Organic Evolution (VSAQs)
Zoology-2 | Unit-7: Organic Evolution – VSAQs:
Welcome to VSAQs in Unit-7: Organic Evolution. This page includes the most important FAQs from previous exams. Each answer is presented in the exam format to help you prepare effectively and aim for top marks in your final exams.
VSAQ-1: What Are Panspermia?
Imagine if life on Earth didn’t actually start here but rather hitchhiked from another part of the universe. This is the essence of the panspermia hypothesis. According to this idea, life might have begun somewhere else in the cosmos and traveled to Earth through tiny spores or microorganisms. Think of it like seeds being carried by the wind or small particles hitching a ride on a comet. Scientists suggest that natural processes like meteoroid impacts, radiation pressure, or even clouds of cosmic dust could have transported these life forms. While it’s a fascinating concept, panspermia is still a hypothesis and requires more research to prove whether it’s true or not.
VSAQ-2: Mention the Names of Any Four Connecting Links That You Have Studied
Connecting links are like evolutionary bridges, showing us how different groups of organisms are related through shared traits. For instance, consider the Eusthenopteron, a fish-like creature that exhibits features connecting fish to amphibians, helping us understand how these groups evolved from one another. Then there’s Seymouria, a fossil that acts as a link between amphibians and reptiles with its combined characteristics. Archaeopteryx is another intriguing example—a feathered dinosaur that links reptiles and birds, showcasing features of both. Lastly, Cynognathus serves as a connecting link between reptiles and mammals, bridging this evolutionary gap with its unique traits. Studying these organisms helps us piece together the puzzle of how different life forms have evolved over time.
VSAQ-3: Define Biogenetic Law, Giving an Example
The Biogenetic law, also known as the Theory of Recapitulation, suggests that an organism’s development stages mirror its evolutionary history. In simpler terms, as an embryo grows, it goes through stages that reflect the evolutionary changes its species has undergone. For example, consider the caterpillar of a butterfly. Early in its development, it resembles a segmented worm, reflecting an evolutionary connection between butterflies and worms. Similarly, a tadpole larva of a frog looks like a fish, with features such as gills and a tail. This mirroring of evolutionary stages provides insights into the history and development of different species.
VSAQ-4: Define Atavism with an Example
Atavism is like a genetic throwback, where traits from an organism’s distant ancestors reappear, even though they are not common in its present-day species. For instance, imagine a human baby born with a tail. This isn’t something you’d see every day, but it’s a rare example of atavism. Our ancient ancestors, including some primates, had tails, and seeing one in a modern human is a glimpse into our evolutionary past.
VSAQ-5: Cite Two Examples to Disprove Lamarck’s Inheritance of Acquired Characters
Lamarck’s theory suggested that traits developed during an organism’s lifetime could be passed on to its offspring. However, this idea doesn’t hold up well against real-life examples. Take athletes with well-developed muscles. Despite their rigorous training, their children aren’t born with those same muscles. Muscular development is not inherited in this manner; it’s based on individual genetics and effort.
Another example is the ear piercing practice. Many people pierce their ears for fashion or cultural reasons. However, this acquired trait of having pierced ears doesn’t get passed on to their children. The next generation isn’t born with pierced ears; they need to get their ears pierced just like their parents did. This shows that acquired characteristics do not influence the genetic makeup of future generations.
VSAQ-6: What Is Meant by Genetic Load? Give an Example
Genetic load refers to the presence of harmful or potentially harmful genes in a population. These genes can lead to various health issues or genetic disorders in individuals who inherit them. For example, sickle cell anemia is a condition caused by a mutation in the hemoglobin gene. Individuals who inherit two copies of this defective gene suffer from sickle cell anemia, which leads to serious health problems like anemia and pain. This condition is an example of genetic load, demonstrating how harmful genes can impact individuals’ health within a population.