Lesson Notes By Weeks and Term - Senior Secondary 2

Balance in nature

Get it on Google Play
Get it on the Apple App Store
  1. Home
  2. Lesson Notes By Weeks and Term
  3. Senior Secondary 2
  4. Balance in nature

TERM – 3RD TERM

WEEK ELEVEN

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Biology

Topic: BALANCE IN NATURE

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

  1. Identify factors affecting population
  2. Describe the equilibrium balance in nature
  3. Identifying factors that maintain dynamic equilibrium
  4. Discuss family planning as a method of population control.

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 factors affecting population,

Students pay

attention

STEP 2

EXPLANATION

Teacher describe the equilibrium balance in nature and the methods of maintaining the dynamic equilibrium

Students pay

attention and

participate

STEP 3

DEMONSTRATIO

N

Teacher explains family planning as a method of population control

Students pay

attention and

participate

STEP 4

NOTE TAKING

The teacher writes a summarized

note on the board

 

The students

copy the note in

their books

 

NOTE

BALANCE IN NATURE

Factors affecting population

Biotic Factors Affecting Population

  1. Competition: Interactions between individuals of the same or different species for limited resources, such as food, water, and territory, can significantly impact population dynamics.
  2. Predation: The presence and activity of predators can influence the size and behavior of prey populations. The dynamics of predator-prey interactions affect the balance within ecosystems.
  3. Disease: The prevalence of diseases, parasites, and pathogens can impact population health and reduce individual fitness, leading to changes in population size and structure.
  4. Mutualism: Positive interactions between different species, such as mutualistic relationships, can affect population growth by providing benefits to the involved species. For example, pollination or symbiotic partnerships.
  5. Parasitism: Parasites can negatively impact host populations by causing diseases or reducing host fitness. This interaction can influence population size and demographics.

Abiotic Factors Affecting Population

  1. Climate: Temperature, precipitation, and other climate factors influence the distribution and abundance of species. Climate changes can impact population size and migration patterns.
  2. Habitat Availability: The type and quality of habitat, including factors like availability of suitable nesting sites and shelter, play a crucial role in determining population size and distribution.
  3. Nutrient Availability: The availability of essential nutrients, such as nitrogen and phosphorus, can affect the growth and reproduction of populations, especially in ecosystems like aquatic environments.
  4. Water Availability: Adequate access to water is essential for the survival of many species. Changes in water availability, whether due to drought or flooding, can impact population dynamics.
  5. Soil Composition: The composition of soil affects plant growth, which, in turn, influences herbivores and organisms higher up the food chain. Soil quality is a critical abiotic factor in terrestrial ecosystems.
  6. Natural Disasters: Events like earthquakes, hurricanes, and wildfires can have significant impacts on populations by disrupting habitats, causing direct mortality, and altering environmental conditions.

Dynamic equilibrium in  nature

Dynamic equilibrium in nature refers to the state of balance within ecosystems where various ecological processes, populations, and environmental conditions are in a constant state of flux, yet the overall system maintains stability over time. Factors contributing to dynamic equilibrium include:

  1. Population Dynamics: Population sizes fluctuate due to births and deaths. Dynamic equilibrium is maintained when these rates balance, preventing rapid population growth or decline.
  2. Ecosystem Processes: Continuous cycling of nutrients through biogeochemical processes helps maintain dynamic equilibrium by ensuring a balance in nutrient availability for organisms. Also dynamic equilibrium is sustained through the flow of energy between trophic levels, with energy being transferred and distributed among different organisms within ecosystems.
  3. Successional Changes: Ecosystems undergo changes over time due to disturbances or natural progression. Dynamic equilibrium is achieved when successional changes lead to a stable and balanced climax community.
  4. Climate and Weather Patterns: Despite seasonal and regional variations, dynamic equilibrium is maintained when climate and weather patterns remain within a certain range, allowing ecosystems to adapt.
  5. Biotic and Abiotic Interactions: The balance between predator and prey populations contributes to dynamic equilibrium, preventing the domination of either group. Also, Interactions between living organisms and their non-living environment maintain equilibrium as ecosystems respond and adapt to changing conditions.

Factors that Maintain Dynamic Equilibrium

  1. Availability of Food: A stable supply of food resources supports balanced population sizes, preventing overconsumption or starvation. Dynamic equilibrium is influenced by the availability and distribution of food sources.
  2. Natural Disasters: While natural disasters can disrupt ecosystems, they also play a role in maintaining dynamic equilibrium. Disturbances trigger adaptation and succession, leading to the recovery and restoration of balance.
  3. Predator-Prey Relationships: The interactions between predators and prey help regulate population sizes. Predators control prey populations, preventing overgrazing or overpopulation.
  4. Climate Stability: Ecosystems adapt to long-term climate patterns, and dynamic equilibrium is maintained when organisms evolve to thrive within specific climatic conditions.

Family planning

Family planning involves making informed choices about the number and spacing of children, taking into consideration the health and well-being of the family and the overall population. It encompasses both natural and artificial methods of population control.

Natural Methods of population control

  1. Abstinence: Choosing to abstain from sexual activity during fertile periods to avoid conception is a natural method of family planning.
  2. Fertility Awareness-Based Methods (FAM):

   - Calendar Method: Tracking menstrual cycles to identify fertile and non-fertile periods.

   - Basal Body Temperature (BBT) Method: Monitoring the body temperature to pinpoint ovulation.

   - Cervical Mucus Method: Observing changes in cervical mucus consistency to determine fertility.

  1. Withdrawal Method (Pull-Out Method): Withdrawing the penis from the vagina before ejaculation to prevent sperm from entering the reproductive tract.
  2. Lactational Amenorrhea Method (LAM): Breastfeeding as a form of contraception during the postpartum period when a woman's menstrual cycle is suppressed.

Artificial Methods of population control

  1. Barrier Methods:

   - Condoms: A physical barrier that prevents sperm from reaching the egg.

   - Diaphragm: A dome-shaped device placed inside the vagina to cover the cervix and block sperm.

      

  1. Hormonal Methods:

   - Birth Control Pills: Oral contraceptives containing hormones (estrogen and progestin) to inhibit ovulation and alter cervical mucus.

   - Patch: A hormonal patch applied to the skin, releasing hormones to prevent ovulation.

   - Injectables: Hormonal injections administered at regular intervals to prevent pregnancy.

   - Implants: Small hormonal devices inserted under the skin to provide long-term contraception.

  1. Intrauterine Devices (IUDs):

   - Copper IUD: Releases copper to create an inhospitable environment for sperm.

   - Hormonal IUD: Releases progestin to prevent ovulation and alter cervical mucus.

Sex Education

Sex education is essential for promoting awareness and understanding of reproductive health and family planning. It includes:

  1. Providing knowledge about the reproductive system, menstrual cycles, and fertility.
  2. Informing individuals about the various contraceptive methods, their effectiveness, and proper usage.
  3. Emphasizing the importance of protection against sexually transmitted infections (STIs) through condom use.
  4. Teaching effective communication within relationships, including discussing family planning preferences and choices.
  5. Encouraging individuals to make informed decisions about their sexual and reproductive health, promoting autonomy and well-being.

EVALUATION: 1. How can sex education help curb the population size

  1. Define family planning
  2. Identify 3 abiotic factors affecting population
  3. Mention 3 factors of maintaining equilibrium balance.

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively