Faunal Diversity: Unit 8

In the Faunal Diversity unit, we delve into the Earth’s animal kingdom; we explore the vast diversity of species that inhabit our planet. From microscopic organisms to majestic mammals, this unit offers a fascinating journey through the intricacies of animal life.

Through comprehensive study and exploration of class 11 biology notes, we aim to deepen our understanding of complexities and interconnections within ecosystems, highlighting the importance of biodiversity and conservation efforts in preserving the wonders of our natural world.

8.1 Protista

Outline Classification

• Protista is a diverse kingdom comprising eukaryotic organisms that are not plants, animals, or fungi.
• They are mostly unicellular, but some are multicellular.
• Protists exhibit a wide range of lifestyles, including parasitism, mutualism, and photosynthesis.
• The classification of Protista is constantly evolving as new research uncovers more about their genetic and physiological characteristics.

Protozoa

• Protozoa are single-celled eukaryotic organisms belonging to the kingdom Protista.
• They display a variety of locomotion methods, including flagella, cilia, or pseudopodia.
• Protozoa can be free-living, commensal, or parasitic.
• Reproduction in protozoa can occur through binary fission, multiple fission, budding, or sexual reproduction.

Diagnostic Features and Classification:

• Protozoa are classified based on their mode of locomotion and other morphological characteristics.
• Major classes of protozoa include:

1. Flagellates: Move using flagella. Example: Euglena.
2. Ciliates: Move using cilia. Example: Paramecium caudatum.
3. Amoebae: Move using pseudopodia. Example: Amoeba proteus.
4. Sporozoans: Non-motile parasites. Example: Plasmodium vivax.

Examples:

1. Paramecium caudatum:

• Habitat: Freshwater environments, such as ponds and streams.
• Structure: Elongated, slipper-shaped body with cilia covering its surface.
• Reproduction: Asexual reproduction through binary fission.
• Life Cycle: Alternates between haploid and diploid stages.
• Economic Importance: Used in laboratories for research and education.

• Plasmodium vivax:

• Habitat: Parasitic protozoan found in the Anopheles mosquito and humans.
• Structure: Microscopic and exists in different life stages: sporozoites, merozoites, and gametocytes.
• Reproduction: Complex life cycle involving sexual reproduction in the mosquito and asexual reproduction in humans.
• Life Cycle: In humans, it causes malaria, a life-threatening disease.
• Economic Importance: Causes significant health and economic burdens in affected regions.

Plasmodium falciparum:

• Habits and Habitat: Found predominantly in tropical and subtropical regions where Anopheles mosquitoes are prevalent.
• Structure: Similar to other Plasmodium species, with different stages in its life cycle.
• Reproduction: Complex life cycle involving both sexual and asexual reproduction.
• Life Cycle: Causes severe malaria in humans, leading to high morbidity and mortality rates if untreated.
• Economic Importance: Significant impact on public health and economic development in affected regions due to its morbidity and mortality rates.

8.2 Animalia

Level of Organization:

• Animals are multicellular eukaryotic organisms with specialized cells organized into tissues, organs, and organ systems.
• They exhibit various levels of organization, including cellular, tissue, organ, organ system, and organismal levels.

Body Plan:

• The body plan of an animal refers to its overall structural organization, including symmetry, segmentation, and presence of specialized structures.
• Animal body plans can be radial or bilateral, with bilateral symmetry being predominant among higher animals.
• The body plan also includes characteristics such as body cavity (coelom) and segmentation.

Body Symmetry:

• Symmetry refers to the arrangement of body parts around a central axis.
• Animals can exhibit radial symmetry (multiple planes of symmetry) or bilateral symmetry (single plane of symmetry).

Body Cavity and Segmentation:

• Body cavity (coelom) is a fluid-filled space between the body wall and the digestive tract.
• Coelom provides space for organs and allows greater complexity and specialization.
• Segmentation refers to the division of the body into repeated segments, allowing for specialization of body parts.

Diagnostic Features and Classification:

• Porifera (Sponges):

• Diagnostic Features: Multicellular, but lack true tissues and organs. Filter feeders with a porous body structure.
• Example: Spongilla (Freshwater sponge).

• Coelenterata (Cnidaria):

• Diagnostic Features: Radial symmetry, specialized stinging cells called cnidocytes. Two body forms: polyp and medusa.
• Example: Hydra (Freshwater polyp), Aurelia (Jellyfish).

• Platyhelminthes (Flatworms):

• Diagnostic Features: Bilaterally symmetrical, flattened body. Incomplete digestive system. Some are parasitic.
• Example: Planaria (Free-living flatworm), Taenia (Tapeworm).

• Aschelminthes (Nemathelminthes):

• Diagnostic Features: Bilaterally symmetrical, cylindrical body with a complete digestive system.
• Example: Ascaris (Roundworm).

• Annelida (Segmented Worms):

• Diagnostic Features: Segmented body with a coelom. Closed circulatory system. Excretory organs called nephridia.
• Example: Earthworm, Leech.

• Arthropoda:

• Diagnostic Features: Segmented body with jointed appendages. Exoskeleton made of chitin. Most diverse phylum.
• Examples: Insects, Arachnids, Crustaceans.

• Mollusca:

• Diagnostic Features: Soft-bodied animals with a muscular foot, mantle, and often a hard shell. Radula present in most.
• Example: Snails, Octopus, Clams.

• Echinodermata:

• Diagnostic Features: Radially symmetrical as adults, pentaradial symmetry. Endoskeleton made of calcium carbonate plates.
• Example: Starfish, Sea Urchin.

• Chordata:

• Diagnostic Features: Notochord, dorsal hollow nerve cord, pharyngeal slits, and post-anal tail at some stage in their life cycle.
• Example: Humans, Fish, Birds, Amphibians, Reptiles.

8.3 Earthworm (Pheretima posthuma)

1. Habit and Habitat:

• Earthworms, specifically Pheretima posthuma, are commonly found in soil.
• They thrive in moist environments, typically inhabiting areas with organic matter, such as gardens, fields, and forests.
• Earthworms play a crucial role in soil fertility by breaking down organic material and improving soil structure through their burrowing activities.

2. External Features:

• Pheretima posthuma typically measures around 15-20 cm in length and has a cylindrical body divided into segments.
• The body is covered by a moist, slimy layer called the cuticle, which helps in respiration and locomotion.
• Each segment, except the first and last, bears tiny bristle-like structures called setae, which aid in movement.

3. Digestive System:

• Alimentary Canal: The digestive system of earthworms consists of a straight tube running from mouth to anus.
• Physiology of Digestion: Earthworms are detritivores, feeding on organic matter in soil. Digestion involves mechanical breakdown by muscular action and chemical breakdown by enzymes secreted by the gut.

4. Excretory System:

• Types of Nephridia: Earthworms possess two types of nephridia: Septal Nephridia and Integumentary Nephridia.
• Structure and Arrangement of Septal Nephridia: These are segmentally arranged along the length of the earthworm’s body and function in excretion and osmoregulation.

5. Nervous System:

• Central Nervous System: Consists of a double ventral nerve cord running along the length of the body, connected by transverse nerves in each segment.
• Peripheral Nervous System: Includes sensory receptors distributed throughout the body, responding to touch, light, and chemicals.
• Working Mechanism: Sensory information is transmitted to the central nervous system, which then coordinates responses, including movement and feeding.

6. Reproductive Systems:

• Male Reproductive Organs: Testes produce sperm, which are stored in seminal vesicles and released through male genital pores during copulation.
• Female Reproductive Organs: Ovaries produce eggs, which travel through oviducts to seminal receptacles where fertilization occurs.
• Copulation: Earthworms are hermaphrodites, meaning each individual has both male and female reproductive organs. During copulation, two earthworms align ventrally and exchange sperm through mutual penetration of the clitellum.

7. Cocoon Formation:

• After copulation, each earthworm secretes a mucous tube called a cocoon from its clitellum.
• The cocoon slides forward, picking up eggs from the ovaries and sperm from the seminal receptacles, where fertilization takes place.
• The cocoon is then sealed and deposited in soil, where the eggs develop into juveniles.

8. Economic Importance:

• Earthworms contribute to soil fertility by decomposing organic matter, aerating the soil, and enhancing nutrient cycling.
• They are also used in vermiculture, the practice of breeding earthworms for composting organic waste and producing nutrient-rich vermicompost, which is an excellent organic fertilizer.

8.4 Frog (Rana tigrina)

Absolutely! Here’s a detailed set of notes covering the various aspects of the Frog (Rana tigrina):

1. Habit and Habitat:

• Frogs, specifically Rana tigrina, are amphibians found in diverse habitats including ponds, lakes, marshes, and damp forests.
• They require water for reproduction but can also inhabit terrestrial environments.
• Frogs have permeable skin, which allows them to breathe through their skin and stay moist.

2. External Features:

• Frogs have a streamlined body adapted for swimming and jumping.
• They possess bulging eyes with nictitating membranes for protection and moistening.
• External features also include well-developed hind limbs for jumping and webbed feet for swimming.

3. Digestive System:

• Alimentary Canal: The digestive system of frogs consists of the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and cloaca.
• Digestive Glands: Frogs have specialized digestive glands such as the liver and pancreas that secrete digestive enzymes to break down food.
• Physiology of Digestion: Frogs are carnivorous and feed on insects and small invertebrates. Digestion involves both mechanical breakdown by teeth and chemical breakdown by enzymes.

4. Blood Vascular System:

• Frogs have a closed circulatory system consisting of a heart, blood vessels, and blood.
• Structure of Heart: The heart has three chambers: two atria and one ventricle. It is divided into right and left halves by a septum.
• Working Mechanism: Deoxygenated blood from the body enters the right atrium, is pumped into the ventricle, and then oxygenated blood is pumped out to the body and lungs.

5. Respiratory System:

• Respiratory Organs: Frogs have lungs for respiration on land and moist skin for respiration in water.
• Physiology of Respiration: When submerged in water, frogs respire through their skin by diffusion. On land, they inflate and deflate their lungs to exchange gases.

6. Reproductive System:

• Male Reproductive Organs: Testes produce sperm, which travel through ducts called vas deferens to the cloaca.
• Female Reproductive Organs: Ovaries produce eggs, which are released into the cloaca during ovulation.
• Frogs reproduce externally, with males releasing sperm and females releasing eggs into water where fertilization occurs.

Faunal Diversity – Exam Questions

8.1 Protista:

1. Outline the classification of Protista and provide examples for each group.
2. Describe the diagnostic features of Protozoa and classify them up to class level with examples.
3. Compare and contrast the habits, habitats, structures, reproduction, and life cycles of Paramecium caudatum and Plasmodium vivax.
4. Discuss the economic importance of Plasmodium falciparum.

8.2 Animalia:

1. Explain the levels of organization in animals and how they relate to different body plans and symmetries.
2. Define and compare the body cavity and segmentation in animals, giving examples for each.
3. Describe the diagnostic features of the following phyla (up to class) and provide examples: Porifera, Coelenterata (Cnidaria), Platyhelminthes, Aschelminthes (Nemathelminthes), Annelida, Arthropoda, Mollusca, Echinodermata, and Chordata.

8.3 Earthworm (Pheretima posthuma):

1. Explain the habitat and external features of Pheretima posthuma.
2. Describe the structure of the alimentary canal and discuss the physiology of digestion in earthworms.
3. Differentiate between the types of nephridia in earthworms and explain the structure and arrangement of septal nephridia.
4. Discuss the central and peripheral nervous systems in earthworms and explain their working mechanism.
5. Outline the reproductive systems of earthworms, including male and female reproductive organs, copulation, cocoon formation, and their economic importance.

8.4 Frog (Rana tigrina):

1. Describe the habitat and external features of Rana tigrina.
2. Explain the structure of the alimentary canal and discuss the physiology of digestion in frogs.
3. Outline the structure and working mechanism of the blood vascular system, focusing on the heart.
4. Discuss the respiratory system of frogs, including respiratory organs and the physiology of respiration.
5. Describe the male and female reproductive organs of frogs and explain their reproductive system.

These questions cover various aspects of each topic and should provide a comprehensive examination of students’ understanding of faunal diversity, from Protista to Frog.