s It is also called facultative mutualism.
s E.g., crocodile bird enters the open mouth of crocodile and rids the latter of leeches.
- Mutualism
s Mutualism is an interaction between two organisms of different species where both the partners are benefitted with none of the
two are capable of living separately.
s E.g., mycorrhiza is a mutualistic interaction between a fungus (e.g., Boletus) and a root (e.g., Pinus). The root provides food
and shelter to fungus. The fungus helps the plant in solubilisation and absorption of minerals, water uptake and protection
against pathogenic fungi.
- Competition
s It is a rivalry between two or more organisms for obtaining the same resources.
s Competition can be intraspecific (among individual of same species) or interspecific (among members of different species).
Table: Differences between intraspecific and interspecific competition
Intraspecific Competition Interspecific Competition
(i) It is competition among individuals of the same species. The competition is amongst the members of different species.
(ii) The competition is for all the requirements. The competition is for one or a few requirements.
(iii) The competing individuals have similar type of adaptations. The competing individuals have different types of adaptations.
(iv) It is more severe due to similar needs and adaptations. It is less severe as the similar needs are few and the adaptations
are different.Gause’s Hypothesis (Principle of Competitive Exclusion)
s “Competitive Exclusion Principle” states that two closely related species competing for same resources cannot co-exist indefinitely
and competitively inferior one will be eliminated eventually.
- Match the column I with column II and select the correct
option.
Column I Column II
(i) Gloger’s rule (p) Fish of cold water and tend
to have more vertebrae.
(ii) Allen’s rule (q) Pigmentation is less in
warm blooded animals of
colder areas.
(iii) Rensch’s rule (r) Animals of colder areas
have shorter extremities.
(iv) Bergmann’s rule (s) Birds have narrow wings in
cold areas and broader
wings in warm areas.
(v) Jordan’s rule (t) Warm blooded animals of
colder areas have larger
size than those of warmer.
areas.
(a) (i)-q, (ii)-r, (iii)-p, (iv)-s, (v)-t
(b) (i)-t, (ii)-p, (iii)-s, (iv)-q, (v)-r
(c) (i)-q, (ii)-r, (iii)-s, (iv)-t, (v)-p
(d) (i)-r, (ii)-q, (iii)-p, (iv)-s, (v)-t- Level of ecological hierarchy where biological community
interacts and exchange materials with its surroundings is
(a) biome (b) landscape
(c) ecosystem (d) biosphere. - Which of the following statement
is correct for the given graph?
(a) A represents
conformers which
maintain constant body
temperature through
thermoregulation.
(b) B are ectothermic organisms and can live comfortably
both in Antarctica and in Sahara desert.
(c) C are partial regulators, which regulate their body
temperature to a limited extent.
(d) A are poikilotherms and stop their development
during unfavourable conditions.