EVR 1001 FSU Midterm

Human Population Growth

-Currently increasing at a rate of 1 billion people every 13 years

-Growth is proportional to population

-Equivalent to doubling in fixed intervals

-Natural populations grow rapidly until they reach carrying capacity

-When a population reaches its capacity: Population stabilizes, Overshoot & crash, Export Emigrants

Carrying Capacity

max number of plants, animals, bacteria, etc. that an environment can sustain. (NOT CONSTANT; health of ecosystem, per capita resource utilization, quality of life, technology)

Sustainability

-Of a resource: harvest no more than is replaced

-Of an ecosystem: human stressors, natural disturbances, ecosystem resilience, biodiversity

Key Characteristics of Sustainability

-Populations that live without conflict with nature

-energy policy that minimizes pollution and risk

-restrained (planned) use of renewable resources

-minimizations of the use of nonrenewable resources(leaving some for future generations)

-a political system that prioritizes long term prosperity over short term gain

Renewable Resources

sunlight, wind energy, wave energy, geothermal energy

Non renewable resources

crude oil, natural gas, coal, copper, aluminum

A Global perspective

-Global perspective is a recent idea (but very real)

-Local actions have distant consequences (linked by atmosphere and water)

-DDT-1962 (industrial pesticide, long half life in soils, transported by runoff and rivers, bio accumulates, linked to declines in aquatic life and birds, human toxicity

-The ozone hole- O3 protects life from harmful UV rays

-O3 is destroyed by halogens (CFC; used in refrigerants)

-CFCs have created an ozone hole in Antarctica

An urbanizing world - people & nature

-Cities are growing rapidly; pos and neg for environment

-Can be more efficient; if designed that way

-Humans are a product of nature and have shaped and been shaped by the rest of the natural word since dawn of our species

-Prehistoric humans drove most of large mammals in North America to extinction (also invented agriculture and reshaped entire ecosystem)

Natural World

ecosystems are in a continual state of flux, evolution is proceeding

Decision Making relies on...

1. Values: Protection of ecosystem & species, human equality, economic progress, future generations

2. Science: determine likely outcomes of different scenarios, assess uncertainty of outcomes

Science & Values

-Scientific Knowledge is always being challenged

-Theories can be disproven, never proven

The "classic" scientific method is:

- Observe phenomena

- Formulate a question

- Develop a hypothesis

- Make predictions from hypothesis

- Conduct experiment (test) with potential to disprove hypothesis

- Analyze results

Precautionary Principle

-Scientific knowledge always comes with a degree of uncertainty

-STATES THAT WHEN THERE IS A THREAT OF SERIOUS, IRREVERSIBLE ENVIRONMENTAL DAMAGE WE SHOULD NOT WAIT FOR PROOF BEFORE TAKING ACTIONS

The Utilitarian Justification

has quantifiable value to humans and provides necessary services) *Justification by economics

The Ecological Justification:

ecosystems are interconnected and healthy ecosystem may be required for the perseverance of many different species

The Aesthetic & Recreational Justifications

beauty of nature, joy from wilderness, recreational activities, spiritual, creative, emotional

Moral Justification

non humans have rights

Cultural Justification

thousands of cultures, each with specific values and beliefs

Scientific Theories

Modern science does not deal with things that cannot be tested by observation

Inductive reasoning-

beings with specific observations and then extends to generalizations, which may be disproved

Deductive Reasoning

if a conclusion follows logically from these assumptions, we say it is proven.

Population dynamics

general study of change in population

5 key properties of any population

abundance,

birth rates,

death rates,

growth rates,

age structure

Exponential growth-

population increasing by a constant percentage per unit time

Rule of 70

dividing annual growth into 70 (double in size)

History of human population:

Stage one-hunters gatherers

Stage two- Rise of agriculture

Stage three- Industrial Rev

Stage four- Current

Saltaire (UK):

increased built houses, wash houses, hospitals, library

Logistic growth

S- shaped curve, growth increases exponentially only temporarily to the inflection point, reaches an upper population limit at the logistic carrying capacity where growth=0

Assumptions:

constant environment, constant carrying capacity, homogeneous population

Total fertility rate

number of children born to an average woman over her lifetime

Exponential and logistic growth curves ignore...

characteristics of environment that affect different age groups (food, water, shelter, disease)

Three stage pattern of change in birth rates and death rates

-unique multi stage pattern of change in birth rates

-Occurred during the process of industrial and economic development of Western nations

-leads to decline in pop growth rate

Life Expentancy

-higher in developed nations

-modern medicines have reduced death rates

-T=P x I Total impact of human pop= Population size x average environmental impact per person

-Short term impact- immediate

-Intermediate: 1-10 yrs

-Long term: after 10 yrs

Why is Earth unique?

Unique in its ability to sustain complex life (temperatures that permit liquid water, an oxygenated atmosphere)

Molecule

Two or more atoms bonded together

Ion

electronically charged molecules or atoms

Basic Systems(types)

-System: set of components or parts that function together to act as a whole, responds to inputs and outputs (cell, body, city, river)

-Open System: some energy or material moves into or out of system

-Closed system: no such movements take place

-Static system: fixed condition

-Dynamic system: changes over time

-Dynamic equilibrium: steady state that all natural systems move towards without influence of people

Average Residence Time

how long, on average, a quantity of something will remain in reservoir of a system (Reservoir size divided by rate of input)

Feedbacks & Types

-Feedback: when one part of the system changes, it affects another part, which then affects first change

-Negative feedback: an increase in output leads to later decrease (self regulating, stabilizing)

-Positive feedback: an increase in output leads to a further increase in output (Destabilizing)

Feedback Effects

-Environmental Damage can be serious when people's use of environment leads to positive feedback.

-Some situations can have pos and neg feedbacks

System Responses (continued)

-Can be represented by a graph, each graph has mathematical equation that can explain the curve

-Linear growth- add a certain amount of individuals each year (forms line)

-Exponential growth-add a fixed proportion of population (forms J shaped curve)

-Calculation EG involved rate of growth measured as % and doubling time in years

-EG is a positive feedback and incompatible with sustainability

Oxygen and Liquid Water info

-Liquid water forms the basis of all life forms on Earth

-Water is an excellent solvent

-Water can break down into H+ and OH- ions

-Oxygen is a highly reducing gas (likes to combine with other molecules in processes that release energy)

-Living organisms store energy in molecules such as fats and sugars that release when combined with oxygen

-Oxygen gas comprises 21% of Earth's dry atmosphere (was almost absent in earth's early life)

-Non existent on Venus and Mars

Uniformitarianism

James Hutton (father of geology) Present is the key to the past, past is key to the future

Energy

-capacity to do work

-cannot be created or destroyed

-Can be converted:

1. Kinetic energy: energy of motion

2. Potential energy: positional energy, in chemical bonds, energy in matter

Laws of Thermodynamics

First law of thermodynamics- total amount of energy in the universe is constant (systems within can gain or lose)

Second Law: every energy transformation increases disorder (entropy)

-energy tends to go from more usable to less, least usable form is heat

Electromagnetic

Electromagnetic radiation- light, travels at the speed of light, amount of energy is determined by wavelength

Electromagnetic spectrum- full range of wavelengths

The electromagnetic radiation emitted by the Earth and the sun are both examples of black body radiation

Atmospheric Circulation

The seasons are caused by this phenomenon and the fact that the Earth is tilted (23.5 degrees( relative to the plane of its orbit around the sun

The mid latitudes receive about 3x more solar energy in summer compared to winter

In polar regions, the outgoing longwave radiation is greater than the incoming shortwave radiation

Density = Mass/Volume

Increased temp=decreased density

Increased pressure=increased density

System Responses

-Linear response—if you add the same amount of anything to a compartment in a system, the change will always be the same (If you add some salt to a glass of water the salinity will increase linearly)

-Nonlinear response—the effect of adding a specific amount of something changes, depending on how much has been added before (If you add 10 wolves to a forest, the amount of deer that they eat will depend on how many wolves were already in the forest)

-Lag time—the delay between a cause and the appearance of its effect

Oceanic Circulation

Wind-driven circulation-wind transfers some of its energy to ocean through friction

Coriolis turns water to the right]

Lead to formation of gyres (a large system of rotating ocean current)

Eastern and Western limbs of the subtropical gyres transport cold and warm water around the globe (warm and cool tropics)

Coastal Upwelling- brings cold, deep, nutrient rich water to surface (Eastern boundaries)

El nino and La nina

climatic patterns driven by changes in ocean circulation

What are biochemical cycles?

pathways for transport and transformation of matter within 4 areas that comprise the Earth ( they are the reason for the difference between Venus & Mars and Earth.

Element

a substance that cannot be broken down into simpler substances by chemical means (composed of atoms that have the same atomic number aka PROTONS)

Isotope

Atoms of an element with different numbers of neutrons and atomic masses

Some isotopes are radioactive, meaning they will spontaneously decay or break apart, releasing energy

Heat

- iskinetic energy of moving molecules

Transferred by:

- Conduction: direct transfer of heat

- Convection: warm (less dense) regions of a gas or liquid rise

- Radiation: matter loses heat by radiation, producing electromagnetic energy

- Latent heat transfer: heat transfer associated with phase transitions (melting, freezing, evaporation, condensation)

Other Types of Energy

Chemical energy: potential energy associated with the formation or breakage of bonds between atoms

Photosynthesis: converts electromagnetic radiation into chemical energy

Nuclear energy- energy contained in atom's nucleus (E=mass x speed of light^2)

Nuclear fission-splitting nucleus

Nuclear fusion-combining 2 nuclei

Energy Transformations

Greenhouse gases- clear to visible light but absorb long wave radiation

Examples...

-Water vapor

-Carbon Dioxide

-Methane

-Ozone

Albedo-reflectivity of an object (percent of light that gets reflected back)

Ion

electronically charged (+ or -) molecules or atoms

Elements

Carbon: basic building block of organic molecules, 4 bonds

Hydrogen: smallest and most abundant element, fills out organic molecules bc it only needs one bond

Oxygen: two bonds-strongly reducing (wants to steal electrons)

Nitrogen: 3 bonds-key elements in protein structure

Phosphorus: key element in cellular energy (ATP) and in CAN

Sulfur: Important component in amino acid proteins

Calcium: Mineral that serves a structural role

Iron: Used in proteins, often for transferring electrons

Atmospheric Circulation (continued)

Spinning planet exerts an apparent force known as Coriolis Effect (caused by the observer's moving frame of reference on the spinning earth)

Ocean retains more heat than land

Storms: areas of surface heating will lead to rising air

The area of rising air: Low Pressure Zone (Coriolis causes moving air to spiral)

Hurricanes: rotating masses of warm humid air--- leads to release of latent energy---which is converted to wind energy

The cause of all these atmospheric motions are imbalances in heating of the earth's surface; result of these motions is to even out the Earth's heat distribution

Types of Oceanic Circulation

Two forms:

- Surface currents (wind-driven circulation)

• Rapid

• Highly variable

- Deepwater flow (thermohaline circulation)

• Overturning ocean

• Long-term transport (1000 years)

• Driven by dense, sinking water

Organic Molecules

made of carbon atoms covalently bonded to other carbon atoms, and atoms of hydrogen , nitrogen, oxygen, and other elements (carbs, lipids, proteins, DNA, hydrocarbons

Thermohaline Cycle

- ocean conveyer belt that redistributes heat around the globe

- Slow circulation of the deep ocean

- Driven by density differences (not wind)

- Dense water (cold & salty) sinks in polar regions

- Replaced by upwelling in other regions of the world

Inorganic Molecules

without carbon-carbon bonds

Carbohydrates:

carbon, hydrogen, oxygen (sugars, like glucose)

Types of Biochemical Cycles

Biosphere - the living Earth

•

Lithosphere - the solid (or molten) Earth

•

Hydrosphere - liquid Earth (cryosphere is the frozen Earth)

•

Atmosphere - gaseous Earth

Lipids

long chains of carbon and hydrogen, one or more oxygen, from most cellular membranes, use energy storage

Hydrocarbons

inorganic molecules comprised of just C & H (methane , ethane, propane)

Macromolecules

combinations of small organic molecules

Polysaccharides

polymers (chains) of simple sugars (e.g. starch & cellulose)

Types of Bonds

Covalent bonds: strong bonds formed by sharing of electrons (equal or unequal)

Ionic bonds: strong bonds formed when one atom transfers its electrons to another

Dipole bonds: weak bonds formed between polar molecules (weaken when heated, strengthened when cooled)

Water molecule is polar (forms dipole hydrogen bonds)

Basic Chem Facts

Water can dissociate into OH- and H+ ions (acidity is high balance of H+)

pH is the -log((H+)), pH of 7=neutral 14=basic

Drainage Basin

fundamental unit of landscape (contributes to surface runoff to particular stream or river, vary in size)

Watersheds transport nutrients with water flows

Rock Weathering Cycle (continued)

Physical weathering (freeze, thaw) produces sediment such as gravel, sand, and silt

Chemical weathering occurs when weak acids in water dissolve chemicals from rocks

Initial chemical comp and specifics of formation determine chemical nature of rocks

Chemical and physical natures affects the elements released during weathering

Carbon Silicate Cycle

Cycling of carbon is involved with cycling of silicon

Weak carbonic acid falls as rain and weathers silicate rich rocks (transferred to oceans and used by marine phytoplankton, organisms sinking to seafloor become part of sedimentary rock layer)

Nitrogen Fixation

process of converting atmospheric N2 to NO3- or NH4+

Nitrogen Cycle

Nitrogen is essential to life bc it is necessary for the production of proteins and DNA

Free nitrogen gas makes up 78% of atmosphere (but most organisms cannot use it , performed by bacteria)

Almost all organisms depend on nitrogen converting bacteria

Ecosystem

a biological community of interacting organisms and their physical environment

Food Chains

Linkage of who feeds on whom. Energy, chemicals and some compounds are transferred from creature to creature along food chains.

Proteins

polymers of amino acids (nitrogen-containing organic molecules)

- There are 20 different amino acids found in all organisms

- Proteins are comprised of 100-1000 amino acids linked in a chain

- Proteins fold in on themselves into complex three-dimensional structures

- Proteins mediate most of the organism's functions

Nucleic acid-polymers of nucleotides (A,T,G,C)

Biology

Earliest forms of life got energy from fermentation

Prokaryotes are single celled organisms that lack cellular organelles *bacterial and archaebacterial

Eukaryotes: organisms that have membrane- enclosed structures in their cells (evolved after prokaryotic, multicellular)

Biogeochemical cycles often involve organisms interacting with abiotic (non living) portion of environment (nutrients, solar energy)

Plate Tectonics

Some continents seem to fit together like a puzzle, rocks of the same type from the same layer on different continents often have same fossils

Earth's crust is broken down into many different plates

-plates float on top of mantle

-movement is driven by convection in the upper mantle

-Plate boundaries are areas where plates come together

Plate tectonics explained diverse phenomena (jigsaw shape, fossil patterns, earthquakes, mountains)

Hydrologic Cycle

The transfer of water from oceans to the atmosphere to the land and back to oceans

Driven by solar energy:

- Evaporation of water from oceans

- Precipitation of water on land

- Transpiration of water by plants

- Evaporation of water from land

- Runoff from streams, rivers & subsurface groundwaters

Food Web is many food chains...

1st- Primary producers, aka autotrophs

2nd- Primary Consumers that feed on autotrophs (Herbivores)

3rd- Secondary Consumers, Carnivores, feed on Herbivores

4th- Tertiary Consumers, feed on Carnivores

Rock Weathering Cycle

Consists of numerous processes that produce rocks and soils

Rocks classified as:

- Igneous: formed through cooling and solidification of

magma or lava

- Sedimentary: formed by sediment that is deposited over time and compressed (glued together)

into layers of rock (limestone, sandstone, etc.)

- Metamorphic: formed from

another rock that has been

altered due to high temperature

& pressure (e.g. limestone[Symbol]marble)

Types of Competition

Competition: Interactions among organisms who compete for limited, shared resources.

Intraspecific competition- Members of the same species pursue shared resources

Interspecific competition- Organisms from different species also compete for shared resources

Interference competition: Aggressive actions designed to drive off a competitor

Exploitation competition: Competition for a shared resource

Herbivory and predation

Carbon Cycle

Anchors all organic substances, has a gaseous phase

Carbon enter biota through photosynthesis and then is returned by respiration or fire

- When organisms die, decomposition of their remains releases carbon

- If buried under certain conditions, carbon is not released

• Transformed into fossil fuels

- Clear cutting and burning of tropical rainforests releases carbon from the biota into the atmosphere

Most carbon in living biomass is found in terrestrial organisms

Carbon Cycle & the Ocean

Oceans , lakes, river contain 38,000 Pg C (more than terrestrial biota and soils combined)

Carbon enters the ocean by:

- Diffusion from atmosphere and then dissolves in the ocean

- Transfer from land in rivers as dissolved carbon

Carbon leaves the ocean by:

- Diffusion of gases out of the ocean

- Sinking (sedimentation) of particles to the bottom of the ocean

- Transport by organisms (e.g. seabirds) that feed in the ocean

Random eating terms

Herbivores: plants

Fructivores: feed on fruits,

Granivores: feed on seeds;

Many insects feed on pollen & nectar

Predation

Capture, kill, and consume other animals.

Two basic feeding strategies- Filter Feeding and Hunting

Types of Successions

Succession: Primary succession- Establishment and development of an ecosystem

where one did not previously exist (lava flow, edge of retreating glacier, etc.)

Secondary succession- Reestablishment of an ecosystem following disturbance (hurricanes, floods, fires)

Nitrogen Cycle(continued)

Industrial processes can now convert molecular nitrogen into compounds usable by plants (Haber process)

N combines with O at high temp

Human activities have doubled the rate of nitrogen exchange between the atmosphere and biosphere (agriculture, fertilizers, burning plants and fossil fuels

Phosphorus Cycle

Phosphorus is often a limiting factor for plant and algae growth

Needed for ATP (short term energy storage) and DNA & RNA

Does not have gaseous stage, abundant in Earth's crust, rate of transfer is slow

Phosphorus mining creates environmental problems

Overabundance in runoff causes pollution problems

Phosphorus Cycle(continued)

-Enters biota through uptake as phosphate by plants, algae, and some bacteria

- Returns to soil when plants die or is lost to oceans via runoff

- Phosphate is particularly important in lake and ocean environments where P (in the form of PO43‐) is often the limiting nutrient for

the growth of algae (phytoplankton)

High Biodiversity

greater genetic potential

Importance of biodiversity

Biodiversity of genes are tool which are used in many worldly purposes

Biomes

similar environments provide similar opportunities and similar constraints

Biodiversity Hotspots

places that have an unusually large number of endemic species

Threats to biodiversity

Habitat loss, habitat fragmentation (human activities subdivide once-continuous habitat into small fragments), Overharvesting ( exploitation of species with slow population growth), Non-native invasive species