APES REVIEW

Basics of Ecosystems

• An ecosystem is a community of living and non-living components interacting in a specific environment.

• Predator (apreder): an organism that eats another organism (prey).

• Symbiosis: a close interaction between two species.

Types of Symbiosis

Competition and Resource Partitioning

• Competition: organisms competing for the same resource (e.g., light, habitat, food).

• Resource partitioning: using resources in different ways to prevent competition (e.g., using resources at different times, in different places).

Terrestrial Biomes 🏞

Note: The distribution of biomes is constantly changing due to climate change, fossil fuel production, and other factors.

Aquatic Biomes 🌊

Carbon Cycle ⚠

"The movement of carbon atoms between sources and sinks."

• Sources: fossil fuel combustion, cellular respiration

• Sinks: trees, photosynthesis, carbon storage

Note: Fossil fuel burning releases CO2 into the atmosphere, contributing to climate change.

Nitrogen Cycle 🌈

"The movement of nitrogen atoms between sources and sinks."

• Sources: nitrogen fixation (bacteria converting atmospheric nitrogen into ammonia), fossil fuel combustion

• Sinks: denitrification (compounds like nitrate turning back into N2), nitrification (ammonia into nitrates and nitrites)

Note: The atmosphere is the primary nitrogen reservoir, comprising over 70% of the atmosphere.

Phosphorus Cycle 💧

"The movement of phosphorus atoms between sources and sinks."

• Sources: rocks and sediments, phosphorus fixation

• Sinks: phosphorus storage in ecosystems, phosphorus limitation in certain ecosystems

Note: Phosphorus is sometimes a limiting factor in ecosystems, and its availability can affect ecosystem functioning.

Hydrologic (Water) Cycle ☁

"The movement of water between sources and sinks."

• Sources: oceans, groundwater, ice caps

• Sinks: precipitation, evaporation, condensation

Note: The sun powers the water cycle movements.

Primary Productivity 🌱

"The rate at which solar energy is converted into organic compounds."

• Units: kilocalories per meter squared per year

• Net Primary Productivity (NPP): gross primary productivity minus energy loss to cellular respiration

Trophic Levels and the 10% Rule 🐯

"Energy flows from the sun to producers, and then to consumers."

• Trophic pyramid: producers (lowest trophic level), herbivores, carnivores, apex predators (highest trophic level)

• 10% rule: only 10% of energy from a lower trophic level is transferred to the higher one

Note: Energy flows from the sun to producers, and then to consumers, with a significant amount of energy lost at each trophic level.

Food Webs and Chains 🍴

• Food web: a complex network of food chains

• Food chain: a series of organisms that eat other organisms, with energy flowing from one organism to the next

Note: Changes to one species in an ecosystem can have cascading effects on other species in the food web.## Populations 🐝

Species can be classified into four types: generalist species, specialist species, K-selected species, and R-selected species.

Generalist and Specialist Species

• Generalist species can thrive in changing conditions, such as raccoons, which can live almost anywhere.

• Specialist species need a certain environment to survive, such as koalas, which are adapted to a specific environment.

K-Selected and R-Selected Species

Biotic potential is the maximum reproductive rate of a population in ideal conditions.

Survivorship Curves

A survivorship curve plots the survival rate of a species as a function of the species' age. There are three types of curves:

• Type 1: High survival rate initially, with a decline at old age (e.g., humans)

• Type 2: Hybrid curve (e.g., birds)

• Type 3: Low survival rate initially, with a slower decline at old age (e.g., fish)

K-selected species generally follow Type 1 curves, while R-selected species follow Type 3 curves.

Carrying Capacity

Carrying capacity is the maximum capacity an ecosystem can have. Overshoot occurs when a population exceeds this capacity, leading to resource depletion and collapse.

Age Structured Diagrams

Age structured diagrams show the distribution of age and sex in a population. The y-axis represents age groups, and the x-axis represents the population percentage of each age group.

"A triangle-shaped age structured diagram, also known as a 'bottom-heavy' diagram, indicates a population with a high proportion of young individuals, leading to rapid growth."

Total Fertility Rate (TFR)

Total Fertility Rate (TFR) is the average number of children born to a woman in a lifetime. TFR depends on educational opportunities, family planning, and access to sexual protection.

Demographic Transition

Demographic transition refers to the transition from high birth rates and death rates to low birth rates and death rates, accompanied by industrialization and improved healthcare. There are four stages, with Stage 1 being the least industrialized and Stage 4 being the most industrialized.

Density Independent and Dependent Factors

• Density independent factors do not depend on the number of people in an area, but affect carrying capacity (e.g., fires, storms).

• Density dependent factors depend on the number of people in an area and affect carrying capacity (e.g., food, disease).

Wind Patterns and Water Distribution 🌪

Wind patterns exist due to differences in temperature and pressure across the Earth's surface. As warm air rises at the equator and moves towards the poles, cool air moves towards the equator, creating global wind patterns that distribute heat and moisture to different areas.

Watersheds 🌊

A watershed is an area where large amounts of water flow into a body of water, coming from many places and connecting in the area. Characteristics of a watershed include:

• Area: The size of the watershed

• Length: The length of the watershed

• Slope: The steepness of the watershed

• Soil: The type of soil in the watershed, which affects the water holding capacity

Insolation and Latitude ☀

Insolation refers to the amount of sunlight received in an area per unit of time. The angle of the Sun's rays with respect to the Earth determines the insolation intensity. The highest solar radiation per area is received at the equator, decreasing towards the poles.

Rain Shadow Effect ☁

The rain shadow effect occurs when areas of land become drier at higher elevations due to mountains blocking air from moving from one side to the other. This results in one side being more precipitous and moisturized, while the other side is dry.

El Niño and La Niña ❄

El Niño and La Niña are events that result from changing ocean temperatures in the Pacific Ocean. They cause changes to rainfall, wind, and ocean circulation in different areas.

Unit 5: Land and Water Use 🌳

Tragedy of the Commons

The tragedy of the commons is the idea that individuals share resources for their own benefit, without considering how much they deplete the resources, leading to large-scale depletion.

Clear Cutting

Clear cutting is the practice of cutting all trees in a given area at once. This is efficient and cost-effective but leads to:

• Loss of biodiversity

• Soil erosion

• Loss of carbon storage

• Increased flooding

• Loss of aesthetic value

The Green Revolution

The Green Revolution is the shift to different agricultural strategies to benefit food production. This includes:

• Mechanization: The use of machinery for increased efficiency and reduced hand labor

• GMOs: Organisms whose genetics have been modified with another organism

• Fertilization: The application of nutrients to improve plant growth

• Irrigation: The use of water to assist in crop growth

• Pesticides: Chemicals used to control pests and protect crops

Irrigation Methods

Salinization

Salinization occurs when salts and groundwater remain in the soil after water evaporation, making it toxic to plants.

Meat Production and Environmental Impact 🐮

Meat production is less efficient than vegetable production due to the required land and food for the animals. This can lead to:

• Deforestation and loss of biodiversity

• Soil erosion and desertification

• Increased CO2, methane, and N2 emissions

• Water conservation issues

Mining Operations 💎

Mining operations require more resources and cause increased waste and pollution. Surface mining removes large rocks and vegetation, making it susceptible to erosion. Deep mining operations can be expensive and lead to environmental problems.

Urbanization 🏙

Urbanization is the shift from rural areas to urban cities. This can lead to:

• Depletion of resources

• Saltwater and fusion in the hydrological cycle

• Increased use of fossil fuels, leading to more CO2 in the atmosphere

• Impervious surfaces, such as roads and buildings, preventing water infiltration and leading to flooding

• Environmental problems related to public health and life quality## Urban Ecology and Sustainability 🌆

Ecological Footprint

The ecological footprint of an individual or people in urban areas is generally higher due to the usage of more resources, materials, and energy.

Sustainability

"Living and using resources without depleting them for future generations."

Sustainability is critical, considering factors such as:

• Biological diversity

• Food production

• CO2 concentrations

Sustainable Yield

The sustainable yield refers to the amount of a renewable resource that can be taken without reducing the supply available.

Sustainable Agriculture

• Soil Conservation: prevents soil erosion

  • Contour plowing: plowing across slope of land following contour lines

  • Wind breaks: using vegetation to protect soil from wind

  • Terracing: using steep slopes to reduce runoff

• No-till agriculture: planning across without breaking up the soil

• Sustainable Forestry: reforestation, integrated pest management, and removal of infected trees

Energy Resources and Consumption ⚡️

Renewable and Non-Renewable Energy Sources

• Renewable energy sources:

  • Hydroelectric power

  • Geothermal energy

  • Solar energy

• Non-Renewable energy sources:

  • Fossil fuels (coal, oil, natural gas)

  • Nuclear power

Fossil Fuels

• Coal:

  • Types: Lignite (low energy content, low cost, high pollutant emissions), Bituminous (medium energy content), Anthracite (high energy content, high carbon content)

  • Uses: electricity generation, industrial processes

• Natural Gas:

  • Cleanest fossil fuel, produces minimal pollutants

  • Uses: electricity generation, heating, cooking

• Petroleum:

  • Mainly composed of hydrocarbons

  • Uses: transportation fuel, industrial processes

Distribution of Natural Energy Sources

Fuel Combustion

A chemical reaction between fuel hydrocarbons and oxygen, yielding CO2, water, and energy.

Nuclear Power

Generated through the fission of uranium 235 atoms, releasing heat used to produce steam, which powers a turbine.

Radioactivity

The nucleus of a radioactive isotope loses energy by emitting radiation.

Three Major Nuclear Disasters

1. Three Mile Island (USA)

2. Chernobyl (Ukraine)

3. Fukushima (Japan)

Biomass Energy

• Produces heat for energy

• Low cost, but produces pollutants like carbon monoxide, nitrogen oxides, and particulates

• Underdeveloped countries are major users of biomass as a fuel source

Ethanol

• Used as a substitute for gasoline

• Low energy investment, but does not introduce carbon into the atmosphere

Solar Energy ☀

Photovoltaic Solar Cells

• Capture light energy from the Sun and transform it into electrical energy

• Limited by sunlight availability

Active and Passive Solar Energy Systems

• Active systems use solar energy to heat a liquid and collect the stored energy

• Passive systems absorb heat from the Sun without mechanical or electrical equipment

Large-Scale Solar Farms

• Can impact ecosystems if they take up a lot of land

Hydroelectric Power 💧

Generation of Hydroelectric Power

• Using dams to collect water in reservoirs and spin a turbine

• Flowing water can also spin a turbine if placed in a river

Tidal Energy

• Uses tidal flows to turn a turbine

Benefits and Drawbacks of Hydroelectric Power

• Renewable, no air pollution or waste generated

• Can affect ecosystems, expensive construction of dams

Geothermal Energy ⛰

Generation of Geothermal Energy

• Using heat from the Earth's interior to heat up water, which is brought back to the surface as steam

• Same process as before: steam powers an electric generator

Drawbacks of Geothermal Energy

• Expensive to access, can release hydrogen sulfide

• Limited to specific areas with suitable geothermal resources

Hydrogen Fuel Cells

• An alternative to non-renewable fossil fuels

• Hydrogen is used as a fuel, combined with oxygen

Atmospheric Pollution 🌫

Non-Renewable Sources of Energy

• Fossil fuel combustion releases:

  • Carbon dioxide (CO2)

  • Sulfur dioxide (SO2)

  • Nitrogen oxides (NOx)

  • Particulates

• These pollutants contribute to:

  • Air pollution

  • Climate change

Primary and Secondary Air Pollutants

• Primary Air Pollutants: Directly emitted pollutants, such as:

  • CO2

  • SO2

  • NOx

  • Particulates

• Secondary Air Pollutants: Formed through chemical reactions of primary air pollutants, such as:

  • Ozone (O3)

  • Photochemical smog

Photochemical Smog

"Formed when nitrogen oxides and hydrocarbons react with heat and sunlight, producing pollutants."

• Common in urban areas

• Causes human health issues, such as:

  • Respiratory problems

  • Eye irritation

Thermal Inversions

"When the normal temperature gradient is altered, trapping air pollutants near the ground."

• Occurs when a layer of warm air is trapped beneath a layer of cool air

• Prevents air pollutants from dispersing

• Can lead to increased respiratory problems and other health issues

Carbon Dioxide (CO2)

• Naturally present in the atmosphere

• High levels associated with global warming

• Mainly caused by anthropogenic activities

Particulate Matter (PM)

• Tiny particles suspended in the air

• PM10: Particles with diameters of 10 micrometers or smaller

• PM2.5: Particles with diameters of 2.5 micrometers or smaller

• Causes respiratory issues

Indoor Air Pollutants

• Carbon Monoxide (CO): A deadly indoor air pollutant that interferes with oxygen transport in the blood

• Asbestos: A carcinogenic substance found in building walls and ceilings

• Radon: A colorless, odorless gas that can seep into homes and cause lung cancer

• Volatile Organic Compounds (VOCs): Hydrocarbons found in furniture, carpets, and paints

• Lead: A toxic substance found in paints and damaging to the central nervous system

Reducing Air Pollution

• Vapor Recovery Nozzles: Capture gasoline vapors at fueling stations

• Catalytic Converters: Convert gases into less harmful compounds

• Wet and Dry Scrubbers: Remove pollutants from exhaust streams

• Electrostatic Precipitators: Collect particulate matter using electrostatic charges

Noise Pollution 🗣

• Causes stress and hearing loss

• Common sources:

  • Urban areas

  • Transportation

  • Construction

  • Industrial activities

• Can affect animals, changing their behavior and migratory routes

Acid Rain ☔

• Caused by nitrogen and sulfur oxides in the atmosphere

• Reacts with water vapor and oxygen to form sulfuric and nitric acid

• Acid rain can:

  • Acidify soil and water

  • Corrode man-made structures

  • Harm ecosystems

Limestone and Acid Rain

• Limestone can neutralize the effects of acid rain

• Commonly used to protect man-made structures from acid rain

Water Pollution 🌊

Thermal Pollution

Thermal pollution is caused by the release of heat into the water, damaging organisms and ecosystems. Warm water contains less dissolved oxygen than cold water, making it harder for animals to breathe. This can lead to stress, death, and a range of other negative impacts on aquatic life.

Nuclear Power Plants: These plants use cooling towers to prevent thermal pollution by cooling the water before releasing it back into the environment.

Persistent Organic Pollutants (POPs)

Definition: POPs are synthetic, carbon-based molecules that do not break down in the environment. They are soluble in fat and can accumulate in an organism's fatty tissue, causing harm.

Examples:

• PCBs (Polychlorinated Biphenyls)

• DDTs (Dichlorodiphenyltrichloroethanes)

Effects:

• Bioaccumulation and biomagnification

• Harmful to organisms and ecosystems

• Can travel long distances through wind and water

Bioaccumulation and Biomagnification

Bioaccumulation: The selective absorption and concentration of elements or compounds in organisms.

Biomagnification: The increase in concentrations of pollutants as you move up the food web.

Effects:

• Developmental deformities and extinctions

• Harmful impacts on organisms and ecosystems

Solid Waste Disposal

Definition: Solid waste is any discarded material that is not liquid or gas.

Types of Disposal:

• Landfills: sanitary municipal landfills with bottom liners, leachate collection systems, and methane collection systems

• Incineration: reduces waste volume, but releases air pollutants

• Ocean dumping: harmful to aquatic organisms and ecosystems

Electronic Waste (E-Waste)

Definition: Electronic waste contains toxic metals like lead, mercury, and cadmium.

Disposal Methods:

• Recycling and reuse

• Proper disposal to prevent harm to humans and the environment

Waste Reduction

Definition: Reduce, Reuse, Recycle

Methods:

• Composting: organic matter decomposition, producing fertilizer

• Combustion of gases: generates electricity from landfills

Sewage Treatment

Types of Treatment:

• Primary treatment: physical removal of large objects

• Secondary treatment: biological process breaking down organic matter

• Tertiary treatment: chemical processes removing extra pollutants

Lethal Dose 50 (LD50)

Definition: The dose of a chemical that will kill 50% of a population of a species.

Units: Milligrams per kilogram (mg/kg)

Importance: Describes the mortality rate based on the dose of a toxin.

Effects of Pollution on Human Health

Diseases:

• Dysentery: infectious disease causing diarrhea and dehydration

• Mesothelioma: form of cancer caused by exposure to asbestos fibers

• Respiratory issues: asthma, aggravation, and decreased lung function

Health Effects:

• Worse in poor countries due to lack of resources and poor healthcare

• Increased risk of infectious diseases

Infectious Diseases

Pathogens: Organisms causing infectious diseases

Vectors: Mosquitoes, fleas, and other organisms spreading diseases

Diseases:

• Plague: bacterial infection spread through fleas and other organisms

• Tuberculosis: bacterial infection attacking the lungs

• Malaria: parasitic disease caused by infected mosquitoes

• SARS: severe acute respiratory syndrome

• Zika: virus spread through mosquitoes, causing birth defects

• Cholera: bacterial disease contracted from infected water

Global Change

Stratospheric Ozone Depletion

• Anthropogenic factors: CFCs (chlorofluorocarbons)

• Natural factors: melting of ice crystals

• Effects: skin cancer, cataracts, and harm to humans and the environment

Greenhouse Effect

• Main greenhouse gases: carbon dioxide, methane, water vapor, nitrous oxide, and CFCs

• Global warming potential (GWP): measures the heat a greenhouse gas traps in the atmosphere over time

• Importance: necessary for life, but excessive levels contribute to climate change

Climate Change and its Impacts 🌎

Rising Global Temperatures

Global warming causes several problems, including:

• Rising sea levels from ice melting, affecting coastal areas of human population

• Spread of disease vectors, as warm temperatures allow disease vectors to thrive

• Extreme weather events, such as hurricanes, droughts, and heatwaves

Impacts on Ecosystems

Ecosystems will be constantly changing, leading to:

• Agricultural impacts, such as changes in crop yields and growing seasons

• Changes in sea levels, creating new habitats and disrupting existing ones

Effects of Climate Change

Physical Effects

• Rising temperatures

• Melting permafrost and ice

• Rising sea levels and displacement of coastal populations

Biological Effects

• Changes in species distribution and migration patterns

• Disruption of marine ecosystems, affecting species and their habitats

• Coral bleaching, as coral expels algae, leading to coral death

Positive Feedback Loops

• Snow melt: As snow melts, more solar energy is absorbed, leading to increased global warming

• Ocean warming: Warmer oceans absorb more CO2, leading to increased ocean warming and acidification

Ocean Acidification

"Ocean acidification is when more CO2 concentrations are absorbed by the ocean, making it more acidic."

• Effects on marine life: Decreased ability to form shells, leading to decreased calcium carbonate levels

Invasive Species

• Definition: Species that thrive outside of their normal habitat and intrude on other habitats

• Examples: Invasive species in water, such as zebra mussels, attach to human boats and spread to new habitats

• Control methods: Cleaning and inspecting boats, natural predators, and legislation to prevent transport

Endangered Species

• Threats: Habitat destruction, hunting, invasive species, and niche habitat requirements

• Examples: Rhinos, threatened by poaching for their horns

• Conservation methods: Criminalizing poaching, creating new habitats, and protecting animals

Human Impacts on Biodiversity

• HIPCO:

  • Habitat destruction: Destruction of natural habitats, leading to loss of biodiversity

  • Habitat fragmentation: Breaking up of large habitats, leading to isolation and loss of species

  • Invasive species: Introduction of non-native species, leading to competition and extinction

  • Pollution: Harmful chemicals and plastics, affecting wildlife and ecosystems

  • Climate change: Changes in precipitation patterns and global warming, altering habitats

  • Overexploitation: Unsustainable use of plants and animals, leading to population decline