Exam 2 Lecture Slide Content Flashcards
HYPOTHESIS, TESTING, & THE SCIENTIFIC PROCESS
What is a theory?
A theory is a broad, yet concise explanation for a wide range of phenomena. Often the generalized product of many hypotheses. Ex.) plate tectonics, natural selection
What are some characteristics of a theory?
-Reinforced and updated by a wide range of experiments and observational studies
-Predictive
What is a hypothesis?
A proposed explanation for a relatively narrow set of phenomena (ex.) addition of amendments to soil will have a significant and positive effect of plants ability to uptake lead)
What is a characteristic of hypothesis?
-Based on background info and/or initial observations
-Specific
-Testable
-Focused
What is the difference between the null and alternative hypothesis?
Null- there is no relation between variables
Alternative- there is a significant relation between variables
In regards to scientific testing, what is the difference between evidence and an argument?
-Expectation + Observation = Evidence; Evidence lends support to help refute without “confirming” with certainty
-Background Information+Expectation+Observation= Argument; Arguments can lead to the support, rejection, revision, or replacement of a Hypothesis
In regards to scientific testing, what is the importance of control?
Controlling variables is paramount in minimizing potential for error or interference between variables
In regards to scientific testing, what is the importance of assumptions?
Assumptions are fundamental in conducting experiments as they allow us to believe in the certainty of specific actions taking place
What are some ways that ideas and hypothesis are shared within the scientific community?
Peer review, replication and discussion, eliminating bias, feedback for publication
SOILS
What the five factors of soil formation?
Organisms, Topography, Time, Climate, Parent Material
What are the Soil Horizons in order?
-O Horizon (Loose and partly decaying organic material)
-A Horizon (Mineral matter mixed with some humus)
-E Horizon (Eluviation layer; zone of leeching)
-B Horizon (Accumulation of minerals transported from above)
-C Horizon (Partially altered parent material)
-R Horizon (Unweathered parent material Bedrock)
What are the three classes of soil?
Sand, Silt, Clay
How does particle size vary between the three soil classes? How do these particle sizes effect water retention in each class?
-Sand has the largest and grittiest particles
-Silt has the medium-sized smooth particles
-Clay has the smallest and stickiest particles
-Too much sand means that there is no small pores and no water retention, but too. much clay means that there is no large pores and no water drainage; happy medium is best for water retention!
In regards to water retention, what is the difference in gravitational water, capillary water, and hygroscopic water?
-Gravitational water: water that drains right through the soil
-Capillary water: water remaining in the soil that is readily available for plants
-Hygroscopic water: Remaining water that is held too tightly for plants to draw
What are the four pools of plant nutrients?
-Soil minerals (naturally occurring inorganic solids, major source of soil-supplied nutrients, longest term storage)
-Organic matter (contains carbon, storage of N and anions)
-Adsborbed nutrients (ions attracted to soil colloids, readily available to plants)
-Dissolved ions (ions in solution, the most readily available to plants)
What is cation exchange capacity?
-Cation Exchange Capacity: Gives an insight into the nutrient retention capacity of soil and the total capacity of soil to hold exchangeable cations; CEC is an important index of nutrient status because available cations are the most important source of immediately available plant nutrients
What are some functions of urban soil?
-Regulation of water flow and quality
-Carbon storage
-Reservoir for biodiversity
-Platform for buildings
-Support for food and biomass production
What are two examples of soil contaminants and their characteristics?
-Lead (Pb): Neurotoxin affecting cognitive development and is immobile (lead-based paint, gasoline emissions)
-Arsenic (As): Human carcinogen that is very slowly leeching through soils (pesticides, pressure treated lumber)
BIODIVERSITY
What is speciation?
Speciation: Process by which evolution generates new species. Speciation rates depend on number of current species and the development of new species from existing species.
What is allopatric vs. sympatric speciation?
-Allopatric speciation: When the population becomes geographically isolated from the parent population (ex.) when a river cuts between two tree populations)
-Sympatric speciation: When two groups live in the same area but become different species (ex.) mutation)
What is Extinction?
Extinction: When species fail to reproduce and no individuals remain
What is the difference between background vs. mass extinction?
-Background extinction: slow on-going rate of extinction
-Mass extinction: when extinction rate is much greater than background rate
What is Biodiversity?
Biodiversity: Number and variety of living organisms
How do we define biodiversity on an ecosystem level, species level, and genetic level?
-Ecosystem Level- Ecosystem diversity: variety in number of biomes and variation within ecosystems for types of organisms, habitats and processes
-Species Level- Species richness (number of species in an area)/species evenness (species distribution)
-Genetic Level- Genetic diversity: information in DNA and raw material for natural selection
What is Functional Biodiversity?
Functional Biodiversity: The value and range of species and their traits that impact ecosystem function; general consensus that there are more species near the equator and in oceans
When relating to species distribution, what is an endemic species? What is dispersal?
-Endemic Species: A species that is restricted to a particular geographic region and thought to have originated from there
-Dispersal: movement of individuals from their birth site to their breeding site (ex.) salmon)
What does the species-area relationship say?
Number of species in an area increases with the area size
What does the species-energy relationship say?
-In terrestrial biomes, net primary production peaks near the equator and declines with latitude
-In marine environments, the coastal areas follow terrestrial patterns but in deeper waters, biodiversity peaks at mid-latitudes
What is the difference in keystone and passenger species?
-Keystone species: controls the integrity of a community or ecosystem
-Passenger species: have a relatively small effect on ecosystems
What are three ways that humans utilize species diversity?
-Diffusing chemical coevolution: natural selection favors individuals that accumulate compounds effective against a wide variety of enemies
-Extremophiles: organisms that live in extreme environments
-Ethnobotany: how different groups of people use plants
What are some threats to biodiversity both human and nonhuman?
-Alien species: a new species to an ecosystem
-Invasive species: displace and threaten indigenous species
-IPAT equation: increased affluence and population reduce biodiversity
-Habitat conversion: changes in land use/cover
-Habitat fragmentation: break-up of continuous habitat
What is the Enemy Release Hypothesis?
-An alien species population grows rapidly if the number of pathogens in native range exceeds ones in naturalized range
What is Nutrient Loading?
idk
How has hunting and harvesting affected biodiversity?
-Creates empty ecosystems
-Human hunting creates a new form of natural selection
-Predator control reduces species that compete with humans for crops or game
How does climate change impact biodiversity?
-Since species have adapted to live within certain temperature ranges, warming temperatures can disrupt biodiversity patterns
What are the four factors to preserving biodiversity?
-Uniqueness: Unique genetic composition and knowledge
-Usefulness: commercial or cultural value
-Probability of extinction: how much effort is necessary
-Cost: economic cost of saving the species
What is the difference betwen In-situ v. Ex-situ conservation?
-In-situ: Preserves species in natural habitat
-Ex-situ: Preserves genetic material
CLIMATE CHANGE
What is the difference between weather and climate?
-Weather: temperature, precipitation, wind speed, cloud cover, etc. at a particular time and place
-Climate: patterns of weather conditions across an annual cycle
What is Radiative Balance? How does radiative balance affect temperature?
Radiative Balance is composed of long wave and short wave radiation that indicates the amount of energy available on Earth’s surface. Earth will heat up until the energy that it radiates away equals the amount of energy that it absorbs from the sun.
Equation: SW(in) + LW(in)= SW(out) + LW(out)
What is the Greenhouse Effect and how does it affect global temperature?
-Greenhouse Effect: Process through which heat is trapped near Earth’s surface in substances known as GHG
-If there was no atmosphere on Earth, the temperature would be far too cold to sustain human life. Because the atmosphere absorbs some of the heat and radiates it back down to Earth through the Effect, the planet is habitable.
What are Greenhouse Gases?
Greenhouse Gases: Gases in the atmosphere that raise the surface temperature of Earth.
What is the role of GHG in warming the planet?
GHG absorb outgoing Longwave radiation and re-emit in all directions warming the planet.
What is the Radiative Equilibrium?
Radiative Equilibrium: Energy In= Energy Out; Pertains to the idea that the Earth cannot keep absorbing energy indefinitely.
What is Radiative Forcing?
Radiative Forcing: An index of measuring the potency of GHG from the amount and frequency of infrared radiation that it can absorb. GHG potency is measured as the radiative forcing per molecule.
What are some ways that humans have altered GHG emissions?
-Humans have altered GHG emissions through agriculture- both in deforestation and agricultural management