2 ECOLOGY.pdf

Ecology Overview

Definition of Ecology

• Ecology: The study of interactions between organisms and their environment (Ernst Haekel, 1969).

• Terms:

  • Oikos: Meaning "house" or "home"

  • Logos: Meaning "the study of something"

Basic Concept of Ecology

• Ecological Niche:

  • Described by Odum:

    • Habitat is an organism's address.

    • Niche is its profession, defined by where it lives and what it does.

• Niche Characteristics:

  • Refers to the physiological space inhabited by an organism and its role in the community.

  • Includes food habits (predator, pollinator, decomposer) and interactions with other species.

Niche and Habitat

Unique Niches

• Each species occupies a unique niche (e.g., Tiger in G. Tahan feeding on wild boars).

• Variations in niche occur with different environmental characteristics (e.g., G. Tahan vs. Endau Rompin).

• Competition occurs when two organisms share the same niche:

  • Example: Tigers vs. Panthers (Panthers prefer smaller prey).

Habitat Definition

• Habitat: Where an organism lives and reproduces.

  • Essential features of a habitat:

    • Food

    • Water

    • Shelter

    • Space

Microhabitats

• Organisms may only occupy small parts of a habitat (e.g., tree in woodland).

• Microhabitats: Distinct small areas within a larger habitat (e.g., species of millipedes in varied microhabitats on a woodland floor).

Levels of Biological Organization

Hierarchical Structure

1. Individual: Single organism.

2. Population: Group of organisms of the same species in a specific area.

3. Community: All organisms in a given area.

4. Ecosystem: Biological community interacting with its physical environment.

5. Biome: Major ecosystem types with similar climate and vegetation.

6. Biosphere: The global sum of all ecosystems; zones of life on Earth.

Ecosystem Concept

Definition

• Ecosystem: A unit of biological organization where interactions occur, leading to energy flow and nutrient cycles.

Components of Ecosystems

• Abiotic Components: Non-living chemical and physical factors (e.g., climate, soil, geography).

• Biotic Components: Living organisms within the ecosystem:

  • Producers (Autotrophs): Organisms that produce energy (e.g., plants).

  • Consumers (Heterotrophs): Organisms that consume producers or other consumers:

    • Primary Consumers: Herbivores.

    • Secondary Consumers: Carnivores feeding on herbivores.

    • Omnivores: Eat both plants and animals.

  • Decomposers: Organisms that feed on dead organic material (e.g., bacteria, fungi).

Types of Ecological Interactions

Interaction Types

1. Competition:

   • Intraspecific: Same species competing.

   • Interspecific: Different species competing.

2. Parasitism: One organism benefits at the expense of another (host).

   • Endoparasites: Live within the host (e.g., tapeworms).

   • Ectoparasites: Live on the surface of the host (e.g., aphids). green plant stems n feed by tapping the phloem sievectube for sap

3. Predation: Interaction where a predator feeds on prey.

   Predator feeds on another called prey.. Predator- animal that catch and kill.. Predators larger than prey and have special adaptation

   -good vision, a keen sence of smell, strong legs for rapid movement

   Prey also have special adaotatioms to help the, survive from attack of the predators

   • camouflage helps them blend in with environment n hide

   • sharp senses warn them of attach

   • speed allows them to escape

4. Commensalism: One organism benefits, the other is not significantly affected. ex: clingfish hiding on its host - a crinoids while the host is unaffecte

5. Symbiosis: An interaction between individuals of different species (e.g., lichen: a symbiotic relationship between a fungus and algae).

Abiotic Components

Definitions

• Abiotic components are the nonliving components of biosphere

  1. Atmosphere: Gaseous envelope surrounding Earth, consisting of layers:

  • Troposphere: Where we live, temperature decreases with height. 78% nitrogen, 21% oxygen, a small amount of Co2. The air pressure at the top of the traposphere (tropopause) is only 10% of that at sea level (0.1atmospheres)

  • Stratosphere: Contains ozone- absorb most of the harmful uv radiation from sun, temperature increases with height due to absorption of uv radiation. The increase in temparature make it a calm layer with movement of the gasses slow. So many jet aircraft fly in stratosphere because it is very stable

  • Mesosphere: Gases thin, temperature decreases, the gases thick enough to slow meteoride hurtling into atmosphere.

  • Thermosphere: Very thin air, absorbs high-energy uv radiation n x ray drom sun; high temperatures but very cold to our skim because of extremely thin air. Total amount of energy from very few molecule in this layer is not sufficient enough to heat our skin- many satellite orbite with it

    2. Hydrosphere: All water on Earth (saltwater and freshwater), involved in the hydrologic cycle.

    3. Lithosphere: Solid earth, includes crust and upper mantle, supports ecosystems.

Ecological Pyramid and Energy Flow

Energy Flow Basics

• Energy enters ecosystems via sunlight, transformed during photosynthesis in producers.

• Food Chain: Represents energy transfer through different trophic levels:

  1. Producers (plants) - 1st Trophic Level

  2. Primary Consumers (herbivores) - 2nd Trophic Level

  3. Secondary Consumers (carnivores) - 3rd Trophic Level

Ecological Efficiency

• Typically, about 10% of energy at one trophic level is transferred to the next; 90% is lost as heat.

Ecological Pyramids

• Number Pyramid: Reflects the number of organisms at each trophic level.

• Biomass Pyramid: Indicates total mass at each level.

• Energy Pyramid: Shows energy transfer efficiency; most accurate representation of feeding relationships in a community.

Ecology Overview

Definition of Ecology

Ecology is the scientific study of the interactions between organisms and their environment, first articulated by Ernst Haekel in 1866. It encompasses various biological disciplines to understand how living beings interact within their habitats and the impacts of environmental changes.

Key Terms:

• Oikos: A Greek word meaning "house" or "home", forming the root of the term ecology.

• Logos: Meaning "the study of something", indicating that ecology is the study of our natural home.

Basic Concepts of Ecology

Ecological Niche:

• Described by Eugene Odum, an ecological niche is defined as the role of an organism within its ecosystem. It encompasses not only where an organism lives (habitat) but also its behaviors, food sources, and interactions with other organisms.

Habitat vs. Niche:

• Habitat: The specific environmental area where an organism lives, characterized by factors such as food, water, shelter, and space necessary for reproduction.

• Niche: Refers to an organism's function within an ecosystem, including its feeding habits (e.g., predator, pollinator, decomposer) and its interactions with competitors and symbionts.

Unique Niches:

Each species occupies a unique niche, allowing it to reduce competition with others. For instance, the Tiger (Panthera tigris) in Gunung Tahan specializes in hunting wild boars, while its role can differ in various environments (e.g., Endau Rompin National Park).

Competition:

• Competition occurs when two organisms share the same niche, leading to resource depletion. For example, Tigers and Panthers may compete for prey, but Panthers often target smaller animals, thus overlapping less with the Tigers' prey choices.

Levels of Biological Organization

Hierarchical Structure:

1. Individual: A single organism.

2. Population: A group of individuals of the same species in a specific area, which may interact and breed with one another.

3. Community: All living organisms in a particular area, interacting in various ways (predation, competition, mutualism).

4. Ecosystem: A biological community interacting with its physical environment, including both biotic (living) and abiotic (non-living) components.

5. Biome: Large geographical biotic units (e.g., tropical rainforest, desert) characterized by similar climate, flora, and fauna.

6. Biosphere: The global sum of all ecosystems; zones of life on Earth, encompassing land, water, and atmosphere.

Ecosystem Concept

Definition:

An ecosystem is a fundamental unit of ecology where living organisms interact with each other and their abiotic environment, facilitating energy flow and nutrient cycling.

Components of Ecosystems:

• Abiotic Components: These include non-living elements in an ecosystem, such as:

  • Climate: Average weather conditions of a region, influencing the types of organisms that can thrive there.

  • Soil: Comprised of minerals, organic matter, water, and air; its composition affects plant growth and thus the entire food web.

  • Geography: Physical terrain and landscape features shape habitats, influencing biodiversity.

• Biotic Components: Living organisms within the ecosystem categorized by their role:

  • Producers (Autotrophs): Organisms like plants and algae that convert sunlight into energy through photosynthesis.

  • Consumers (Heterotrophs): Organisms that rely on other organisms for energy:

    • Primary Consumers: Herbivores that consume producers.

    • Secondary Consumers: Carnivores that consume herbivores.

    • Omnivores: Consume both plants and animals.

    • Decomposers: Organisms like bacteria and fungi that break down dead organic matter, recycling nutrients back into the ecosystem.

Types of Ecological Interactions

Interaction Types:

• Competition:

  • Intraspecific: Competition among individuals of the same species.

  • Interspecific: Competition between individuals of different species, which can lead to niche differentiation or competitive exclusion.

• Parasitism: One organism benefits at the expense of another (the host).

  • Endoparasites: Organisms like tapeworms that live inside their hosts.

  • Ectoparasites: Organisms like lice or aphids that live on the surface of their hosts.

• Predation: A predator feeds on prey, driving natural selection and population control.

• Commensalism: A relationship where one organism benefits while the other is neither helped nor harmed (e.g., barnacles on whales).

• Symbiosis: A close, often long-term interaction between two different species, which can be mutualistic (both benefit) or parasitic (one benefits at the other's expense).

Abiotic Components

Definitions:

• Atmosphere: The gaseous envelope surrounding Earth, consisting of several layers:

  • Troposphere: Where we live, temperature decreases with height, contains weather.

  • Stratosphere: Contains the ozone layer, which absorbs UV radiation; temperature increases with height.

  • Mesosphere: Cooler and less dense; meteors burn up in this layer.

  • Thermosphere: Very thin air, where high-energy radiation is absorbed; experiences extremely high temperatures.

• Hydrosphere: Encompasses all of Earth's water, both saltwater and freshwater, involved in the hydrologic cycle, playing a crucial role in climates and ecosystems.

• Lithosphere: The solid part of the Earth, including the crust and upper mantle; supports ecosystems through providing essential minerals and nutrients.

Ecological Pyramid and Energy Flow

Energy Flow Basics:

• Energy enters ecosystems through sunlight (solar energy), which is captured by producers during photosynthesis, leading to energy transformation into chemical energy. Only 1% of visible light reach orimary producer is converted to chemical energy by photosunthesis.

• Food Chain: A linear representation of energy transfer through different trophic levels:

  • Producers (1st Trophic Level): Autotrophs that produce energy.

  • Primary Consumers (2nd Trophic Level): Herbivores feeding on plants.

  • Secondary Consumers (3rd Trophic Level): Carnivores that consume herbivores.

Ecological Efficiency:

• Typically, about 10% of energy at one trophic level is transferred to the next, while approximately 90% is lost as heat, metabolic processes, or through waste.

• Ecological Pyramids:

  • Number Pyramid: Reflects the number of organisms at each trophic level.

  • Biomass Pyramid: Represents the total mass of living matter at each level.

  • Energy Pyramid: Most accurately illustrates energy flow efficiency and the structure of feeding relationships in an ecosystem.

Biogeochemical Cycles

Nitrogen Cycle:

• Nitrogen Fixation: Conversion of atmospheric nitrogen (N2) into ammonium (NH4+) through various processes, including atmospheric fixation (lightning), biological fixation (by bacteria), and industrial fixation (Haber Process).

• Nitrification: The conversion of ammonium into nitrates (NO3-) that plants can assimilate.

• Assimilation: Plants utilize nitrates to form organic compounds.

• Decay: Decomposition processes release nitrogen back into the environment, ensuring nutrient cycling.

• Denitrification: Conversion of nitrates back into nitrogen gas, replenishing the atmosphere and completing the cycle.

Carbon Cycle:

• Carbon dioxide (CO2) is absorbed by plants during photosynthesis and enters food webs.

• Carbon is returned to the atmosphere through respiration and human activities like combustion of fossil fuels, impacting global climate balance.

Biogeochemical Cycles

Nitrogen Cycle

1. Nitrogen Fixation: Conversion of atmospheric nitrogen (N2) into ammonium (NH4+).

   • Processes: Atmospheric fixation (lightning), biological fixation (bacteria), industrial fixation (Haber Process).

2. Nitrification: Conversion of ammonium into nitrates (NO3-).

3. Assimilation: Plants use nitrates to form proteins.

4. Decay: Decomposition involves breaking down organic materials to release nitrogen back into the environment.

5. Denitrification: Conversion of nitrates back to nitrogen gas, replenishing atmosphere.

Carbon Cycle

• Carbon dioxide (CO2) enters via photosynthesis, moving through food webs. Organisms release CO2 back during respiration, maintaining balance but disrupted by fossil fuel consumption.