Biology MCQs
Topic Notes: Biology
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
31
Which of the following factors are recognized as significant contributors to the extinction of species?
Answer:
all of above
Extinction is driven by a combination of anthropogenic and environmental factors. Deforestation destroys critical ecosystems, overhunting reduces population numbers below sustainable levels, and general habitat loss removes the resources necessary for survival. Together, these pressures significantly increase the risk of species extinction in modern ecosystems.
32
In which geographical region is biological diversity typically found to be the highest?
Answer:
tropical
Tropical regions, particularly tropical rainforests, exhibit the highest levels of biodiversity on Earth. This is due to a combination of stable, warm temperatures, high annual rainfall, and long growing seasons, which support a vast array of ecological niches and complex food webs, allowing for the coexistence of numerous species.
33
How is the process of establishing new forests on land that was not previously forested defined?
Answer:
afforestation
Afforestation is the deliberate process of planting trees or sowing seeds in an area that has not been forested in recent history. This practice is a key strategy in environmental conservation, aimed at increasing carbon sequestration, restoring biodiversity, and preventing soil erosion in previously barren or non-forested regions.
34
Why are forest ecosystems considered to be highly valuable?
Answer:
all of above
Forests provide multifaceted value to human society. Beyond their critical ecological roles in carbon sequestration and biodiversity support, they are significant for their aesthetic appeal, cultural heritage, and as hubs for ecotourism and recreation.
35
How does the extinction of a species typically affect an ecosystem?
Answer:
stability
Ecosystems rely on biodiversity to maintain functional balance. The extinction of a species can disrupt food webs and nutrient cycling, leading to a loss of ecological stability, which may cause further declines in other dependent species.
36
Which concept best describes the source of food supply for human populations?
Answer:
biodiversity
Biodiversity refers to the variety of life forms on Earth, which provides the essential biological resources, including crops, livestock, and wild species, that form the foundation of human food security and agricultural systems.
37
What does the acronym 'WWF' stand for in the context of global environmental conservation?
Answer:
World Wildlife Fund
The World Wildlife Fund (WWF) is an international non-governmental organization founded in 1961. It is dedicated to wilderness preservation and the reduction of human impact on the environment. It is one of the world's largest conservation organizations, focusing on protecting endangered species and their natural habitats.
38
What is the definition of the term 'deforestation' in an ecological context?
Answer:
clearing of forest
Deforestation refers to the large-scale removal or clearing of forested land, typically for agricultural, industrial, or urban development purposes. This process leads to significant environmental impacts, including loss of biodiversity, disruption of water cycles, and increased carbon dioxide levels in the atmosphere.
39
What is the name of the list maintained by the International Union for Conservation of Nature (IUCN) that tracks endangered species?
Answer:
Red List
The IUCN Red List of Threatened Species is the world's most comprehensive inventory of the global conservation status of biological species. It uses a set of criteria to evaluate the extinction risk of thousands of species and subspecies.
40
What term is used to describe the variety of life forms and the number of species present within a specific geographic area?
Answer:
Biodiversity
Biodiversity refers to the variety and variability of life on Earth or within a specific ecosystem. It is typically measured by the number of different species, genetic variation within species, and the complexity of the ecosystems they inhabit.