IB Biology - Ecology Unit

the study of relationships between living organisms, and also between organisms and their environment

ecology

a group of organisms with similar characteristics that can potentially interbreed and produce fertile offspring

species

members of a species may be reproductively isolated, but as long as they could still _____ if they came together again, then they are considered the same species

interbreed

give an example of interbreeding between species

the wood mouse lives in Britain and on Iceland. These two populations do not actually interbreed, but they could, so they are considered the same species.

a group of organisms of the same species, who live in the same area at the same time

populations

the area in which an organism lives

habitat

a group of populations living and interacting with each other in an area

community

a community and its abiotic (nonliving) environment

ecosystem

technical name for a producer

autotroph

another word for non-living

abiotic

technical term for sugar

carbon compounds

autotrophs absorb _______, _______, and ________ nutrients such as _____ from the abiotic environment and uses them to synthesize the _________ they need

carbon dioxide, water, inorganic
nitrates
carbon compounds

autotrophs typically use ______ to obtain energy

photosynthesis

most plants and algae are autotrophs, but there are some exceptional species that no longer make food by photosynthesis and instead obtain _____ from ______... this makes them what?

carbon compounds from other organisms
heterotrophs

give a counterclaim to the claim that all plant or algae is autotrophic

dodder - feeds on the stems of other plants is heterotrophic algae
ghost orchid - lives entirely underground until it flowers and obtains carbon compounds from fungi living on roots of trees

consumer

heterotroph

an organism that uses the energy in organic matter, obtained from other organisms

heterotroph

examples of heterotrophs

animals, some protists, decomposers

organisms that ingest other organic matter that is living or recently killed

consumers

ingest non-living organic matter

detritivores

decomposers

saprotrophs

lives on or in non-living organic matter, secreting digestive enzymes into it and absorbing the products of digestion

saprotrophs

what is the difference between detritivores and saprotrophs?

detritivores - internal digestion -ingests material and then breaks down the piece internally
saprotrophs - external digestion - breaks down the material externally and then ingests it in pieces

a sequence of relationships between trophic levels where each member feeds in the previous one

food chain

a position on a food chain

trophic level

the first trophic level is typically a ...

producer

the second trophic level is usually a ...

herbivore/carnivore (aka primary consumer)

every level after the second trophic level is an ...

omnivore/carnivore (aka secondary consumer, tertiary consumer.....)

these are not included on food chains

decomposers

arrows on a food chain indicate...

energy flow

give 1 example of a food chain

Galapagos Islands : sea lettuce >marine iguana > Galapagos snake > Galapagos hawk

why are sorting organisms into trophic levels difficult?

species can exist partly in one trophic level and partly in another

give an example of why sorting species into trophic levels is difficult

chimpanzees mainly feed on fruit and other plant mater, but they also sometimes eat termites and even larger animals such as monkeys

only show some of the trophic relationships in a community

food chain

is a complex network of trophic relationships and is a much more realistic representation

food web

ecosystems have the potential to be ____ over long periods of time

sustainable

as long as nutrients are recycles, ecosystems only require a supply of ____, usually in the form of _____ to continue indefinitely

energy - light

in what cycle are nutrients recycled

autotroph > heterotroph > saprotrophs > autotroph

a small experimental area sup in an ecological research program - basically an ecosystem in a bottle

mesocosm

what must a mesocosm have to be successful?

autotroph - produce carbon compounds and regenerate oxygen used in cell respiration by organisms, saprotrophs - decompose dead organic matter and recycle nutrients, consumers - not essential

a part of a population, part of an area or some other whole thing, chosen to illustrate what the whole population, area or other thing is like

sample

every individual has an equal chance of being selected

random sample

this of a plant population involves counting numbers in small, randomly located parts of the total

random sampling

where do producers get their energy?

THE FREAKING SUN! duh

the initial energy source for almost all communities

light

producers convert light energy into chemical energy of sugars and other organic compounds in this

photosynthesis

how do energy trapped by the producers eventually leave them in these three ways? (same pattern would continue for secondary consumers, tertiary consumers and so on)

heat - produced in chemical reactions like cellular respiration, as the primary consumer is eaten b y a secondary consumer, or due to death of the primary consumer and passes onto detritivores and/or saprotrophs

how does energy leave decomposers?

eventually released by cell respiration and lost as heat - in most communities all light energy is lost as heat when flowing through the food chain

at each successive stage of the food chain less food is available and therefore less ______

chemical energy

loss of food and energy restricts the _____ of food chains and the ____ of higher energy levels

length, biomass

diagrams that show how much energy flows through each trophic level in a community.

energy pyramids

unit of amounts of energy shown per square meter of area occupied by the community per year

kJm year

energy pyramids are shaped like so because less energy flows through each....

successive trophic level

list 3 ways that energy is lost

organisms die before energy reaches the next trophic level, some parts are not eaten, some parts of organisms are indigestible and pass out as feces - all energy goes to detritivores and saprotrophs in each of these

only about ___% of energy is transferred from one trophic level to the next

10

much of the energy absorbed by an organism is released through ...

cell respiration

energy from cell respiration, in the form of ___, is used in processes such as ..... and ...... that requires energy

ATP, muscle contraction, active transport

processes involve ____ ____ which change energy from one form to another and are never 100% efficient

energy transformers

most energy released b y cell respiration is lost from the organism as ...

heat

energy absorbed by living energy is only available to the next trophic level if it remains as ____ ____ in the growth of the organism - this is only a very small portion of the energy absorbed

chemical energy

energy enters as ___ and usually leaves as ____

light, heat

these do not usually enter an ecosystem and must be used again and again

nutrients

nutrients include ______, ______, and _______

carbon, nitrogen, phosphorus

when an organism dies, it is digested by a _______ or a _______. they return these nutrients to the environment so that they can be used again and again

detritivores and saprotrophs

a term that is used to encompass the diversity of ecosystems on earth, the diversity of species within them, and the genetic diversity of each species

biodiversity

one of the main tasks of ecologists is _____ of the worlds biodiversity

conservation

some _____ are absorbed into living organisms and accumulate because they are not efficiently excreted

pollutants

when a predator consumes prey containing the ____ and absorbs it, the level in the body of the predator rises and can reach levels much higher than those in the bodies of its prey

pollutant

the process by which chemical substances become more concentrated at each trophic level

biomagnification

when can biomagnification happen?

at each stage of the food chain

chemicals that were used as insulators in electrical devices and as flame retardants

Polychlorinated biphenyls (PCBs)

PCBs have escaped into the environment and are now detectable throughout the world. They are _____ and _____.

persistent and highly toxic

.... for PCBs vary considerably

biochemical factors (BAF)

has very damaging effect on living organisms and biological diversity

ultra-violet radiation

what are 4 negative effects of ultra-violet radiation?

-increases mutation rates by causing damage to DNA
-can cause cancers, especially of the skin
-causes severe sunburn and cataracts of the eye
-reduces photosynthesis rates and so affects food chains

the amounts of damaging ultra-violet radiation reaching the earth's surface would be much greater without the...

ozone layer of the atmosphere

ozone absorbs...

shortwave radiation, especially ultra-violet

ozone is much more concentrated where?

in the stratosphere

measurements of ozone concentrations in the stratosphere have shown that there has been a ____ throughout the world

depletion

since the 1980s an ozone hole has appeared over the _____ every year between ______ and _______

Antarctica, September & October

the chemical compounds manufactured by humans and released into the atmosphere

CFCs

the main cause of ozone depletion

CFCs

ultra-violet light causes CFCs to dissociate and release atoms of ...

chlorine

chlorine atoms are highly reactive and cause complex reactions in which ozone is converted into ...

oxygen (one chlorine atom can potentially cause the destruction of hundreds of thousands of ozone molecules)

supplied in the form of light and then converted into chemical energy by autotrophs. This chemical energy is used in a cell and eventually converted to heat.

Energy

heat cannot be recycled ad is ultimately ___ from the ecosystem

lost

ecosystems have limited supply of ___ but these supplies do not run out because they can be recycled

nutrients

these 3 essential elements are absorbed from the environment, used by living organisms, and then returned to the environment to be used again

carbon, nitrogen, phosphorus

absorb carbon dioxide from the atmosphere or from water

autotrophs

CO2 is converted to ____ and other ____ ____ in the process of photosynthesis

carbohydrates, carbon compounds

in aquatic ecosystems, carbon can be found in the form of...

hydrogen carbonate ion (HCO3-)
HCO3- is formed when water and CO2 combine to form carbonic acid which then dissociates into ions

many aquatic autotrophs can use both dissolved ___ and ___ in photosynthesis

CO2, HCO3-

how is CO2 produced

by the combustion (burning) of carbon compounds

combustion is caused by...

humans - it isn't natural

combustions can only occur naturally when

lightening starts fires

know the carbon cycle diagram

!!!

methane is produced naturally by a group of ____ called ____ ____

prokaryotes, methanogenic archeans

methanogenic archeans break down organic matter in ____ conditions and release methane as a ...

anaerobic, waste product

where are areas where decomposition cannot happen and methane is released due to methanogenic archeans

swamps, bogs, and other oxygen-free areas

methane can accumulate in the ____ or diffuse into the _____

ground, atmosphere