# data[].attributes.body
Ecological interactions are the biological interactions that a pair of organisms living together in a community have on each other.
They can be either of the same species or of different species.

# data[].attributes.body
1. Predation

2. Parasitism

3. Competition

4. Mutualism

5. Commensalism

# data[].attributes.body
Predation - It is an interaction between two different species where one is called predator and the other is prey.

Examples:

1. Locust insects harm the seed crop by predating on it.

2. Lion(predator) eating a deer(prey).

3. Snake(predator) killing rat(prey).

# data[].attributes.body
Parasitism:The interaction between an organism (called parasite) which is unable to prepare its own food and have to depend upon other organism (called host) for obtaining food and shelter is known as parasitism.

In such kind of interaction one species (parasite) gains while the other (host) is harmed but not killed by the association.

Examples:

1. Ticks, tapeworms (animal parasite);

2. Cuscuta (plant parasite)

# data[].attributes.body
Competition is a population interaction between two closely related species that are fighting for the same resources.

Competition is harmful for both the species involved, and the stronger partner outlives the weaker one, sometimes driving the weaker one to extinction.

Examples:

1. Lions and cheetahs compete for the prey in the African Savanna.

2. Dogs compete for territory and mark it with urine.

3. Gorillas fight with each other to be the alpha male

# data[].attributes.body
Mutualism: a relationship in which both species are mutually benefited.

This relationship can either be within the species or between the two different species.

The species with this relationship is termed as symbionts.

Mutualism is a type of relationship between the host and a symbiont, where both organisms benefit and no one is harmed.

This relationship may either continue for longer or for shorter-term.

The term mutualist is used to indicate the small partner and the host are the other partners present in the Mutualism.

Examples:

1. Ants live and feed on the nectar of acacia trees. Here ants are the mutualist and acacia trees is the host. The acacia tree provides home and food for the ants. As they have hollow huge thorns – homes for the ants and yellow swellings on the leaves- food for the ants. In reverse ants acts a guard attacking insects and protects the tree from grazing animals.

2. Oxpecker (a kind of bird) and the rhinoceros or zebra

3. Mycorrhizae is a mutualism between fungi and the roots of higher plants. In this, the fungi help the plant in the absorption of essential nutrients from the soil. In return, the plant provides food to the fungi.

# data[].attributes.body
Commensalism is a relationship between two organisms where one organism is benefited from the other, whereas the other is neither harmed nor benefited.

It is a biological interaction that organisms form, in the quest of food and shelter.

The organism that benefits from this biological interaction is known as the commensal and the other is known as the host species.

The host species remains unmodified in this relationship; however, the commensal shows great adaptations related to its habit and habitat.

Examples of Commensalism

1. Staphylococcus and Aspergillus:

2. Nitrobacter and Nitrosomonas

# data[].attributes.body
1. The natural place of an organism or community is known as

1. Niche

2. Biome

3. Habitat

4. Habit

The correct answer is – 3. Habitat.

2. Which is the renewable exhaustible natural energy resource?

1. Coal

2. Petroleum

3. Kerosene

4. Biomass

The correct answer is – 4. Biomass.

Also read: Coal and Petroleum

3. According to Shelford’s Law of Tolerance, the organisms wide environmental factor tolerance limit show

1. Narrow distribution with low population size

2. Wide distribution with high population size

3. Narrow distribution with high population size

4. Wide distribution with low population size

The correct answer is – 2. Wide distribution with high population size.

4. Plants growing under direct sunlight are known as

1. Heliophytes

2. Sciophytes

3. Psamophytes

4. Dicots

The correct answer is – 1. Heliophytes.

5. Plants growing under shade are known as

1. Psamophytes

2. Sciophytes

3. Heliophytes

4. Monocots

The correct answer is – 2. Sciophytes.

6. An orchid living on a tree exhibits

1. Predator

2. Mutualism

3. Commensalism

4. Parasitism

The correct answer is – 3. Commensalism.

Also read: Parasitism

7. Which statement is correct with respect to the food chain?

1. Every component of the food chain forms a trophic level

2. Inter-relation between different food chains is known as a food web

3. All the chains formed by nutritional relations is used to understand energy flow.

4. All of the above

The correct answer is – 4. All of the above.

8. The process of vernalization is practised in

1. Cold countries

2. Hot countries

3. Only in sub-tropical countries

4. Only in tropical countries

The correct answer is – 1. Cold countries.

Also read: Photoperiodism and Vernalization

9. Which of the following requires maximum energy?

1. Secondary consumer

2. Decomposer

3. Primary consumer

4. Primary producer

The correct answer is – 4. Primary producer.

10. The bottom area where production is less than respiration in a pond ecosystem is termed as

1. Profundal zone

2. Tidal zone

3. Benthic zone

4. Limnetic zone

The correct answer is – 1. Profundal zone.

Also read: Aquatic Ecosystem

11. Which is not the characteristic of ‘r’ selected species?

1. Reproduce quickly

2. Parental care

3. A low survival rate of progenies

4. Produce a large number of progenies

The correct answer is – 2. Parental care.

12. Which is not the characteristic of a population?

1. Natality

2. Mortality

3. Stratification

4. Sex ratio

The correct answer is – 3. Stratification.

Also read: Introduction to Population Growth

13. Lincoln index measures

1. Population mortality rate

2. Population natality rate

3. Population size

4. Population density

The correct answer is – 3. Population size.

14. Allelopathy refers to

1. Inhibition of growth of one species by another by the production of toxins

2. Inhibition of sporulation of pathogen by the host

3. Altering the reproductive cycle of one organism by another

4. Inhibition of growth of one species by another by preventing reproduction

The correct answer is – 1. Inhibition of growth of one species by another by the production of toxins.

15. The ratio between energy flow at different points in a food chain is known as

1. Ecological capacity

2. Ecological efficiency

3. Ecological assimilation

4. Ecological potential

The correct answer is – 2. Ecological efficiency.

Also read: Energy Flow in an Ecosystem

16. The ability of a population to increase under ideal environmental conditions is called

1. Natality

2. Carrying capacity

3. Biotic potential

4. Absolute natality

The correct answer is – 3. Biotic potential.

17. In an ecosystem, the energy flow is always

1. Always unidirectional

2. Always bidirectional

3. In any direction

4. Always down directional

The correct answer is – 1. Always unidirectional.

Also read: Ecosystem

18. In thermal stratification, the middle region which shows vertical temperature change is called

1. Mesolimnion

2. Epilimnion

3. Metalimnion

4. Hypolimnion

The correct answer is – 3. Metalimnion.

19. Select a non-denitrifying bacteria

1. Pseudomonas aeruginosa

2. Thiobacillus

3. Thiobacillus denitrificans

4. Bacillus ramosus

The correct answer is – 4. Bacillus ramosus.

20. Which one is a ‘K’ selected species?

1. Aspergillus

2. Human

3. Taraxacum

4. Grass

The correct answer is – 2. Human.

21. All species of Lemur are endemic to which area?

1. Madagascar

2. Seychelles Island

3. Galapagos Island

4. New Caledonia

The correct answer is – 1. Madagascar.

22. The upper part of an aquatic ecosystem contains

1. Nekton

2. Plankton

3. Benthos

4. both (1) and (2)

The correct answer is – 2. Plankton.

23. What type of food chain is it?

dead animals → blowfly maggot →  maggots → frog → snake

1. Detrital food chain

2. Decomposer food chain

3. Predator food chain

4. Grazing food chain

The correct answer is – 1. Detrital food chain.

24. Identify the mismatched pair

1. Tundra – Permafrost

2. Savanna – Acacia trees

3. Prairie – Epiphytes

4. Coniferous forest – Evergreen trees

The correct answer is – 3. Prairie – Epiphytes.

25. “The pyramid of energy is always upright” states that

1. The energy conversion efficiency of herbivores is better than carnivores

2. The energy conversion efficiency of carnivores is better than herbivores

3. Producers have the lowest energy conversion efficiency

4. Energy conversion efficiency is the same in all trophic levels

The correct answer is – 1. The energy conversion efficiency of herbivores is better than carnivores.

26. The population of birds declined in an area where DDT was extensively used. Why?

1. The birds stopped laying eggs

2. The eggs laid by the birds did not hatch

3. The snakes ate the eggs

4. The DDT spray killed all the birds

The correct answer is – 2. The eggs laid by the birds did not hatch.

27. Which of the following lake zones has phytoplanktons in abundance?

1. Littoral zone

2. Benthic zone

3. Limnetic zone

4. Profundal zone

The correct answer is – 3. Limnetic zone.

28. Plant species with a wide range of genetic distribution evolve into a local population known as

1. Ecotype

2. Population

3. Ecosystem

4. Biome

The correct answer is – 1. Ecotype.

29. dB is the abbreviation used for the quantitative expression of

1. The density of bacteria in a medium

2. A Particular Pollutant

3. Dominant Bacillus in a culture

4. A pesticide

The correct answer is – 2. A Particular Pollutant.

30. The eggshell of birds becomes thin by the pollution from pesticides due to the interference in the activity of

1. Calmodulin

2. MgATPase

3. CaATPase

4. Calcium

The correct answer is – 3. CaATPase

# data[].attributes.body
https://www.nature.com/scitable/knowledge/library/species-interactions-and-competition-102131429/#:~:text=At%20the%20coarsest%20level%2C%20ecological,are%20called%20inter%2Dspecific%20interactions.

# data[].attributes.attachment_link.title
Species Interactions and Competition | Learn Science at Scitable

# data[].attributes.attachment_link.description
Organisms live in complex assemblages in which individuals and species interact in a variety of ways. We can better understand this complexity by considering how they compete with, prey upon and parasitize each other.