Population Interactions

Question 1

Intraspecific relationship

Answer 1

Relationship between the organisms of the same species is known as intraspecific relationship

Question 2

Mutualism (symbiotic)

Answer 2

Mutualism is an interaction between two species in which both are benefited

Question 3

Mutualism- examples

Answer 3

1. Rhizobium (soil bacteria- nitrogen fixation) and root of leguminous plants (provide water, minerals and shelter)
2. Lichens (epiphyte): Algae (photosynthetic partner) and fungi (substratum- anchor: H2O and minerals)
3. Trichonymph (digest cellulose) in the gut of termites (shelter)
4. Pollination: insects (pollinate flowers) and flowers (provide nectar)
5. Mycorrhiza- Fungi seen entangled in roots of higher plants
   penetrates into roots (endo)
   cab be seen entangled (ecto)
   helps prevent soil erosionn

Question 4

Commensalism

Answer 4

Positive interaction where one organism is benefitted and the other organism is neither benefitted nor harmed

Question 5

Commensalism examples

Answer 5

1. Clown fish and sea anemone (not benefitted): Clown fish hide in the sea anemone for protection
2. Trees (not benefitted) and birds building nests
3. Epiphytes on trees (not benefitted)
4. Egrets on cattle (not benefitted)
5. Shark and barnacles (when shark catches prey, barnacles eat the crumbs)

Question 6

Predation

Answer 6

Negative interaction which is a kind of direct food relationship between two species of animals in which one, called predator, captires and feeds on the other, prey

Question 7

Predator prey interaction examples

Answer 7

Venus fly trap - insect
Pitcher plant - insect

SEDENTARY PREDATORS

Question 8

Parasitism

Answer 8

Negative interaction between two species in which one (known as parasite) obtains its food in ready-made form from the other living organism (host)

Question 9

Types of parasitism

Answer 9

1. Endoparasitism
2. Ectoparasitism
3. Brood parasitism

Question 10

Endoparasitism

Answer 10

Parasite seen inside/within body of the host

E.g. Tapeworm, liver fluke, blood fluke, hookworm, Ascaris (roundworm)

Question 11

Ectoparasitism

Answer 11

Parasite seen on the outside/surface of the body of the host

E.g. Tick, flea, leech, lice

Question 12

Brood parasitism

Answer 12

E.g. cuckoo bird (parasite) lays eggs in crow (host) nest and lets the crow incubate them

Question 13

Competition

Answer 13

competition is rivalry between two individuals which require a resource that is in short supply

Question 14

Interspecific competition

Answer 14

Survival instinct in the community for food shelter
Two species utilizing the same limited resource

Question 15

Intraspecific competition

Answer 15

Competition occuring between members of the same species
Competition for food, shelter, mating

Individual survival instinct

Question 16

Population

Answer 16

A group of individuals of the same speicies is known as a population

Question 17

Biotic community

Answer 17

An association of a number of different interrelated populations belonging to different species in a common environment

Question 18

Gause’s competitive exclusion principle

Answer 18

No two species of organisms can occupy the same niche at the same time

Question 19

What can intense competition between two organisms occupying the same niche lead to

Answer 19

1. One species becomes extinct
2. One species is forced to migrate to a different area
3. The two species may adjust to slightly different niches to avoid competition