Sustainability and Interdependence, KA 5-7

Question 1

What is symbiosis?

Answer 1

Co-evolved intimate relationships between members of two different species.

Question 2

Parasitic relationships

Answer 2

A parasite benefits in terms of energy or nutrients, whereas its host is harmed by the loss of these resources.

Question 3

Why can’t parasites survive out of contact with a host?

Answer 3

Parasites often have limited metabolism and cannot survive out of contact with a host.

Question 4

Transmission of parasites

Answer 4

Transmission of parasites to new hosts using direct contact, resistant stages and vectors.

Question 5

Parasitic life cycles

Answer 5

Some parasitic life cycles involve intermediate (secondary) hosts to allow them to complete their life cycle.

Question 6

Mutualism

Answer 6

Both mutualistic partner species benefit in an interdependent relationship.

Question 7

What do animals living in social groups have?

Answer 7

Many animals live in social groups and have behaviours that are adapted to group living such as social hierarchy, co-operative hunting and social defence.

Question 8

What is social hierarchy?

Answer 8

Social hierarchy is a rank order within a group of animals consisting of a dominant and subordinate members.
In a social hierarchy, dominant individuals carry out ritualistic (threat) displays whilst subordinate animals carry out appeasement behaviour to reduce conflict.

Question 9

Why is social hierarchy beneficial?

Answer 9

Social hierarchies increase the chances of the dominant animal’s favourable genes being passed on to offspring.

Question 10

Why do animals form alliances in social hierarchies?

Answer 10

Animals often form alliances in social hierarchies to increase their social status within the group.

Question 11

Give three benefits of co-operative hunting

Answer 11

1. Co-operative hunting may benefit subordinate animals as well as dominant ones, as they may gain more food than by foraging alone.
2. Less energy is used per individual.
3. Co-operative hunting enables larger prey to be caught and increases the chance of success.

Question 12

Social defence

Answer 12

Social defence strategies increase the chance of survival as some individuals can watch for predators whilst others can forage for food.
Groups adopt specialised formations when under attack, protecting their young.

Question 13

What is altruism?

Answer 13

An altruistic behaviour harms the donor individual but benefits the recipient.
Behaviour that appears to be altruistic can be common between a donor and a recipient if they are related (kin).

Question 14

Why does the donor benefit in kin selection?

Answer 14

The donor will benefit in kin selection in terms of the increased chances of survival of shared genes in the recipient’s offspring or future offspring.

Question 15

Reciprocal altruism

Answer 15

Reciprocal altruism, where the roles of donor and recipient later reverse, often occurs in social animals.

Question 16

Give four examples of social insects

Answer 16

Social insects include bees, wasps, ants and termites.

Question 17

What is the structure of social insects’ society?

Answer 17

Only some individuals (queens and drones) contribute reproductively.
Most members of the colony are sterile workers who co-operate with close relatives to raise relatives

Question 18

What other roles do workers carry out?

Answer 18

Other examples of workers’ roles include:
Defending the hive
Collecting pollen
Carrying out waggle dances to show the direction of food.

Question 19

Why do sterile workers raise relatives?

Answer 19

Sterile workers raise relatives to increase survival of shared genes.

Question 20

Why do primates have a long period of parental care?

Answer 20

Primates have a long period of parental care to allow learning of complex social behaviour.

Question 21

Social hierarchies in groups of primates

Answer 21

Complex social behaviours support the social hierarchy.
This reduces conflict through ritualistic display and appeasement behaviour.
Alliances form between individuals, which are often used to increase social status within the group.

Question 22

Give four examples of primate behaviours

Answer 22

Grooming, facial expression, body posture and sexual presentation.

Question 23

What are components of biodiversity?

Answer 23

Components of biodiversity are genetic diversity, species diversity and ecosystem diversity.

Question 24

What is genetic diversity?

Answer 24

Genetic diversity is the number and frequency of all the alleles within a population.

Question 25

Loss of genetic diversity

Answer 25

If one population of a species dies out then the species may have lost some of its genetic diversity, and this may limit its ability to adapt to changing conditions.

Question 26

What is species diversity?

Answer 26

Species diversity comprises the number of different species in an ecosystem (the species richness) and the proportion of each species in the ecosystem (the relative abundance).

Question 27

Species diversity and dominant species

Answer 27

A community with a dominant species has a lower species diversity than one with the same species richness but no particularly dominant species.

Question 28

What is ecosystem diversity?

Answer 28

Ecosystem diversity refers to the number of distinct ecosystems within a defined area.

Question 29

Overexploitation

Answer 29

With overexploitation, populations can be reduced to a low level but may still recover.
Some species have a naturally low genetic diversity in their population and yet remain viable.

Question 30

What is the bottleneck effect?

Answer 30

Small populations may lose the genetic variation necessary to enable evolutionary responses to environmental change.

Question 31

What is the impact of the bottleneck effect?

Answer 31

In small populations, this loss of genetic diversity can be critical for many species, as inbreeding can result in poor reproductive rates.

Question 32

What has led to habitat fragmentation?

Answer 32

The clearing of habitats has led to habitat fragmentation.

Question 33

Why does habitat fragmentation decrease biodiversity?

Answer 33

Degradation of the edges of habitat fragments results in increased competition between species as the fragment becomes smaller.
This may result in a decrease in biodiversity.

Question 34

Isolated and smaller fragments

Answer 34

More isolated fragments and smaller fragments exhibit a lower species diversity.

Question 35

How do we remedy widespread habitat fragmentation?

Answer 35

Isolated fragments can be linked with habitat corridors.

Question 36

What are the benefits of habitat corridors?

Answer 36

The corridors allow movement of animals between fragments, increasing access to food and choice of mate.
This may lead to recolonization of small fragments after local extinctions.

Question 37

What are introduced species?

Answer 37

Introduced (non-native) species are those that humans have moved either intentionally or accidentally to new geographic locations.

Question 38

What are naturalised species?

Answer 38

Introduced species that become established within wild communities are termed naturalised species.

Question 39

What are invasive species?

Answer 39

Invasive species are naturalised species that spread rapidly and eliminate native species, therefore reducing species diversity.

Question 40

Why do invasive species thrive?

Answer 40

Invasive species may well be free of the predators, parasites, pathogens and competitors that limit their population in their native habitat.

Question 41

Why are invasive species a problem?

Answer 41

Invasive species may prey on native species, out-compete them for resources or hybridise with them.