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Evolution Class 12th Biology CBSE Solution

Class 12th Biology CBSE Solution

Exercises
Question 1.

Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory.


Answer:

• Darwinian Selection Theory states that “The organisms with the characteristics that enable them to survive better in natural conditions (the existing environmental conditions) would outbreed others that are less-endowed to survive under those conditions.


• Bacteria have been subjected to antibiotics since the earliest discovery of the first antibiotic i.e. Penicillin. Due to these constant treatments, certain strains of bacteria, due to mutations, developed resistance, or the already present resistance gene, now got selected as they could still survive in the presence of the antibiotics.


• Only the ones that survived the antibiotic treatment could further perpetuate and produce offsprings, resulting in the increase of antibiotic resistance in the bacterial population.


• Hence, the antibiotic resistance was observed in bacteria.



Question 2.

Find out from newspapers and popular science articles any new fossil discoveries or controversies about evolution.


Answer:

STUNNING DISCOVERY


Some 110 million years ago, this armoured plant-eater lumbered through what is now western Canada, until a flooded river swept it into open sea. The dinosaur’s undersea burial preserved its armour in exquisite detail. Its skull still bears tile-like plates and a grey patina of fossilized skins.



In life this imposing herbivore—called a nodosaur—stretched 18 feet long and weighed nearly 3,000 pounds. Researchers suspect it initially fossilized whole, but when it was found in 2011, only the front half, from the snout to the hips, was intact enough to recover. The specimen is the best fossil of a nodosaur ever found.



A cluster of pebble-like masses may be remnants of the nodosaur's last meal.


Quote from the article:


The more I look at it, the more mind-boggling it becomes. Fossilized remnants of skin still cover the bumpy armor plates dotting the animal’s skull. Its right forefoot lies by its side, its five digits splayed upward. I can count the scales on its sole. Caleb Brown, a postdoctoral researcher at the museum, grins at my astonishment. “We don’t just have a skeleton,” he tells me later. “We have a dinosaur as it would have been.”



Question 3.

Attempt giving a clear definition of the term species.


Answer:

A Species includes all those organisms with the characteristics similar enough, so that they can interbreed and perpetuate.



Question 4.

Try to trace the various components of human evolution (hint: brain size and function, skeletal structure, dietary preference, etc.)


Answer:

The various components of human evolution are as follows:






Question 5.

Find out through internet and popular science articles whether animals other than man has self-consciousness.


Answer:

i. Various animals such as Chimpanzees, Bottlenose dolphins, Gorillas, Orcas and even elephants have been observed to show variable levels of self-consciousness.


ii. Self-consciousness is the ability to introspect and identify self from the others. It is checked through various techniques and one such is mirror test in which many animals including Dolphins passed.


iii. They exhibit intimacy and chemistry with their partners and communicate with through various body gestures including certain specific sounds and movements.



Question 6.

List 10 modern-day animals and using the internet resources link it to a corresponding ancient fossil. Name both.


Answer:




Question 7.

Practise drawing various animals and plants.


Answer:


Darwin’s finches



Kangaroo-A marsupial



Thorns in Bougainvillea and tendrils in Cucurbita- examples of homology.



Question 8.

Describe one example of adaptive radiation.


Answer:

i. Adaptive radiation is the evolution of organisms such that a single species diverges into many through changes in the habitat and other habits so as to survive in a particular geographical area without facing competition. The best example of adaptive radiation is Darwin’s Fiches.


ii. During his journey, Darwin observed a variety of birds in the Galapagos Islands. He observed that all these birds had evolved from a common ancestor.


iii. The birds, originally fed on seeds. But due to increase in population and limited resources, started facing competition. As a result, various birds acquired different features depending on the kind of food they procured.


iv. So, earlier to be of a single kind, these birds diverged into having different variety of beaks depending on their food habits- Seeds, insects, nectar, etc. thus enabling them to survive in the same geographical area without facing any competition.


v. Another example of adaptive radiation is Australian marsupials.



Question 9.

Can we call human evolution as adaptive radiation?


Answer:

No, we cannot call human evolution as adaptive radiation.


Adaptive radiation is the diversifying of organisms from a single species due to various factors such as competition for resources, isolation in a different environment, etc.


Human evolution was a gradual process of anatomical, physiological and changes that took place over a long period of time. The humans did not diversify into many species from a common ancestor. They rather enhanced over the period of time, suiting best according to their current environment.



Question 10.

Using various resources such as your school Library or the internet and discussions with your teacher, trace the evolutionary stages of any one animal, say horse.


Answer:

Evolutionary stages of a horse (Equus) occurred in the following way:




Kids Worksheets

 

English 

Handwriting practice sheets

Cursive Writing – Small Letters

Alphabet Tracing

Tracing

Trace the Path

Positions

Sizes

​​Classroom Alphabets

Center Signs

Mother's Day

Father's Day

Circle The Shape

A TO Z WORKSHEET

A TO Z SMALL LETTERS

CVC Words Building

Write the First Letter of Given Picture

Circle the Correct Letter Worksheets

Circle the Cursive Letter Worksheets

Match the Letter with Correct Picture

Match the Picture with Cursive Letter

Circle two pictures that begin with same letter sound

Circle two pictures that begin with same letter sound (Cursive)

CVC Worksheets Letter ‘a’

CVC Worksheets Letter ‘e’

CVC Worksheets Letter ‘i’

CVC Worksheets Letter ‘o’

CVC Worksheets Letter ‘u’

Look and write with vowels a, e, i, o, u

Opposite Words

2 Letter words - sight words

Activities 

Princess Activities

Earth Day Activities

Witches and Wizards Activities

Animal Activities

Scissor Activities

Train Activities

Dinosaur Activities

Under the Sea Activities

Unicorn Activities

Transportation Activities

Space Activities

Color Activities

Shape Activities

Reading Passages.

Reading Passages for Kids 

Story PDF.

White Magic Story

Sunshine and Reeva in China

The Little Red Hen

The Sun,Moon and Wind

The Arab and the Camel

The Tortoise and the Hare

The Lion and the Mouse

Goldilocks and the Three Bears

The Three Little Pigs

The Princess and the Pea

The Shepherd Boy and the Wolf

Rapunzel

The Goose and the Golden Eggs

The North Wind and the Sun

The Miser and his Gold

The Country Maid and her Milk Pail

Goodnight Moon

The Ugly Duckling

The Boy Who Cried Wolf

Cinderella

Two Cats and Clever Monkey

The Lion and the Rabbit

The Lion and the Mouse

Mathematics.

Trace Numbers 1 to 10

Classroom Numbers

Measuring Things

Additional Worksheet.

Additional Worksheet.

Additional Worksheet

Subtraction Worksheets

Same, Less, More

Count and Write Worksheets

Count and Match Worksheets

Count and Circle Worksheets

Fill in the Missing Number Worksheets

What Comes After & Between

Write Missing Numbers

Shape worksheets

Backward counting

Trace the numbers 1-10

Multiplication Sheet practice for Children

Counting practice from 1 to 100 Worksheet

Miscellaneous in Maths

Science.

Science

Science Activity Plans

Miscellaneous.

Animal Decorations

Classroom Decorations

Foldable Boxes

Teacher's Planner

Classroom Rules

Graduation Certificates

Placemats

UKG Worksheets 

Geography.

Geography

Weather

Calendar

Hindi

Hindi Alphabets. (Swar)

Hindi Alphabets. (Vanjan)

Colours name in Hindi | रंगों के नाम

Fruits name in Hindi | फलों के नाम

Vegetables name in Hindi | सब्जियों के नाम

Days in Hindi

Parts of Body

Hindi Swar Tracing Worksheets

Hindi Vyanjan Tracing Worksheets

Write the First Letter of picture - Hindi Swar Worksheets

Look and Match - Hindi Swar Worksheets

Circle the correct letter - Hindi Swar Worksheets

Write the first letter - Hindi Vyanjan Worksheets

Circle the Correct Letter - Vyanjan Worksheets

Choose the Right Image - Vyanjan Worksheets

Miscellaneous Hindi Worksheets

2 Letter Words Hindi Worksheets

3 Letter Words Hindi Worksheets

4 Letter Words Hindi Worksheets

AA (ा) – AA ki Matra | आ (ा) की मात्रा

i ( ि) - i ki Matra | इ ( ि) की मात्रा

EE ( ी) – EE ki Matra | ई ( ी) की मात्रा

U (ु) - U ki Matra | उ (ु) की मात्रा

O (ू ) – OO ki Matra | ऊ (ू) की मात्रा

E ( े) - E ki Matra | ए ( े ) की मात्रा

AI (ै) - AI ki Matra | ऐ (ै)की मात्रा

o ( ो) - o ki Matra | ओ (ो) की मात्रा

ou ( ौ) - ou ki Matra | औ ( ौ) की मात्रा

General Knowledge.

GK Worksheets

50 Mazes

Preschool Assessment

Nursery GK Worksheet

Creative Worksheets

Social Skills

Feelings

People at Work

Finger Puppets

Shapes

Good Or Bad

Things That Go Together

Things That Do Not Belong

Match the following.

Match the fruit to its shadow. [5 Pages]

Match Letters [35 Pages]

Matching Worksheets

Sorting Worksheet

Shadow Matching

Match the uppercase letter to its lowercase [6 Pages]

Circle 2 Matching Pictures

Games.

Cut and Paste

Matching Cards

Puzzles and Mazes

Spot the Differences

Freak - Out !!!

Freak - Out !!! 

Sudoku

Cut and Glue

This Week

Literature.

Nursery Rhymes

Cursive Alphabet Trace and Write

Letters A to G Upper and Lower Case Tracing Worksheet

Cute Phrases A-Z

Beginning Sounds. Kindergarten Worksheet

Cursive Writing Small Letters.

Capital Letters.

Small Letters.

Alphabet Trace.

Alphabet Trace and Write.

Alphabet Worksheet 

Consonant Vowel Consonant (CVC) Flashcards

Coloring.

Coloring for Fun

100 Pages to Color

100 Animals to Color

100 Bracelets

Dot to Dot

Color Cute Dinosaurs

Color Cute Animals

Alphabet Coloring.

Coloring Images

Colors

Drawing

Circle the Color

English Alphabet Color it. 

English Alphabet Color it and Match it with Pictures

Alphabet Color it. [26 Pages]

Alphabet Color it 2. [7 Pages]

English Alphabet Color it. 2 

Numbers PDF.

Numbers 1 to 10 Color it. [2 Pages]

1 to 10 Numbers Coloring. [4 Pages]

Flash Cards PDF.

Plant Flashcards

Letters and Numbers

Tell the Time Flash Cards [6 Pages]

​​Reward Cards

Posters

Animal Flashcards

Name Cards

Happy Birthday

Flashcards English vocabulary [12 Pages]

Alphabet Letters with Pictures [5 Pages]

Numbers Flash Cards. [5 Pages]

Shapes FlashCards. [4 Pages]

Colors FlashCards. [3 Pages]

English Alphabet Learning Flash Cards. [26 Pages]

Alphabet Flashcards. [26 Pages]

Alphabet Identification Flash Cards. [26 Pages]

….

Addition

Addition Worksheet. [5 Pages] (V.1-5)

Addition Worksheet. [5 Pages] (V.1-5)

Addition Worksheet. [36 Pages] (V.1-5)

Additional Worksheet. 

Subtraction

Subtracting by Pictures [5 Pages] (V.1-5)

Subtracting by Numbers [5 Pages] (V.1-5)

Subtracting by Pictures and Numbers [5 Pages] (V.1-5)

Subtract and circle the correct number [5 Pages] (V.1-5)

General Knowledge.

Fruits [6 Pages] (V.5)

Vegetables [6 Pages] (V.5)

Positions [7 Pages] (V.5)

Colors [10 Pages] (V.5)

Match the following.

Match the fruit to its shadow. [5 Pages] (V.1-5)

Match Letters [35 Pages] (V.1-5)

Match the uppercase letter to its lowercase [6 Pages] (V.1-5)

Mathematics.

Count and Write Worksheets

Count and Match Worksheets

Fill in the Missing Number Worksheets

Trace the numbers 1-10.

Multiplication Sheet practice for Children [14 Pages] (V.1-5)

Counting practice from 1 to 100 Kindergarten Math Worksheet

Games.

Freak - Out !!! [10 pages] (V.5)

Freak - Out !!! [10 pages] (V.5)

Literature.

Nursery Rhymes

Cursive Alphabet Trace and Write [26 Pages] (V.1-5)

Letters A to G Upper and Lower Case Tracing Worksheet

Beginning Sounds. Kindergarten Worksheet

Cursive Writing Small Letters. [7 Pages] (V.1-5)

Capital Letters. [26 Pages] (V.1-5)

Small Letters. [26 Pages] (V.1-5)
Alphabet Trace. [9 Pages] (V.1-5)

Alphabet Trace and Write. [26 Pages] (V.1-5)

Alphabet Worksheet [26 Pages] (V.1-5)

Consonant Vowel Consonant (CVC) Flashcards [33 Pages] (V.1-5)

Hindi PDF Download.

Hindi Alphabets. (Swar) [13 Pages] (V.1-5)

Hindi Alphabets. (Vanjan) [34 Pages] (V.1-5)

Story PDF Download.

Two Cats and Clever Monkey [5 pages] (V.1-5)

The Lion and the Rabbit [4 Pages] (V.1-5)

The Lion and the Mouse [2 Pages] (V.1-5)

Reading Passages PDF Download.

Reading Passages for Kids [5 Pages] (V.1-5)

Coloring PDF Download.

Alphabet Coloring. [26 Pages] (V.1-5)

Coloring Images. [12 Pages] 

English Alphabet Color it. [5 Pages] (V.1-5)

English Alphabet Color it and Match it with Pictures. [5 Pages] (V.1-5)

Alphabet Color it. [26 Pages] (V.1-5)

Alphabet Color it 2. [7 Pages] (V.1-5)

English Alphabet Color it. 2 [5 Pages] (V.1-5)

Numbers PDF Download.

Numbers 1 to 10 Color it. [2 Pages] (V.1-5)

1 to 10 Numbers Coloring. [4 Pages] (V.1-5)

Flash Cards PDF Download.

Tell the Time Flash Cards [6 Pages] (V.5)

Flashcards English vocabulary [12 Pages] (V.5)

Alphabet Letters with Pictures [5 Pages] (V.5)

Numbers Flash Cards. [5 Pages] (V.1-5)

Shapes FlashCards. [4 Pages] (V.1-5)

Colors FlashCards. [3 Pages] (V.1-5)

English Alphabet Learning Flash Cards. [26 Pages] (V.1-5)

Alphabet Flashcards. [26 Pages] (V.1-5)

Alphabet Identification Flash Cards. [26 Pages] (V.1-5)


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