CBSE Class 4 EVS Reproduction In Animals Worksheet

REPRODUCTION IN ANIMALS

Question 1. Draw, label and explain.
a. Life cycle of a cockroach
Answer: The life cycle of a cockroach consists of three main stages:
1. Egg: Female cockroaches lay eggs in protective cases called oothecae.
2. Nymph: The egg hatches into a nymph, which looks like a small, wingless adult cockroach. The nymph sheds its skin (moults) several times as it grows into an adult.
3. Adult: The final stage with fully developed wings and reproductive organs.
In simple words: A cockroach goes through three stages: egg, nymph, and adult.

Exam Tip: Remember that cockroaches have an incomplete metamorphosis because they do not have a pupa stage.

Question 1(b). Life cycle of a butterfly
Answer: The life cycle of a butterfly consists of four complete stages (complete metamorphosis):
1. Egg: Female butterflies lay tiny eggs on the underside of leaves.
2. Larva (Caterpillar): The egg hatches into a caterpillar, which spends its time eating leaves and growing rapidly.
3. Pupa (Chrysalis): The caterpillar forms a protective shell called a chrysalis where it undergoes a major transformation.
4. Adult Butterfly: A fully formed adult butterfly emerges from the chrysalis with beautiful wings.
In simple words: A butterfly transforms completely through four stages: egg, caterpillar, pupa, and adult.

Exam Tip: Mention that the larval stage of a butterfly is specifically called a caterpillar.

Question 1(c). Life cycle of a frog
Answer: The life cycle of a frog consists of three main stages:
1. Eggs (Spawn): Female frogs lay clusters of soft eggs in water.
2. Tadpole: The egg hatches into a tadpole, which lives entirely in water, has a tail, and breathes through gills.
3. Adult Frog: Through metamorphosis, the tadpole develops legs, loses its tail, develops lungs to breathe air, and transforms into an adult frog.
In simple words: Frogs lay eggs in water that hatch into fish-like tadpoles, which later grow legs and turn into adult frogs.

Exam Tip: Note that tadpoles breathe through gills, while adult frogs breathe through lungs and skin.

Question 2. Define and give one example.
a. Mammals
Answer: Mammals are advanced animals that give birth to fully formed babies and feed them with their own milk. They usually have hair or fur on their bodies.
Example: Human beings (or Dog, Cow, Whale).
In simple words: Mammals are animals that give birth to live babies and feed them milk.

Exam Tip: Always state both characteristics: giving birth to live young and feeding milk.

Question 2(b). Moulting
Answer: Moulting is the process by which an animal sheds its old skin or outer covering to make room for new body growth.
Example: Snakes casting off their old skin.
In simple words: Shedding old skin to grow new skin is called moulting.

Question 2(c). Reproduction
Answer: Reproduction is the biological process by which living organisms produce new individuals of their own kind to maintain their species on Earth.
Example: A dog giving birth to puppies.
In simple words: The process of producing babies of one's own kind is called reproduction.
Exam Tip: Reproduction is essential for the survival and continuation of a species.

Question 3. Why do fish lay a thousand eggs in water?
Answer: Fish lay thousands of eggs at a time because many of these eggs are eaten by other aquatic animals, and many others get destroyed by water currents or harsh environmental conditions. Laying a large number of eggs ensures that at least a few survive to become adult fish.
In simple words: Fish lay many eggs because predators eat most of them, ensuring some babies survive.

Exam Tip: Use the keywords predators and survival in your answer.

Question 4. What is hatching?
Answer: Hatching is the process in which a young animal breaks open its eggshell and emerges out into the world.
In simple words: The emerging of a baby animal from its egg is called hatching.

Exam Tip: Birds sit on their eggs to keep them warm until hatching takes place.

Question 5. Fill in the blanks.
a. The baby growing inside the egg is called embryo.
b. Tadpoles breathe through gills.
c. The shell protects the embryo.
d. Lizard, turtles and snakes are reptiles.
e. Cockroaches hide their eggs in dark and damp places (or ootheca).
f. The larva of butterfly is called caterpillar.
g. A chick does not have teeth.
h. Turtles and crocodiles bury their eggs in the ground.
i. Yolk of the egg provides food to the embryo.
j. Whales and dolphins look like fish but are mammals.
Answer: As filled above.
In simple words: Fill in the blanks with correct biological terms.

Exam Tip: Learn all key terms related to animal anatomy and life cycles.

OUR UNIVERSE

Ques 1. Read the clues and identify the planet-
Largest planet: Jupiter
Hottest planet: Venus
Planet with rings: Saturn
Red planet: Mars
Answer: Jupiter, Venus, Saturn, Mars.
In simple words: Identify planets based on their special features.

Exam Tip: Venus is the hottest planet due to a strong greenhouse effect, not Mercury (even though Mercury is closer to the Sun).

Ques 2. Write any three differences between (give one example for each) - Stars and Planets
Answer:

In simple words: Stars make their own light and twinkle, while planets reflect sunlight and do not twinkle.
Exam Tip: Remember that the Sun is also a star.

Ques 3. Write one similarity and difference between-
(i) Natural satellite and artificial satellite
Answer:
Similarity: Both revolve around a planet in a fixed orbit.
Difference: Natural satellites are celestial bodies created by nature (like the Moon), whereas artificial satellites are man-made objects launched into space for communication, weather forecasting, and research.
In simple words: Both orbit planets, but one is natural while the other is man-made.

Exam Tip: Give examples like the Moon for natural satellites and INSAT for artificial satellites.

(ii) Asteroids and comets
Answer:
Similarity: Both are small rocky or icy celestial bodies that revolve around the Sun.
Difference: Asteroids are rocky objects mostly found between Mars and Jupiter, whereas comets are made of ice, dust, and gases and have a glowing tail when they get close to the Sun.
In simple words: Both orbit the Sun, but asteroids are made of rock while comets are made of ice and dust with tails.

Exam Tip: Comets develop tails when approaching the Sun due to melting ice.

Ques 4. Identify the object shown below and write its four uses.
Answer:
Identification: Artificial Satellite (Communication Satellite with solar panels).
Four uses:
1. Used for telecommunication, television broadcasting, and mobile network signals.
2. Used for weather forecasting and tracking storms.
3. Used for GPS navigation and finding locations.
4. Used for scientific research, space observation, and military reconnaissance.
In simple words: It is an artificial satellite used for TV, weather updates, navigation, and science.

Exam Tip: Mention solar panels as a key visual feature that provides power to the satellite.

Ques 5. Look at the diagram given below and answer the following questions.
i) What does the picture below show? What does it consist of?
Answer: The picture shows the Solar System. It consists of the Sun at the centre, eight planets revolving around the Sun in fixed orbits, dwarf planets, moons, asteroids, and comets.
In simple words: It is our Solar System containing the Sun, planets, and other heavenly bodies.

Exam Tip: The Sun is the head of the solar system and contains 99.8% of its mass.

ii) Identify the following-
- Number 6 - Saturn
- Number 8 - Uranus
- The Red planet (write the number) - 4 (Mars)
- The planet farthest away from the sun - Neptune (Number 9)
- Present between numbers 5 and 6 - Jupiter and Saturn (Number 5 is Jupiter, Number 6 is Saturn, Asteroid belt is between them)
- Which planet(s) don't have any natural satellites - (write the number) - 1 and 2 (Mercury and Venus)
- Only place where we can live (write the number) - 3 (Earth)
- Number 3 is also known as - The Blue Planet
- Number 10 - Halley's Comet (or Pluto / Asteroid / Comet path shown as 10)
Answer: As answered above based on standard solar system diagrams.
In simple words: Identify the planets by their sequence numbers from the Sun.

Exam Tip: Memorize the order of planets from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.

Ques 6. Define (give one example)-
i) Planet
Answer: A large natural celestial body that revolves around the Sun in a fixed elliptical orbit and does not have its own light.
Example: Earth.
In simple words: A large round body that orbits the Sun is called a planet.

Exam Tip: Planets shine only by reflecting sunlight.

ii) Asteroid
Answer: Small, rocky celestial bodies that orbit the Sun, mostly found in the asteroid belt between Mars and Jupiter.
Example: Ceres.
In simple words: Rocky space objects orbiting the Sun are called asteroids.

Exam Tip: Asteroids are sometimes called minor planets.

iii) Constellation
Answer: A group of stars that form a recognizable pattern or shape in the night sky.
Example: Ursa Major (Saptarishi) or Orion.
In simple words: A group of stars forming a pattern in the sky is a constellation.

iv) Space
Answer: The vast, limitless expanse that exists beyond Earth's atmosphere and contains all celestial bodies.
Example: Outer space containing galaxies, stars, and planets.
In simple words: The endless empty area outside Earth's atmosphere is called space.
Exam Tip: Space is a vacuum, meaning there is no air or sound.

v) Comet
Answer: An icy celestial body that orbits the Sun and develops a bright glowing tail of gas and dust when it gets close to the Sun.
Example: Halley's Comet.
In simple words: An icy space object with a glowing tail when near the Sun is a comet.

Exam Tip: Comets are often referred to as "dirty snowballs".

vi) Saptarishi
Answer: A prominent constellation consisting of seven bright stars forming the shape of a large ladle or question mark, part of the Ursa Major constellation.
Example: The Great Bear group.
In simple words: A group of seven bright stars forming a ladle shape in the night sky is the Saptarishi.

Exam Tip: The pointer stars in Saptarishi always point directly towards the Pole Star (North Star).

Please refer to attached file for CBSE Class 4 EVS Revision Worksheet - Reproduction in Animals