Midterm #1 Flashcards
Define Science and Pseudoscience
Science: The collection of knowledge and the process for the collection of knowledge.
Science Focuses on questions of the natural and physical world and is grounded in evidence based decision making.
Pseudoscience is a tradition that tries to explain or predict natural and physical phenomena but
1) does not rely on measurable, verifiable evidence, and
2) invokes mysterious or unnamed mechanisms rather than known physical mechanisms.
Can you change pre-existing views in science?
Yes, when new information challenges existing views, conclusions can change to better align with the evidence.
Why is it helpful to develop a hypothesis when designing an experiment?
The hypothesis suggests an explanation for an observation, which can then be tested.
What is a treatment group?
A group of subjects that are exposed to the variable being tested
What is ecology?
The study of how organisms interact with each other and the enviornment?
What is the difference between abiotic and biotic organisms?
Abiotic are the physical or non-living components of an ecosystem (rain, amount of salt in the water)
Biotic are the living components of an ecosystem, meaning the organisms present (exchange of sugar between fungi, outbreaks of insects)
What is an ecosystem?
The interacting biotic and abiotic components present in a geographic area
What is a population?
A group of individuals of the same species that live in the same region and interac with each other
What is a species?
An evolutionary unit in nature, comprised of more populations that evolve as a union and thus share genetic and physical characteristics
Define “community”
The collection of species found in the same area at the same time
What is the order from the smallest to the largest of this?
- Individual (exp: Impact of diet)
- Population (exp: How sizes of human populations in Eurasia are projected to change)
- Species (exp: How advances in healthcare mitigate impact of alleles)
- Community (exp: How declines in bee’s are effecting human food)
- Ecosystem (exp: How fossil fuel by humans effect the atmosphere)
What is finite rate of increase for geometric growth (lambda)?
N0 = Pop Size at start and N1 for the size at the end of one breeding interval.
Anything >1.00 is growth and anything <1.00 is a decline
If the finite rate of increase (lambda) stayed the same, how would you calculate the finite rate of increase over a given number of years?
What is instantaneous rate of increase for exponential growth?
The growth rate at any moment. (Exponential growth)
You would use the instantaneous rate of increase which is symbolized by “r”
Anything >0 is growth
Anything <0 is decline
What is exponential (instantaneous) growth?
A growth pattern produced when r stays the same over time.
Occurs when there is no limiting factors. Happens more often in a new enviornment.
What is density-dependent growth?
Population growth that is limited by density dependent factors such as disease, predation, and access to food or other resources.
What is carrying capacity?
The population size that can be sustained over time in a particular habitat.
What are ecosystems services?
Goods and services provided to humans by the natural environment such as oxygen, high-quality and abundant water, productive soils, food and fiber, and recreational and spiritual resources.
What is an ecosystems niche? Fundamental Niche? and Realized Niche?
Niche: The range of conditions that a species lives in.
Fundamental niche: Spaces where a species could survive based on a set of conditions regarding that species’ range of physiological tolerances (abiotic conditions) The range of tolerance defines the fundamental niche.
Realized niche: Spaces within the fundamental niche where the biotic factors are also sufficient - and thus where the species could survive.
What is the difference between slow life history and fast life history?
Fast Life History: Animals with usually small body size who produce large numbers of small offspring. They usually produce offspring once before dying.
Slow Life History: Large body size who produce small numbers of larger better-developed offspring.
What is a disturbance?
An event that removes biomass
Define “biomass”
The total mass of living organisms in a specific area
What is habitat fragmentation?
The conversion of large continuous areas of native plant and animal communities to small fragments separated by tracts of human development.
What is a keystone species?
A species that has a disproportionately large impact on a community relative to its number
What are the three main factors that influence the distribution and abundance of individual species in nature?
- Abiotic conditions
- Biotic interactions
- Life history
What is primary productivity?
In most ecosystems, the amount of light energy captured by photosynthetic organisms.
What is gross primary productivity?
The total amount of primary productivity in an area, often reported as a rate with units of g/m2/year
Define net primary productivity (NPP)?
The amount of productivity present in biomass, often reported as a rate with units of g/m2/year
What is the human appropriation of net primary productivity (HANIPP)?
The amount of primary productivity used by humans, often reported as a rate with units of gigatons of carbon per year.
How is chemical energy stored long-term for photosynthetic organisms?
In the C-C and C-H bonds of sugars and other carbohydrates
What are the distinct levels of the food chain called?
Trophic levels
When measuring biomass present at each level what is the distribution of biomass?
How much biomass is present as you go up in trophic levels?
Only 10% is present at the next highest level.
What is the distribution of biomass in aquatic ecosystems?
It looks more like an inverted pyramids or an hourglass-shape
Why is there a variation in biomass between the different trophic levels in aquatic ecosystems?
In marine and freshwater environments, most primary producers are single-celled bacteria and algae that have extremely short lifespans and are readily eaten by primary consumers.
How much of the global NPP do humans consume?
Humans use around 25% of the planets total NPP.
What is parasitism?
a relationship between the two living species in which one organism is benefitted at the expense of the other
What is mutualism?
association between organisms of two different species in which each benefits
Define predation and provide an example?
The population dynamics of both lynxes and snowshoe hares are intricately linked. Lynx populations can thrive with high snowshoe hare densities that provide an abundant food source. As hare populations decline, lynx populations often decrease and relocate to new areas.
What is the primary way that plants contribute to the atmosphere?
They release oxygen through photosynthesis
Define “sink”
A long-term repository where a particular atom or molecule may remain for millions to hundreds of millions of years.
The input outpaces the output
What is dentirification?
A collection of metabolic processes in different bacteria and archaea species that results in the release of N2 as an end-product. Analogous reactions release N2 when biomass burns during wildfires.
Na
NA
What is a source?
When the output greatly outpaces the input.
What is a carbon sink?
A long-term repository for reduced carbon atoms (carbon atoms not in CO2)
What is a negative feedback loop?
An event or process that causes greenhouse gas concentrations in the atmosphere to drop, making climate change less extreme.
What is a positive feedback loop?
An event or process that causes even more greenhouse gases to be released into the atmosphere, making climate change even more extreme.
Define phenology
The study of the timing or seasonality of life events in organisms.
What is a phenological mismatch?
Changes in phenology that change the way that two species interact.
What green house gases are released as a result of human action?
Carbon dioxide (CO2) is released when humans burn coal, natural gas, and petroleum-based fuels, and methane
(CH4) is released when those substances are extracted from the Earth and processed.
What is occurring when “carbon dioxide absorbs solar radiation?”
CO2 molecules gain kinetic energy, meaning that they start moving faster and have a higher temperature.
What two forms does carbon exist on earth?
It exists in an oxidized and a reduced form.
Oxidized: In molecules like CO2 where carbon is oxidized, the electrons in the C-O bonds are far from the carbon atom.
Reduced: in proteins and other molecules where carbon is bonded to hydrogen (C-H) or to other carbon atoms (C-C), the electrons in the bond are shared equally and are thus closer to the carbon atom than they are in CO2, like so:
Why is climate change occuring?
Humans are oxidizing reduced forms of carbon at massive scales.
What kind of process does science follow?
Iterative process (past works inform the future work) - scientific method.
What method is used to generate Why? Questions?
Observations
Once we have a scientific observation, what is needed?
A question and then a hypothesis.
What is a prediction?
A statement of expected outcome of a test assuming the hypothesis is correct
Define the term “null hypothesis”
A statement that the effect being studied does not exist
What is the “counter-factual” in relation to science?
The counter-factual is what would have happened if you did something different. We do not know the counter-factual in science.
What is a time series?
A sequence of data points collected over time to study and analyze population size
What is geometric growth?
Involves reproduction at regular time intervals
What is logistic growth?
When a population grows at a decreasing rate as it approaches its carrying capacity
What are density-independent factors that can cause fluctuations in population size?
Often abiotic factors with no clear patterns (extreme weather, natural disaster, human disturbances)
What are the four key processes that cause changes in popuation size?
- Birth
- Death
- Immigration
- Emigration
inputs > outputs = growth
outputs > inputs = decline
inputs = outputs = dynamic equilibrium
When does growth happen?
When birth and immigration outweighs death and emigration
What does population decline happen?
When death and emigration outweight birth and immigration
What is an extremophile?
An organism that is able to live in extreme conditions. These organisms have amazing adaptations to survive within their niche but are generally unable to survive elsewhere.
What is an energy budget?
The trade-offs that organisms have when allocating their limited resources to different uses.
What is an ecological niche?
The position of a species within an ecosystem, describing both the range of conditions necessary for persistence of the species, and its ecological role in the ecosystem
What is a range of tolerance?
Conditions within which an organism can survive, grow, and reproduce
What is a realized niche shaped by?
Species interactions:
- Competition: An interaction in which two species that depend on the same limit resources have a negative effect on each other.
Interspecific - between species
Infraspecific - within a species - Predation
- Parasitism
- Mutualism
What is “exploitative competition”
The indirect competition between individuals or species for limited resources within an environment. If one competitor uses a resource, it is no available for competitors
What is interference competition?
Direct interactions between individuals r species that impede the access of competitors to essential resources.
What is “apparent competition”
Two or more prey species are indirectly linked through a shared predator. The presence of one prey species boosts predator numbers, increasing predation pressure on other species
What is the competitive exclusion principle?
Two species with identical niches compete, then one will inevitably drive the other to extinction.
What can competitors do to co-exist?
- Temporary co-existence (at a reduced carrying capacity)
- Competitive exclusion: One of the species disappears from that area
- Niche partitioning: Both species continue to co-exist, but they diverge to occupy slightly different ecological niches within the shared habitat.
What is a foundation species?
They provide an ecological foundation for many other species, even though they might not benefit from the interaction. (i.e. coral, trees, kelp)
What is the difference between autotrophs and heterotrophs and Chemoautotrophs
Autotrophs can “produce their own food”. They are primary producers who use sunlight for photosynthesis
Chemoautotrophs obtain energy by oxidizing inorganic substances (sulfur and ammonia) - found in extreme enviornments
Heterotrophs must consume other organisms energy and nutrients such as herbivores or decomposes
What are the signficant differences between the levels of consumers?
- Primary Consumers: Typically herbivores and consume primary producers
- Secondary consumers: omnivores or carnivores that consume primary consumers
- Tertiary Consumers: Feed on secondary consumers.
What is a limiting factor?
Any environmental or ecological factor that restricts the growth, distribution, or abundance of organisms within that ecosystem (abiotic or biotic factors)
What occurs regrading phosphorus during algal blooms
Phosphorus stays in the water. It sticks around.
What are the differences between pools, fluxes, and forms?
Pools: Are storage compartments or reservoirs (traditionally for longer periods of time)
Fluxes: Are exchanges between pools (inputs and outputs)
Forms: The physical/chemical states of a nutrient
What does net primary productivity represent?
The amount of carbon storage in plant biomass.
What is a disturbance?
Any physical or enviornmental event that disrupts the structure or function of an ecosystem
What is the intermediate disturbance hypothesis?
The highest species richness will occur at an intermediate level of intensity of frequency of natural disturbance because disturbance creates many habitats but does not drive many species extinct.
What is the order of return following a disturbance?
- Pioneer species: good at disperal, grow fast, short lived, thrive in poor/absent soil but help build soil. (Grasses and perennials)
- Intermediate species: Require some soil nutrients, grow moderatley fast, moderate dispersal, helps build soils. (grasses, shrubs, pines)
- Climax community species: Slow dispersal, long lived, require rich soils, great competitros (old growth tree’s)
What is succession?
The process by which the community of species and habitat in an area change over time
What s the intermediate disturbance hypothesis?
When disturbance is too low good cometitors outcompete other species
When disturbance is too high it prevents the establishment of new species
When disturnace is intermediate a balance between establishment and competitive exclusion occurs
What is species evenness?
It measures the relative abundance of the different species in a given area. Proportion of total individuals that each species has.
