Lesson Notes By Weeks and Term - Senior Secondary 2

TERM – 3^RD TERM

WEEK TEN

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Biology

Topic: ECOLOGY OF POPULATION 2

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

1. Describe the relationship between competition and succession
2. Identify factors that causes overcrowding
3. Identify ways of avoiding overcrowding
4. Describe effects of food shortage

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

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

NOTE

ECOLOGY OF POPULATION

Relationship between competition and succession

Competition and succession are interrelated ecological processes that influence the structure and dynamics of ecosystems over time. Below is how they are connected:

1. Competition as a Driver of Succession:

   - Early Successional Stages: In the early stages of succession, after a disturbance has cleared an area, there is often intense competition among pioneer species to establish and colonize the available space. These early colonizers are often well-adapted to rapidly colonize disturbed environments.

   - Resource Utilization: The competition is primarily for resources such as light, water, and nutrients. The species that can efficiently utilize these resources often gain dominance in the early stages of succession.

2. Succession as a Response to Competition:

   - Facilitation: As pioneer species modify the environment and accumulate organic matter, they may create conditions that favor the establishment of other species. This process, known as facilitation, can lead to the development of more complex communities over time.

   - Tolerance and Persistence: Species that are more tolerant to the environmental conditions created by earlier species can become established in later successional stages. Over time, the community transitions from early successional pioneers to more mature, late-successional species.

3. Shifts in Competitive Interactions:

   - Changing Competitive Relationships: Over the course of succession, the nature of competition often shifts. In the early stages, competition may be more intense for basic resources. In later stages, competition might involve more complex interactions, such as niche differentiation, where species specialize in different ecological niches.

   - Stabilization of Community Structure: Succession tends to stabilize the community structure by reducing the intensity of competition and establishing a more balanced arrangement of species. This can lead to a more diverse and complex ecosystem.

4. Dynamic Equilibrium:

   - Climax Community: Succession typically leads to the development of a climax community, which represents a relatively stable and mature ecosystem. In this stage, the balance of species interactions, including competition, contributes to the long-term sustainability of the community.

   - Dynamic Equilibrium: While there may still be some level of competition, the climax community reaches a dynamic equilibrium where the rates of species births and deaths, as well as resource cycling, are relatively balanced.

Factors that Cause Overcrowding in Ecology

1. High Reproductive Rates: Species with high reproductive rates can quickly increase their population size, leading to overcrowding if resources are limited.
2. Abundant Resources: Temporary abundance of resources, such as food, can lead to population booms, causing overcrowding until resources are depleted.
3. Absence of Predators: Lack of natural predators or effective control mechanisms can allow populations to grow unchecked, leading to overcrowding.
4. Human Activities: Habitat destruction, urbanization, and pollution from human activities can disrupt ecosystems and contribute to population overcrowding..
5. Climate Changes: Shifts in climate patterns can affect resource availability, leading to fluctuations in population sizes and, in some cases, overcrowding.

Ways of Avoiding Overcrowding in Ecology

1. Population Control Measures: Implementing population control measures, such as natural predation, hunting, or reproductive management, can help maintain populations at sustainable levels.
2. Habitat Restoration: Restoring degraded habitats and creating protected areas can provide additional space and resources, reducing the likelihood of overcrowding.
3. Conservation and Management: Conservation efforts focused on protecting ecosystems and managing natural resources sustainably contribute to preventing overcrowding.
4. Introduced Predators: In some cases, introducing natural predators to control populations of certain species, especially invasive ones, can help maintain ecological balance.
5. Education and Awareness: Increasing public awareness about the impact of human activities on ecosystems can lead to more responsible behaviors, reducing the risk of overcrowding.
6. Ecosystem Monitoring: Regular monitoring of ecosystems helps identify early signs of population imbalances, allowing for timely intervention to prevent overcrowding.

Effect of Food Shortage on Ecological Dynamics

1. Competition:

   - Intensified Competition: When food becomes scarce, individuals within a population often experience heightened competition for the limited resources available. This competition can lead to increased aggression, territorial disputes, and a struggle for access to essential nutrients.

   - Shifts in Dominance: Individuals with better competitive traits, such as efficient foraging or territorial defense, may have a competitive advantage during periods of food shortage. This can result in shifts in dominance within the population.

   - Stress and Health Impacts: Intense competition for limited food resources can lead to stress among individuals. This stress can have negative effects on overall health, potentially making individuals more susceptible to diseases.

2. Reproduction:

   - Reduced Reproductive Success: Food shortage often results in decreased reproductive success. Individuals may delay or reduce their reproductive efforts due to the challenges of providing sufficient nutrition for offspring.

   - Population Decline: Prolonged food scarcity can lead to a decline in overall population size as individuals may struggle to meet the energy demands of reproduction and raising offspring.

   - Adaptive Strategies: Some species may exhibit reproductive strategies in response to food shortages, such as adjusting the timing of reproduction or producing fewer offspring with a higher investment in their survival.

3. Emigration Rate:

   - Increased Emigration: In response to food scarcity, individuals may emigrate from their current habitat in search of areas with better resource availability. This movement is a strategy to find more favorable conditions and reduce competition.

   - Population Redistribution: High emigration rates can result in the redistribution of individuals across different habitats, impacting population dynamics and potentially influencing the composition of communities.

   - Migratory Behaviors: Some species exhibit migratory behaviors as a response to fluctuating food availability. Migration allows individuals to follow seasonal changes in resource abundance, enhancing their chances of survival.

EVALUATION: 1. Describe the relationship between competition and succession

2. Mention 4 ways of avoiding over population in an ecology.
3. Discuss the effects of food shortage on ecological dynamics

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively