Organisms And Population Flashcards
Father of ecology
Von Humboldt
Father of ecosystems ecology
E. P. Odum
Father of Indian ecology
Ramdeo Mishra
Ecology is basically concerned with four levels of biological organisation
Organisms
Populations
Communities
Biomes
The group of individuals resulting from even……… reproduction is also generally considered a population for the purpose of ecological studies
asexual
Assertion: Population ecology is an important area because it links ecology to population genetics and evolution.
Reason: Although an individual organism is the one that has to cope with a changed environment, it is at the population level that natural selection operates to evolve the desired traits
Whatever ecological processes we wish to investigate in a population, be it the outcome of competition with another species, the impact of a predator or the effect of a pesticide application, we always evaluate them in terms of any change in the……….
population size
Assertion: Population size, technically called population density (designated as N), need not necessarily be measured in numbers only.
Reason: Although total number is generally the most appropriate measure of population density, it is in some cases either meaningless or difficult to determine.
Parthenium hysterophorus refers to
Carrot grass
The tiger census in our national parks and tiger reserves is often based on
Pug marks
Fecal pellets
The density of a population in a given habitat during a given period, fluctuates due to changes in four basic processes
Natality
Immigration
Mortality
Emigration
Immigration is the number of individuals of the……… species that have come into the habitat from elsewhere during the time period under consideration.
same
Emigration is the number of individuals of the………. who left the habitat and gone elsewhere during the time period under consideration.
population
If a new habitat is just being colonised……… may contribute more significantly to population growth than…….
immigration
birth rates.
r values in exponential growth for following organisms is
Norway rat
Flour beetle
Human (old and new)
Norway rat= 0.015
Flour beetle =0.12
Humans (1981)=0.0205
The base of natural logarithms’e’ equal to
2.71828
Some organisms breed only once in their lifetime
Pacific salmon fish
bamboo
Some produce a large number of small-sized offspring
Oysters
Pelagic fishes
Pacific salmon
This kind of reproduction is ‘r’ type selection
Some produce a small number of large-sized offspring
Birds
Mammals
This kind of reproduction is ‘k’ type selection
The prickly pear cactus introduced into Australia in the early 1920’s caused havoc by spreading rapidly into millions of hectares of rangeland. Finally, the invasive cactus was brought under control only after a cactus-feeding predator……………….. from its natural habitat was introduced into the country.
Cactoblastis cactorum (moth)
Assertion: Predators also help in maintaining species diversity in a community
Reason: They reduce intensity of competition among competing prey species.
In the rocky intertidal communities of the American Pacific Coast the starfish………. is an important predator
Pisaster
In a field experiment, when all the starfish (Pisaster) were removed from an enclosed intertidal area, more than……. species of…….. became extinct within a year, because of inter-specific competition.
10
invertebrates
Statement 1: The Monarch butterfly is highly distasteful to its predator (bird) because of a special chemical present in its body.
Statement 2: The butterfly acquires this chemical during its caterpillar stage by feeding on a poisonous weed.
Both are correct
Nearly…….. per cent of all insects are known to be phytophagous
25%
feeding on plant sap and other parts of plants
Calotropis produces highly poisonous …………..and that is why you never see any cattle or goats browsing on this plant
cardiac glycosides
As per Darwin………. competition is a potent force in organic evolution
interspecific
Some totally unrelated species could also compete for the same resource.
True
In some shallow South American lakes, visiting flamingoes and resident fishes compete for their common food, the zooplankton in the lake.
The competition is best defined as a process in which the fitness of one species (measured in terms of its ‘r’ the intrinsic rate of increase) is significantly lower in the presence of another species
True
The………….in Galapagos Islands became extinct within a decade after goats were introduced on the island, apparently due to the greater browsing efficiency of the goats
Abingdon tortoise
A species whose distribution is restricted to a small geographical area because of the presence of a competitively superior species, is found to expand its distributional range dramatically when the competing species is experimentally removed
This phenomenon is referred to as
Competitive release
Example of competitive release
On the rocky sea coasts of Scotland, the larger and competitively superior barnacle Balanus dominates the intertidal area, and excludes the smaller barnacle Chathamalus from that zone.
In general……… & ………….. appear to be more adversely affected by competition than carnivores.
herbivores and plants
………………. of …………. states that two closely related species competing for the same resources cannot co-exist indefinitely and the competitively inferior one will be eliminated eventually
‘Competitive exclusion principle’
Gause
Statement 1: The species facing competition might evolve mechanisms that promote co-existence rather than exclusion.
Statement 2; One such mechanism is ‘resource partitioning’
Both are correct
For instance could avoid competition by choosing different times for feeding or different foraging patterns
………… showed that……. closely related species of warblers living on the same tree were able to avoid competition and co-exist due to behavioural differences in their foraging activities.
MacArthur
five
In order to be successful with the host species parasites evolved special adaptations such as
(4)
Loss of unnecessary sense organs
Presence of adhesive organs or suckers to cling on to the host
Loss of digestive system
High reproductive capacity.
The human liver fluke (a trematode parasite) depends on two intermediate hosts (2) to complete its life cycle.
a snail and a fish
Various species of freshwater fish, particularly those in the Cyprinidae family
Freshwater snails, particularly those from the family Lymnaeidae
Majority of the parasites harm the host they may reduce……./……/……of the host and reduce its population density.
the survival
growth
reproduction
Ectoparasites examples
Ticks on dogs
Live on humans
Copepods on marine fishes
…………… a parasitic plant that is commonly found growing on hedge plants, has lost its chlorophyll and leaves in the course of evolution.
Cuscuta
Assertion: The female mosquito is not considered a parasite
Reason: They just feed on blood for reproduction, they don’t live on or in the host, unlike true parasites
Statement 1: The life cycles of endoparasites are more complex because of their extreme specialisation.
Statement 2: Their morphological and anatomical features are also complex emphasising their reproductive potential.
Statement 1 is correct and 2 is incorrect
Their morphological and anatomical features are greatly simplified while emphasising their reproductive potential.
………….. in birds is a fascinating example of parasitism in which the parasitic bird lays its eggs in the nest of its host and lets the host incubate them
Brood parasitism
Brood parasitism is seen in ………… & ………….. during breeding season ie………….. season
Cuckoo (Koel) and crow
The Asian Koel, a cuckoo bird, is a brood parasite that lays its eggs in the nests of House Crows, which then raise the Koel chicks, while the Koel does not build its own nest
……………… is the interaction in which one species benefits and the other is neither harmed nor benefited.
Commensalism
Examples of commensalism
(4)
An orchid growing as an epiphyte on a mango branch
Barnacles growing on the back of a whale
The cattle egret and grazing cattle
Sea anemone clown fish
Explain example of egret and cows
The egrets always forage close to where the cattle are grazing because the cattle, as they move, stir up and flush out insects from the vegetation that otherwise might be difficult for the egrets to find and catch
Explain commensalism in sea anemone (Heteractis magnifica) and clown fish (Amphirion ocellaris)
The clown fish that lives among anemones and gets protection from predators which stay away from the stinging tentacles. The anemone does not appear to derive any benefit by hosting the clown fish.
Lichens represent an intimate mutualistic relationship between a fungus and photosynthesising algae only
False
Algae or Cyanobacteria
Statement 1: In many species of fig trees, there is a tight one-to-one relationship with the pollinator species of wasp.
Statement 2: It means that a given fig species can be pollinated only by its ‘partner’ wasp species and no other species.
Both are correct
The female wasp uses the fruit as an ……………… site and developing seeds within the fruit for……….
oviposition (egg-laying) site
nourishing its larvae.
The Mediterranean orchid……… employs ‘sexual deceit’ to get pollination done by a species of bee……..
Ophrys speculam
Colpa
In Ophrys a petal of flower bears an uncanny resemblance to the female of the bee in
(3) aspects
size
colour
markings
Statement 1: The male bee is attracted to what it perceives as a female, ‘pseudocopulates’ with the flower, and during that process is dusted with pollen from the flower.
Statement 2: When this same bee ‘pseudocopulates’ with another flower, it transfers pollen to it and thus, pollinates the flower.
Both are correct
Co evolution operates in the example of Colpa and Ophrys
True
If the female bee’s colour patterns change even slightly for any reason during evolution, pollination success will be reduced unless the orchid flower co-evolves to maintain the resemblance of its petal to the female bee.
Aposematic colouration means
Warning colouration where organisms display bright colors to signal toxicity or unpalatability to predators.
Correct, because the caterpillar’s bright colors warn predators of its toxic nature.
Batesian Mimicry refers to
This occurs when a harmless species mimics a toxic species to avoid predation.
Müllerian Mimicry refers to
This happens when two or more toxic species
resemble each other to reinforce the warning signal.
