Class XII Practical: Spotting

Objective

To identify and draw various biological specimens, slides, charts, and models, and infer their characteristics or principles.

Guidelines

For each item presented (slide, chart, model, or specimen):

1. Identification: Correctly identify the given item.
2. Drawing: Make a neat, labeled diagram of the identified item. For slides, draw what is observed under the microscope. For specimens/models, draw the external features. For charts, reproduce the key information.
3. Observation: Note down key observable features or structures.
4. Inference/Comment: Briefly explain the biological significance, function, or classification of the item.

Items for Spotting

Slides/Charts/Models

• T.S. of mammalian ovary (prepared slide/model)
• T.S. of mammalian testis (prepared slide/model)
• Germinating pollen grain (prepared slide/chart)
• Types of placentation (charts/models)
• Mammalian blastula/blastocyst (prepared slide/model/chart)
• Plasmodium sporozoite (prepared slide)
• Entamoeba histolytica (prepared slide)
• Ascaris specimen (specimen/model)

Adaptations

• Xeric Plants/Animals: (Specimens/charts/models demonstrating adaptations to dry environments)
  • Identify: The organism and its xeric adaptation(s).
  • Draw: Labeled diagram showing the adaptation.
  • Observation: Note features like thick cuticle, sunken stomata, water storage, burrowing habits, etc.
  • Inference: Explain how the adaptation helps in water conservation or survival in arid conditions.
• Aquatic Plants/Animals: (Specimens/charts/models demonstrating adaptations to aquatic environments)
  • Identify: The organism and its aquatic adaptation(s).
  • Draw: Labeled diagram showing the adaptation.
  • Observation: Note features like aerenchyma, reduced roots, streamlined body, gills, webbed feet, etc.
  • Inference: Explain how the adaptation helps in buoyancy, gas exchange, movement, or survival in water.

Pollination Types

• Insect Pollination (Entomophily): (Flowers/charts/models showing features for insect attraction)
  • Identify: Features indicating insect pollination (e.g., large, colorful petals, nectar guides, scent, sticky pollen).
  • Draw: Labeled diagram of an insect-pollinated flower.
  • Observation: Note the specific adaptations.
  • Inference: Explain how these features facilitate pollination by insects.
• Water Pollination (Hydrophily): (Plants/charts/models showing features for water pollination)
  • Identify: Features indicating water pollination (e.g., small, inconspicuous flowers, pollen released on water surface, mucilaginous covering).
  • Draw: Labeled diagram of a water-pollinated plant/flower.
  • Observation: Note the specific adaptations.
  • Inference: Explain how these features facilitate pollination by water.
• Wind Pollination (Anemophily): (Plants/charts/models showing features for wind pollination)
  • Identify: Features indicating wind pollination (e.g., small, inconspicuous flowers, no scent/nectar, large feathery stigmas, abundant light pollen).
  • Draw: Labeled diagram of a wind-pollinated plant/flower.
  • Observation: Note the specific adaptations.
  • Inference: Explain how these features facilitate pollination by wind.