RBSE Solutions Class 10 Science Chapter 16 Universe and Organic Evolution

I. Multiple Choice Questions

Question 1. Which of the following was present before the creation of the universe?
(a) Water
(b) Truth
(c) Untruth
(d) None of these
Answer: (d) None of these
In simple words: Before the universe was created, there was nothing that we can currently understand or define. It's a state beyond what we know as existing.

🎯 Exam Tip: When dealing with philosophical or conceptual questions about creation, consider that scientific models often describe the universe *after* its beginning, not before. The question asks what was "present," implying something discernible.

Question 2. Which scientist reinvigorated the concept of static universe?
(a) Darwin
(b) Oparin
(c) Einstein
(d) Stanley Miller
Answer: (c) Einstein
In simple words: Albert Einstein was a scientist who helped bring back the idea of a universe that doesn't change or expand over time. However, later observations showed that the universe is actually expanding.

🎯 Exam Tip: Remember the key contributions of famous scientists in cosmology. Einstein initially favored a static universe but later accepted the expanding universe model based on evidence.

Question 3. Which is the most accepted theory on origin of universe?
(a) Static universe
(b) Big Bang
(c) Biocentrism
(d) Indian cosmology
Answer: (b) Big Bang
In simple words: The Big Bang theory is the most widely accepted scientific explanation for how the universe began. It suggests the universe started from a very hot and dense state, then expanded.

🎯 Exam Tip: Understand that "most accepted" implies scientific consensus based on current evidence. The Big Bang theory is supported by observations like cosmic microwave background radiation.

Question 5. Which term is used for a group of individuals which maintain its form through many generations?
(a) Genus
(b) Order
(c) Family
(d) Species
Answer: (d) Species
In simple words: A species is a group of living things that can breed with each other and produce offspring that can also breed. This group keeps its main characteristics for many generations.

🎯 Exam Tip: Clearly distinguish between different levels of biological classification (taxonomy). A species is the most fundamental unit, defined by its ability to interbreed and produce fertile offspring.

Universe and Organic Evolution Very Short Answer Type Questions

Question 6. Origin of universe has been discussed in which part of Rigveda?
Answer: The origin of the universe is talked about in Sukti 10, Hymn 129 of the Rigveda. This ancient text gives insights into early cosmological thoughts. It discusses philosophical ideas related to creation.
In simple words: The Rigveda, an old Indian book, talks about how the universe began in a part called Sukti 10, Hymn 129.

🎯 Exam Tip: When answering about specific ancient texts, ensure accuracy in naming the precise chapter or section where the concept is discussed.

Question 7. Can life be considered as a group of molecules?
Answer: Yes, life can indeed be thought of as a very complex and organized group of molecules. These molecules work together in specific ways to create living organisms. All living things, from simple bacteria to humans, are made up of basic molecules that interact in complex systems.
In simple words: Yes, living things are basically many molecules working together in a very organized way.

🎯 Exam Tip: While life is more than just molecules, understanding that it fundamentally relies on complex molecular interactions is key in biology and biochemistry.

Question 8. Modern life is considered to be based on which molecule?
Answer: Modern life forms are based on the DNA molecule. DNA carries all the genetic information that tells a cell how to grow, function, and reproduce. This molecule acts like a blueprint for all living things on Earth.
In simple words: All modern living things are built upon the DNA molecule, which holds their genetic information.

🎯 Exam Tip: DNA is the fundamental genetic material in almost all organisms, crucial for heredity and the continuation of life. Always remember its central role.

Question 9. What has changed in scientific thinking about primitive atmosphere on earth?
Answer: Scientific ideas about Earth's early atmosphere have changed. It is now believed that the primitive atmosphere might not have been "reducing" in nature. This means it might not have had as many easily reactive chemicals as once thought, changing how scientists imagine life first began.
In simple words: Scientists now think that Earth's early air might not have been as good at making chemical reactions happen as they once believed.

🎯 Exam Tip: Be aware of how scientific understanding evolves. Initial theories about Earth's primitive atmosphere being strongly reducing have been refined with new geological evidence.

Phylogeny

Universe and Organic Evolution Short Answer Type Questions

Question 11. How do we get to know about extinct species?
Answer: We learn about species that no longer exist mainly through fossils. Fossils are the preserved remains or traces of ancient life, and they can show us nearly the complete structure of an organism. By using carbon dating, scientists can also find out how old these fossils are, helping to map out Earth's history.
In simple words: We find out about animals and plants that died out by studying their fossils. We can also use carbon dating to know their age.

🎯 Exam Tip: Mention both fossils as physical evidence and carbon dating as a method for determining age to score full marks. These two points are crucial for explaining how we study extinct species.

Question 12. The fossil of archaeopteryx was found in which condition?
Answer: The fossil of archaeopteryx was discovered as a diagram-like impression. This happens when an organism is buried under many layers of sediment, creating a flattened outline rather than a full three-dimensional body. This fossil is crucial for understanding the link between dinosaurs and birds.
In simple words: The archaeopteryx fossil was found as a flat, diagram-like imprint. It was like a picture pressed into rocks.

🎯 Exam Tip: Focus on describing the *type* of preservation. An "impression" fossil differs from a fully preserved specimen or a cast, and understanding this distinction is important.

Question 13. What are vestigial organs? Write the name of any one such organ in human body.
Answer: Vestigial organs are body parts that have lost their original function through evolution and are now mostly useless. In the human body, the appendix is an example of a vestigial organ. These organs offer clues about the evolutionary history of a species.
In simple words: Vestigial organs are body parts that used to have a purpose but don't anymore, like the appendix in humans.

🎯 Exam Tip: Define vestigial organs by their reduced function or lack of function compared to ancestors, and provide a clear example from the human body.

Question 14. Can life on earth come from extraterrestrial sources?
Answer: Yes, the idea that life on Earth originated from sources beyond our planet is a concept accepted by some scientists. This theory suggests that life, possibly in the form of tiny spores, came to Earth from another celestial body. Figures like Lord Kelvin and Fred Hoyle supported this idea, known as panspermia. However, it is generally less accepted than the Primordial Soup Theory. This idea explains that life may not have started *on* Earth itself, but rather arrived here from space.
In simple words: Some scientists think life on Earth might have come from space, carried here by tiny life forms or seeds.

🎯 Exam Tip: When discussing alternative theories of life's origin, name key proponents if possible, and compare their acceptance level to the most widely held theories (like abiogenesis).

Universe and Organic Evolution Long Answer Type Questions

Question 16. Describe the theory of biocentrism. What is the difference between this concept and physical concept of origin of universe?
Answer: The theory of biocentrism was introduced by Robert Lanza and Bob Berman in 2007. This idea proposes that the universe exists because of life itself, meaning the universe was created in a way that allows life to form and grow. It suggests that consciousness is key to understanding the universe. In biocentrism, every event in the universe seems to happen in a way that benefits mankind. For example, the meteor that wiped out dinosaurs is seen as clearing the way for mammals to evolve. In contrast, physical theories about the universe's origin state that life evolved simply as a result of the laws of physics and chemistry. These theories believe physical and chemical changes led to life, not the other way around like in biocentrism.
In simple words: Biocentrism says the universe was made for life, and life is central. Physical theories say life came about because of physics and chemistry, not that the universe was designed for it.

🎯 Exam Tip: Clearly define biocentrism by highlighting its core belief (life-centered universe). Then, contrast it effectively with the standard physical theories of the universe's origin, which focus on matter and energy first.

Question 17. What do you understand by Big Bang Theory? What is the difference between Indian cosmology and Big Bang Theory?
Answer: The Big Bang Theory states that the universe began with a huge explosion 13.8 billion years ago. This happened from a very dense and extremely hot point. After this explosion, pieces and matter flew outwards, causing the universe to expand.
In simple words: The Big Bang Theory says our universe started from a very hot, tiny point and then burst out, spreading everything apart.

🎯 Exam Tip: Briefly explain the core idea of the Big Bang Theory (a hot, dense origin followed by expansion). Since the source content for comparison with Indian cosmology is incomplete, focus on the available information for Big Bang Theory.

Question 18. What do you understand by organic evolution? Explain organic evolution in your own words.
Answer: Organic evolution is the idea that all living beings we see today share a common ancestor. This means every life form on Earth started from the very first life form that appeared. Over a very long time, many modern species have developed through different stages. Evidence supporting this includes the similar basic bone structures in the forelimbs of humans, cheetahs, fish, and bats, showing they came from a shared ancestor. Also, all multicellular organisms are made of eukaryotic cells, and vital processes like protein digestion (using trypsin) and genetic control (by DNA) work the same way across diverse organisms, from simple single-celled life to humans. These facts strongly support the idea of organic evolution.
In simple words: Organic evolution means that all living things today came from a common ancestor, changing and developing over millions of years. This process explains how new types of life have appeared.

🎯 Exam Tip: Define organic evolution as descent with modification from a common ancestor. Support your explanation with examples of homologous structures and molecular similarities across different life forms.

Universe and Organic Evolution Additional Questions Solved

I. Multiple Choice Questions

Question 1. Which of the following has given good explanation of Vedic hymns on creation of the universe?
(a) Mahatma Gandhi
(b) Swami Vivekanand
(c) Krishna
(d) Rajendra Prasad
Answer: (b) Swami Vivekanand
In simple words: Swami Vivekanand offered clear explanations of the old Vedic songs about how the universe was created. He helped people understand these ancient ideas better.

🎯 Exam Tip: For questions about interpretations of ancient texts, remember key figures who provided significant philosophical or spiritual explanations.

Question 3. Big Bang is supposed to have happened how many years ago?
(a) 4.5 billion years
(b) 7 billion years
(c) 13.8 billion years
(d) 20 billion years
Answer: (c) 13.8 billion years
In simple words: Scientists believe the Big Bang, which started our universe, happened about 13.8 billion years ago.

🎯 Exam Tip: Memorize the approximate age of the universe according to the Big Bang theory, as it's a fundamental constant in cosmology.

Question 4. Who conducted experiment to verify Oparin's theory about creation?
(a) Haldane
(b) Jagdish Chandra Bose
(c) Birbal Sahni
(d) Miller
Answer: (d) Miller
In simple words: Stanley Miller carried out an experiment to test Oparin's theory on how life might have begun on early Earth.

🎯 Exam Tip: Connect key scientists with the experiments or theories they are famous for. The Miller-Urey experiment is a classic example of early Earth conditions simulated to produce organic compounds.

Question 5. Who was the first to logically explain organic evolution?
(a) Charles Darwin
(b) Urey
(c) Lamarck
(d) Mendel
Answer: (a) Charles Darwin
In simple words: Charles Darwin was the first person to offer a clear and logical explanation of how living things change over time through a process called natural selection.

🎯 Exam Tip: Charles Darwin's theory of evolution by natural selection is foundational to modern biology. Ensure you know his central role in explaining this concept.

Universe and Organic Evolution Very Short Answer Type Questions

Question 3. The term 'mutation' was coined by whom?
Answer: The term 'mutation' was first coined by Hugo De Vries. He was a Dutch botanist who introduced the concept of mutations in the early 20th century. His work was key in understanding how new traits appear in living things.
In simple words: Hugo De Vries was the scientist who first used the word 'mutation' to describe sudden changes in living things.

🎯 Exam Tip: Remember important scientific terms and the individuals credited with coining or popularizing them. Mutations are a vital part of genetic variation.

Question 4. What is eukaryotic organism?
Answer: A eukaryotic organism is a living thing whose cells have a clear, organized nucleus. This nucleus holds the cell's genetic material, and the cells also contain other special parts called organelles. Animals, plants, fungi, and protists are all examples of eukaryotic organisms.
In simple words: A eukaryotic organism is any living thing whose cells have a proper nucleus inside them.

🎯 Exam Tip: The defining feature of a eukaryotic cell is the presence of a membrane-bound nucleus. Contrast this with prokaryotic cells, which lack a true nucleus.

Question 5. What is the full form of DNA?
Answer: The full form of DNA is Deoxyribonucleic acid. It is a vital molecule that carries genetic instructions for the development and functioning of all known living organisms. DNA stores all the important information for building and keeping an organism alive.
In simple words: DNA stands for Deoxyribonucleic acid, which is the chemical that carries all the genetic information for life.

🎯 Exam Tip: Know the full form of common scientific abbreviations like DNA, and understand its primary function in genetics.

Universe and Organic Evolution Short Answer Type Questions

Question 1. Briefly explain Ekpyrotic model.
Answer: The Ekpyrotic Model was suggested by Paul Steinhardt of Princeton University. It proposes that our universe began when two three-dimensional universes collided in a fourth dimension. This theory also accepts that the universe is expanding, but in a different way than the Big Bang theory describes. It pictures the universe expanding like a rubber sheet, where objects move apart without a single central point of expansion. This model offers an alternative view of the universe's origin and expansion.
In simple words: The Ekpyrotic model says our universe started from two other universes bumping into each other, and it expands like a stretching rubber sheet.

🎯 Exam Tip: When explaining cosmological models, state the key scientists involved and the central mechanism proposed for the universe's origin and expansion, noting differences from other models like the Big Bang.

Question 2. How was life created, as per Oparin and Haldane?
Answer: As per Oparin and Haldane, life was created through the gradual formation of complex compounds. They believed that over time, primitive life forms went through a long period of struggle and competition. This process eventually led to the diverse living world we see today. They proposed that Earth's early conditions allowed simple chemicals to react and form more complex organic molecules, which then assembled into living structures.
In simple words: Oparin and Haldane believed life started from simple chemicals on early Earth, slowly forming complex parts and then living things through a long process of change.

🎯 Exam Tip: When explaining Oparin and Haldane's hypothesis (abiogenesis), emphasize the chemical evolution from simple inorganic molecules to complex organic ones, forming the basis of primitive life.

Question 3. How can we say that modern life form is fully based on DNA?
Answer: Modern life forms are completely based on DNA. The DNA contains all the genetic information, which is then carried from the cell's nucleus to its cytoplasm by RNA. In the cytoplasm, structures called ribosomes use the RNA's message to create proteins, which are also enzymes. These proteins control all the important biological processes inside a cell. Every part a cell makes, and many proteins it uses, are involved in creating and maintaining its DNA. This shows DNA is the central control molecule.
In simple words: Modern life relies fully on DNA because it holds all the instructions. DNA uses RNA to make proteins, and these proteins control all the cell's work.

🎯 Exam Tip: Explain the central dogma of molecular biology: DNA makes RNA, and RNA makes protein. Highlight how DNA stores information, RNA transmits it, and proteins execute cellular functions.

Question 4. How do scientists determine the age of a fossil?
Answer: Scientists use two main methods to figure out how old a fossil is. The first way is by looking at the depth at which the fossil was found. Fossils found in deeper rock layers are generally older than those found in shallower layers. The second method is called carbon dating. This technique works by measuring the amount of a specific type of carbon, C-12 (an isotope of carbon), present in the fossil. The decay rate of radioactive isotopes helps determine the time passed since the organism died.
In simple words: Scientists find a fossil's age in two ways: by how deep it was buried in the ground and by using carbon dating, which measures a type of carbon in the fossil.

🎯 Exam Tip: Distinguish between relative dating (depth in rock layers) and absolute dating (carbon dating). Explain briefly how carbon dating works by measuring isotope levels.

Question 5. How did giraffes evolve, as per Lamarck?
Answer: According to Lamarck, giraffes evolved through the following steps:

• Groups of giraffes with short necks existed.
• Some giraffes were born with necks that were unusually longer.
• Giraffes with longer necks could reach higher branches for food, giving them better access. This advantage helped them survive better.
• These healthier giraffes then had more offspring, passing on their longer neck trait.
• Over time, giraffes with longer necks gradually replaced those with shorter necks in the population. This illustrates how acquired traits, like a stretched neck, were thought to be inherited.

In simple words: Lamarck thought giraffes got long necks by stretching for leaves. He believed they passed these stretched necks to their babies, making necks longer over time.

🎯 Exam Tip: Clearly outline Lamarck's key ideas, especially the inheritance of acquired characteristics. Be ready to contrast this with Darwin's theory of natural selection.

Universe and Organic Evolution Long Answer Type Questions

Question 2. Explain Darwin's theory of evolution.
Answer: Darwin's theory of evolution explains how species change over time. It has several key points:

• Every species produces many offspring, but not all of them look exactly alike; they show variation.
• Because many individuals are born, there is intense competition for important resources like food, shelter, and living space.
• Only the individuals best suited to their environment, or "fittest," survive this competition, while others die out.
• Nature chooses the traits that help an individual survive and thrive. These successful individuals then produce more offspring, passing on these helpful traits to future generations.
• Through this continuous process of variation, competition, survival of the fittest, and inheritance of desirable traits, new species eventually develop. The environment constantly filters individuals based on their traits.

In simple words: Darwin's theory says that living things produce many offspring, but only the strongest survive to pass on their useful traits. Over long periods, this process leads to new species.

🎯 Exam Tip: Clearly list Darwin's four main points: overproduction, variation, struggle for existence/competition, and natural selection (survival of the fittest leading to inherited traits).