Topic 22 -Symbiosis

Question 1

Symbiosis is

Answer 1

an intimate relationship between two organisms. (‘together living’)

one or both species depends on the other for survival
relationship can be + - or neutral

Question 2

Parasitism includes

Answer 2

parasite, host

+/-

Question 3

Mutualism includes

Answer 3

sp. 1 and sp.2

+/+

Question 4

Commensalism includes

Answer 4

commensal, host

+/0

Question 5

Parasitism increases their fitness by exploiting a host organism

Answer 5

Food, habitat (safe), dispersal

both the parasite and host can regulate each others population growth (Lotka-Volterra)

Question 6

Parasites tend to not kill their hosts

Answer 6

no advantage to killing its host because host provides habitat and food source (dead host-> dead parasite)

host uses energy to defend against the parasite-> redirects energy from growth and reproduction

Question 7

results of parasitism

Answer 7

decreased reproduction success, redirect energy to growth and survival, reduced expression of of secondary sexual characteristics (attraction)

increased mortality due to secondary infections

increased mortality due to increased susceptibility to predation -decreased ability to escape predators, more conspicuous to predators via abnormal behaviour

Question 8

Parasites can be

Answer 8

specialists, generalists, short lived or long lived

Question 9

parasites can be classified as

Answer 9

microparasites -viruses, bacteria and fungi, small size and develop rapidly

macroparasites -flatworms, roundworms lice, fleas, ticks, rusts, and smuts
large size and develop slowly

Question 10

ectoparasites

Answer 10

live on the skin, within the hair, or feathers of their host

Question 11

endoparasites

Answer 11

live within the hosts body, in the heart, brain, spinal cord, nasal tracts, lungs, digestive tract or circulatory system

Question 12

Direct transmission

Answer 12

parasite is transferred from one host to the other directly
influenza, smallpox, sexually transmitted diseases
fleas, ticks, lice, mites, round worms
direct physical contact, water or air

Question 13

indirect transmission

Answer 13

parasite is transferred from one host to an intermediate (vector) and then to another host
malaria by mosquitoes
protozoan parasite
can result in complex lifestyles

Question 14

Mutualism

Answer 14

during coevolution -host-parasite and predator-prey relationships may become beneficial to both species

ex cnidarian polyp and photosynthetic algae

Question 15

reciprocal exploitation

Answer 15

using each other

Question 16

cooperative effort

Answer 16

combine efforts

Question 17

Commensalism

Answer 17

a relationship between two species where one species benefits without significantly effecting the other (+/0)
uncommon and unrealistic
ex. Barnacle-whale
ex. Shark- remora
shark -no cost/benefit
but remoras may remove bacteria and parasites from host -> mutualism?