Tree of Life Class 8 Questions and Answers Notes Basic Science Chapter 16 Kerala Syllabus

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Class 8 Basic Science Chapter 16 Chemistry of Matter Question Answer Notes

Class 8 Basic Science Chapter 16 Notes Kerala Syllabus Chemistry of Matter Question Answer

Chemistry of Matter Class 8 Questions and Answers Notes

Let’s Assess

Question 1.
Examine the following passage and correct the errors if any, found in the underlined parts.
Classifying living beings into larger groups based on similarities and further into smaller groups based on differences is the basis of the cell theory. The various levels of classification were developed by Theophrastus. He is known as the Father of Taxonomy. The smallest unit in classification is phylum. The method of scientifically naming organisms was developed by Carl Linnaeus. The practice of identifying an organism by using both its genus and species name is known as taxon. According to this, when writing the scientific name of an organism, the species name should be written first.
Answer:

Original Underlined Text	Correction and Reason
…is the basis of the cell theory	Correction: Taxonomy or Classification. Classification is the basis for grouping organisms.
The various levels of classification were developed by Theophrastus	Correction: Carl Linnaeus. Linnaeus ‘ introduced the different levels of classification.
The smallest unit in classification is phylum	Correction: Species. Species is the most basic/smallest level of classification.
..practice of identifying an organism by using both its genus and species name is known as taxon	Correction: Binomial Nomenclature. Taxon refers to the classification levels themselves (like Kingdom, Phylum, etc.).
…the species name should be written first	Correction: Genus name. The genus name comes first, and the species name comes second in Binomial Nomenclature.

Question 2.
Match the following.

A	B
1. John Ray	a) Living things were classified into 5 kingdoms
2. Carl Linnaeus	b) Plants were classified as trees, shrubs, and herbs
3. Ernst Haeckel	c) Living things were classified into 3 kingdoms
4. Robert H. Whittaker	d) Father of taxonomy
5. Aristotle	e) Initiated the scientific method of classification
	f) Animals were classified into those with red blood and those without red blood.

Example: Aristotle classified animals into two groups – those with red blood and those without red blood.
Answer:
1. John Ray – e) Initiated the scientific method of classification
2. Carl Linnaeus – d) Father of taxonomy
3. Ernst Haeckel – c) Living things were classified into 3 kingdoms
4. Robert H. Whittaker – a) Living things were classified into 5 kingdoms
5. Aristotle – f) Animals were classified into those with red blood and those without red blood

Question 3.
Which of the following does not belong to the group? What is the common feature of the others?
A. Housefly, Lizard, Butterfly, Grasshopper
B. Cat, Dog, Tiger, Snake
C. Arecanut tree, Coconut tree, Jack tree, Palm tree
Answer:
A. Housefly, Lizard, Butterfly, Grasshopper
Does not belong: Lizard Common feature of others: They are all insects (belonging to Class Insecta,
Phylum Arthropoda). Lizards are reptiles (Class Reptilia, Phylum Chordata).

B. Cat, Dog, Tiger, Snake Does not belong: Snake Common feature of others: They are all mammals (belonging to Class Mammalia). Snakes are reptiles (Class Reptilia).

C. Arecanut tree, Coconut tree, Jack tree, Palm tree
Does not belong: Jack tree
Common feature of others: They are all types of palm trees (belonging to the Family Arecaceae, Class Liliopsida – Monocots). Jack tree belongs to a different family (Moraceae) and is a dicot.

Basic Science Class 8 Chapter 16 Question Answer Kerala Syllabus

Textbook Page No : 255

Question 1.
What is the main idea conveyed by the poster?
Answer:
The main idea conveyed by the poster is the vastness of biodiversity on Earth, by showing the large and varied number of identified species in major groups of living organisms (Animals, Plants, Fungus, Protista, and Bacteria/Archaea).

Question 2.
Can you suggest a suitable title for the poster?
Answer:
A suitable title for the poster could be:

• The World of Life: A Glimpse of Biodiversity
• Biodiversity on Earth: Identified Species Count
• Tree of Life: Species Numbers

Question 3.
How is it possible to identify and study so many living organisms?
Answer:
It is possible to identify and study so many living organisms through the branch of science called Taxonomy.

Taxonomy deals with:

• Classifying organisms by comparing their characteristics, and identifying similarities and differences.
• Giving them scientific names (Nomenclature).
• This systematic approach, using different levels of classification (Taxa), allows scientists to organize and understand the relationships between the vast number of organisms (biodiversity).

Textbook Page No : 257 & 258

Question 4.
What are the classification levels between species and phylum?
Answer:
Referring to the levels of classification, the levels between species and phylum are:

• Genus
• Family
• Order
• Class

Question 5.
Complete Table 16.1 for the classification levels of the Tiger:

Answer:

Levels of classification	Group and characteristics	Organisms (Example/ Group)
Kingdom:	Animalia (Animals) – Multicellular, eukaryotic, heterotrophic organisms.	Tiger, Cat, Human, Fish etc.
Phylum:	Chordata (Vertebrates) – Presence of vertebrae and vertebral column.	Tiger, Cat, Human, Fish
Class:	Mammalia (Mammals) – Warmblooded, body covered with hair, nourish young ones with milk.	Tiger, Cat, Human
Order:	Carnivora (Carnivores) – Sharp teeth and claws adapted for hunting and eating meat.	Tiger, Cat
Family:	Felidae – Retractable claws, excellent night vision.	Tiger, Cat
Genus:	Panthera (Big cats) – Ability to roar, large and powerful body structure.	Tiger, Lion, Leopard
Species:	Panthera tigris (Tiger) – Orange fur with black stripes and strong large body.	Tiger

Textbook Page No : 260

Question 6.
Can we include Bacteria, Paramecium, Mushroom, and Yeast in the Plant or Animal kingdoms? Why?
Answer:
No, we cannot include them in the Plant or Animal kingdoms.
Reason: The Two-Kingdom classification (Plantae and Animalia) was insufficient because it did not account for characteristics of these organisms.

• Bacteria are prokaryotes (no distinct nucleus).
• Paramecium is a unicellular eukaryote.
• Fungi (Mushroom/Yeast) are saprophytes and do not have chlorophyll to perform photosynthesis like plants.

Textbook Page No : 262

Question 7.
Complete Table 16.3: Five Kingdom Classification

Answer:

Kingdom	Characteristics	Examples
Monera	Prokaryotes, do not have a distinct nucleus.	Bacteria
Protista	Mostly unicellular eukaryotes. Can be autotrophs or heterotrophs. Move via flagella, cilia, or pseudopodia.	Amoeba, Paramecium, Euglena
Fungi	Eukaryotic saprophytes. Do not have chlorophyll.	Mould, Yeast, Mushroom Plantae
Plantae	Multicellular eukaryotes that produce their own food (photosynthesis).	Plants (Coconut tree, etc.)
Animalia	Multicellular eukaryotes and heterotrophs. Have locomotory organs.	Sponges, Humans, Tiger

Textbook Page No : 264

Question 8.
Complete Table 16.4 for Scientific Names:

Answer:

Organism	Scientific Name
Tiger	Panthera tigris
Coconut tree	Cocos nucifera
Dog	Canis familiaris (The text provides no specific information, but this is the correct scientific name)

Textbook Page No : 266
Indicators

Question 9.
Limitations of classification based only on external features
Answer:
Classification based solely on external appearance is often inaccurate because it can separate organisms that are actually closely related biologically.

• The text uses the example of Wolffia (a tiny floating plant) and Anthurium (a larger flowering plant). Despite looking very different externally, they belong to the same family (Araceae) because they are genetically related and share a common ancestor.
• Conversely, Salvinia and Wolffia might look somewhat similar (both small aquatic plants), but Salvinia is a non-flowering fern (Family Salviniaceae) while Wolffia is a flowering plant.

Therefore, relying only on external structure can lead to errors in grouping.

Question 10.
Changes in the criteria of classification
Answer:
The criteria for classification have evolved from simple observations to complex scientific analysis.

• Past Criteria: In early days, classification was based merely on external structure and utility (usefulness).
• Modern Criteria: Today, classification considers evolutionary (phylogenetic) relationships and genetic characteristics.
• Result: This shift led to the splitting of Kingdom Monera into Archaebacteria and Eubacteria based on molecular studies.

Textbook Page No : 267

Question 11.
Do all humans belong to the same species?
Answer:
Yes.
Although humans living in different parts of the world show variations in external appearance (due to local geography and environmental factors), there are no significant genetic or other fundamental differences among them. All humans around the world share a common ancestor and can interbreed to produce fertile offspring. That is why all humans are classified under the same species, sapiens (within the genus Homo).

Class 8 Basic Science Chapter 16 Question Answer Extended Activities

Question 1.
Prepare a magazine including pictures and contributions of scientists related to the history of classification.

Question 2.
List the plants found in the school surroundings and biodiversity parks, find their scientific names, and display them.

Tree of Life Class 8 Notes

Class 8 Basic Science Tree of Life Notes Kerala Syllabus

Introduction: Biodiversity
The Earth is home to a vast number of diverse living organisms, including plants, animals, fungi, bacteria, and protists. How is it possible to identify and study so many different living things?. Attempts to classify and study them began a long time ago.

Early Attempts at Classification

• Aristotle (അരിസ്റ്റോട്ടിൽ): Classified living beings based on whether they had red blood or not.
• Theophrastus (തിയോഫാസ്റ്റസ്): Classified plants into trees, shrubs, and herbs.

• Carl Linnaeus (കാൾലിനേയസ്): Introduced the different levels of classification and provided a scientific foundation for it. He is considered the Father of Taxonomy.

• John Ray (ജോൺ റേ): Initiated the scientific method of classification and was the first to use the term ‘species’.

• Ernst Haeckel (ഏണസ്റ്റ് ഹെക്കൽ): Classified living organisms into three kingdoms: Animalia, Plantae, and Protista.

Taxonomy (വർഗ്ഗീകരണശാസ്ത്രം)
The branch of science that deals with classifying organisms by comparing characteristics, identifying similarities/differences, and giving scientific names.
Importance: Helps understand biodiversity and relationships between organisms.

Father of Taxonomy: Carl Linnaeus.
ജീവികളെ തിരിച്ചറിയുകയും, സാമ്യതകളുടെയും വ്യത്യാസങ്ങളുടെയും അടിസ്ഥാനത്തിൽ തരംതി രിക്കുകയും, ശാസ്ത്രീയ നാമം നൽകുകയും ചെ യ്യുന്ന ശാസ്ത്രശാഖയാണ് ടാക്സോണമി. ഇതി ലൂടെ ജീവവൈവിധ്യത്തെക്കുറിച്ചും ജീവികൾ ത മ്മിലുള്ള ബന്ധങ്ങളെക്കുറിച്ചും മനസ്സിലാക്കാം.

Levels of Classification (വർഗ്ഗീകരണ തലങ്ങൾ)
Linnaeus proposed a hierarchical system for classifying organisms, starting from broad categories and becoming more specific.

The Main Steps in Classification:

1. Identification (തിരിച്ചറിയൽ)
2. Classification (വർഗ്ഗീകരണം)
3. Naming (നാമകരണം)
   The Hierarchy (Illustration 16.1):
   The levels, from broadest to most specific, are:

Species

• A species is a group of organisms that can naturally reproduce to form fertile offspring (പ്രത്യുത്പാദന ശേഷിയുള്ള തലമു).
• This is the most basic level of classification.
• Examples: Human beings, cats, dogs, and cashew trees are examples of different species. All humans belong to the same species, sapiens.

Classification Systems (വർഗ്ഗീകരണ രീതികൾ)

• The classification levels developed by Carl Linnaeus are still used today. These levels (Kingdom, Phylum, Class, etc.) are called Taxa. Plants can also be classified using these levels, from species to kingdom.
• Two-Kingdom Classification System (ദ്വികിങ്ഡം വർഗീകരണം)
  • Proposed by Carl Linnaeus.
  • Divided all living organisms into two kingdoms:
    1. Kingdom Animalia (Animals)
    2. Kingdom Plantae (Plants).
• Classification level of the coconut tree

Kingdom	Plantae (Plants) – Multicellular, eukaryotic, autotrophic organisms.
Division	Magnoliophyta (Flowering plants) – Plants with seeds enclosed inside fruits.
Class	Liliopsida (Monocotyledons) – Plants with parallel leaf venation and fibrous roots.
Order	Arecales – Plants with long and hard stems.
Family	Arecaceae – Plants with large compound leaves and unbranched stems.
Genus	Cocos – Produces large, single-seeded fruits.
Species	Cocos nucifera (Coconut) – Produces fruits with a hard shell, fibrous husk, with a liquid and solid endosperm, inside.

Limitations of the Two-Kingdom System

• Many organisms (like Bacteria, Paramecium, Mushroom, Yeast – see Fig 16.8) do not fit neatly into either the Plant or Animal kingdom.
• Bacteria: Unicellular, Prokaryote. (Plants/Animal are Eukaryotes).
  • Paramecium: Unicellular, Eukaryote, Heterotroph, Mobile. (Plants are autotrophs; some animals are multicellular).

• • Mushroom/Yeast: Eukaryote, Heterotroph (saprophyte), No mobility. (Plants are autotrophs; Animals are usually mobile).

• This showed the need for a more comprehensive system.

Five-Kingdom Classification System (പഞ്ചകിങ്ഡം വർഗീകരണം)

• Proposed by Robert H. Whittaker to overcome the limitations of the two-kingdom system.
• Classified organisms into five kingdoms:

Kingdom	Cell Type	Multicellularity	Mode of Nutrition	Key Characteristics & Examples
Monera	Prokaryotes	Unicellular	Autotrophic or Heteroirophic	Do not have a distinct nucleus. Simplest and most ancient organisms. Eg: Bacteria.
Protista	Eukaryotes	Unicellular	Autotrophic or Heterotrophic	Mostly aquatic. Have locomotory structures like flagella, cilia, and pseudopodia. Eg: Amoeba, Paramecium, Euglena.
Fungi	Eukaryotes	Mostly Multicellular	Heterotrophs (Saprophytes)	Do not have chlorophyll. Absorb nutrients from dead and decaying matter. Cell wall made of chitin. Eg: Mould, Yeast, Mushroom.
Plantae	Eukaryotes	Multicellular	Autotrophs (Photosynthesis)	Primary producers. Have roots, stems, and leaves.
Animalia	Eukaryotes	Multicellular	Heterotrophs	Have locomotory organs and definite receptors. Eg: Sponges to humans.

• Advantage of Five-Kingdom Classification: It provides a more accurate and detailed way to group organisms, especially microorganisms like bacteria, protists, and fungi, which didn’t fit well into the older two-kingdom system.

Closer Look at Some Kingdoms

• Kingdom Monera
  • Characteristics: The simplest and most ancient organisms. They are all unicellular and prokaryotic (lack a distinct nucleus).
  • Main Group: Bacteria.
  • Occurrence: Found everywhere – soil, water, air, food, inside our bodies.
  • Role: Important in nutrient cycles (like nitrogen fixation). Most are useful, but some cause diseases.
• Kingdom Protista

• • Characteristics: Unicellular eukaryotes. Most live in aquatic habitats.
  • Examples: Paramecium, Amoeba, Euglena.
  • Disease-causing Protists: Plasmodium (causes malaria), Entamoeba histolytica (causes amoebic dysentery).
• Kingdom Fungi
  • Characteristics: Eukaryotes. Mostly multicellular (except for unicellular yeast). Have a cell wall made of chitin. Do not have chlorophyll and cannot perform photosynthesis. They are saprophytes, absorbing nutrients from dead and decaying matter.
  • Examples: Mould on bread, mushrooms, yeast.

• • Uses: Edible mushrooms, yeast (used in baking wine alcohol production) candidiasis and ringworm.

The section discusses:

• The variety of local names for a plant (like Papaya).
• The difficulty in identifying and studying the same organism when it is known by different names.
• The solution: giving names that are universally accepted beyond language barriers.
• This solution is Binomial Nomenclature, a scientific method developed by Carl Linnaeus, where the name consists of the genus and species name.
• The names are often in Latin or transformed to the Latin style to ensure they are the same everywhere in the world.
• For example, the scientific name of a human is Homo sapiens.

Binomial Nomenclature (ദ്വിനാമ പദ്ധതി)

• Developed by: Carl Linnaeus.
• A universally accepted scientific method of naming organisms using two parts: the Genus name (first, capitalized) and the Species name (second, lowercase).
• Format: Written in italics or underlined.
• Importance: Provides a unique, universal name for each organism, avoiding confusion from common names.
• Example: Homo sapiens (Human), Panthera tigris (Tiger).

ജീവികൾക്ക് ലോകമെമ്പാടും അംഗീകരിക്കപ്പെട്ട ഒരു ശാസ്ത്രീയനാമം നൽകുന്ന രീതിയാണ് ദ്വിനാ മ പദ്ധതി. ഇതിൽ ആദ്യപദം ജീനസിനെയും (Genus) രണ്ടാം പദം സ്പീഷീസിനെയും (Species) കുറിക്കുന്നു. ഉദാ: Homo sapiens (മനുഷ്യൻ).

New Paths in Classification (വർഗ്ഗീകരണത്തിലെ പുതിയ രീതികൾ)
Classification methods are not static; they are constantly being revised based on new discoveries and understanding.

Limitations of Early Methods:

• Early classification was often based only on external features (morphology) and utility.
• Problem: Organisms that look similar externally might not be closely related, and organisms that look different might actually be closely related.
• Example (Fig 16.16): Wolffia (a tiny flowering plant) and Salvinia (a non-flowering fern-like plant) look some what similar externally but belong to completely different families based on evolutionary and genetic characteristics. Wolffia is in the family Araceae (like Anthurium), while Salvinia is in Salviniaceae (like Azolla).

Modern Classification Methodology:
Today, classification considers not only physical characteristics but also:

• Evolutionary relationships (Phylogenetics)
• Genetic characteristics

Six-Kingdom Classification System (ആറ് കിങ്ഡം വർഗ്ഗീകരണം)
As scientific understanding, particularly in molecular studies, progressed, the Five-Kingdom system was further refined.

• Proposer: The scientist Carl Woese introduced the Six-Kingdom classification system.
• Change: Based on modern scientific observations, the Kingdom Monera (which contained all prokaryotes) was divided into two distinct kingdoms.
• The Split: Monera was split into:
  • Kingdom Archaebacteria ( കീരിയ ആർക്കിബാ)
  • Kingdom Eubacteria (യുബാക്ടീരിയ).

ശാസ്ത്രീയ നിരീക്ഷണങ്ങളുടെ അടിസ്ഥാനത്തിൽ, കാൾ ഷൂസ് എന്ന ശാസ്ത്രജ്ഞൻ വർഗ്ഗീകരണ രീതി പരിഷ്കരിച്ചു. അദ്ദേഹം മൊണീറ എന്ന കി ങ്ഡത്തെ ആർക്കിബാക്ടീരിയ, യൂബാക്ടീരിയ എ ന്നിങ്ങനെ രണ്ടായി വിഭജിച്ചു. അങ്ങനെ മൊത്തം ആറ് കിങ്ഡങ്ങൾ നിലവിൽ വന്നു.

Do all Humans Belong to the Same Species?
Despite differences in external appearance among humans living in different parts of the Earth, which may be due to the influence of local geography and environmental factors, there is no significant genetic or other fundamental difference among them.

• All humans around the world share a common ancestor.
• Therefore, all humans are classified under the same species: sapiens.