Grade-3 Social Science, Term-2 Chapter-8 Prehistoric Animals

Chapter-8

Prehistoric Animals

Fill in the blanks

(photosynthesis, bacteria, Mesozoic, turtles, crocodiles, eras, 4.5 billion, muscles or bones)

     1.    Life on the earth can be divided into different phases called eras.

     2.    The first signs of life were tiny bacteria in Pre-Cambrian Era.

     3.    The Earth is believed to have formed 4.5 billion years ago.

     4.    Early bacteria carried out photosynthesis.

     5.    The first animals of pre-cambrian era had soft bodies without muscles or bones.

     6.    Mesozoic era saw the emergence of dinosaurs.

     7.    Dinosaurs, turtles, crocodiles, frogs and the first birds lived at the same time.

Name a prehistoric

• Flying reptile 

Pterodactyl- Pteranodon

• Swimming creature

Ichthyosaur

• Plant

Fern

• Dinosaur

Stegosaurus

Give two examples of prehistoric animals that lived

• Before dinosaurs

 (trilobites, eel like fish, giant spiders, ancestors of shark)

• Along with dinosaurs

(turtles, crocodiles, frogs, first birds)

• After dinosaurs died

(snakes, mammoth, monkeys and apes)

Give reason 

There were no flowers or grasses in the early parts of the mesozoic era. 

In the early parts of the mesozoic era, there were no flowers or grasses because the earth was hot and dry.

Dinosaurs are extinct.

Dinosaurs are extinct because probably-

1.    A giant rock from space may have hit them

2.    The climate changed and they were not able to adjust/adapt.

3.    A disease struck them- they fell sick and died

Answer in one word

  

     1.    Ankle-length plant of Paleozoic Era having leafless branching stems with rounded tips. 

Cooksonia 

     2.    Dinosaurs rules during this era.

Mesozoic Era

     3.    Dinosaurs became extinct in this era.

Cenozoic Era

     4.    An animal that looked like a big hairy elephant and had long tusks.

Mammoth

     5.    A prehistoric bird.

Archaeopteryx

     6.    A prehistoric animal that had hard shells.

Trilobites

     7.    An animal which was probably the ancestor of modern lions and tigers.

Sabre-toothed cat

    8.    An insect that has been there since prehistoric times.

Cockroach

     9.    A dolphin-like giant marine animal that lived in the Mesozoic Era.

Ichthyosaur

10.    A flying reptile having wing-span of 6 to 7 metres, having boneless beak and crest on the head.

Pteranodon

11.    A carnivorous dinosaur that was about the size of a dog.

Eoraptor

12.    A flying, carnivorous dinosaur that had featherless wings.

Pterodactyl

13.    Dinosaur that had a head like a crocodile and is known to have eaten fish.

Baryonyx

14.    One of the largest carnivorous dinosaurs that weighed around eight tonnes and hunted in packs.

Giganotosaurus

15.    One of the largest herbivorous dinosaurs, having a very long neck, walked on four legs and is called the 'gentle giant’.

Apatosaurus

16.    A herbivorous dinosaur that had spikes along its back and tail and it walked on four legs.

Stegosaurus

17.    A herbivorous dinosaur that had a bony frill and horns like a rhinoceros, having three big horns in its large head.

Triceratop

18.    A herbivorous dinosaur having long spikes on its thumbs.

Iguanodon

19.    A large and strong herbivorous dinosaur having an eight metres long neck and a small brain.

Diplodocus

20.    One of the tallest herbivorous dinosaurs with a very long neck and the height of a four-storey building.

Brachiosaurus

21.    An omnivorous dinosaur that had very good vision, an intelligent brain and it rained on two legs.

Troodon

Answer these questions:

Q. What do you understand by prehistoric period?

Ans- The period of history about which there are no written records,  is called the Prehistoric period.

Q. If there was no written record of prehistoric times, how do we know about the animals and people who lived then?

Ans- We know about the animals and people who lived from 

1) paintings in caves

2) objects used by people in those days

3) bones and fossils of animals and plants.

Q. What are fossils?

Ans- Fossils are unspoilt remains of prehistoric plants and animals and the Impressions or marks left by them when they were caught in mud or rock. 

Q. What can we know from the bones of a dinosaur?

Ans- From the bones of a dinosaur we learn-

1.    its behaviour and appearance 

2.    Weather it was primitive or advanced dinosaur

3.    Whether it ate plants or meat

4.    Whether it had small or large brain

5.    It had good or bad eyesight

6.    About hearing and sense of smell

7.    What other Dinosaurs it was related to

8.    Lifestyle and habits

Q. How did animals on Earth change?

Ans- Animals on Earth changed because of the change in climatic conditions and adaptations in a process called evolution.

               

Q. What is a dinosaur? What does it mean?

Ans- Dinosaurs are a diverse group of prehistoric reptiles. The word dinosaur means “terrible lizard”.

Q. Describe dinosaurs.

Ans- The word dinosaurs means “terrible lizards”. They can be described as:

1.    While some were small, most were very large and heavy creatures.

2.    Large bones

3.    Sharp claws and teeth.

4.    Leathery-scaly skin that made them look terrifying.

5.    Many walked on four legs while somewhat on two.

6.    Huge animals with small brains

7.    Laid eggs like birds

8.    Mostly herbivores or carnivores. Some were omnivore

Q. When did dinosaurs roam the earth?

Ans- Dinosaurs first appeared 247 million years ago. They ruled the Earth for about 175 million years until an extinction event 65.5 million years ago wiped out all of them, expect for the avian dinosaurs.

Q. What did dinosaurs eat?

Ans- Some dinosaurs ate lizards, turtles, eggs, or early mammals. Some hunted other dinosaurs or scavenged dead animals. Most, however, ate plants (but not grass, which hadn't evolved yet).

Q. In which period of the Mesozoic era, forests came into existence and why?

Ans- In the Jurassic period of the Mesozoic era, forests came into existence as more oceans were formed and rain became heavier.

Q. What happened to the dinosaurs by the time man evolved?

Ans- The dinosaurs became extinct by the time man evolved.

Q. Describe some prehistoric animals that lived alongside the dinosaurs.

Ans- Turtles, crocodiles, frogs and first birds lived alongside the dinosaurs. There were also mammals at the same time.

Q. Which prehistoric animals lived alongside early man?

Ans- These prehistoric animals lived alongside early man-

       1.    Mammoths

       2.    Giant ground sloth

       3.    Dire wolves

       4.    saber-toothed cats

       5.    Monkeys

       6.    Apes

Q. Give the names of some animals of today that lived in prehistoric times.

Ans- Following are the animals of today that lived in prehistoric times:

1.    Sponges

2.    Snails

3.    Spiders

4.    Sharks

5.    Jellyfish

6.    Coral

7.    Cockroaches

8.    Apes 

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