Biology-Wesley-Hammond-Ecology

UNIT 1 Overview

• Weight on Biology Paper: 25% - 32.5%

• Short Questions (10%): Topics include scientific method, food, and ecology.

• Long Question (15%): Focuses on scientific method, food, and ecology.

• Experiment Question (7.5%): Can appear in Section B.

Ecology in the Curriculum

• Importance: Asked every exam year since 2004.

• Weight: 15% - 27.5% in Leaving Certificate.

• Marks History: Various marks ranging from 60 to 110 in different years.

Definition of Ecology

• Definition: Study of interactions between living organisms and their environment.

• Key Concepts:

  • Biosphere: Part of planet with living organisms. Example: Oceans, mountains.

  • Ecosystem: Group of organisms interacting with their environment. Example: Woodlands, grasslands, etc.

  • Habitat: Specific location where an organism lives.

  • Population: Group of the same species in an area. Example: Rabbits in a field.

  • Community: Different populations in a given area. Example: Bacteria, fungi, plants, and animals in a field.

Environmental Factors Affecting Organisms

• Abiotic Factors: Non-living, e.g., temperature, rainfall.

• Biotic Factors: Living influences, e.g., predation, competition.

• Key Abiotic Factors:

  • Altitude: High altitudes lead to cooler climates.

  • Aspect: Orientation of land (e.g., south-facing slopes are warmer).

  • Soil pH: Affects plant growth depending on acidity.

Biotic Factors and Interactions

• Competition: Struggle for resources (food, mates, space).

• Predation: One organism kills and eats another.

• Parasitism: One organism lives on another, harming it.

• Humans: Can significantly damage ecosystems.

Energy Flow in Ecosystems

• Primary Energy Source: The sun.

• Producers: Organisms that perform photosynthesis (e.g., trees, plants).

• Consumers:

  • Primary Consumers: Herbivores (e.g., deer).

  • Secondary Consumers: Carnivores (e.g., foxes).

  • Tertiary Consumers: Top predators.

• Decomposers: Bacteria and fungi that recycle nutrients.

Food Chain and Food Web

• Food Chain: Sequence showing energy transfer, e.g., Grass -> Rabbit -> Fox.

• Food Web: Interconnected food chains showing various organisms' relationships.

• Pyramid of Numbers: Illustrates number of organisms at each trophic level; typically decreases as one moves up.

• Limitations: Doesn't consider organism size; may not be to scale due to large populations.

Niche and Competition

• Niche: Role of an organism in its environment. Examples:

  • Swallows: Feed on aerial insects.

  • Thrushes: Feed on ground insects.

• Competition Types:

  • Intraspecific: Within the same species.

  • Interspecific: Between different species.

Human Impact on Ecosystems

• Pollution: Harmful substances added to the environment.

  • Sources: Electricity generation, transportation, and farming.

  • Types: Agricultural, industrial, and domestic pollution.

• Conservation: Management to prevent extinction and maintain diversity; benefits include ecological balance and preserving species.

• Waste Management: Strategies to manage waste effectively:

  • Agricultural: Through proper slurry storage and timing.

  • Fisheries: Recommended nets and quotas to sustain fish populations.

Population Dynamics

• Factors Affecting Populations:

  • Predation: Determines population levels of prey.

  • Competition: For resources like food, water, and space.

  • Parasitism: Control of host populations.

• Types of Competition:

  • Contest Competition: Physical struggle for resources.

  • Scramble Competition: All get resources, but none thrive.

Adaptations in Predators and Prey

• Predator Adaptations:

  • Speed, keen senses (e.g., foxes, owls).

• Prey Adaptations:

  • Camouflage, defensive mechanisms (e.g., ladybirds).

Nutrient Cycles

• Carbon Cycle: Processes like photosynthesis and decomposition recycle carbon in ecosystems.

• Nitrogen Cycle: Involves bacteria to convert nitrogen into useful forms for living organisms, crucial for proteins and DNA.