Species Interactions & Ecosystems

Question 1

name 2 species interactions where both species benefit

Answer 1

Mutualism,

Proto-cooperation

Question 2

name 4 species interactions where 1 species benefits and 1 species is hindered

Answer 2

Predation,
Parasitism,
Herbivory,
Disease

Question 3

name a species interaction where both species are hindered

Answer 3

competition

Question 4

define ammensalism

Answer 4

species interaction where 1 species is harmed and the other is unaffected

Question 5

define neutralism

Answer 5

a species interaction where neither species is affected

Question 6

define commensalism

Answer 6

a species interaction where one species benefits and the other is unaffected

Question 7

what is direct competition

Answer 7

species competing for the same essential resource e.g. plants for sunlight

Question 8

what is indirect competition

Answer 8

competition by altering the micro-habitat, and thus affecting other individuals

Question 9

what is monopoly of space

Answer 9

first arrivals prevent establishment of late arrivals

krebs 2001

Question 10

what is asymmetrical competition

Answer 10

one species impairs the performance of another (s)

Question 11

what is reciprocal competition

Answer 11

performance of both/all species is reduced

also known as diffuse competition

Question 12

what is diffuse competition

Answer 12

performance of both/all species is reduced

also known as reciprocal competition

Question 13

what is complete competition

Answer 13

species do not occur together – spatial exclusion, zonation along gradients of resources, disturbance etc

Question 14

what is exploitative competition

Answer 14

utilising the same resource that is in short supply

also known as resource competition

Question 15

what is resource competition

Answer 15

utilising the same resource that is in short supply

also known as exploitative competition

Question 16

what is interference competition

Answer 16

Organisms harm each
other directly while using the same resource – although
the resource may not be in short supply

also known as contest competition

Question 17

what is contest competition

Answer 17

Organisms harm each
other directly while using the same resource – although
the resource may not be in short supply

also known as interference competition

Question 18

what is apparent competition

Answer 18

Species of the same trophic level not using the same resources may influence the other species via regulation of common predator densities

here the competition is not for a resource, but for predator-free space

Question 19

how does character displacement enable avoidance of direct competition

Answer 19

differences among similar species whose distributions overlap geographically are accentuated in regions where the species co-occur, but are minimized or lost where the species’ distributions do not overlap to enable occupation of different niches (evolve slightly differently morphology when occuring with other species in similar niches)

Question 20

give 2 examples of character displacement

Answer 20

Darwin finches Geospiza fortis and G. fuliginosa differ in beak sizes when occurring together.
(Krebs 2001)

giant rhinozeros beetles (Chalcosoma spp.) vary in body size where occurring together, whereas no significant difference is detected between body sized where only one species occurs.
(Begon et al 2006)

Question 21

what are the 4 forms of predation within the food web hierarchy

Answer 21

herbivores

parasites

carnivores

parasitoids

Question 22

which forms of predation involve killing the prey

Answer 22

carnivores and parasitoids

Question 23

what are herbivores

Answer 23

animals preying on (parts of) green plants – often not killing the plant

Question 24

what are parasites

Answer 24

plants/animals living on a host, depending on itshost for nutrition – normally without killing the host

Question 25

what are carnivores

Answer 25

animals (or plants) preying on other animals – normally killing the prey

Question 26

what are parasitoids

Answer 26

Parasitoids – laying eggs into insects which are subsequently eaten alive from within and finally killed

Question 27

what is the common growth response to predation in plants

Answer 27

Compensatory growth and increased fitness – clipping at some stages increased the number of fruits, whereas it had a negative effect at other times.

Question 28

how do carnivores select prey?

Answer 28

In carnivores, common prey is often favoured and | eaten in over-proportionally high numbers, with predators becoming increasingly specialised on one prey

Question 29

what is batesian mimicry

Answer 29

mimicry in which an edible animal is protected by its resemblance to one avoided by predators.

Question 30

example of batesian mimicry

Answer 30

moths, beetles, hoverflies etc have evolved to resemble the common wasp

Question 31

what is mullerian mimicry

Answer 31

a form of mimicry in which two or more harmful or unpalatable animals develop similar appearances as a shared protective device.

Question 32

example of mullerian mimicry

Answer 32

many Heliconius butterflies have identical morphology

Question 33

which interaction takes place between coral polyps and zooxanthellae

Answer 33

mutualism Coral polyps live in close association with algae (Zooxanthellae), which provide them with oxygen and carbohydrates, receiving CO2, nutrients and protection in exchange. If the algae die / are „ejected“ from polyp, the coral “bleaches“ and (after a while) the polyps die

Question 34

what is a community

Answer 34

A collection of co-ocurring individuals of different | species (i.e. being in the same place at the same time).

Question 35

what is an ecosystem

Answer 35

an organism and its surroundings, any one of the parts of which constantly acts on the rest, in so far as they at the same time act on it (Haldane 1884)

Question 36

characteristics of an ecosystem

Answer 36

- interacting system of organisms and their environment - no clear boundaries - homogeneous in relation to biogeochemical cycling - including all fluxes of energy and matter above and below the soil surface

Question 37

how do mountains effect biomes

Answer 37

Mountains form specific oro-biomes which may differ greatly from the surrounding environment

Question 38

what is a biome

Answer 38

major terrestrial ecosystem with unique and specific climatic conditions, soils, organisms, and location generally following a latitudinal distribution