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Biodiversity And Conservation Class 12th Biology CBSE Solution

Class 12th Biology CBSE Solution

Exercises
Question 1.

Name the three important components of biodiversity.


Answer:

Biodiversity refers to the variability of living organisms on Earth. The main biological components or levels of biodiversity are:

• Genetic diversity: It is the genetic variability among a species.


• Species diversity: It refers to the number of species that live in a particular place.


• Ecological diversity: It refers to the variation in ecosystems in a particular region or variation in ecosystem across the planet.



Question 2.

How do ecologists estimate the total number of species present in the world?


Answer:

• According to International Union for Conservation of Nature (2004), more than 1.5 million species of plants and animals have been described so far. Robert May have estimated the global species diversity to be around 7 million.


• Species inventory is more complete in temperate than in tropical countries and hence, more species are yet to be discovered in the tropical area.


• Biologists make a statistical comparison of temprate-tropical species richnes of an intensively studied group of insects and extrapolate this ratio with other groups of plants and animals to come up with a gross estimate of total species on the planet.


• This conventional taxonomic method is not suitable for estimating microbial species.



Question 3.

Give three hypotheses for explaining why tropics show greatest levels of species richness.


Answer:

Scientists have proposed various hypotheses to justify the higher species diversity in tropics. They are as follows:

• Tropical regions have been relatively undisturbed for millions of years compared to temperate region which have been subjected to glaciations in past which led to higher species diversification as it got more evolutionary time.


• Tropical regions have more constant and predictable climate compared to temperate which can promote niche specialization and higher species diversity.


• Solar energy is available more to tropics causing higher productivity and leading to higher diversity.



Question 4.

What is the significance of the slope of regression in a species – area relationship?


Answer:

• German naturalist and geographer, Alexander von Humboldt observed that within a region, the species richness increased utpo a limit with increased explored area. The relation between species richness and area is a rectangular hyperbola. On a logarithmic scale, it is straight line where Z is the slope of line (slope of regression).


• Z ranges from 0.1 to 0.2 for all taxa and regions except very large areas like continents.


• For larger areas, the slope of regression is steeper and Z ranges from 0.6 to 1.2.



Question 5.

What are the major causes of species losses in a geographical region?


Answer:

There are four major causes that can lead to species loss in an area.

• Habitat loss and fragmentation: Changes caused in a habitat due to uncontrolled and unsustainable human activities such as deforestation, slash and burn agriculture, mining, and urbanization can result into breaking up of the habitat into small pieces, which effects various species and the movement of migratory animals. This leads to decrease in the genetic exchange between populations leading to decreased population of species. It is the most important cause leading to species extinction.


• Over-exploitation: Human greed has led to over-exploitation of various natural resources which has led to endangering and extinction of various species over years.


• Alien species Invasions: Alien species that the introduced unintentionally or delibrately can become invasive and can cause declination or extinction of indigenous species.


• Co-extinctions: Various species can be connected to each other in an obligatory way. When one species gets extinct, other plants or animal species associated with it also gets extinct.



Question 6.

How is biodiversity important for ecosystem functioning?


Answer:

• Biodiversity gives ecosystem services such as photosynthesis and pollination that the nature provides.


• The higher the diversity, more stable is the ecosystem.


• If an ecosystem is rich in biodiversity, then the ecological balance would not get affected.



Question 7.

What are sacred groves? What is their role in conservation?


Answer:

• Sacred grooves are communally protected forest fragments that usually have a religious importance attached to it.


• In India sacred groves are found in certain regions of Rajasthan, Western Ghats of Karnataka, Maharashtra, Meghalaya, and Madhya Pradesh.


• Sacred grooves help in protection of various rare and threatened species as deforestation is strictly restricted in such areas.



Question 8.

Among the ecosystem services are control of floods and soil erosion.

How is this achieved by the biotic components of the ecosystem?


Answer:

• The biotic components of an ecosystem refers to the living organisms.


• Trees help soil become more porous by creating minuscle channels which helps seeping rain water in soil much faster and hence prevent flooding.


• Plants slow down water flow and roots hold soil which helps in preventing soil erosion.



Question 9.

The species diversity of plants (22 per cent) is much less than that of animals (72 per cent). What could be the explanations to how animals achieved greater diversification?


Answer:

• Animals are more diverse than plants because they have adapted better to the changing environment.


• Animals have more complex body structure and brain capacity as compared to the plants.


• Animals are locomotive and can migrate.


Hence, species diversity of plants is less compared to that if the animals.



Question 10.

Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?


Answer:

There are various disease causing microbes in humans that we would like to eliminate. Small pox causing virus have already being eradicated by using vaccines to prevent humans from the deadly disease. There are programs that are on to eliminate deadly microbes such as Polio virus and hepatitis B virus.


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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