Chordata - Aves and Mammals

Grade 12 · Biology

Semester 1 | Period 1 | Week 5

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Subject: Biology

Semester: 1

Period: 1

Week: 5

School Name:
Teacher’s Name:
Subject: Biology
Grade Level: Grade 12
Date: Week 5
Lesson Duration: 45 minutes
Week & Period: Week 5, Period I
Topic: Chordata – Aves and Mammals
Sub-topic: Mammals – Dentition, Dental Formulae & Temperature Control

 

Learning Objectives

By the end of this lesson, learners should be able to:

  1. Identify the types and functions of mammalian teeth.
  2. Draw and label the structure of a mammalian molar.
  3. Write and interpret dental formulae.
  4. Describe how mammals regulate their body temperature.
  5. Explain the role of homeostasis in temperature control.

 

Previous Knowledge

Learners have been introduced to the general characteristics and classification of mammals.

 

Instructional Materials

  • Charts or diagrams showing types of teeth
  • Model or 3D picture of a molar tooth
  • Flashcards with dental formulas
  • Thermoregulation flowchart (e.g., sweating, shivering, vasodilation, vasoconstriction)
  • Pictures of endothermic and ectothermic animals

 

Lesson Development – ABC Model

A – Anticipation (Warm-up / Starter)

Time: 5–10 minutes
Ask:

  • “Why do different animals have different types of teeth?”
  • “What happens to your body when you are too hot or too cold?”
    Let learners feel their own molars with their tongue. Ask what they think they’re used for.

 

B – Building Knowledge (Main Lesson Body)

Time: 25–30 minutes

Types of Teeth in Mammals:

  • Incisors – cutting
  • Canines – tearing
  • Premolars & Molars – grinding

Structure of a Mammalian Molar:

  • Enamel, dentine, pulp cavity, nerves, blood vessels, root
  • Importance: designed for crushing and grinding food

Dental Formula:

  • A way to represent the number and types of teeth
  • Example (Human adult):
    Dental formula = 2/2, 1/1, 2/2, 3/3
    Meaning: 2 incisors, 1 canine, 2 premolars, 3 molars on each half of the jaw (upper/lower)

Control of Body Temperature in Mammals (Homeostasis):

  • Mammals are warm-blooded (endothermic)
  • Maintain constant internal temperature regardless of environment
  • Mechanisms:
    • Sweating to cool down
    • Shivering to generate heat
    • Vasodilation and vasoconstriction
    • Behavioral adaptation (e.g., seeking shade, huddling)

 

Learners’ Activities (Expanded)

  • Label a Tooth Diagram: Learners draw and label a molar tooth in their notebooks.
  • Match-the-Tooth Game: Match tooth type to its function.
  • Practice Dental Formulae: Write the dental formula for humans and compare with carnivores/herbivores.
  • Role-play Thermoregulation: Act out what happens in heat vs cold.

 

C – Consolidation (Conclusion & Assessment)

Time: 5–10 minutes
Quick recap through guided oral questions:

  • “Which teeth are used for tearing?”
  • “How does the body cool down in hot weather?”
  • “Why is a molar tooth thick and flat?”

Evaluation Methods

  • In-class oral review and labeling exercise
  • Homework: Write the dental formula for a dog or goat
  • Short quiz on temperature regulation methods and types of teeth

 

Short Notes (Expanded)

  • Mammals have four types of teeth for different feeding functions.
  • The dental formula is a shorthand way of describing teeth arrangement.
  • The molar has a broad surface for grinding food.
  • Mammals maintain a stable body temperature using internal mechanisms like sweating or shivering.

 

Extra Instructions for Expanded Work

  • Expanded Notes: Add comparison between herbivore and carnivore dentition.
  • Assignment: Research 2 mammals in Liberia, compare their dentition and food habits.
  • Optional Experiment: Measure body temperature before and after light exercise to observe homeostasis.

 

Differentiation / Inclusive Strategies

  • Visuals and diagrams for visual learners
  • Group labeling tasks for collaborative learners
  • Break information into short bullet points for struggling readers
  • Extension task on hibernation and estivation for advanced learners

Teacher Reflection

  • Did learners understand how to read and write dental formulae?
  • Were they able to relate types of teeth to food habits?
  • Should I revisit thermoregulation in more detail?