week 12

Question 1

What is the definition of symbiosis?

Answer 1

A situation in which dissimilar organisms are working together, whether mutualistic or parasitic

Question 2

What is the definition of mutualism?

Answer 2

This is where both the host and the parasite benefit from their relationship

Question 3

What is the definition of Commensalism?

Answer 3

This is where parasites benefit from the relationship but the host is not harmed.

Question 4

What interaction type are mutualism and commensalism?

Answer 4

Facilitation

Question 5

What is the definition of facilitation?

Answer 5

An interaction in which either one or both parties benefit with no harm to the others

Question 6

What is the definition of parasitism?

Answer 6

Parasite harms its host, or lives at the expense of the host

Question 7

What is the definition of a parasitoid?

Answer 7

A parasite that causes the death of its host

Question 8

What is definition of a phoresis?

Answer 8

A parasite is transported by the host

Question 9

Why do species have mutalism?

Answer 9

This is because they have gradually evolved to become reliant on each other
They do this for resources, habitats and pollination

Question 10

What are 2 examples of mutualism for resources?

Answer 10

legumes and rhizobium
coral and zooxanthellae

Question 11

What is an example of mutualism for habitat?

Answer 11

Acacia and ants
The ants protect the tree from herbivores and other competing plants
In return they provide enlarged thorns as a home and concentrated food sources

Question 12

What are the benefits of commensalism?

Answer 12

Food (sea birds feeding off a bait ball)
Habitats (microorganisms on our faces)
Reproduction (seed dispersal)

Question 13

Give an example of commensalism

Answer 13

Cattle egret and cattle
They feed on the insects which are disturbed by cattle grazing

Question 14

What are the two types of competition?

Answer 14

Interspecific and intraspecific

Question 15

What is the definition of intraspecific competition?

Answer 15

This is competition that takes place between individuals- This can be for food, water, nutrients or a suitable habitat.

Question 16

What is the definition of scramble competition?

Answer 16

Where many individuals within a niche are competing for the same resource so all individuals get a small part

Question 17

What is the consequences of scramble competition?

Answer 17

All competitors will decline equally in fitness

Question 18

What is an example of scramble competition?

Answer 18

Plants in a pot
All are competing for the same amount of nutrients but only a set amount can be provided

Question 19

What is the definition of contest competition?

Answer 19

Where multiple individuals compete for the same resource with only one remaining victorious

Question 20

What are the consequences of contest competition?

Answer 20

Some individuals succeed, others do not

Question 21

What is an example of contest competitions?

Answer 21

Birds and their territory
Some succeed in securing a territory where others go without
this deprives them of food, mates and a habitat

Question 22

What is intraspecific competition?

Answer 22

Competition amongst individuals of different species

Question 23

What is intraspecific competition?

Answer 23

Competition among individuals of the same species

Question 24

What is Gause’s principle of competitive exclusion?

Answer 24

Two species with two identical niches cannot coexist indefinitely

Question 25

Give an example of interspecific competition

Answer 25

Grey vs Red squirrels They had a direct competition (for resources) and an indirect competition (introduction of paramyxovirus)

Question 26

What is the definition of antagonistic coevolution?

Answer 26

Where two species in a predator prey relationship evolve together to try and work against each other

Question 27

What are the four types of defences prey employ?

Answer 27

Physical (spines on acacias) Chemical (pheromones/toxins) Morphological (mimicry) Behavioural (hiding or warning others)

Question 28

What are three predatory hunting tactics?

Answer 28

Ambush Stalking Pursuit

Question 29

What are some defences that plants use to deter predators?

Answer 29

Physical barriers (thorns etc) Chemical (nitrogen- based, terpenoids and phenolic)

Question 30

How would you describe a graph showing the relationship between predator and prey?

Answer 30

An out of phase cycle- the prey population always peaks slightly before the predator population peaks

Question 31

What is the definition of community?

Answer 31

When many different species live together within one habitat (the biotic component of an ecosystem)

Question 32

What is the definition of a guild?

Answer 32

A group of species that depend on the same resource

Question 33

Describe the calculations for food webs

Answer 33

L= number of links S= number of species L/S= Linkage density L/S2= Direct connectedness (Max L, cannibalism incl) L/[S(S-1)/2]= connectivity (no cannibalism and unidirectional)