BIO 121 Exam #1
What are the 3 types of heterotroph groups? How are they different from each other? (examples of each)
- consumers- eat other living things (primary eat producers, secondary eat primary, etc): humans, sharks, deer, birds, etc - detritivores & decomposers- break down non-living matter into smaller molecules; eat dead organic matter; scavenge waste & dead bodies: vultures, worms, mushrooms, etc
What is the pH of pure water?
7
Explain the components of the BIDE equation
B= birth rate I= immigration rate D= death rate E= emigration rate pop. growth rate= (B-D)+(I-E)
carrying capacity (K)
The maximum population size of a given organism that a given environment can sustain overshoot and dieback; negative feedback loop
What is the environment?
all living and nonliving things around you
What are the different types of ecosystem services?
cycling of nutrients, store and regulate water supplies, pollinate plants and control crop pests, provide recreation such as ecotourism, provide aesthetic amenities
What components are involved in calculating the ecological footprint?
food, shelter, mobility, goods, and services
biotic components of environment
living things around you
What has allowed human populations to grow at an exponential rate?
Changing human carry capacity- healthcare/medical advances; sanitation advances; agriculture advances; technological advances
How does the pH scale work?
H₂0 splits up, scale measures acidity and is logarithmic (each step in scale represents 10-fold change in H⁺ concentration
How is genetic diversity important in the context of rapid environmental change?
In rapid environmental change, genetic diversity occurs quicker and happens less as the population is lower with shorter lifespans; must adapt quicker in order to continue existing
Why were Thomas Malthus and Paul Ehlich wrong?
Malthus- 1798: "Essay on the Principle of Population Growth"- humans will overuse food supply, need to reduce birth rate Ehlich- 1968: "The Population Bomb"- similar warning, not enough food to support growing pop. "Green Revolution" has prevented this- drastically increased food production (new tech, new crop varieties, new farming practices)
What variables affect population growth? What components are in the BIDE model?
Natality- # of births in a pop. Mortality- # of deaths in pop. Immigration- arrival of individuals from outside pop. Emigration- departure of individuals from pop. B(birth rate) I (immigration rate) D (death rate) E (emigration rate) population growth rate= (B-D)+(I-E)
What are examples of autotrophs?
autotrophs/ producers: phytoplankton, plants
What is an ecological footprint?
cumulative area of biologically productive land and water needed by a person or population to provide resources and accept waste
fecundity
fertility
What is the difference between a generalist and a specialist? How does this affect their fundamental niche? (example)
generalist- wide niche specialist- shallow niche - generalists can live almost anywhere and thrive while specialists require a more specific environment (generalist- raccoon, specialist- panda)
How do humans modify the Phosphorous Cycle?
present in many fertilizers as it is a limiting nutrient for many plants; runoff leads to increase in phosphorous in water leading to eutrophication; detergents in waste water also lead to an increase in phosphates in waterways
What are some misconceptions about the nature of how science works?
science never proves anything is right, just produces data that supports theory; science is collaborative (involves many people); theories can be altered or rejected
Where are the largest stores (sinks) of Carbon?
sedimentary rock (oceans-2nd)
allopatric speciation
species form in the aftermath of the physical separation of populations over some geographic distance
What is succession? What causes succession to occur?
succession- A stereotypical series of changes in the composition and structure of an ecological community through time - severe disturbances may eliminate all or most of a species in a community, initiating series of changes called succession
environmental science
the study of how the natural world works, how environment affects us, and how we affect the environment
How do TFR, life expectancy, and age structure affect population growth?
↑ TFR, ↑ pop. growth (more children) ↑ life expectancy, ↑ pop. growth (people still alive as new generation is born) ↑ proportion of pre-reproductive age people, ↑ future pop. growth
What are the largest stores (sinks) of Nitrogen?
atmosphere (78%)
independent vs dependent variables
both variables change; independent variable- variable manipulated by scientist, dependent variable- variable measured by scientist predicted to change based on independent variable
resistance vs resilience
both work to retain original state; both fight against disturbance resistance- a community that resists change & remains stable resilience- community that is changed by disturbance but returns to its original state
What are the building blocks of life?
macromolecules
convergent evolution
The evolutionary process by which very unrelated species acquire similar traits as they adapt to similar selective pressures from similar environments
What is sustainability? What are some things you can do personally?
The practice of living within our planet's means so that Earth can sustain us and all life for the future Use less water, More plant-based diet, Get vaccinated, Family planning in future, Get an education (one day teach children)
What do algae have to do with eutrophication?
algae booms, producing lots of O₂ & allowing life to grow and thrive; when they die, O₂ drops & marine life dies
What is biocapacity?
amount of productive land available to generate resources and absorb waste
What spheres are involved in the Carbon Cycle?
atmosphere, biosphere (plants, animals, marine life, soil), hydrosphere (oceans, rivers), lithosphere (fossil fuels, sedimentary rock)
What spheres are involved in the Phosphorous Cycle?
atmosphere, biosphere (soil, plants, marine life), lithosphere (sedimentary rock), hydrosphere (oceans, rivers)
What spheres are involved in the Nitrogen Cycle?
atmosphere, hydrosphere (oceans, rivers, & groundwater), biosphere (soil, plants, marine life, industry & automobiles), lithosphere (fossil fuels, sedimentary rock)
autotroph vs heterotroph
both are organisms in biosphere; both use process to gain energy autotroph- organisms that directly take energy from sun's radiation to produce food (photosynthesis & cellular respiration) heterotroph- organisms that gain their energy through consumption of other organisms (cellular respiration)
source vs sink
both are reservoirs; both in all spheres source- when a reservoir releases more materials than it accepts (short resistance time, large flux) sink- when a reservoir accepts more materials than it releases (long resistance time, short flux)
covalent vs ionic bonds
both bonds that can create molecules and compounds covalent- occur when atoms share electrons (non-metal atoms) ionic- occur when atoms of different charges combine (usually metal and non-metal atoms)
hypothesis vs theory
both data-driven, both can be adjusted or rejected; hypothesis tested repeatedly; if hypothesis survives repeated testing and consistently predicts experimental outcomes accurately, may be incorporated into a theory; theory- widely accepted, well-tested explanation of cause-and-effect relationships that have been extensively validated
extirpation vs extinction
both have to do with loss of species; extirpation leads to extinction extirpation- loss of species from one area, but not the entire world extinction- disappearance of a species from the planet
kinetic vs potential energy
both types of energy; energy constantly being converted between these 2 forms potential- energy of position (stored in body through chemical bonds called chemical energy) kinetic- energy of motion
What are the first and second laws of thermodynamics?
first law- energy can change forms, but cannot be created or destroyed; second law- nature of energy is that it will change from more ordered to less ordered state
What are the largest stores (sinks) of Phosphorous?
rocks, soil, sediments, and the oceans
What processes are involved in the Phosphorous Cycle to transfer nutrients from one sphere to another?
weathering, precipitate & burial, uptake (marine life and plants), decomposers
***Why is the water cycle important for understanding other cycles?
***involved in every cycle?
What are the major causes of biodiversity loss?
- habitat degradation: small habitats , less connection between habitats (considered greatest threat to biodiversity today) - pollution: air, noise & light, water - overharvesting: harvesting a pop. at a rate that is unsustainable (poaching) - invasive species: non-native species introduced to new environments, can proliferate & displace native species - climate change: w/ warming temps causing some animals to shift their ranges poleward or higher in elevation, organisms already living here (polar bears) have nowhere left to go & are especially vulnerable
r-selected vs k-selected species
- both 2 extremes on same continuum of strategies that have been produced by natural selection r-selected species: unstable environment, density independent - small size of organism, energy used to make each individual is low, many offspring are produced, early maturity, short life expectancy, each individual reproduces only once, type III survivorship K-selected species: stable environment, density dependent interactions - large size of organism, energy used to make each individual is high, few offspring are produced, late maturity (often after prolonged period of parental care), long life expectancy, individuals can reproduce more than once in their life, type I or II survivorship
What are some examples of how we are attempting to conserve biodiversity?
- laws and treaties: Endangered Species Act of 1973; 1973 Convention on International Trade in Endangered Species of Wild Fauna & Flora (CITES); Convention on Biological Diversity - captive breeding and reintroduction: zoos & botanical gardens breed & raise w/ intention of reintroducing their progeny back into the wild - flagship & umbrella species: protection of umbrella species helps to protect many others; environmental organizations use large charismatic vertebrates as flagship species to promote conservation (giant panda) - habitat restoration & protected areas: parks and preserves= protected areas that seek to maintain habitats & ecological services (area of ocean now being set aside too); ecosystems can also be restored by reestablishing natural processes that were interrupted by human development - community based conservation: actively engages local people (community science, environmental ethics); approach will be vital to preserve biodiversity in face of growing future human populations
What makes something a species? (Explain different species concepts) Which is most widely used?
- morphological species concept- based on observable & measurable physical traits - ecological species concept- classified in terms of ecological niche, role in ecosystem, & unique adaptations - phylogenetic species concept- set of organisms w/ a unique genetic history, based on DNA sequences - *biological species concept*- have potential to interbreed & produce fertile offspring **biological most widely used as general definition
What are the goals of ecological restoration?
2 aims: 1. restore functionality of ecosystem 2. return community to its "pre-settlement" condition
sustainability
A guiding principle of environmental science, entailing conserving resources, maintaining functional ecological systems, and developing long-term solutions, such that Earth can sustain our civilization and all life for the future, allowing our descendants to live at least as well as we have lived.
natural resources
Any of the various substances and energy sources that we take from our environment and that we need in order to survive.
Why is the Chesapeake Bay having problems with eutrophication?
Bay polluted w/ N&P nutrients from fertilizing, animal manure, and fossil fuel combustion; commercial harvesting reduced oyster populations
Why is genetic diversity important to natural selection?
Diverse gene pool gives a population more flexibility to survive in a changing environment; The more genetically diverse a population, the more ways it has to adapt
How does the overshoot day relate to the earth's biocapacity?
Earth overshoot day- the day of the year when we have surpassed earth's biocapacity
What is the Endangered Species Act?
Endangered Species Act of 1973 offers protection to species that fall within 2 categories: - endangered (in danger of becoming extinct in near future) - threatened (likely to become endangered soon) forbids US gov't & citizens from taking actions that destroy individuals within identified species
What is eutrophication and what causes it?
Eutrophication- The process of nutrient enrichment, increased production of organic matter, and subsequent ecosystem degradation in a water body; over nutrition in a lake or body of water causes it- run off from the land then excesses in waterways then plants grow then algae booms then algae dies and O₂ drops and fish and other animals die.
How does family planning influence population growth? (explain using birth control and contraception as ex)
Family planning decreases pop. growth because w/ access to contraceptives and birth control, women are better able to control when they have children, usually later in life, limiting the # of children they have, bringing the TFR down
What processes are involved in the Carbon Cycle to transfer nutrients from one sphere to another?
GPP, respiration, burial of marine life, volcanic emissions & extraction, ocean-atmosphere exchange (weathering, fossil fuel combustion, deforestation)
Describe the IPAT model and how it relates to human population growth
I= impact on the environment P= population A= affluence (wealth) T= technology population growth increases environmental degradation & leads to unsustainable resources use (cut forests, deplete biodiversity, hunt endangered species)
Why is net primary productivity (NPP) important to ecosystems?
NPP- energy that remain after respiration (NPP=total energy-respiration); shows how much energy will be gained from eating something based on level of ecosystem consumers is eating from
How does China's sex ratio differ from the world's?
Sex ratio- M:F World: 106M:100F China- 116M:100F (due to one-child policy; leaves more males single- more likely to engage in risky behavior)
Do organisms try to match their environment? Can they change the way they are genetically programmed to be better suited to their environment?
Yes (like in bunny lab- bunnies matching environment more likely to survive) Yes, certain trait can be chosen based on natural selection; selection patterns can change to increase survivability
Can evolution occur quickly enough for us to see it happen in out lifetime? What organisms evolve rapidly?
Yes it can evolve rapidly- organisms with short lifespans (flies, bacteria, rodents), when strong selective pressures, adaptive radiation (COVID and how there's talk of new strands that the vaccine won't work against)
How does biodiversity provide ecosystem services?
air & water purification, pollution, controlling pests & disease; loss of keystone species & ecosystem engineers can affect countless other species
ions vs isotopes vs neutral element
all are atoms involving protons, neutrons, and electrons; none lose protons ions- atoms that are electrically charged due to addition or subtraction of electrons: + or - isotopes- occur when nucleus of atom contains different # of neutrons & therefore a different atomic weight: ↑ or ↓ in weight neutral element- has the normal amount of neutrons expected for element and all electrons
nitrogen fixation vs nitrification vs denitrification
all involve nitrogen; all are processes allowing nitrogen to move thru spheres by plants nitrogen fixation- N₂ combined w/ H₂ to form ammonia (NH₃), whose water-soluble ions of ammonium (NH₄⁺) can be taken up by plants nitrification- process preformed by bacteria which converts ammonium ions into nitrite ions (NO₂⁻), then into nitrate (NO₃⁻) ions, which plants can directly take up convert nitrates back into nitrogen gas, releasing it back into the atmosphere and completing the cycle
biocentric vs anthropocentric vs ecocentric (domains of ethical concerns)
anthropocentrism- human centered view (determine costs and benefits only in relation to effect on human life), biocentrism- life centered view (determine costs and benefits in relation to effect on human and non-human life), ecocentrism- system centered view (determine costs and benefits in relation to effect on whole system, living and non-living)
environmental ethics
application of ethical standards to relationships between humans and non-humans
background extinction
background extinction rate- pace at which organisms independently go extinct - "natural" rate, prehuman→ currently 100-1,000x higher
Explain in a stepwise fashion how an ecosystem could change from a rocky habitat with no soil to a climax community. Explain what sort of plants/animals colonize at each step along the way
bare rock→lichens (secrete acids that break down rock, beginning process of soil formation→ (pioneer species) grasses, small herbs, & forbs begin to grow→shrubs & fast-growing trees→ shade intolerant trees→forest of shade-tolerant trees &animal life
Why should we conserve biodiversity?
biodiversity provides potential new or unused food resources; boosts tourism & recreation, biodiversity provides ecosystem services & functions, organisms provide drugs & medicines, people have a connection w/ nature
How biodiversity can include species diversity, genetic diversity, and ecosystem diversity
biodiversity- variety of all life across all level of biological organization (encompasses all of these) - species diversity- # or variety of species found in a particular area - genetic diversity- differences in DNA composition among individuals in a population - ecosystem diversity- # & variety of of ecosystems, communities, & habitats
What are the 4 spheres? What areas of the environment do they span?
biosphere- consists of all planet's biotic and abiotic entities interacting in a system; lithosphere- the rock and sediment; atmosphere- the air surrounding the planet; hydrosphere- all water including fresh and salt; liquid, solid, and vapor; surface, underground, and atmospheric
negative feedback loop vs positive feedback loop
both feedback loops (when system's output becomes input to that system- circular process) negative feedback loop- occurs when output of system moving in one direction acts as input to move system in opposite direction (increase in variable leads to decrease in same variable; "stabilizing system") ex: temp in body; predator-prey positive feedback loop- occurs when output from system moving in one direction acts as input to continue moving system in same direction (increase in variable leads to increase in same variable) ex: glacier melting; pop. growth
manipulative experiment (controlled study) vs natural experiment (observational study)
both focus on how independent variable affects dependent variable both show data and don't PROVE anything; manipulative experiment- independent variable manipulated by scientist while all other variables intentionally kept constant, directly tests causality; natural experiment- independent variable varies naturally instead of being manipulated, unable to fully control all variables, tests correlation
primary vs secondary succession
both have to do w/ alteration of a community; both involve pioneer species primary succession- occurs when disturbance removes all plant or soil life secondary succession- begins w/ disturbance that alters community but leaves soil life intact
Density dependent vs density independent limiting factors
both keep pop. regulated, seen in nature density dependent- influence scales w/ pop. density (ex: disease, competition, predation) density independent- influence is not related to pop. density (ex: temp, natural disasters)
net primary productivity (NPP) vs gross primary productivity (GPP)
both measuring amount of energy organism has GPP- total amount of energy produced by autotrophs NPP- energy that remains after respiration (NPP=GPP-respiration)
Artificial selection vs natural selection
both select for certain traits, traits carry on in population natural selection- inherited characteristics (genes) that enhance survival and reproduction are passed on more frequently to future generations (nature, survival of the fittest) artificial selection- occurs when humans breed organisms that have traits we like & cull organisms w/ traits we don't like (forced, traits may not be best for survival)
species richness vs species evenness
both species diversity; both focused on #s species richness- # of species species evenness- how much species differ from each other in #s of individuals
open system vs closed system
both systems (network of relationships the interact w/ & influence one another) open system- energy can be exchanged w/ surroundings (mass of system changes over time) closed system- energy cannot be exchanged w/ surroundings (mass of system remains constant)
photosynthesis vs cellular respiration
both use same elements and molecules in process; both occur in autotrophs; both somehow release energy photosynthesis- only autotrophs, 6CO₂+6H₂O+sun's energy→C₆H₁₂O₆+6O₂ cellular respiration- autotrophs & heterotrophs C₆H₁₂O₆+6O₂→6CO₂+6H₂O+energy
What is a community and how is it different from a population?
community- an assemblage of populations of interacting species that inhabit the same area - community is many populations
What are the different types of species interactions? (example of each)
competition (specialist vs generalist- panda v raccoon; fundamental vs realized niche- adaptive radiation vs new species using resources) exploitive interactions: predation (fox v squirrel), parasitism (tape worm v human), herbivory (giraffes v leaves) mutualism (hummingbird v flower)
What is competitive exclusion? How is it different from resource partitioning?
competition exclusion- 2 species using exact same resource cannot coexist in long term- one will always win & exclude other resource partitioning- individuals use shared resources in different ways
What is competition? What causes competition?
competition- occurs when each participant negatively affects other by taking resources - competition occurs because of overlapping niches
conservation biology
conservation biology- a study that seeks to understand the factors, forces, & processes that influence the loss, protection, & restoration of biological diversity - integrates field data, lab data, theory, & experiments - use genetic data to determine min. viable population size to reduce consequences of inbreeding depression
What is evolution?
consists of changes in populations of organisms from generation to generation
What is primary production?
conversion of solar energy to sugars through process of photosynthesis
Difference between correlation and causation
correlation ≠ causation; correlation- statistical association, causation- one event leads to another (evidence with controlled variables)
What type of experiments might provide correlation or causation?
correlation- natural experiments, causation- controlled experiments
How do humans modify the water cycle?
damming rivers slows movement off water & increases evaporation; removing vegetation increases runoff & erosion and decreases infiltration & transpiration
What is the demographic transition model? What happens during each stage?
demographic transition model- process that has taken some pop. from Pre-indutrial to Post-industrial stage - pre-industrial: death rates ↑ due to widespread disease, bad health care, & unreliable food supplies; people compensate for ↑ infant mortality by having many kids; pop. growth: steady (B=D) - transitional: death rates declining due to food production & health care; birth rates remain ↑ as society has not yet adjusted to new economic conditions; pop. growth: very high (B>>D) - industrial: employment opportunities increasing for women & birth control becomes more widely available, declining birth rate; pop. growth: slows & begins to stabilize (B>D) - post-industrial: pop. growth: stabilizes or begins to shrink (B=D)
What is disturbance? What does disturbance do to the ecosystem?
disturbance- any event that alters environmental conditions in a way that alters the community & ecosystems -facilitates invasion: opens new habitat; humans modified habitats; makes extreme environments more friendly (nutrient additions to low nutrient streams, lakes, coastal environments); stresses native species- become less competitive
population bottleneck
drastic reduction in population size; can randomly remove certain genes; lose genetic diversity
How does a person's ecological footprint relate to their biocapacity?
ecological debt/deficit= ecological footprint > biocapacity ecological reserve= ecological footprint < biocapacity
How does species diversity relate to ecosystem diversity (Give an example)
ecosystem diversity is important for more species diversity (terrestrial→tree richness (# of species))
What are ecosystem engineers? What are Keystone species? How are they different in their effects on the ecosystem?
ecosystem engineers- organisms that significantly modify habitats Keystone species- organism (often top predator) that has disproportionate effect on environment ecosystem engineers: result- increase biodiversity by creating new habitats Keystone species: if removed, effects will ripple thru food web & alter community
What are ecological/environmental consequences of overpopulation? How does poverty negatively impact the environment? How does wealth negatively impact the environment?
environmental degradation (other things to worry about, intense farming- soil degradation- desertification, waste not disposed of safely, large pop. lead to unsustainable resource use (cut forests, deplete biodiversity, hunt endangered species) poor nations= ↑ pop.- increases environmental degradation, unsustainable resource use, desertification wealth- ↑ ecological footprint- enormous resource consumption & waste production (use resources from other areas, as well as their own)
environmental science vs environmentalism
environmental science- study of Earth and human interactions (unbiased, data-driven); environmentalism- social movement/ ideology (lobbyists/ activists, often have agenda); skepticism about environmentalist agenda can be a barrier to the message from environmental science
mass extinction event
events that eliminated 1/2 of the species on the Earth - 5 have already occurred, in the midst of 6th due to human impacts
What is an example of a keystone species? How do people know they are a keystone species?
ex: sea otter; know because of trophic cascades- if a top predator is lost suddenly, primary consumers will over consume & alter entire community
Exponential vs. Logistic Growth
exponential: assumes that growth rate remains constant; J-shaped curve, population growth accelerates over time; positive feedback loop logistic: populations are regulated & growth rate changes; S-shaped curve, limiting factors influence growth
What are the consequences of a skewed age distribution?
extremely old population: shrinking population, creates strain on social welfare programs in some countries, as fewer young workers are supporting more elderly extremely young population: potential rapid future growth, not enough resources to support exponential growth
How is it possible that census population size continues to increase, even though the population growth rate is decreasing?
fertility rates have declined dramatically in nearly every region of the world (except Africa) over past 50 years; however, decrease in infant mortality rate and increased life expectancy increases census population (old people still alive as children are born and survive)
What is a food web? How is it different from a food chain?
food web- A visual representation of feeding interactions within an ecological community that shows an array of relationships between organisms at different trophic levels - more accurate representation than food chain; show feeding relationships w/ many potential paths; all interlinking food chains within a community
What are some ways technology harms the environment? What ways does it help?
harms- chemical pollution, light & sound pollution, deforestation, climate change, weapons, tech increased population growth, damming rivers helps- recycling, help endangered species, cleaning water, decreases TFR in long run, control of invasive species, education about environment, green solutions to energy (solar power)
How does the amount of hydrogen ions and hydroxide ions relate to acidity?
high concentration of hydrogen ions- acidic solution; high concentration of hydroxide ions- basic solution
fitness
how well an organism can survive and reproduce in its environment
What spheres are involved in the water cycle?
hydrosphere (oceans, rivers & lakes, groundwater, ice caps & glaciers & snowfields, soil), atmosphere & biosphere
What is inbreeding depression? Why are small populations more vulnerable to environmental change?
inbreeding depression- loss of genetic diversity resulting from breeding of related individuals - small pop. have little genetic diversity, pop. w/ little genetic diversity= less able to adapt to environmental change, as they lack raw materials needed for natural selection
Give 2 examples of how biodiversity is unevenly distributed
increases as one approaches equator due to: higher GPP, stable climate, lack of glaciation events; diverse habitats, like forests, - generally more biodiverse (all species→animals→ insects→ants)
What are limiting factors? Why are they important?
limiting factors: factors that keep the population from growing past carrying capacity keeps the population from growing beyond means of environment ex: resource limitation, abiotic environment (temp), predators, competitors, parasites, disease
What is the law of conservation of mass?
matter can be transformed but not destroyed or created
Why does "energy flow" but "matter cycles"? Where is energy flowing? Where does energy come from?
matter is all material that has mass and takes up space, it is never created or destroyed just transformed (cycles); energy is the capacity to change position, physical composition, or temperature of matter, converts between potential and kinetic energy (flows from one form to other); energy comes from the need to change
examples of things people can do to decrease their footprints
more plant-based diet, carpool, take the bus, use less water (turn off while brushing teeth & washing hands, shorter showers), turn off lights
Why is ecosystem diversity important?
more variety for different species' needs; more niches; more species diversity
Natural selection & 3 important things must be true about a population in order for natural selection to occur
natural selection- inherited characteristics (genes) that enhance survivability & reproduction are passed on more frequently to future generations (survival of the fittest) 1. organisms face a constant struggle for survival 2. organisms produce more offspring than can survive to reproductive maturity 3. individuals vary in their attributes (4. attributes are heritable via genes)
What are the mechanisms of genetic change?
natural selection- inherited characteristics (genes) that enhance survival & reproduction are passed on more frequently to future generations (larger pop- slower change) mutations- accidental changes in DNA that happen when DNA is being copied (small pop- seen more) artificial selection- occurs when humans breed organisms that have traits we like & cull organisms w/ traits we don't like genetic drift-when random chance causes one allele to increase in a population, even if there's no fitness benefit due to random survivability (small pop- more dramatic) bottleneck- drastic reduction in population, can randomly remove certain genes gene flow- movement of individuals & genetic info they carry from one population to another (migration can be very important source of genetic variation) sexual selection- occurs when one sex prefers to mate w/ individuals of other sex
What are niches? How is the fundamental niche different from the realized niche?
niche- thought as set of requirements that allow an organism to thrive - fundamental niche- all environmental conditions in which a species can live - realized niche- conditions in which species actually lives (possible environment vs actual environment)
What cycles are most important for understanding eutrophication?
nitrogen and phosphorous cycles (availability of N&P is often a limiting factor in aquatic systems, increases in these nutrients can cause eutrophication)
How are organisms (the biosphere) especially important for the carbon and nitrogen cycle?
nitrogen cycle- plants take up ammonia; bacteria form nodules on plant roots, absorbing sugars from roots in exchange for nitrogen fixation; denitrifying bacteria convert nitrates back into nitrogen gas, releasing it back into atmosphere & completing cycle carbon cycle- producers pull CO₂ out of air and use it to produce glucose; plants consume organic molecules & release some of carbon as CO₂; aquatic animals die and remains settle in sediments that turn into rocks
How do humans modify the Nitrogen Cycle?
nitrogen fixation now occurs more quickly than denitrification leading to more nitrogen per hectare of land; nitrogen runoff & eutrophication are a huge problem (ex. Chesapeake Bay or locally- Actin Lake in Hueston Woods)
What processes are involved in the Nitrogen Cycle to transfer nutrients from one sphere to another?
nitrogen-fixing by lightning, fixation by crops, nitrification, denitrification (also emissions, runoff, assimilation, extraction and combustion)
abiotic components of environment
non-living things around you
How does eutrophication lead to death zones?
nutrient pollution = increase in nutrients that lead to eutrophication = marine life dies = dead zone
What are the steps of the scientific method and what happens in each step?
observations (notice something you become curious about), questions (asking what you want to know), hypothesis (educated guess as to what the answer is), predictions (guessing what the data will show), test (performing experiment), results (reject hypothesis- form a new one; fail to reject hypothesis- test new prediction)
Where are the largest stores (sinks) of water?
ocean (97%)
What are pioneer species? How are they involved in succession?
pioneer species- A species that arrives earliest, beginning the ecological process of succession in a terrestrial or aquatic community - succession begins w/ colonization of pioneer species because they spread over long distances easily & are adapted for growing quickly
Describe the process of photosynthesis
plants take in water from roots, absorb CO₂ from air thru leaves, and harness power of solar radiation to generate sugars and oxygen 6CO₂+6H₂O+sun's energy→C₆H₁₂O₆+6O₂
Define population distribution, density, growth, and how they might be used to understand population dynamics
population distribution- special arrangement of organisms in an area population density- # of individuals per unit area population growth- rate of change in population per unit time can be used to understand distributions, demographics, etc
"Individuals don't evolve, but populations do" Why was Lamarck incorrect?
populations have genetic diversity, allowing for one trait to be selected for over others, and with more people, that trait is able to be selected for; individual doesn't have variation, need more people for variations (if trait doesn't vary, evolution can't change it, even if changing it would make organisms more fit) Lamarck was incorrect because he believed an individual could change and pass that change to their offspring (not the case)
What processes are involved in the water cycle to transfer nutrients from one sphere to another?
precipitation, evaporation, transpiration, infiltration (also runoff, groundwater flow, extraction & human use, & uptake)
What ecosystems have the highest NPP?
primary producers
How are primary succession and secondary succession different in what they start with?
primary succession- occurs when disturbance *removes all plant or soil life* secondary succession- begins w/ disturbance that alters community but *leaves soil life intact*
Age structure diagram
pyramid w/ wide base: large proportion of pre-reproductive age people & potential for rapid future growth pyramid w/ even age distribution: stable pop. pyramid w/ higher proportion of pos-reproductive age adults: shrinking population
How is a K selected species different from an r selected species? (examples) Do all organisms fit into these categories?
r-selected species: unstable environment, density independent - small size of organism, energy used to make each individual is low, many offspring are produced, early maturity, short life expectancy, each individual reproduces only once, type III survivorship K-selected species: stable environment, density dependent interactions - large size of organism, energy used to make each individual is high, few offspring are produced, late maturity (often after prolonged period of parental care), long life expectancy, individuals can reproduce more than once in their life, type I or II survivorship - 2 ends of a continuum of strategies that have been produced by natural selection (they can all fall somewhere on continuum)
Describe 3 ways in which populations are distributed in space
random distribution- individuals are placed indiscriminately (ex: trees) uniform distribution- individuals are evenly placed (ex: feudal land tenure) clumped- individuals form groups around randomly-placed resources (ex: people living around water)
What happens during the Calvin cycle of photosynthesis?
reactions link together carbon atoms to form sugars fueled by ATP and NADPH
renewable vs nonrenewable resources
renewable resource- A natural resource that is virtually unlimited or that is replenished by the environment over relatively short periods (hours to weeks to years). Ex: Trees, soil, water, etc. nonrenewable resource- A natural resource that is in limited supply and is formed much more slowly than we use it. Ex: minerals, and FOSSIL FUELS
What selection patterns can natural selection lead to?
stabilizing selection- average value of trait is selected for, trait becomes less variable directional selection- one extreme is selected for so average shifts diversifying selection- both extremes are selected for & population begins to diverge
What is survivorship and what are the 3 types of survivorship curves? What are organisms that fit those curves?
survivorship- relationship between age and mortality Type I: mortality increases with age (have few children, but most survive to adulthood) ex: humans Type II: mortality constant ex: birds Type III: mortality decreases with age (have many children, but few survive) ex: frogs
Why is environmental science an interdisciplinary field?
synthesizes info, tech, and perspectives from multiple disciplines; includes both natural and social studies; environmental studies focuses more on social side of it
What is a system? What is an ecosystem?
system- network of relationships among parts, elements, or components that interact with and influence one another through exchange of energy, matter or info; ecosystem- an assemblage of all organisms and nonliving entities that occur and interact in a particular area at the same time
What are ecosystem services?
the natural processes that humans benefit from
What is total fertility rate (TFR)? How does it differ from replacement fertility rate? What factors decrease TFR? How does education of women affect TFR?
total fertility rate (TFR)- average # of children born per woman during her life replacement fertility rate- maintains stable pop., 2 children replace parents =2.1 children in developed countries, 2.33 globally education of women ↑, TFR ↓ (want to be educated and pursue career)
How do humans modify the Carbon Cycle?
use of fossil fuels decreases amount of carbon stored in soil and increases amount in atmosphere; deforestation decreases amount of carbon sequestered in vegetation; carbon from atmosphere is absorbed into ocean: ocean acidification
What happens during the light reactions of photosynthesis?
water molecules split into H+ ions, O₂ molecules, and synthesize small high-energy molecules of ATP and NADPH
Describe associations between population growth rates (family sizes) and: education status of women, employment of women, contraceptive use, wealth, poverty
↑ education= ↓ fam. size ↑ employment= ↓ fam. size ↑ contraceptive use= ↓ fam. size ↑ wealth= ↓ fam. size ↑ poverty= ↑ fam. size