SCI Section 1 Flashcards
What is environmental science?
the study of the impacts of human activities on environmental systems
What are examples of large–scale human activities that impact the environment?
clearing land for agriculture, fishing the oceans for food, mining land for minerals and duels, and changing the climate through greenhouse gases
What are examples of small–scale human activities that impact the environment?
driving a car, turning on your lights, and choosing single–use products over reusable products
What is an environment?
the sum of all conditions, living, and nonliving factors that surround an organisms
What is a local environment?
the area that immediately surrounds an organism
What is the global environment?
the sum of all aspects of Earth
What disciplines does environmental science cover?
biology, earth and atmospheric sciences, fundamental principles of chemistry and physics, human population dynamics, and biological and natural resources
What type of discipline is environmental science?
a science–based discipline
What is a science–based discipline?
a discipline based on the scientific method
What is a system?
a set of living and/or nonliving components connected in a way where one change can affect other areas
What might you use to determine if a person is healthy?
their body temp, heart rate, blood pressure, and respiration rate
What is an environmental indicator?
a measure that reflects the environmental health of a system
Is there a single indicator that assesses the whole planet?
No
The same environmental indicator can tell a different story depending on what?
where and when the measurement is taken
What are the 6 main categories of environmental indicators?
- Biological diversity
- Human population growth
- Food Production
- Resource Consumption
- Global Temp and atmospheric greenhouse gas levels
- Pollution levels
What is biological diversity?
the diversity of genes, species, habitats, and ecosystems on Earth
What can help us measure the biological status of the planet?
the number of species on Earth and whether that number is increasing or decreasing
What is a species?
a group of organisms that is distinct from others in morphology, physiology, or biochemical properties
What is morphology?
body type
How many known species are on Earth?
1.8 million
About how many species are there actually on Earth?
more than 10x more than the known number (known: 1.8 million)
Why is the actual number of species higher than the known number of species?
because most species haven’t been identified or cataloged yet
What percent of the total number of species that have ever lived on Earth are now extinct?
99.9%.
What periods of time are used to determine the background rate of extinction before humans played a role?
the quiet periods
What are the quiet periods?
Time periods with no massive environmental or biological upheaval
What are background extinctions now?
2 mammal extinctions per 10,000 species per 100 years
How much have humans accelerated extinction rates?
100x higher than background
What is the main cause of extinction today?
habitat degradation/loss
How many species per year are now going extinct?
roughly 40,000 species per year
The number of species on Earth is declining at a rate to rival what?
past mass extinction events
The Bengal tiger, snow leopard, and West Indian Manatee are all __________________ species.
endangered
What are endangered species?
species that are declining at a rate at which it will go extinct in the near future
The loss of which species can cause many other extinctions?
the keystone species
The extinction rate of species tells us what?
how biodiversity on Earth is increasing/decreasing, the state of land, water, and air
What can we conclude if we use species diversity as an indicator of environmental quality?
the environmental quality is getting much worse and is not sustainable
When did the global population reach 8 billion people?
November 2022
How babies are born each day?
378,000
How many people die each day?
148,000
How much does the human population increase each day?
230,000 people
Until which decade was the world population undergoing exponential growth?
the 1960s
How long is the human population predicted to increase?
50–100 years
What is the world population expected to be by the year 2150?
8–12 billion people
What is a major question regarding world population?
Can Earth sustain so many people?
The additional people will create a greater demand for what?
Earth’s finite resources
The additional people will also create what?
more pollution and waste
What type of crop provides more than half the calories eaten by humans?
food grains
What is worldwide grain production a result of?
land area under cultivation, quality of soils, energy, climatic conditions, human labor, water used for growing crops, and other influences
Therefore, a change in grain production for human consumption is what?
an environmental indicator
What are developed countries?
countries that have a stable economy, government, population, etc. Ex: the US, Canada
What percent of the population lives in developed countries?
20%
How much of the world’s resources do the poorest 20% use?
less than 5%
How much of all meat and fish do people in developed countries consume?
45%
How much of all energy do people in developed countries use?
58%
What are developed countries?
countries that have a stable economy, government, population, etc.
How much of all paper do people in developed countries use?
84%
How much of all automobiles and trucks do people in developed countries use?
87%
The gases that trap heat and warm the Earth are known collectively as ________________ _______.
greenhouse gases
Why are greenhouse gases called this?
because they act like a greenhouse by trapping heat
What are the 2 main greenhouse gases?
methane and carbon dioxide (CO2)
What is the primary activity that produces CO2?
the combustion of fossil fuels
For the past 130 years, global temperatures show an overall __________.
increase
The increase in carbon dioxide during the last 2 centuries is caused by what?
human activities
What does anthropogenic mean?
a result of humans or human activity
What is the chemical symbol for lead?
Pb
Why is lead so useful?
because it is soft, malleable, and resists corrosion
What is the definition of malleable?
the ability to be shaped easily
What part of the human body does lead impair?
the human central nervous system
What is particularly sensitive to lead?
developing brains, usually found in children and fetuses
The amount of lead in the environment is an indicator of what?
the amount of pollution that has been introduced to an environment
What fossil fuels contain small amounts of lead?
oil and coal
Lead was used as an additive to what fuel?
gasoline
Why was lead added to gasoline?
to improve engine performance
When did Clean Air Legislation begin?
1975
What did clean air legislation do?
it caused car manufacturers to switch to making cars that used unleaded gas, significantly reducing lead emissions
True or False: There is no more lead in gasoline.
False, even though lead stopped being used as an additive, gasoline, coal, and oil still contain some lead
Lead was also a major ingredient in ________.
paint
How does paint made after 1960 compare with paint before?
paint made after 1960 contains significantly less lead
Paint made before 1960 can be comprised of up to __% lead.
50%.
What is the main source of lead contamination in the US?
our drinking water
How does lead get into our drinking water?
through lead pipes and other plumbing material that corrodes, leaving traces of lead into the water
What type of water corrodes lead faster?
highly acidic water
Where is lead plumbing most common?
lower–income communities
What is the scientific method?
a method used by scientists to explore topics and conduct experiments
True or False: A simple experiment by college students follows the same principles as an experiment done by professionals.
True, they both follow the principles of the scientific method
What is the 1st step of the scientific method?
Observe and ask questions about the observations
What is the 2nd step of the scientific method?
Write a hypothesis that could answer the question being asked
What is the 3rd step of the scientific method?
Make a preliminary decision of whether the hypothesis is true or false using existing information
What is the 4th step of the scientific method?
Test the hypothesis with an experiment
What is the 5th step of the scientific method?
Accept, revise, or reject the hypothesis, and reconcile any differences between the predictions and the results
What is the 6th step of the scientific method?
Report your findings to others
What is the 7th step of the scientific method?
Replicate the experiment and see if there is much variation between the two
If a hypothesis is widely accepted, it becomes a __________.
theory
If a theory is widely accepted and can be applied universally with no exceptions, it becomes a __________ _______.
universal law
The First Law of Thermodynamics is an example of what?
a universal law
What is the First Law of Thermodynamics?
energy can’t be created nor destroyed, it can only change forms
1 hectare = ____ acre(s)
2.47
What is the experimental variable in an experiment?
the value being manipulated
When can a scientific experiment gain significance?
when it is repeated over and over again with similar or the same results
What is the control group in a scientific experiment?
the group the experimental variable is being compared to, the value that is not changed
To have a scientifically sound study, what is needed?
a large enough sample size
What type of relationship do the manipulation and result need in an experiment?
a cause–and–effect relationship
Will a simple correlation between the manipulation and the result in an experiment suffice?
No, they must have a direct relationship
The saying “A butterfly stirring the air in Beijing can affect weather patterns in New York a month
The saying ‘A butterfly stirring the air in Beijing can affect weather patterns in New York a month later’ describes what?
the interconnectedness of Earth’s systems
What is the study of the environment?
the study of its systems
In practice, systems are defined by whom?
the people looking at them
What are the interactions of systems and components within systems called?
system dynamics
What do environmental systems involve?
the exchange of matter/materials and energy
What is the most important material in environmental systems?
water
Where does all energy in environmental systems ultimately come from?
the Sun
A system can be one of which 2 states?
a system can be either open or closed
What is an open system?
A system where the exchange of matter or energy occurs
What is a closed system?
A system where the exchange of matter or energy doesn’t occur
Is the Earth system open or closed with respect to energy?
It is open because solar energy enters and heat energy exits
Is the Earth system open or closed with respect to matter?
It is closed because nothing ever leaves or enters Earth, except for the occasional spacecraft or meteor
Is the ocean open or closed with respect to matter?
Open, because sediments and nutrients enter through streams and water exits through evaporation
Is the ocean open or closed with respect to energy?
Open, because solar energy enters and energy from the ocean is transferred to other systems
What non–scientific, human areas affect environmental systems?
- Economics
- Social structures and institutions, including various levels of government
- Laws
- Policy
- Environmental advocacy and action
What is a system analysis?
an analysis on what goes in, comes out, and what has changed in a system
An analysis done on a checking account is very similar to what?
a system analysis
In a checking account, what is the sum of money you start with called?
your balance
What do system analysts call the starting value of what they’re analyzing?
a pool
Depositing money into a checking account is called a(n) ______.
input
What are amounts added to a system called?
inputs
What are amounts taken out from a system called?
outputs
Money that is taken away from a checking account is called what?
outputs
How do you determine your checkbook balance?
You start from the beginning and add inputs and subtract the outputs
What is a change in pool called?
a flux
What is a flux rate?
a flow per unit of time
What is a mass balance analysis?
an accounting of inputs and outputs to determine fluxes in a system
What is the formula for net flux?
Net Flux = Inputs – Outputs
What is the most important aspect of conducting an analysis?
Finding out if your system is in steady state
What is steady state?
When a system is in balance and the input equals the output
What is the net flux of a system in steady state?
Net Flux = 0
What is the first step of finding out whether your system is in steady state?
Find the size of the pool
What are the 2 ways to measure a pool?
Directly and estimation
When do you measure a pool directly?
When the pool is a size that can be easily measured or has an exact way of measuring it
When do you estimate the size of a pool?
When the pool is very large or doesn’t have an exact way of measuring it
How would you measure the size of a large or immobile pool?
Through estimation
How would you measure the size of a bucket?
Directly
How would you measure a flock of birds?
through estimation
How would you measure an ocean?
through estimation
What is the 2nd step of finding out if a system is steady state?
calculating the net flux
If a bucket of water has a pool size of 10L and water is flowing in at 1L/min and leaving at 1L/min, what is the Net Flux?
Net Flux = 0
Input = 1, output = 1
1–1=0
Is the water in the atmosphere at steady state?
Yes, because the amount that enters through evaporation is roughly the same as the amount that exits through precipitation
Are the oceans at steady state?
Yes, the water that exits through evaporation is roughly the same as the amount that enters through rivers and streams
Why would a community ban watering lawns and washing cars?
because their water supply is not at steady state, more is being taken away than can be replenished
Is a resource that is decreasing in size being used in a sustainable way?
No
Can one part of a system be in steady state while the other isn’t?
Yes
Is CO2 in the atmosphere at steady state?
No
Is the amount of CO2 in the atmosphere increasing or decreasing?
it is slowly increasing
What may you want to know if a system is not in steady state?
the rate it is accumulating or depleting material
Is a resource that is decreasing in size being used in a sustainable way?
No
Is the amount of CO2 in the atmosphere increasing or decreasing?
It is slowly increasing
What may you want to know if a system is not in steady state?
The rate it is accumulating or depleting material
What formula can you use to calculate accumulation or depletion rates?
The net flux formula:
Net Flux = Inputs – Outputs
Any change in simple systems involves what?
Simply increasing or decreasing inputs or outputs
For more complex environmental systems, what are the important factors?
The mechanisms that regulate the inputs and outputs
In regulatory systems, what does a change in the system lead to?
It either leads to further change or returns the system to or closer to its original state
If you notice your checkbook balance (pool) is decreasing, what might you do to combat this?
You may spend less money or work more hours
What are changes in behavior in response to certain events?
Feedbacks
What is a negative feedback loop?
When the feedback returns the system variable back to the starting point
What is a positive feedback loop?
When the feedback moves the system variable farther away from the stable point
What can a positive feedback loop be called?
A vicious cycle
Balancing your checkbook is an example of what type of feedback loop?
A negative feedback loop
A gambler gambling his life savings away is an example of what type of feedback loop?
A positive feedback loop
What type of feedback loop is Earth’s heating system?
A positive feedback loop and a negative feedback loop
How is Earth’s heating system a positive feedback loop?
Because warmer temperatures lead to greater evaporation and additional moisture in the atmosphere enhances heat–trapping gases, make Earth warmer, going in a cycle
How can Earth’s heating system be a negative feedback loop?
More evaporation leads to more cloud cover, which reflects sunlight and could lead to lower temperatures
Is the sum of all the loops in Earth’s testing system result in an increase or decrease in temperature?
It is unknown
What is the balance in many environmental systems dependent on?
The smooth operation of feedback loops
What occurs when the negative feedback loop in a system breaks down?
The environmental system gets sent away from its set point
What is a set point in a system?
The stable value for a parameter under examination
What is the final systems dynamics concept to consider?
The time between when a signal is generated and when it is received
What is an overshoot?
Exceeding the set point of a system
When a population’s birth rate is high, can the factors controlling compensate fast enough?
No
Disease and reduced fertility are two examples of what?
Factors that control a population’s birth rate
What is a carrying capacity?
The number of individuals that can be supported by their environment
What is usually the result of an overshoot in population?
A dramatic population crash from disease or starvation
What is a population?
A group of individuals of a single species
What is a population controlled by?
2 inputs and 2 outputs
What are the inputs in the size of a population?
Birth and immigration
What are the outputs in the size of a population?
Death and emigration
What is immigration?
People moving into an area
What is emigration?
People moving out of an area
What is the formula for net population change?
Net Population Change = Input – Output
What is the formula for input regarding population size?
Input = Births + Immigration
What is the formula for output regarding population size?
Output = Deaths + Emigration
In general, population change is more affected by which two factors as these outweigh the other factors?
Deaths and Births
True or False: Scientists find it easy to estimate birth rates.
True
What is the real challenge involving the size of a population and population change?
Determining how the inputs and outputs are regulated
What 2 factors usually regulate birth and death rates?
Various feedbacks, by abiotic and biotic components
How does less food affect a population?
It means less energy for females to put into reproduction, causing fewer births
In more complex systems, what may a population be regulated by?
The size of another
In predator–prey systems, the amount of predation will _____________ as the number of prey increases.
Increase
