1.
S.No. Criteria
1
2
a
b
3
4
Vulnerable
Reduction in
population size over
> / = 50 %
last 10 years or 3
generations
Geographic range in
the form of
Extent of
20000 km2
occurrence
Area of occupancy 2000 km2
Population size
10000 mature
estimated to
individuals
number fewer than
Quantitative
analysis showing the
probability of
10%
extinction in the
wild in last 10 years
is at least
Non Vulnerable
< 50 %
> 20000 km2
> 2000 km2
> 10000 mature
individuals
< 10%
2. Predation rates increased with increasing prey population density. This
resulted from 2 effects:
(1) each predator increased its consumption rate when exposed to a higher prey
density, and (2) predator density increased with increasing prey density.
These effects can be visualized as 2 kinds of responses of predator population to
prey density:
(1) the functional response and
(2) the numerical response
The functional response assumes that a predator spends its time on 2 kinds of
activities:
1. Searching for prey
2. Prey handling which includes: chasing, killing, eating and digesting.
Consumption rate of a predator is limited because even if prey are so abundant
that no time is needed for search, a predator still needs to spend time on prey
handling.
Numerical response means that predators become more abundant as prey
density increases. However, the term "numerical response" is rather confusing
because it may result from 2 different mechanisms:
1. Increased rate of predator reproduction when prey are abundant
(numerical response per se)
2. Attraction of predators to prey aggregations ("aggregational response")
Reproduction rate of predators naturally depends on their predation rate. The
more prey consumed, the more energy the predator can allocate for reproduction.
Mortality rate also reduces with increased prey consumption
3. In Batesiian mimics the mimic resembles the successful species but does
not share the attribute that discourages predation. Mimic in this case is
defenseless. e.g., Monarch butterfly (contains toxins in body) is mimicked by
Viceroy butterfly (contains no toxins)
In Müllerian mimics the mimic resembles the successful species and shares
the anti-predation attribute. Mimic share the same defense mechanism as
those of model. e.g., Monarch butterfly (contains toxins in body) is mimicked
by Queen butterfly (contains toxins)
4. Micro & Macroparasite
Character
Body Size
Intrinsic rate of
population growth
Interactions with host
individuals in natural
population
Effect of the interaction
on host
Stability of the
interaction
Ability to regulate lower
tropic level
Micro parasite
Very smaller than host
Much faster than host
Macro parasite
Smaller than host
Faster than host
One host usually
supports several
population of different
species
Mildly to fairly
deleterious
Intermediate
One host supports few to
may individuals of
species
Moderate
Low
Intermediate
High
5. Mutualism is relationship between two organisms that benefit both. In
facultative mutualism partners can survive in the absence of mutualism and
can lead independent life. Plant – Myccorrhiza is an example of facultative
mutualism.
However, in Obligatory mutualism partners cannot survive independently.
For survival both partner has to enter into mutualism. Lichen for example is
obligate mutualism between specific fungi & specific algae. In the absence of
such association both fungi and algae will not survive.
6. In ecology, a niche is a term describing the relational position of a species
or population in an ecosystem. More formally, the niche includes how a
population responds to the abundance of its resources and enemies (e. g., by
growing when resources are abundant, and predators, parasites and
pathogens are scarce) and how it affects those same factors (e. g., by reducing
the abundance of resources through consumption and contributing to the
population growth of enemies by falling prey to them). The abiotic or physical
environment is also part of the niche because it influences how populations
affect, and are affected by, resources and enemies. The full range of
environmental conditions (biological and physical) under which an organism
can exist describes its fundamental niche.
As a result of pressure from, and interactions with, other organisms (e.g.
superior competitors) species are usually forced to occupy a niche that is
narrower than this and to which they are mostly highly adapted. This is
termed the realized niche