8. Faunal Diversity

8. Faunal Diversity

8.1 Protista

• Outline Classification of Protista:

  • The kingdom Protista includes a diverse group of eukaryotic microorganisms, typically unicellular, that do not fit into the other kingdoms (Animalia, Plantae, or Fungi). Protista is often divided into three main categories: protozoa (animal-like), algae (plant-like), and slime molds (fungus-like).

• Protozoa:

  • Diagnostic Features:
    • Unicellular eukaryotic organisms.
    • Lack cell walls, typically have a flexible cell membrane.
    • Exhibit various modes of locomotion (flagella, cilia, or pseudopodia).
    • Heterotrophic or autotrophic nutrition.

• Classification of Protozoa (up to Class):

  • Phylum Sarcomastigophora:
    • Class Mastigophora (Flagellates): e.g., Trypanosoma
    • Class Sarcodina (Amoebae): e.g., Amoeba proteus
  • Phylum Ciliophora:
    • Class Ciliate: e.g., Paramecium
  • Phylum Apicomplexa:
    • Class Sporozoa: e.g., Plasmodium

• Examples:

  • Paramecium caudatum:
    • Habits and Habitat: Found in freshwater environments; feeds on bacteria and small particles.
    • Structure: Covered with cilia, has an oral groove for feeding, and a contractile vacuole for osmoregulation.
    • Reproduction: Asexually through binary fission and sexually through conjugation.
  • Plasmodium vivax:
    • Habits and Habitat: Lives in the bloodstream of humans and mosquitoes; transmitted by Anopheles mosquitoes.
    • Structure: Unicellular, with a complex life cycle involving both human and mosquito hosts.
    • Life Cycle: Includes stages such as sporozoite, merozoite, gametocyte, and oocyst.
    • Economic Importance: Causes malaria, leading to significant health impacts and economic burden.

8.2 Animalia

• Level of Organization:

  • Animals exhibit various levels of organization, from cellular (e.g., sponges) to organ systems (e.g., mammals).

• Body Plan:

  • Refers to the arrangement of the animal’s body parts; includes symmetry, segmentation, and the presence of body cavities.

• Body Symmetry:

  • Animals can be classified based on symmetry:
    • Asymmetrical: No symmetry (e.g., sponges).
    • Radial Symmetry: Symmetry around a central axis (e.g., jellyfish).
    • Bilateral Symmetry: Divisible into mirror-image halves (e.g., humans).

• Body Cavity:

  • Refers to the fluid-filled space in the body:
    • Acoelomate: No body cavity (e.g., flatworms).
    • Pseudocoelomate: Fluid-filled cavity between mesoderm and endoderm (e.g., nematodes).
    • Coelomate: True body cavity within the mesoderm (e.g., annelids, mammals).

• Segmentation:

  • Refers to the division of the body into repetitive segments (e.g., in annelids).

• Diagnostic Features and Classification of Phyla (up to Class):

  • Phylum Porifera:
    • Class Calcarea: e.g., Grantia.
    • Class Hexactinellida: e.g., Glass sponges.
  • Phylum Coelenterata (Cnidaria):
    • Class Hydrozoa: e.g., Hydra.
    • Class Scyphozoa: e.g., Aurelia (jellyfish).
  • Phylum Platyhelminthes:
    • Class Turbellaria: e.g., Planaria.
    • Class Cestoda: e.g., Taenia (tapeworms).
  • Phylum Aschelminthes (Nemathelminthes):
    • Class Nematoda: e.g., Ascaris (roundworms).
  • Phylum Annelida:
    • Class Polychaeta: e.g., Nereis.
    • Class Clitellata: e.g., Lumbricus (earthworm).
  • Phylum Arthropoda:
    • Class Insecta: e.g., Drosophila (fruit fly).
    • Class Arachnida: e.g., Araneae (spiders).
  • Phylum Mollusca:
    • Class Gastropoda: e.g., Snails.
    • Class Bivalvia: e.g., Clams.
  • Phylum Echinodermata:
    • Class Asteroidea: e.g., Starfish.
    • Class Echinoidea: e.g., Sea urchins.
  • Phylum Chordata:
    • Class Mammalia: e.g., Humans.
    • Class Aves: e.g., Birds.

Faunal Diversity: Earthworm (Pheretima posthuma) and Frog (Rana tigrina)

Earthworm (Pheretima posthuma)

Habit and Habitat

• Habit: Earthworms are primarily terrestrial and are known for their burrowing activity in soil, which aids in aeration and nutrient mixing.
• Habitat: They prefer moist, dark environments in rich, organic soils, such as gardens, forests, and agricultural fields.

External Features

• Body Structure: The body is elongated, cylindrical, and segmented into numerous annuli (rings). Each segment contains setae (bristle-like structures) that aid in locomotion.
• Coloration: The earthworm is typically reddish-brown due to the presence of hemoglobin in the blood.

Digestive System

• Alimentary Canal: The digestive system consists of the following parts:

  • Mouth: Located at the anterior end, where food intake occurs.
  • Pharynx: Muscular structure that helps in swallowing food.
  • Esophagus: Connects the pharynx to the crop.
  • Crop: Temporary storage for food.
  • Gizzard: Muscular structure that grinds food.
  • Intestine: Site for digestion and absorption of nutrients, lined with epithelial cells that secrete digestive enzymes.

• Physiology of Digestion: The process involves the mechanical breakdown of food in the gizzard and chemical digestion in the intestine. Nutrients are absorbed through the intestinal walls into the blood.

Excretory System

• Types of Nephridia: Earthworms possess two types of nephridia:

  • Septal Nephridia: Found in each segment, involved in the excretion of nitrogenous waste.
  • Metanephridia: Function in osmoregulation.

• Structure and Arrangement: Septal nephridia consist of a nephrostome, a convoluted tubule, and an excretory duct. They filter waste from the coelomic fluid and excrete it through the body surface.

Nervous System

• Central Nervous System: Composed of a pair of cerebral ganglia (brain) and a ventral nerve cord with segmental ganglia.

• Peripheral Nervous System: Includes sensory and motor neurons that control movement and respond to environmental stimuli.

• Working Mechanism: The nervous system coordinates muscular contractions for locomotion and processes sensory information from the environment.

Reproductive System

• Male Reproductive Organs: Includes testes, seminal vesicles, and sperm ducts. Sperm are produced in the testes and stored in the vesicles.

• Female Reproductive Organs: Includes ovaries, oviducts, and the spermatheca (sperm storage).

• Copulation: During mating, earthworms align ventrally, exchange sperm, and store them in the spermatheca.

• Cocoon Formation: After copulation, a cocoon is secreted from the clitellum, where fertilization occurs, and eggs are deposited.

Economic Importance

• Earthworms improve soil fertility through their burrowing activities, enhancing aeration and nutrient cycling. They are also used in composting and as bait in fishing.

Frog (Rana tigrina)

Habit and Habitat

• Habit: Frogs are primarily aquatic during their larval stage (tadpoles) and are often found near freshwater bodies. Adult frogs can be terrestrial or semi-aquatic.
• Habitat: Commonly found in ponds, marshes, and tropical rainforests.

External Features

• Body Structure: Frogs have a smooth, moist skin, elongated hind limbs for jumping, and webbed toes for swimming. The body is generally divided into a head, trunk, and limbs.

Digestive System

• Alimentary Canal: Consists of:

  • Mouth: Equipped with maxillary teeth and a sticky tongue for catching prey.
  • Esophagus: Connects to the stomach.
  • Stomach: Site of initial digestion.
  • Small Intestine: Major site for digestion and absorption.
  • Large Intestine: Absorbs water and forms feces.

• Digestive Glands: The pancreas and liver produce digestive enzymes and bile to aid in digestion.

• Physiology of Digestion: Food is broken down mechanically in the stomach and chemically in the small intestine. Nutrients are absorbed into the bloodstream.

Blood Vascular System

• Structure: The heart has three chambers (two atria and one ventricle), allowing for a mix of oxygenated and deoxygenated blood.

• Working Mechanism: Blood circulates through the body, delivering oxygen and nutrients to tissues and removing waste products.

Respiratory System

• Respiratory Organs: Frogs breathe through lungs and their skin (cutaneous respiration).

• Physiology of Respiration: During inhalation, the buccal cavity expands, drawing air in. The air is then forced into the lungs. Frogs can also absorb oxygen directly through their moist skin, especially when submerged in water.

Reproductive System

• Male Reproductive Organs: Includes testes and a cloaca. Males often exhibit external fertilization during amplexus (mating embrace).

• Female Reproductive Organs: Includes ovaries and a cloaca. Females lay eggs in water.