Environmental Systems
In environmental science, what is a system?
A set of interacting components that function together.
Identify the four major Earth systems discussed in environmental science.
Geosphere, hydrosphere, atmosphere, and biosphere.
What is the continuous movement of nutrients through organisms and the environment called?
A biogeochemical cycle.
What distinguishes a population from a community?
A population consists of individuals of the same species, while a community contains populations of different species living together.
What four processes directly change the size of a population?
Births, deaths, immigration, and emigration.
Why can a change in one component of an environmental system affect another component?
Because the components of environmental systems are interconnected, and the output of one process may become the input of another.
Which Earth system contains the crust, mantle, and core?
The geosphere.
Why are primary producers especially important to the carbon cycle?
They remove carbon dioxide from the environment through photosynthesis and convert it into organic matter.
Two populations occupy the same-sized habitat. Population A contains 400 organisms and Population B contains 150. Which population has the greater population density?
Population A.
A population experiences 120 births, 60 deaths, 30 immigrants, and 50 emigrants. Does the population increase or decrease overall?
It increases by 40 individuals.
Calculation:
120 + 30 - 60 - 50 = +40
The law of conservation of matter states that matter is not created or destroyed. What does this imply about matter in an ecosystem?
Matter must be recycled or transferred between organisms and the environment rather than disappearing.
Compare evaporation and transpiration.
Evaporation is the conversion of liquid water into water vapor from surfaces, while transpiration is the release of water vapor from plants.
How do photosynthesis and cellular respiration have opposite effects on atmospheric carbon dioxide?
Photosynthesis removes CO₂, while cellular respiration releases CO₂.
A species nests at roughly equal distances from neighboring individuals because of territorial behavior. Which population distribution pattern is present?
Uniform distribution.
Under ideal conditions with abundant resources and few limiting factors, which type of population growth would most likely occur?
Exponential growth.
A change in one part of a system causes another change that eventually affects the original part of the system. What concept does this describe?
A feedback loop.
Rainwater enters the soil and eventually becomes groundwater. Which Earth spheres are directly interacting in this process?
The atmosphere, hydrosphere, and geosphere.
Phosphorus availability is naturally low in many ecosystems. What effect could this have on organisms?
Phosphorus can become a limiting nutrient, restricting organism or ecosystem productivity.
Animals gather primarily around a few available water sources in a dry environment. Which population distribution would most likely occur, and why?
A clumped distribution, because essential resources are concentrated in particular locations.
Why does logistic population growth slow as a population becomes larger?
As the population approaches its carrying capacity, resources become more limited and environmental resistance increases.
A decrease in vegetation causes less water to be released into the atmosphere, which may then affect precipitation. Why is this an example of an environmental system rather than an isolated event?
Because a change in the biosphere affects the hydrosphere/atmosphere, demonstrating interactions between connected components of Earth’s systems.
Water evaporates from the ocean, condenses into clouds, falls as precipitation, and enters an underground aquifer. Identify the processes in order.
Evaporation → condensation → precipitation → infiltration/groundwater storage in an aquifer.
Most organisms cannot directly use nitrogen gas from the atmosphere. What process makes atmospheric nitrogen biologically available, and what organisms are especially important in this process?
Nitrogen fixation is carried out primarily by certain bacteria.
Two habitats contain the same number of organisms, but one habitat has half the area of the other. How would their population densities compare?
The smaller habitat would have twice the population density because the same number of individuals occupy half the area.
A crowded deer population experiences increased disease transmission, while a wildfire affects the population regardless of how crowded it is. Classify each limiting factor and explain the difference.
Disease: density-dependent
Wildfire: density-independent
Density-dependent factors become stronger as population density increases, while density-independent factors can affect populations regardless of density.