Organisms and evolution - 4

Question 1

ecological niche

Answer 1

multidemensional summary of tolerances and requirements of a species

Question 2

fundamental niche

Answer 2

set of resources species is capable of using in absence of interspecific competition

Question 3

realised niche

Answer 3

set of resources species actually uses in response to interspecific competition

Question 4

what is the competitive exclusion principle?

Answer 4

when realised niche of two species are similar, one population starts to decline leading to local extinction

Question 5

what is resource partitioning?

Answer 5

species with similar niches co-exist and exploit different components of the same resource

Question 6

what is symbiosis?

Answer 6

close relationships between individual organisms of different species

Question 7

what type of parasite lives on surface of host?

Answer 7

ectoparasite

Question 8

what is an endoparasite?

Answer 8

parasite that lives within a host

Question 9

do parasites have a broad or narrow niche?

Answer 9

narrow niche

Question 10

what does the term degenerate mean?

Answer 10

lack structures and organs found in other organisms

Question 11

what is a definitive host?

Answer 11

where parasite reaches sexual maturity

Question 12

in which host does sexual reproduction occur?

Answer 12

definitive host

Question 13

what occurs in the intermediate host?

Answer 13

developmental stages

Question 14

what is a vector?

Answer 14

transfers parasite from host to host

Question 15

what does sexual reproduction in parasites allow?

Answer 15

rapid evolution

Question 16

what does the asexual phase in parasites allow?

Answer 16

rapid build up of parasite population for dispersal into next host

Question 17

what are the 6 types of parasites?

Answer 17

• bacteria
• viruses
• nematodes
• platyhelminths
• arthropods
• protists

Question 18

what is transmission?

Answer 18

spread of parasite to new host

Question 19

what is the term used to describe the harm that parasite causes host species?

Answer 19

virulence

Question 20

what are the two evolutionary stable strategies?

Answer 20

• low transmission, low virulence

- high transmission, high virulence

Question 21

what are the two evolutionary unstable strategies?

Answer 21

• low transmission, high virulence

- high transmission, low virulence

Question 22

what are four factors that can increase transmission rates?

Answer 22

• overcrowded, high density (host)
• use of vector
• waterborne dispersal stages
• exploiting natural behaviour of host

Question 23

what happens when a parasite exploits the natural behaviour of host?

Answer 23

host behaviour is modified and becomes part of extended phenotype

Question 24

what are four factors that can increase virulence?

Answer 24

• selection pressure increases parasite growth and reproduction in host
• suppress the host immune system
• modify size of host
• reduce host’s reproductive rate