EVS final

What limits population growth?

amount of usable energy, sunshine, climate, energy input, nutrients

variation in aquatic biomes

salinity vs light vs temperature vs pressure

Freshwater biomes

streams, lakes

brackish biomes

estuaries, mangroves, salt marshes

Obliquity

40,000 year cycle, how tilted the earth’s axis is

precission

23,000 year cycle, direction of earth’s tilt over time

eccentricity

1000,000 year cycle, how elliptical earth’s orbit is

milankovitch cycles

changes in earth’s orbit

what is life?

metabolism, growth, reproduction, evolution

bioaccumulation

uptake is more rapid than loss, but can also accumulate toxic substances

autotrophs

make organic molecules using energy from the sun (phototrophs) or from chemical reactions (chemoautotrophs)

photosynthesis

co2+h2o+energy(sunlight) → ch2o(glucose) + o2

Eukaryotic cells

animals, plants, fungi, have a nucleus containing DNA as well as specialized organelles such as mitochondria

Bioconcentration

active uptake of nutrients from the environment organisms can concetrate elements up to 100000x in cells to build molecules

protokaryotes

like bacteria, blue-green algae, no nucleus, no specialized parts, DNA not stored in a specialized part of the cell

heterotrophs

obtain organic molecules by decomposing or consuming another organism

proxy records

records of natural events that are controlled by and closely mimic climate tree rings → sediment → records → thicker rings → wetter conditions or other things

eutrophication

excessive plant growth and decay which leads to decreased o2

carrying capacity

maximum number of organisms of a species that can e supported in an area

biomass

total mass of living things in a ecosystem, usually expressed in mass per area (g/m2)

net production

growth that occurs in an ecosystem per year, photosynthesis - respiration, expressed in mass per area time (g/m2/yr)

primary production

carbohydrate (glucose) production by autographs

respiration

CH2O(glucose)+O2→ CO2+H2O+energy

primordial soup

products of chemosynthesis collected in surface waters and combine to form larger molecules due to clumping volcanic/solar heat, reactions on surface of clays

gene flow

movement of genes from one population to another

genetic drift

chance changes in gene frequencies, not based on fitness

genetic variation

caused by evolution, mutation, gene flow, sexual reproduction

when did life begin on earth?

about 3.9 billion years ago, after the hadean era

cambrian explosion

570 milllion years ago, increase in organism diversity, internal and external skeletons

why did the cambrian explosian occur?

maybe sexual reproduction or O2 buildup allowed the formation of carbonate skeletons

cretaceous-tertiary extinction

65.5 million years ago, 80% to 90% loss of species, occurred rapidly, under 10 thousand years

causes of cretaceous-tertiary extinction

impact event → flood → sea level fall → climate change

which sphere is not involved in the cycling of phosphorus?

atmosphere

phosphorus is only usable to living organisms in the form of

phosphate

phosphorus is found in soils and water due to

chemical weathering

we get phosphorus for fertilizers by

mining phosphate rock

nitrogen makes up __ percent of our atmosphere

80

nitrogen fixation

conversion of atmospheric N2 to more useful forms of N such as ammonia, nitrates, or nitrites. done through lightening, or more commonly bacteria

after being fixed by bacteria, nitrogen is

taken up by plants and algae and then consume dby animals

denitrification

bacteria convert fixed nitrogen from dead animals back to N2 and release it back to the atmosphere

too much human made nitrogen fixation contributes to

smog, aerosol pollution, climate change

excess nitrogen depositation causes

algal blooms, increases of invasive plants, loss of native plant species, changes in soil chemistry that lead to leaching of N into groundwater

carbon enters the atmosphere through

respiration, fires, volcamoes, decay, ocean diffusion

carbon is removed from the atmosphere through

photosynthesis, or is dissolved into water to make carbonic acid

carbonate in the ocean is

used by organisms then buried in sediments and stored

carbon is transformed into fossil fuels, graphite and diamond, and stored over ____ period of time

tens of millions of years, long

short term carbon biochemical cycles

photosynthesis, respiration, burning, volcanic eruptions, dissolution in surface ocean

mid term carbon biochemical cycles

cycling of carbon in soils, land use, cycling of carbon in deep oceans

long term carbon biochemical cycles

cycling of carbon in deep oceans, chimical weathering and erosion, formation of sediments and rock, formation of fossil fuels

what is likelhy to happen to biomass and net production forest area two years after a forest fire?

Biomass- increase, net production- vary due to conditions

what constrains production on land?

Often water

what constrains production in the water?

often nutrients

how much of the net primary production each year is mow used y humans for fuel/energy or food?

20%

phoenix is a metropolitan community in the

Sonoran desert

water access is becoming unreliable in the

south west of north america

air quality is worsening in phoenix fue to

increasing population leading to pollution and ozone problems

phoenix’ summers are regularly

above 100 degrees

phoenix’ built environment has an abundance of concrete with little vegetation which causes a

urban heat island effect

phoenix’ climate action plan reduces greenhouse gases by

expanding public transportation, walking, and biking paths

to adapt to rising temperatures, phoenix is adding

native and drought tolerant trees to increase shade coverage in public and vulnerable spaces

the phoenix action plan is mitigating water waste by

asking businesses to reduce their water use to 155 Gallons per Capita per Dat by 2030 as well as using wastewater and stormwater when appropriate

a city planner or engineer in phoenix could adapt to high temperatures by

design urban infrastructure to maximize shade, use cool materials such as reflective pavements and lighter colored surgaced to reduce heat absorption

a city planner could adapt to the drought or mitigate water waste by

designing water efficient landscaping, irrigation, and water reuse systems

obstacles city planners could face to implementing drought and heat adapting designs

people who don’t want taxes to go up, businesses that do not want trees or designs to be in or around their property, car and gas lobbyists that do not want more public transport

3 things needed for organisms to develop (the first time)

chemosynthesis, biosynthesis, development of chemical processes needed for metabolism and replication (DNA/RNA)

chemosynthesis

synthesis of small organic molecules eg amino acids

biosynthesis

combination of small organic molecules into larger more complex, molecules eg proteins

carbon dissolves more readily in

cold water than warm water

methane hydrates

methane frozen in ice within sediments on ocean floor near continents

human impact on carbon cycle

fossil fuel burning, deforestation

how has fossil fuel burning impacted the carbon ycle

released 280 Gt C to atmosphere since 1900, 6-7 Gt C per year

how has deforestation impacted the carbon cycle

200 Gt C released to atmosphere since 1850, 0.5 to 2 Gt C per year

how much ppm does co2 increase in the atmosphere per year?

1.8 ppm/year

what are sources of CO2 increase in the atmpsphere?

respiration, volcanoes, anthropogenic combustion

what are sinks of CO2 from the atmosphere?

photosynthesis, dissolving into the sea

How do we know CO2 rises are human caused?

Global oxygen as well as carbon 13 and 14 ratios go down with increased combustion of fossil fuels.

human impacts on geosphere

Soil is needed to grow crops but can be lost by erosion or degraded with contamination or loss of nutrients, green revolution increased productivity due to irrigation, pesticides, and fertilizers

how much soil does the us lose per year?

4.6 billion tons

desertification causes

deforestation, overgrazing, intensive farming, water diversion, rising temperatures, extreme weather

where is desertification occurring today?

sahel region of africa - places that are already generally arid

human impacts on hydrosphere

warming in artic potentially reduces thermohaline circulation

energy is used for

transportation and electricity generation

how much of our fossil fuels have we used out?

less than 25%

human effect on atmosphere

ozone destruction by cfcs