1. Why do we classify organisms?


Explanation:

Organisms are classified for several reasons, including:

  1. Identification: Classification helps in identifying and naming organisms, making it easier to communicate about them across different regions and languages.

  2. Understanding diversity: There are millions of different organisms on our planet, and classifying them helps us understand the diversity of life and the relationships between different species.

  3. Evolutionary history: Organisms are classified based on their evolutionary relationships, helping us understand how different groups of organisms have evolved over time.

  4. Predicting traits: Classification allows us to predict certain characteristics of an organism based on its classification. For example, we can predict that all mammals will have certain features such as hair, mammary glands, and three middle ear bones.

  5. Conservation: Understanding the classification of organisms helps us identify species that are endangered or threatened and prioritize conservation efforts to protect them.

Overall, classification helps us organize and make sense of the vast diversity of life on our planet and can inform important scientific, medical, and conservation decisions.


2. Give three examples of the range of variations that you see in life forms around you.


Explanation:

There are countless examples of variations in life forms around us, but here are three:

  1. Variation in size: From the smallest bacteria to the largest whales, there is an incredible range in the size of organisms on our planet. For example, the blue whale, the largest animal on earth, can grow up to 30 meters (100 feet) in length and weigh as much as 200 tons, while the fairyfly, a tiny parasitic wasp, measures just 0.14 millimeters in length.

  2. Variation in adaptations: Different organisms have evolved a variety of adaptations that allow them to survive in their respective environments. For example, camels have adapted to living in arid desert regions by storing fat in their humps, which they can draw on for energy when food and water are scarce. In contrast, penguins have adapted to living in the cold waters of Antarctica by having a layer of fat and feathers that keep them warm.

  3. Variation in reproduction: Organisms have evolved different reproductive strategies to ensure the survival of their offspring. Some organisms reproduce asexually, such as bacteria, which simply divide to produce identical copies of themselves. Others reproduce sexually, such as mammals, where two individuals contribute genetic material to produce offspring that are genetically unique.



3. Which of the following do you think is a more basic characteristic for classifying organisms?

  1. The place where they live.

  2. The kind of cells they are made of. Why?

Explanation:

The kind of cells an organism is made of is a more basic characteristic for classifying organisms than the place where they live. This is because cells are the fundamental unit of life, and all living organisms are made up of cells.

The type of cells an organism is made of determines many of its characteristics, such as its metabolic processes, reproduction, and ability to adapt to its environment. Therefore, the kind of cells an organism is made of is a more fundamental characteristic for classifying organisms than the place where they live.


4. What is the primary characteristic on which the broad division of organisms is made?

Explanation:

The primary characteristic on which the broad division of organisms is made is the type of cells they are made of.

All living organisms can be broadly classified into two categories based on their cellular organization: prokaryotes and eukaryotes.

Prokaryotes: are organisms that lack a membrane-bound nucleus and other complex cell organelles. They are typically single-celled organisms that include bacteria and archaea.


Eukaryotes: are organisms whose cells have a membrane-bound nucleus and other complex cell organelles, such as mitochondria and chloroplasts. Eukaryotes include animals, plants, fungi, and protists.



5. On what basis are plants and animals put into different categories?

Explanation:

Plants and animals are put into different categories based on several characteristics that distinguish them from each other. These include:

  1. Cell Structure: Plant cells have a cell wall made of cellulose, while animal cells do not have a cell wall. Additionally, plant cells have chloroplasts for photosynthesis, while animal cells do not.

  2. Mode of Nutrition: Plants are autotrophic, meaning they can produce their own food through photosynthesis, while animals are heterotrophic, meaning they rely on other organisms for food.


6. Which organisms are called primitive, and how are they different from the so-called advanced organisms?

Explanation:

Primitive organisms are those that have simpler structures compared to more complex organisms. 

These organisms are unicellular or simple multicellular organisms with relatively simple structures and functions.

Examples of primitive organisms include bacteria, protists, and some fungi. 


Advanced organisms are those that have more complex structures and functions. These organisms have complex, multicellular structures with specialized organs, systems, and functions.

Examples of advanced organisms include animals, plants, and some fungi. 


7. Will advanced organisms be the same as complex organisms? Why?

Explanation:

The terms "advanced organisms" and "complex organisms" can be used interchangeably to describe organisms that have evolved more complex structures, functions, and behaviors. 

Advancement led to the formation of multicellular complex organisms.

Therefore, while advanced organisms can be considered complex, it is not always the case that complex organisms are more advanced in their evolutionary status. The evolutionary history and adaptations of each organism are unique and cannot be fully captured by simplistic labels or classifications.



8. What is the criterion for the classification of organisms as belonging to the kingdom Monera or Protista?

Explanation:

The classification of organisms as belonging to the kingdom Monera or Protista is based on their cellular organization and other characteristics.

Organisms in the kingdom Monera are typically unicellular and prokaryotic, which means they lack a membrane-bound nucleus and other complex cell organelles. The kingdom Monera includes bacteria and archaea.

Organisms in the kingdom Protista are also typically unicellular, but they are eukaryotic, which means they have a membrane-bound nucleus and other complex cell organelles. Protists include a diverse range of organisms, such as algae, amoebas, and protozoans.


9. In which kingdom will you place an organism which is single-celled, eukaryotic and photosynthetic?

Explanation:

An organism that is single-celled, eukaryotic, and photosynthetic would be classified as a member of the kingdom Protista. This is because Protista is a diverse kingdom that includes a variety of unicellular eukaryotic organisms, including some that are photosynthetic.

Specifically, if the organism is photosynthetic, it could be classified as a member of the sub-kingdom Algae, which includes unicellular and multicellular photosynthetic protists.



10. In the hierarchy of classification, which grouping will have the smallest number of organisms with maximum common characteristics and which will have the largest number of organisms?

Explanation:

The grouping with the smallest number of organisms with maximum common characteristics is the species. A species is a group of individuals that can interbreed and produce viable offspring. This grouping is the smallest because it is based on the most specific set of characteristics that organisms can have in common.


b) The grouping with the largest number of organisms is the kingdom. The kingdom is the broadest level of classification, and it includes a wide range of organisms that share a few basic characteristics, such as cellular organization and mode of nutrition.


11. Which division among plants has the simplest organisms?

Explanation:

The division among plants that has the simplest organisms is the Thallophyta division, also known as the mosses or algae. They are non-vascular plants that lack true roots, stems, and leaves. They have a simple body structure consisting of a single cell layer, and they reproduce by spores rather than seeds. Mosses are considered to be some of the most primitive plants, and they evolved early in the history of plant life on Earth.



12. How are pteridophytes different from phanerogams?


Explanation:

Category

Pteridophytes

Phanerogams

Seed Formation

Seedless

Seeds formed

Vascular System

Have vascular system but no flowers

Have vascular system and flowers

Embryo

Embryo is naked

Embryo is covered

Reproduction

Reproduce by spores

Reproduce by seeds

Examples

Ferns, horsetails and club mosses

Gymnosperms and angiosperms

13. How do gymnosperms and angiosperms differ from each other?

Explanation:

The characteristic differences between gymnosperms and angiosperms are:

Category

Gymnosperms

Angiosperms

Seed Formation

Naked seeds i.e. not enclosed in an ovary

Enclosed seeds within an ovary

Flower

Absent

Present

Fruit

Absent

Present

Examples

Pines, spruces, firs, ginkgoes, cycads, and gnetophytes

Flowering plants such as orchids, roses, and grasses

14. How do poriferan animals differ from coelenterate animals?


Explanation:

Some of the differences between poriferan and coelenterate animals:

Category

Poriferan Animals

Coelenterate Animals

Symmetry

Asymmetrical

Radial symmetry

Body Structure

Multicellular with pores, no true tissues

Multicellular with tentacles, true tissues

Digestive System

Absence of a digestive system

Presence of a digestive system

Labour

No division of labour

Division of labour present

Nervous System

Absent

A simple nervous system

Examples

Sponges

Jellyfish, sea anemones, coral

15. How do annelid animals differ from arthropods?

Explanation:

Some of the basic differences between annelid animals and arthropods:

Feature

Annelids

Arthropods

Body Segmentation

True segmentation with repeated units

Body divided into regions or tagmata

Exoskeleton

Absent

Present, made of chitin

Jointed Appendages

Absent

Present, allows for versatile movement

Respiratory System

Primarily through skin or gills

Primarily through a network of tubes (tracheae or book lungs)

Nervous System

Ventral nerve cord and ganglia

Dorsal nerve cord and ganglia

Circulatory System

Closed circulatory system

Open circulatory system

Reproductive System

Hermaphroditic

Mostly separate sexes


16. What are the differences between amphibians and reptiles?

Explanation:

Amphibians and reptiles are two distinct classes of animals that have some similarities, but also many differences. Here are some of the key differences between amphibians and reptiles:

Feature

Amphibians

Reptiles

Skin

Thin, moist, and permeable to water

Tough, dry, and impermeable to water

Respiration

Larvae breathe through gills, adults through skin and lungs

Breathe entirely through lungs, no gills

Eggs

Soft and jelly-like, laid in water or moist environments

Hard and shelled, laid on land

Thermoregulation

Ectothermic (cold-blooded)

Ectothermic (cold-blooded)

Limbs

Four limbs, no claws or nails

Four or no limbs, may have claws or nails

Hearing

Eardrums absent, rely on inner ear bones

Eardrums present

Sight

Mostly rely on vision

Some species have poor vision


17. What are the differences between animals belonging to the Aves group and those in the mammalian group?

Explanation:

The Aves group, also known as birds, and the Mammalia group, also known as mammals, are two distinct classes of animals that have some similarities but also many differences. Here are some of the key differences between birds and mammals:

Feature

Aves (Birds)

Mammalia (Mammals)

Body temperature

Endothermic (warm-blooded)

Endothermic (warm-blooded)

Body covering

Feathers

Hair or fur

Skeleton

Light and thin, with hollow bones

Heavy and thick, with solid bones

Heart

Four-chambered

Four-chambered

Reproduction

Lay eggs, external fertilization

Live birth, internal fertilization

Feeding

Beaks, no teeth

Teeth, some with specialized dentition

Body shape

Streamlined body

Streamlining absent

Hearing

Large, asymmetrical ears absent

Large, asymmetrical ears present

Sight

Well-developed vision, color perception

Well-developed vision, some color vision

Vocalization

Complex vocalizations, songs and calls

Variety of vocalizations, including speech



18. What are the advantages of classifying organisms?


Explanation:

There are several advantages of classifying organisms including:

  1. Identification: Classification helps in identifying and naming organisms, making it easier to communicate about them across different regions and languages.

  2. Understanding diversity: There are millions of different organisms on our planet, and classifying them helps us understand the diversity of life and the relationships between different species.

  3. Evolutionary history: Organisms are classified based on their evolutionary relationships, helping us understand how different groups of organisms have evolved over time.

  4. Predicting traits: Classification allows us to predict certain characteristics of an organism based on its classification. For example, we can predict that all mammals will have certain features such as hair, mammary glands, and three middle ear bones.

  5. Conservation: Understanding the classification of organisms helps us identify species that are endangered or threatened and prioritize conservation efforts to protect them.

Overall, classification helps us organize and make sense of the vast diversity of life on our planet and can inform important scientific, medical, and conservation decisions.


19. How would you choose between two characteristics to be used for developing a hierarchy in classification?


Explanation:

Choosing between two characteristics to be used for developing a hierarchy in classification depends on several factors, such as the level of importance of the characteristic, the degree of variation within the group being classified, and the level of complexity required for the classification scheme.

Overall character will be the basis of the hierarchy and then fine character is going to be the basis of further steps in developing a hierarchy.


20. Explain the basis for grouping organisms into five kingdoms.


Explanation:

The five-kingdom system of classification was proposed by Robert Whittaker in 1969 as a way to classify living organisms based on their characteristics and evolutionary relationships. The five kingdoms are:

  1. Monera

  2. Protista

  3. Fungi

  4. Plantae

  5. Animalia

The basis for grouping organisms into these five kingdoms is based on differences in cellular structure, nutrition, and organization.

  1. The Monera kingdom is based on the absence of a true nucleus and membrane-bound organelles.

  2. The Protista kingdom is based on the presence of a true nucleus but unicellularity.

  3. The Fungi kingdom is based on heterotrophic nutrition and chitinous cell walls.

  4. The Plantae kingdom is based on autotrophic nutrition and cellulose cell walls.

  5. The Animalia kingdom is based on heterotrophic nutrition and the absence of cell walls.



21. What are the major divisions in the Plantae? What is the basis of these divisions?


Explanation:

There are five major divisions in the plantae kingdom:

  1. Thallophyta or Algae

  2. Bryophyta

  3. Pteridophyta

  4. Gymnosperm

  5. Angiosperm


Some of the key basis of the division of these classes are as follows:

Division

Basis of divisions

Thallophyta or Algae

Thallus like body

Bryophyta

The body is separated into leaf and stem

Pteridophyta

The body is divided into root, stem and leaf

Gymnosperm

They bear seeds, and the seeds are naked

Angiosperm

They bear seed, and the seeds are enclosed



22. How are the criteria for deciding divisions in plants different from the criteria for deciding the subgroups among animals?

Explanation:

The criteria for deciding divisions in plants are different from the criteria for deciding the subgroups among animals due to differences in their structural and physiological characteristics.


In plants, the primary criteria for deciding divisions are based on the presence or absence of specific structures, such as vascular tissue, seeds, and flowers.

For example, bryophytes lack vascular tissue, while pteridophytes have vascular tissue but reproduce via spores. 

Coniferophyta have seeds that are not enclosed in a fruit, while angiospermophyta have seeds enclosed in a fruit.

These criteria are largely based on the evolutionary development of plants and their adaptations to terrestrial environments.


In contrast, the criteria for deciding subgroups among animals are based on a variety of factors, including structural characteristics, reproductive strategies, developmental patterns, and genetic relationships.

For example, animals can be divided based on the presence or absence of certain structures, such as notochords or jointed appendages, but they can also be grouped based on reproductive strategies, such as external or internal fertilization. Additionally, animals can be grouped based on developmental patterns, such as the presence or absence of a larval stage, or based on genetic relationships, as determined by molecular analysis.


23. Explain how animals in Vertebrata are classified into further subgroups.

Explanation:

Animals in the Vertebrata are classified into further subgroups based on several characteristics such as their physical and physiological traits, evolutionary history, reproductive strategies, developmental patterns, and genetic relationships.

For example, the classification of bony fish and cartilaginous fish is based on differences in their skeletal structure, while the classification of birds is based on their feathers and ability to fly.

The classification of mammals is based on the presence of mammary glands and hair, among other characteristics.

The classification of these subgroups provides a framework for understanding the diversity and complexity of the vertebrate lineage.


The major subgroups of Vertebrata are:

  1. Agnatha (jawless fish)

  2. Chondrichthyes (cartilaginous fish)

  3. Osteichthyes (bony fish)

  4. Amphibia

  5. Reptilia

  6. Aves (birds)

  7. Mammalia (mammals)