question 6

Gause experiement

Answer 6

Studies competition among 3 species of Paramecium grown in culture tubes feeding on the same bacteria.
2 experiments = growing alone and growing together. Constant carrying capacity. Same bacteria. Removed waste materials. Monitored population growth over time.

Conclusions:
Competitive exclusion principle - populations of 2 or more species that rely on the same limiting resource and exploit them in the same way cannot exist indefinitely.
One species in more successful and will harvest resources more efficiently and produce more offspring.

Question 7

Ecological niches

Answer 7

No 2 species can have the same niche.
How it utilizes resources of its environment.
Space, Food consumption, temperature range, Moisture requirements.

Question 8

What is a habitat?

Answer 8

The place where an organism lives. Same habitat but different niches.

Question 9

Fundamental niche

Answer 9

The environemntal conditions and the resources that a population can tolerate and use = total abiotic niche available

Question 10

Realised niche

Answer 10

The environmental conditions and resources that a population truly uses = used by organisms after competition have been taken into account.
Smaller than the fundamental niche.
Some resources are utilised by other species

Question 11

Interactions and ecological niches

Answer 11

Experiments by Joseph Connel
Studies rocky shores and interspecific competition in barnacles.
How interspecies interaction affects the niche.

Question 12

Resource partitioning

Answer 12

Simpatric species divide resources to prevent direct competition.
Utilise different resources for the different species.
They are uniquely adapted for a specific resource
Focus on one specific adaption to avoid competition.

Question 13

What is character displacement?

Answer 13

Reducing interspecific competition
Allopatric - same but different geographic area
Sympatric - Different but in the same geographic area

Question 14

3 types of symbiosis?

Answer 14

Commensalism - one species benefits other is unaffected.
Mutaluism - both species benefit
Parasitism - One benefits the other is harmed.

Question 15

What is commensalism?

Answer 15

One species have positive gai whilst the other is unaffected.
Highly co-evolved mutualism

Question 16

What is mutal cooperation?

Answer 16

Both species gain something. both make inputs
Ants an acacia

Question 17

What is parasitsm?

Answer 17

Exremely small predators
Prey loses something and they gain something.

Ecto-parasites:
External
Have elaborate sensory and behavioural mechanisms.

Endo-parasites:
Internal
complete lifecycle inside hosts

Parasitoids = insects that lay eggs inside larvae, young consume the tissues as they grow.

Question 18

What is a keystone species?

Answer 18

Changes the entire community composition.
Beavers, figs and rhinos
Conserving keystone species = conserves other species.

Question 19

Trophic structure

Answer 19

Primary producers
Primary consumers
secondary consumers
tertiary consumers
quatenary consumers.

Question 20

Food chain

Answer 20

What eats what?
One organism eats another
Links organisms from food to the consumers.

Question 21

Factors that influence biodiversity

Answer 21

Disturbance
Evolutionary age
Climate - type of environment
Immigration rate - the area is conducive for immigrating or extinction
Are extinction effects - How easily does an are expend extinction

Question 22

Ecological succession

Answer 22

Communities change over time = succession
response to disturbance
alter habitats and resources in ways that favor other species

Question 23

Primary succession

Answer 23

devastated lifeless basin with no previous communiy or after a volcanic eruption.

Question 24

Secondary succession

Answer 24

After fire in fynbos
Existing communities are disturbed,

Question 25

Climax vs. Pioneer

Answer 25

Pioneer - was the first and can be dispersed quite far.
Climax - end of succession has a long lifecycle and limited offspring. It occurs once the ecosystem has been established.

Question 26

What are the 3 different models of succession?

Answer 26

Tolerance
Facilitation
Inhibition

Question 27

Tolerance

Answer 27

succession proceeds because competitively superior species replace competitively inferior ones
early-stage species neither facilitate nor inhibit the growth of later-stage species
more species arrive at a site and resources become limiting, competition eliminates species that cannot harvest scarce resources successfully

Question 28

Facilitation

Answer 28

that species modify the local environment in ways that make it less suitable for themselves but more suitable for colonization by species typical of the next successional stage
changes in species composition are both orderly and predictable because the presence of each stage facilitates the success of the next

Question 29

Inhibition

Answer 29

that new species are prevented from occupying a community by whatever species are already present
Succession is neither orderly nor predictable because each stage is dominated by whichever species happen to colonize the site first

Question 30

Processes of Succession

Answer 30

results from a combination of facilitation, inhibition, and tolerance
with interspecific differences in dispersal, growth, and maturation rates
Disturbance and density-independent factors also play important roles, in some cases speeding successional change
In other cases, disturbance inhibits successional change, establishing a disturbance climax (disclimax) community

Question 31

Effect of disturbance on communities

Answer 31

intermediate disturbance hypothesis, species richness is greatest in communities that experience fairly frequent disturbances of moderate intensity
Moderate disturbances allow K-selected species to survive while creating openings for r-selected species to arrive
Where disturbances are severe and frequent, communities include only r-selected species with fast life cycles
Where disturbances are mild and rare, communities are dominated by long-lived K-selected species

Question 32

Why is species richness is the highest in the tropics and decrease as you move towards the poles?

Answer 32

High temperatures allows for high metabolic activity in animals and areas of plentiful food sources.

Question 33

Evolutionary age and latitude diversity gradient

Answer 33

The poles experienced ice ages.
Nearly all the species in the poles died during the ice age and thus these regions may still be busy recovering.

Question 34

Latitude and Climate gradients

Answer 34

the primary reason for latitudinal species richness.
The two major climatic factors: sun light and water availability

Question 35

Variations in Species Richness

Answer 35

Difference in species richness based on latitude and climate

Question 36

Species richness on islands depends on?

Answer 36

• Size of island
• Distance from mainland
• Immigration and emigration
• Extinction

Question 37

equilibrium theory of island biogeography

Answer 37

Robert MacArthur & Edward O Wilson
addresses variations in species richness on islands of different size and different levels of isolation from other landmasses
An equilibrium between immigration and extinction ultimately determines the number of species that occupy an island
The mainland forms a species pool from which species immigrate to offshore islands as new colonizers
As the number of species on an island increases, the extinction rate rises –influenced by competition and predator-prey interactions

Question 38

MacArthur en Wilson

Answer 38

Island species richness depends on the balance between colonisation and extinction.
The mainland holds a species pool that act as source of immigration.
Balance between immigration and extinction
Islands further away from the mainland is harder for colonisers to find
Larger islands can maintain larger populations as they have a lower chance of extinction

Question 39

Effect of Island Size

Answer 39

At equilibrium, large islands have more species than small islands
Large islands have higher immigration rates than small islands do because they present a larger target
Large islands have lower extinction rates because they can support larger populations and provide a greater range of habitats and resources

Question 40

Effect of Distance from Mainland

Answer 40

At equilibrium, islands that lie closer to a mainland source have more species than more distant islands
Islands near the mainland have higher immigration rates than distant islands because dispersing organisms are more likely to locate them
Distance does not affect extinction rates

Question 41

why is island biogeography so important?

Answer 41

Species overall area started to reduce
More compititons
More chance of extinction
One species will always start to out-compete the others
Species start to diversify and speciate.

Question 42

Immigration of Arthropods to Mangrove Islands

Answer 42

The island nearest to the mainland had more species than the most distant island