Lecture 9-10 Mutualism and Symbiosis

Question 1

What Is Symbiosis?

Answer 1

Symbiosis is when organisms live together

Question 2

what is mutualism

Answer 2

Mutualism when species live together in a mutually beneficial relationship

Question 3

How does mutualism and symbiosis differ?

Answer 3

For organisms to engage in a mutualistic relationship, both species must be benefiting the other in some way that is usually related to food and resources

Question 4

What are the different types of reciprocal change

Answer 4

Nutritional, Defensive, and dispersal

Question 5

Nutritional Mutualism

Answer 5

When species get food or shelter from a plant, that plant will receive nutrients from the organism

Question 6

Defensive Mutualism

Answer 6

Exchange of protection for food

Question 7

Dispersal mutualism

Answer 7

Plants and animals will exchange seed dispersal for food. So the animals will eat the food from plants, expel them with seeds and the seeds will flower

Question 8

Invasional Meltdown

Answer 8

This is when 2 non native species facilitate mutualism and propel each other’s growth

Question 9

What is Reciprocal Adaptation?
Give an example

Answer 9

Reciprocal Adaptation includes two species that have specific traits that seem to fit together, and this match will facilitate an evolutionary growth with each other and benefit each other’s fitness

An example is Darwin’s Orchid where this orchid has a very narrow path and in order for it to be pollinated it requires an insect wit a vary long and narrow sucking tube.

Question 10

Mutualist Networks

Answer 10

Mutualist networks explain that mutualist relationships are strictly tied to 2 species alone, in most cases 2 species will benefit each other, which benefit others. New generations will produce new partners to form mutualist interactions, known as horizontal transmission

Question 11

Microbiomes

Answer 11

All the microbes living in a community

Question 12

Dispersal

Answer 12

Species moving out to a new area nearby

Question 13

What are the benefits of dispersal

Answer 13

• avoid competition
• avoid in breeding
  -colonize new areas

Question 14

Metapopulation

Answer 14

Spatially distinct populations that are connected through dispersal

Question 15

What is a patch? How does it relate to metapopulations?

Answer 15

A patch is a distinct population in a metapopulation

Question 16

What is the benefit of metapopulations in terms of avoiding or recovering from extinctions

Answer 16

If a patch goes extinct, it can be locally repopulated by neighbouring patches

Question 17

How can metapopulations allow for species co-existence

Answer 17

When predators and prey exist in unstable communities where they are quickly being killed off because of resource limitation, the solution usually involves in pairing these numbers so they can form a stable communities, through dispersal

Question 18

What is involved in patch dynamics?

Answer 18

Patch dynamics looks at patch occupancy over time.
in patch occupancy, we look at the colonization, which is affected by the fraction of average occupied patches, P and the fraction of empty patches, 1-P

Question 19

What is the model of Levin’s Patch occupancy? Explain each variable.

Answer 19

dP/dT= cP(1-P)-eP

c= constant
P=Patches
1-P= fraction of empty patches
e= constant that relates the rate at which patches go extinct

Question 20

What does global co-existence require?

Answer 20

Species A must be better at dispersing, or a faster disperser
Species B must always outcompete them
This is a competition-colonization trade-off

Question 21

Example of a metapopulation

Answer 21

Pikas are an example of a metapopulation because they have a varying occupancy in different patches and a source sink pattern

Question 22

What are the different ways a population can be driven to extinction?

Answer 22

competitive exclusion
predator-prey interactions
Allee effect at low tendencies
stochasticity fluctuations in population numbers

Question 23

How are these tendencies countered

Answer 23

Predation through preventing competitive exclusion
variation in life-history trade-off, competition colonization

Question 24

What is a Metacommunity and how does it differ from a metapopulation

Answer 24

metacommunity is a set of local communities that are linked through the dispersal of local species.

This is different from metapopulation because the latter is spatially distinct population linked through dispersal

Question 25

What determines the number of species on an island

Answer 25

colonization
extinction
in-situ speciation

Question 26

What is the goal of the theory of island biogeography?

Answer 26

Predict the population of a species by looking at the island’s size and isolation
MacArthur and Wilson only considered colonization and extinction

Question 27

What is the difference in the equilibrium value at a far and near island

Answer 27

Sn>Sf

Question 28

What is the difference in equilibrium value at a small and large island?

Answer 28

Sl>Ss

Question 29

For all types of island, list equilibrium value in terms of largest to smallest

Answer 29

Snl>Sns>Sfl>Sfs

Question 30

How does habitat size and isolation affect species richness

Answer 30

Habitat size decreases with isolation and increases with are

Species richness will be very small if habitat size decreases with isolation