Lesson Notes By Weeks and Term - Senior Secondary 2

Reproductive system in birds and mammals 2

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TERM – 2ND TERM

WEEK SIX

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Biology

Topic: Reproductive system in Birds and mammals 2

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

  1. Identify the structural differences in the egg of a vertebrates
  2. Compel the Reproductive system of fish, reptiles, birds and mammals
  3. Discuss the functions of a floral parts

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION

TEACHER’S ACTIVITY

STUDENT’S

ACTIVITY

STEP 1

INTRODUCTION

The teacher discusses the structural differences in egg vertebrates

Students pay

attention

STEP 2

EXPLANATION

Teacher compel and explain the reproductive system in fish, reptiles, birds and mammals

Students pay

attention and

participate

 

STEP 3

DEMONSTRATIO

N

Teacher discusses the functions of a floral parts.

Teacher guide students to examine various parts of a flower

Students pay

attention, observe and record their observation

 

STEP 4

NOTE TAKING

The teacher writes a summarized

note on the board

 

The students

copy the note in

their books

 

NOTE

REPRODUCTIVE SYSTEM

Structural differences in the egg of vertebrates

Structural differences in vertebrate eggs are influenced by factors such as the reproductive strategy, environment, and embryonic development. The following are a general overview of structural differences in the eggs of vertebrates:

  1. Size:

   - Fish and amphibian eggs are relatively small and often numerous.

   - Reptile eggs are larger than those of fish and amphibians.

   - Bird eggs are larger compared to reptiles, reflecting the increased demands for embryonic development.

  1. Yolk Distribution:

   - Fish and amphibian eggs have a moderate amount of yolk evenly distributed.

   - Reptile eggs have a significant amount of yolk concentrated in the center (telolecithal).

   - Bird eggs have a large amount of yolk, primarily concentrated at one end (telolecithal).

  1. Shell:

   - Fish and amphibian eggs lack a protective shell.

   - Reptile eggs have a leathery or calcified shell to protect against desiccation.

   - Bird eggs have a hard, calcified shell for protection and support.

  1. Amniotic Membranes:

   - Reptile, bird, and mammalian eggs have extraembryonic membranes (amnion, chorion, yolk sac, and allantois) for protection, nutrient exchange, and waste storage.

   - These membranes are absent or less developed in fish and amphibian eggs.

  1. Fertilization Location:

   - Fish eggs are usually fertilized externally.

   - Amphibian eggs may be fertilized externally or internally, depending on the species.

   - Reptile, bird, and mammalian eggs are typically fertilized internally.

Tabulation and comparison of reproduction in fish, reptiles, birds and mammals. 

Tabulated comparison of reproduction in fish, reptiles, birds, and mammals:

Characteristics

Fish

Reptiles

Birds

Mammals

Fertilization

External

Mostly internal(some exceptions)

Internal

Internal

Egg development

External (in water)

External (terrestrial and aquatic environment)

Internal (oviparous)

Internal (Viviparous, oviparous)

Egg covering/shell

Jelly-like coating or none

Leathery or calcified shell 

 Hard calcified shell (oviparous)      

No external shell (except monotremes) 

Parental care

Variable, often limited

Limited or none (some exceptions)

  Extensive (both parents may contribute) 

Extensive, often maternal care            

Embryonic membrane

Limited development    

Amnion, chorion, yolk sac, allantois    

Amnion, chorion, yolk sac, allantois   

Amnion, chorion, yolk sac, allantois

Birth

Larvae hatch from eggs (oviparous)

Live birth (some exceptions)        

Hatch from eggs (oviparous)  

Live birth (viviparous), or eggs (oviparous)

Feeding of young ones

Varied (some parental care)               

Limited or none (some exceptions)  

Extensive, regurgitation or hunting            

Milk from mammary glands        

Placenta

Absent

Absent(except some reptiles)

Absent (except some birds like pigeons)

Present in most, varies in structure

 

Structure and function of the floral parts

Floral parts are those various components that make up a flower. Flowers are reproductive structures in angiosperms (flowering plants) that play a crucial role in the process of pollination and subsequent seed formation.

 The following are the main floral parts and their functions:

  1. Sepals: Protect the developing flower bud and support the other floral parts.
  2. Petals: Attract pollinators (insects, birds) with their colors and fragrances.
  3. Stamens: Produce pollen in the anther; the pollen contains male gametes (sperm).
  4. Carpels (Pistils): The ovary contains ovules, which develop into seeds when fertilized. The stigma captures pollen, and the style connects the stigma to the ovary.
  5. Ovary: Contains and protects the ovules, which, when fertilized, develop into seeds.
  6. Style: Provides a path for pollen to reach the ovary for fertilization.
  7. Stigma: Captures pollen; a receptive surface for pollination.
  8. Receptacle: Supports and holds the floral organs in place.

Reproductive parts (whorls)

The major reproductive parts of a flower are arranged in distinct whorls, which are concentric circles of modified leaves. These whorls, from the outermost to the innermost, are the calyx, corolla, androecium, and gynoecium.

  1. Calyx: The outermost whorl. It consist of the sepals, which are individual or fused green leaf-like structures.

The primary function is to protect the flower bud; collectively referred to as the calyx.

  1. Corolla: Situated on the second whorl, inside the calyx. It comprises of the petals, which are often brightly colored and may be fused or separate. It aid the attraction of pollinators; collectively referred to as the corolla.
  2. Androecium: Position at the third whorl, inside the corolla. Consisting of the stamens, each consisting of a filament and an anther. Which aid in the production of pollen (male gametes); collectively referred to as the androecium.
  3. Gynoecium: Innermost whorl, located at the center of the flower. It is made up of the carpels or pistils, each consisting of an ovary, style, and stigma which aid in the reception of pollen, development of ovules into seeds, and protection of the developing seeds; collectively referred to as the gynoecium.

EVALUATION: 1. Discuss the structural differences in egg of vertebrates

  1. Identify the parts and functions of a floral plant
  2. Identify the major reproductive parts of a flower

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively