Organisms and Populations MCQ Quiz in मल्याळम - Objective Question with Answer for Organisms and Populations - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

The correct answer is Carrying capacity

Concept:

• The carrying capacity of a habitat refers to the maximum number of individuals that the environment can sustain indefinitely without degrading the resource base. This concept is crucial in understanding population dynamics and managing ecosystems sustainably.
• Factors that determine the carrying capacity include availability of resources (such as food, water, and shelter), predation pressures, disease, and competition among species.
• When a population exceeds its carrying capacity, it can lead to resource depletion and environmental degradation, ultimately causing the population size to decline to sustainable levels.
• In contrast, if the population size is below the carrying capacity, there are generally sufficient resources to support population growth until the carrying capacity is reached.

Explanation:

• Carrying capacity: This is the correct term for the maximum population size that a habitat can support sustainably. It includes considerations of all limiting factors that might cap the population growth.
• Growth limit: While similar in concept, this term is less precise and not commonly used in ecological contexts to refer to the carrying capacity.
• Population threshold: This term may refer to specific points or limits in population sizes for various purposes, but it does not specifically denote the sustainable maximum of a habitat.
• Survival rate: This refers to the proportion of individuals that survive to a certain age or stage within a population and does not reflect the concept of maximum sustainable population size.

The correct answer is A - I, B - II, C - III, D - IV

Explanation:

• Both the species benefit in mutualism and both lose in competition in their interactions with each other.
• In both parasitism and predation only one species benefits (parasite and predator, respectively) and the interaction is detrimental to the other species (host and prey, respectively).
• The interaction where one species is benefitted and the other is neither benefitted nor harmed is called commensalism.
• In amensalism on the other hand one species is harmed whereas the other is unaffected.
• Predation, parasitism and commensalism share a common  characteristic– the interacting species live closely together.

Table: Population Interactions

Concept:

• Soil plays a critical role in plant growth.
• Soil provides necessary nutrients to plants.
• Apart from nutrients, oxygen and water is also provided to a plant root through the soil it grows in.
• Soil provides anchorage to plant roots, helping the plant to grow vertically with stability.
• Following are some of the types of soils in which different plants grow:
  • Sandy soil
  • Peaty soil
  • Silty soil
  • Clay soil
  • Saline soil

Important Points

• Lithophytes - 
  • ​These are the plants that grow on or in the crevices of rocks.
  • They can be of two types:
  1. Epilithic i.e. grow on the surface of the rock.
  2. Endolithic i.e. grow in the crevices of the rock.
  • E.g.: Species of ferns like Rock Felt Fern, orchids like Paphiopedilum, etc.
• Psammophytes - 
  • Psammophytes are plants that require sandy soil to thrive.
  • These are generally found in deserts.
  • Most of the psammophytes are xerophytes with reduced or no leaves at all.
  • Some species of Psammophytes are also found in sands along seas, large lakes, or rivers.
  • E.g.: Haloxylon, Aristida, etc.
• Oxylophytes - 
  • ​Oxylophytes are plants that grow in acidic soils.
  • Owing to the soil's dryness due to high acidity, these plants have developed xeromorphism.
  • E.g.: Bog mosses, Cotton grass, etc.
• Halophytes - 
  • ​Halophytes are plants that have a natural ability to withstand salinity.
  • These plants are found in areas with high salinity such as marshes, seashores, saline semi-deserts, etc.
  • These plants are often used as model plants to study stress tolerance in plants.
  • E.g.: Salicornia, Spergularia marina, etc.

Hence, the correct answer is option 2.

Important Points

• Interaction refers to the associations between species that favor or inhibit mutual growth and evolution of populations.
• The interactions may take the form of competition, predation, parasitism, commensalism or mutualism.
• Based of their effects, the interspecific interactions can be of 3 types:
  • Beneficial - These are positive interactions where either one or both of the species are benefitted.
  • Detrimental - These are the negative interactions where one or both of the species are harmed.
  • Neutral - These are interactions where the species is not affected.

Explanation:

Scavenging - 

• It is a type of interaction where organism eats dead or rotting biomass, such as animal flesh or plant material.
• Here the scavenging organism is always benefitted and no other organism is harmed.
• Therefore, it is a positive type of interaction.

Additional Information

• Amensalism - 
  • ​It is the type of interaction in which one of the organism is harmed and the other organism is neither harmed nor benefitted.
  • It is a negative type of interaction air, food, shelter, water, and space.
• Competition - ​
  • The interaction of individuals for a common resource that is in limited supply, 
  • Organisms compete for the resources like air, food, shelter, water, and space that they need to survive, grow, and reproduce.
  • The stronger organisms survive and the others die.
  • Therefore, it is a negative type of interaction.
• Predation - 
  • Predation is a biological interaction where one organism, the predator hunt and kill other organisms i.e. it's prey for food. 
  • Therefore, it is a negative type of interaction.

Concept:

Population:

• Growth of population is the change in the number of people living in a particular area between two points in time.
• Its rate is expressed in percentage.
• Population growth has two components namely; natural and induced.

The density of the population:

• It is expressed as the number of persons per unit area.
• It helps in getting a better understanding of the spatial distribution of the population in relation to land.

Explanation:

Carrying capacity or pressure capacity:

• Carrying capacity indicates the maximum limit up to which the ecosystem or environment can support the existence of the population.
• Its formula is dN/dt = rN(1−N/K), where K is the population carrying capacity.
• Environmental elements including sufficient food, shelter, water, and mates are able to control the population number of the species.
• The population will decline until the resource recovers if these needs are not supplied.

Thus, the cooperation of a maximum number of people by the environment is called pressure capacity or carrying capacity.

Additional InformationNatality rate:

• It is the ratio between the number of live-born births in the year and the average total population of that year.

Mortality rate:

• The infant mortality rate is the number of deaths of babies before the age of one year per 1000 live births. 

The correct answer is A - IV, B - I, C - II, D - III

Explanation:

• Both the species benefit in mutualism and both lose in competition in their interactions with each other.
• In both parasitism and predation only one species benefits (parasite and predator, respectively) and the interaction is detrimental to the other species (host and prey, respectively).
• The interaction where one species is benefitted and the other is neither benefitted nor harmed is called commensalism.
• In amensalism, one species is harmed whereas the other is unaffected.
• Predation, parasitism and commensalism share a common  characteristic– the interacting species live closely together.

Table: Population Interactions

The correct option is 2

Concept:

Adaptation 

• A physical or behavioural characteristic of an animal that enhances its ability to survive in its environment is known as an adaptation.
• To put it another way, an adaptation is something a person does or has on them that makes it easier for them to locate food, water, mates, and shelter.

Three categories of adaptations:

• Structure 
• physiology
• behaviour 

Explanation:

Polar Bears

• Polar Bear lives Northern Hemisphere. In the Arctic Region.
• They are white in colour. 
• Their bodies are covered with furs.

The polar bear has developed a variety of adaptations to survive in a very cold environment

(i) An insulation-producing layer of fat beneath the skin.

(ii) Long, curved claws with a pointy tip for gliding across the ice.

• Animals can survive in their environment thanks to adaptations, which are special traits. 
• To survive in such a bitter environment, polar bears have undergone significant modifications. Subcutaneous fat serves as an insulating layer. For moving around and running on ice, long, curving claws with points.

(iii) The polar bears are white in colour which help in blending in the snowy surroundings, a thick coat of white fur serves as protection from predators and acts as the heat insulator between bodies.

Hence the statement (i), (ii) and (iv) are correct.

The correct answer is 1

Explanation:

• Symbiosis is a broad term that includes any type of close and long term biological interaction between two different biological organisms, including mutualism, commensalism, and parasitism.
• Parasitism: An interaction where one species benefits, and the other is harmed. (e.g., ticks feeding on a host animal)
• Mutualism: An interaction where both species benefit. (e.g., bees pollinating flowers and obtaining nectar in return)
• Amensalism: An interaction where one species is harmed, and the other is unaffected. (e.g., the release of chemicals by a plant that inhibits the growth of other plants nearby)
• Commensalism: An interaction where one species benefits, and the other is neither harmed nor benefited. (e.g., barnacles growing on a whale; the barnacles get a place to live and access to food, while the whale is unaffected)

Table: Popular Interactions

Note:

• '+' : Beneficial
• ' ' : Detrimental (Harmful)
• '0' : Neutral (Neither benefitted nor harmed)

The correct answer is 1951 - 1981.Key Points

• The period of population explosion in India is referred to as 1951-1981.
• During this period, India's population grew at an unprecedented rate, increasing from around 361 million in 1951 to over 846 million in 1981.
• This period was marked by several factors, including improvements in healthcare and sanitation, increased agricultural productivity, and a decline in infant mortality rates.
• The population explosion had several social and economic consequences, including increased pressure on resources, urbanization, and poverty.

Additional Information

• 1901-1921 was a period of relatively slow population growth in India, with the population increasing from around 238 million to 251 million.
• 1921-1951 was a period of moderate population growth, with the population increasing from around 251 million to 361 million.

The correct option is 2 that is penguins cannot swim.

Concept​:

• A group of aquatic flightless birds is known as the penguins. They are distributed in the Southern Hemisphere;
• The only species found north of the equator is the Galápagos penguin.
• Penguins have counter-shaded dark and white plumage and flippers for swimming, making them exceptionally well-adapted for life in the sea.

Explanation:

Penguins

• The penguins can swim well as they have webbed feet.
• The flippers act as an arm and help in swimming.
• Penguins lack wings and have flippers in place of wings. With certain species being able to attain speeds of up to 15 miles per hour, their bodies are designed for swimming and diving in the water.
• They are skilled swimmers thanks to their fusiform (tapered at both ends) and streamlined bodies.
• Penguins have short, powerful legs. Webbed and clearly clawed feet are present.
• To help with streamlining and steering while swimming, the legs are positioned very far back on the body.
• Penguins also stand vertically and walk upright as a result of this placement.

Hence we can conclude that penguins cannot swim is the incorrect statement