Page 1

• Species, Communities, and Ecosystems

  • Species

    • Defined as groups of organisms capable of interbreeding to produce fertile offspring.

    • Can have autotrophic or heterotrophic nutrition methods.

  • Communities

    • Formed by populations of different species living together and interacting.

  • Ecosystems

    • Formed by communities interacting with the abiotic environment.

    • Autotrophs obtain inorganic nutrients from the environment.

    • Nutrient cycling maintains the supply of inorganic nutrients.

• Sustainability and Classification

  • Ecosystems can be sustainable over long periods.

  • Classifying species based on their nutrition mode.

  • Setting up mesocosms to establish sustainability.

  • Testing species association using statistical methods.

Page 2

• Species, Communities, and Ecosystems (Continued)

  • Reiteration of species, communities, and ecosystems definitions.

• Nutrition Modes and Classification

  • Autotrophs synthesize organic molecules from inorganic sources.

  • Heterotrophs classified as consumers, detritivores, and saprotrophs.

  • Examples of different feeding patterns in heterotrophs.

Page 3

• Species and Nutrition

  • Characteristics of species members and their ability to interbreed.

  • Challenges in defining species for organisms like bacteria and hybrids.

  • Modes of nutrition: autotrophs and heterotrophs.

• Feeding Patterns

  • Classification of heterotrophs based on feeding habits.

  • Autotrophs produce their own organic molecules, while heterotrophs consume them.

Page 4

• Detritivores and Saprotrophs

  • Detritivores obtain nutrients from decaying organic matter.

  • Saprotrophs digest dead organisms externally.

• Mixotrophs and Sustainability

  • Some organisms can exhibit both autotrophic and heterotrophic nutrition.

  • Components required for ecosystem sustainability: energy availability, nutrient recycling, and waste management.

• Nutrient Cycling

  • Nutrient cycling is essential to maintain nutrient availability in ecosystems.

Page 5

• Autotrophs produce organic molecules from inorganic molecules

  • Consumers obtain organic molecules by consuming producers

  • Decomposers break down dead consumers' cells, returning nutrients to the soil

• Mesocosm

  • Enclosed environments to observe a part of nature under controlled conditions

  • Used to test sustainability of nutrient cycles

• Chi-Squared test

  • Determines species interactions in an environment

  • Positive association: predator-prey or symbiotic relationships

  • Negative association: competition for the same resources

  • No interaction: independent distribution

Page 6

• Quadrat

  • A square measuring 1m on all sides

  • Helps count a small percentage of a sample

  • Used to estimate total number of organisms in a location

• Applying Chi-Squared test to quadrat sampling data

  • Five steps: hypotheses, table of frequencies, chi-squared formula, degree of freedom, p-value

Page 7

• Example of Chi-Squared Test Application

  • Testing association between ling and bell heather on moorland

  • Null hypothesis: no significant difference in species distribution

  • Alternative hypothesis: significant difference in species distribution

• Constructing a table of frequencies for observed versus expected distribution

Page 8

• Expected Results

  • Calculating expected distribution frequencies assuming random distribution

  • Calculating expected values based on probabilities

• Checking calculated values against observed results in the table

• Statistical Test: Observed and expected distribution of ling and bell heather

Page 9

• Applying the chi-squared formula to calculate a statistical value

• Determining the degree of freedom (df) for the test

• Identifying the p-value to determine statistical significance

Page 10

• Significance Level and Chi-Square Distribution

  • A value is significant if p < 0.05

  • Chi-square values for different probabilities

  • Critical value for df = 1 is 3.841

• Niche

  • Definition and components of an ecological niche

  • Fundamental vs. realized niche

Page 11

• Positive and Negative Associations

  • Predator-prey relationships and their impact on populations

  • Symbiotic relationships: mutualism, commensalism, parasitism

  • Competition types: intraspecific and interspecific

Page 12

• Energy Flow in Ecosystems

  • Energy flow from sunlight to chemical energy

  • Energy transfer through food chains and heat loss

  • Energy storage in ATP and its usage

• Energy Loss and Efficiency

  • Reasons for energy loss in organisms

  • Energy efficiency in living organisms

  • Pyramids of energy and their characteristics

Page 13

• Biomass and Energy Conversion

  • Biomass definition and its relation to energy storage

  • Energy conversion forms: kinetic, electrical, light energy

  • Heat energy as a by-product in living organisms

Page 14

• Biomass and Energy

  • Biomass as the total mass of organisms

  • Diminishing biomass along food chains

• Final Note

  • Caution regarding the pyramid of numbers

  • Importance of understanding biomass and energy flow in ecosystems

Energy and Nutrient Movement in Ecosystems

• Energy Flow in Ecosystems

  • Energy moves from one organism to another through feeding.

  • Arrows in food chains represent energy transfer.

  • Food chains start with producers and continue with consumers.

• Food Webs

  • Represent complex feeding relationships in ecosystems.

  • Show how food chains are interconnected.

  • Organisms can have multiple food sources and predators.

• Trophic Levels

  • Define the feeding position of organisms in a food chain.

  • Producers occupy the first trophic level.

  • Consumers occupy subsequent trophic levels.

Carbon Cycling in Ecosystems

• Carbon Cycle Overview

  • Carbon exchanges occur in the hydrosphere, biosphere, lithosphere, and atmosphere.

  • Various forms of carbon include atmospheric gases, oceanic carbonates, organic materials, and non-living remains.

• Processes in Carbon Cycle

  • Autotrophs convert carbon dioxide into carbohydrates via photosynthesis.

  • Heterotrophs obtain carbon compounds through feeding.

  • Sources of CO2 production include combustion and respiration.

• Carbon Cycle in Aquatic Ecosystems

  • Carbon exists as dissolved carbon dioxide and hydrogen carbonate ions.

  • Rising CO2 levels lead to acidic water, affecting organisms.

Impact on Climate Change

• Consequences of Carbon Cycle Processes

  • Complete decomposition forms fossil fuels like oil and gas.

  • Incomplete decomposition leads to peat formation, releasing CO2 when burned.

Peat Formation and Fossil Fuels

• Peat Formation

  • Peat forms in waterlogged soil due to partial decomposition.

  • Factors favoring peat production include organic matter, anaerobic, and acidic conditions.

• Fossil Fuels

  • Oil and gas result from decay of marine organisms over millions of years.

  • Burning fossil fuels releases CO2 and other pollutants into the atmosphere.

Page 22

Combustion and Biofuels

• Combustion:

  • Carbon dioxide produced by burning biomass and fossilized organic matter.

  • Organic compounds with hydrocarbons heated with oxygen undergo combustion, releasing energy, carbon dioxide, and water.

• Biofuels:

  • Derived from living matter.

  • Advantages over fossil fuels:

    • Habitats not disrupted for mining.

    • Faster absorption of released carbon dioxide compared to fossil fuels.

• Challenges:

  • Biofuels and bioenergy compete for finite land resources affecting food production and carbon storage.

Page 22

Methane Production

• Methane:

  • Produced by methanogens in anaerobic conditions like wetlands, marine sediments, and ruminant animal digestive tracts.

  • Methane released into the atmosphere persists for about 12 years before oxidizing to carbon dioxide and water.

Page 23

Limestone and Carbon Sequestration

• Limestone:

  • Majority made of calcium carbonate.

  • Formed by marine organisms absorbing carbon dioxide, which turns into calcium carbonate in their shells.

• Bio-sequestration:

  • Process of removing carbon from the environment and locking it up.

• Impact:

  • Over-mining limestone releases carbon dioxide back into the air, disrupting carbon sequestration.

Page 24

Climate Change and CO2 Emission

• Greenhouse Gases:

  • Carbon dioxide and water vapor are significant greenhouse gases.

  • Impact depends on absorption of long-wave radiation and concentration in the atmosphere.

• CO2 Concentration:

  • Human activities like deforestation, farming, and combustion increase CO2 levels.

  • Efforts to reduce reliance on fossil fuels are ongoing, promoting alternative energy sources.

Page 25

Greenhouse Gases and Impact

• Greenhouse Gases:

  • Trap and hold heat in the atmosphere.

  • Water vapor and carbon dioxide have the largest warming effect.

• Impact:

  • Determined by absorption capacity of long-wave radiation and concentration in the atmosphere.

• Greenhouse Effect:

  • Earth's ability to retain heat and maintain moderate temperatures for life processes.

Page 26

Climate Change and Global Temperatures

• Climate Change:

  • Greenhouse gases trap heat, leading to increased global temperatures.

  • Higher concentrations result in more extreme weather conditions and changes in circulating currents.

• Vostok Ice Core:

  • Provides evidence of historical CO2 levels and temperatures.

  • Shows a positive correlation between CO2 concentrations and temperature.

• Industrial Definitions:

  • Weather refers to current conditions, while climate pertains to long-term temperature and precipitation patterns.

Page 27

• Industrial revolution increased fossil fuel use

  • Fossil fuel burning releases carbon dioxide, increasing atmospheric concentration

• Trends related to fuel emissions, CO2 concentrations, and global temperatures

  • Strong positive correlation between fossil fuel emissions and CO2 levels

  • Atmospheric CO2 increased by ~38% since pre-industrial times

  • 40% of CO2 emissions stayed in the atmosphere

  • Increase in CO2 correlates with global temperature rise

• Consequences of greenhouse effect

  • Disease spread due to more temperate climates

  • Melting ice caps and permafrost

  • Extreme weather conditions

  • Extinction events due to climate change

Page 28

• Consequences of enhanced greenhouse effect

  • Acidification of oceans

  • Rising sea levels displacing communities

  • Habitat destruction and expansion of temperate species

• Global temperature rise effects on arctic ecosystems

Page 29

• Relationship between atmospheric gases concentration and enhanced greenhouse effect

• Ocean acidification

  • Oceans absorb a third of human CO2 emissions

  • CO2 solubility decreases as temperatures rise

  • Acidification threatens marine organisms and coral reefs

Page 30

• Precautionary Principle

  • Calls for action when human activities pose environmental or health threats

  • Enhanced greenhouse effect requires precautionary measures due to complex climate changes

• Onus for action lies on contributors to the enhanced greenhouse effect

Page 31

• Action on climate change as a global issue involving various entities

• Precautionary principle versus burden of proof

• Arguments for and against action on climate change

Page 32

• Diagrams to know: Carbon Cycle

  •