ESS unit 2

species

organisms that are able to interbreed to produce fertile offspring

Habitat

a place where an organism lives

community

all the different populations within the same habitat

population

all the members of the same species within the same habitat

ecosystem

the community and habitat together

niche

when and how an organism lives, completely defines a species

ecosystems are…

open systems (energy and matter are exchanged across the boundaries of the system)

photosynthesis word equation

carbon dioxide + water —> glucose + oxygen

photosynthesis chemical equation

CO2 + H2O —> C6H12O6 + O2

biomass

the dry mass/weight (no water) of the organism in the environment

how to measure biomass?

kill the organism and dry it out to remove all water

assimilation

the process through which an organism incorporates nutrients from outside its body to the more complex structures needed inside it

producers (autotrophs)

convert sunlight energy into chemical energy, manufacture own food from inorganic substances

consumers (heterotrophs)

obtain energy by consuming other organisms

decomposers

obtain food and nutrients from the breakdown of dead organic matter

1st thermodynamic law

in an isolated system, energy can be transformed but not destroyed or created

2nd thermodynamics law

energy transformation in ecosystems are inefficient (example, when transformed into more useless for, like heat energy)

respiration

the process by which living organisms convert oxygen and glucose into a useful energy form, releasing carbon dioxide and water in the process

respiration word equation

glucose + oxygen —> carbon dioxide + water

respiration chemical equation

C6H12O6 + O2 —> CO2 + H2O

Trophic level

the position that an organism occupies in a food chain, or a group of organisms in a community that occupy the same position in food chains

food chains

the flow of energy from one organism to the next. It shows the feeding relationships between species in one ecosystem

10% rule

The efficiency of transfer from one level to the other is 10% on average

food web

complex network of interconnecting and overlapping food chains showing feeding relationships within a community

productivity

the conversion of energy into biomass over a given period of time

primary productivity

the gain by producers in energy or biomass per unit area per unit time

net productivity

the amount of biomass remaining after energy losses due to cellular respiration, shows the rate at which plants accumulate biomass after allowing for respiratory losses

gross productivity

a measure of the rate of photosynthesis in producers or the rate at which carbon dioxide is fixed or being converted into glucose by plants, shows the total gain in biomass by an organism

ecological pyramids

graphical models of the quantitative differences between amounts of living material stored at each trophic level of a food chain

pollution

the addition of a substance or an agent to an environment through human activity at a rate greater than that at which it can be rendered harmless and has an impact on the organisms in the environment

biodegradable

do not persist in the environment and break down quickly over time

non biodegradable

resistant to breaking down and remain active in the environment for a long time

bioaccumulation

the increasing concentration of non-biodegradable pollutants in organisms overtime

biomagnification

the increasing concentration of non-biodegradable pollutants in a food chain

examples of biogeochemical cycles

water cycle, nitrogen cycle, carbon cycle

stores

elements held for varying durations in reservoirs such as oceans, soil, atmosphere

sink

areas of net accumulation where elements are absorbed faster than they are released such as forests absorbing more carbon dioxide than they’re released

source

areas of net release where elements are discharged faster than absorbed, such as fossil fuel combustion emitting carbon dioxide

human activity

burning fossil fuels, deforestation, urbanisation, agriculture

heavy tillage

when agriculture machinery ploughs soil, removing nutrients from soil, causing erosion

monocultures

growing the same crop type over many harvests, reduces nutrient levels in the soil

draining wetlands

wetlands have high biodiversity and store high quantities of decaying organic matter. draining them releases carbon dioxide gas

agriculture systems as a source

heavy tillage, monocultures, draining wetlands

crop rotation

grow different types of crops during each farming season, allows soil to regenerate, stay healthy, maintain carbon levels

cover crops

between crop harvests, plant non-profitable species such as clover, peas. they add nitrogen and other elements into the soil

no till

farmers don’t use machinery to plough soil at the end of each harvest, remaining plant material is allowed to decompose naturally back into the soil system

ocean acidification

• caused by human carbon dioxide emissions from burning fossil fuels

• carbon dioxide assimilated as biomass into marine organisms

• when carbon dioxide dissolves in seawater it turns to carbonic acid and acidifies seawater, interferes with calcium carbonate deposition in mollusc shells and coral skeletons

• calcium carbonate is building material for many marine exoskeletons (e.g. marine snail, lobsters)

strategies to diminish the effects of human activity on the environment

low carbon technologies, reducing use of fossil fuels, CSS (carbon capture and sequestration), DAC (direct air capture), reforestation

low carbon technology

low carbon technology produce energy with low carbon emissions

reducing use of fossil fuels

reduce emissions by conserving use of fossil fuels, use alternatives

CSS (carbon capture & sequestration) & DAC (direct air capture)

capture carbon dioxide from factories or the atmosphere and inject it into reservoirs deep in Earth for storage

reforestation

planting trees in forests that have been cleared for agriculture or urban expansion, more trees = less carbon dioxide in environment

weather

the state of the atmosphere at any particular moment in time

climate

the average and extreme states of the atmosphere over a period of not less than 30 years

biosphere

the parts of earth where life exists

biomes

collections of ecosystems sharing similar climatic conditions. have distinctive abiotic factors and species that distinguish them from other biomes, all earth biomes make up the biosphere

6 types of land biome

desert, tundra, taiga, temperate deciduous forest, grasslands, tropical rainforest

6 types of aquatic biomes

freshwater, marsh/swamp, river, estuary, deep ocean, coral reef

high pressure =

descending, cold air

low pressure =

rising, hot air

altitude

height above ground or at sea level

laititude

the angular distance north or south of the equator

consequences of shifting biomes

• temperature increases

• some areas drier, some areas warmer

• stronger storms

top 10% of ocean water

surface currents

other 90% of ocean water

deep ocean currents

surface currents form

gyres

gyres because?

earth rotation affects the wind patterns

gyres help

redistribute warmth across the globe

coriolis effect

circulating air is deflected toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere

thermohaline circulation/deep water currents

in polar areas, seawater gets saltier and colder, increasing density and therefore sinking. warmer surface water is pulled in to take its place.

global conveyer belt

thermohaline circulation + wind driven surface currents =

factors that affect water density and ocean currents

temperature and salinity

abiotic

non living factors that may influence organisms

parasitism

interaction between 2 species where the parasite gets the resources they need from the other organism, potentially harming the host in the process

zonation

refers to change over gradient caused by changes in abiotic factors

examples of zonation

altitudinal zonation, rocky shore zonation

succession

the process of change over time in an ecosystem involving pioneer, intermediate and climax communities

primary succession

when ecosystems develop from bare substrate (no soil) over time

sere

the communities within a stage in succession

hydrosere

succession in freshwater (e.g. small lakes disappear and be replaced by plant communities)

halosere

succession in salt water marshes

psammosere

succession along sand dunes. stabilizes dunes and stops them from shifting

lithosere

succession on bare rock surfaces (e.g. lava flows)

xerosere

succession in dry areas

secondary succession

when ecosystems develop from where previous communities were destroyed. fast because of soil and dormant seeds

tipping point

the minimum amount of change within an ecosystem that will destabilise it, causing it to reach a new equilibrium/state

resilience

the capacity of a system to resist damage and recover or adapt efficiently to disturbance

factors that support resilience

complexity of ecosystem, stage of succession, limiting factors, diversity and storage size

carrying capacities

the maximum amount of organisms an area can sustain without significant consequences