Populations & Ecosystems Flashcards
What are some Carbon stores/sinks in the Carbon cycle
coal,oil,gas, soil and organic matter, sedimens and sedimentary rock, ocean surface, deep ocean, atnosphere
What are some processes in carbon cycle
weathering and run-off, rock formation, sinking sediment, deep circulation, carbon dioxide exchange, burning(e.g. forest fires), burning fossil fuels, respiration, decay, feeding, photosynthesis
How does deforestation impact the carbon cycle?
removes a carbon reservoir, burning releases more to the atmosphere, removes lots of plants which through photo synthesis removes Carbon (CO2)
How does the burning of fossil fuels impact the carbon cycle?
releases lots of greenhouse gases, and is a leader in climate change
How does global warming impact the carbon cycle?
Higher temperatures mean more evaporation so less carbon stored in the ocean = more in atmosphere
more dissolved into oceans at the poles (melting ice) making it more acidic
how does carbon moves through a food chain or web?
the production of carbohydrates, proteins and fats by autotrophs
plant growth
consumption - consumer feeds on another plant or animal it uses the proteins carbohydrates and fats for energy and for raw materials
consumer growth through complex food webs
how is the carbon cycle important in climate change and the greenhouse effect?
carbon sinks (fossil fuels) and (forests) release carbon from human impact
combustion increased releases carbon
removing plants reduces photosynthesis
more carbon absorbed by oceans = acidification
all increase global temperatures and a change in ocean currents/climates
what are some examples of decomposers?
detrivores, fungi, bacteria, protists
what is fragmentation?
initial stage of decomposition, breakdown of detritus into smaller pieces by detrivores
what is leaching?
When water-soluble substances are washed out from the soil, like nutrients, fertilisers or pesticides
what is catabolism?
the conversion of detritus into simpler inorganic compounds. This process is carried out by various fungal and bacterial enzymes
what is humification?
the process of formation of a dark-coloured layer of soil called humus. It cannot be decomposed easily as it is highly resistant to the action of microbes. The layer of humus is very rich in nutrients as it provides high fertility to the soil
what is mineralisation?
final stage of decomposition, degradation of the hummus to release inorganic nutrients
What are the ammonium ions (NH4+) formed in putrefaction converted by, via, and to?
Converted by nitrification, via nitrites (NO2-) to nitrates (NO3-)
What bacteria converts ammonium ions to nitrite, under what conditions?
Nitrosomonas, under aerobic conditions
What bacteria convert nitrite to nitrate, under what conditions?
Nitrobacter, under aerobic conditions
What is nitrogen fixation?
The biological process by which nitrogen in the atmosphere is converted into ammonia
What plant type and where are rhizobium found?
Legumes, in root nodules
Explain the symbiotic relationship between rhizobium and the legumes
Rhizobium use nitrogenase enzyme to split triple bond in nitrogen gas and covert into ammonia and then amino acids which the plant uses for growth.
in return, Rhizobium gains a stable internal environment and utilises glucose made from photosynthesis by the plant
How do Legumes attract rhizobium?
they make leghaemoglobin which binds to oxygen in plant roots, this attracts rhizobium from the soil into the plant roots, leghaemoglobin is a pinky pigment seen in leguminous roots
What is excretion?
the process of removing nitrogenous waste from an organism
what is a legume?
a plant which atmospheric nitrogen is converted into nitrates (peas,beans,clover,gorse)
what is a nodule?
root organ in which rhizobium inhabitat
what is dentrification?
nitrogen is lost from an ecosystem
what is putrefaction?
decomposition of organisms and waste
What is a population?
A group of organisms of a single species interbreeding and occupying a particular area
What causes increases and decreases in population size?
Births and immigration increase the population
Deaths and emigration decrease the population
WWhat is a community?
A group of interacting organisms sharing an environment
What is a habitat?
A physical environment where a particular population or community are found
What is a biotic factor? + examples?
A living component, Autotrophs(producers), Heterotrophs(consumers), Detrivores(decomposers)
What is an abiotic factor?
A non living component
What is an ecological niche?
The place where an organism is found and its role
What is a species?
A group of similar organisms capable of interbreeding and producing fertile offspring
What is the lag phase (on a graph of growth)?
Little or no cell multiplication or growth
A period of adaptation/acclimatisation/preparation for growth
Intense metabolic activity, especially enzyme synthesis, finding carbon source/ finding food
What is the exponential phase (on a graph of growth)?
The population increases rapidly
As the numbers increase more individuals become available for reproduction
What is the stationary phase (on a graph of growth)?
Population growth enters this phase when birth rate is equal to deat h rate
The population has reached its maximum size called carrying capacity
What is the death phase (on a graph of growth)? why might it occur?
When death rate is greater than birth rate
May occur when all the food in a nutrient solution has been used up
What are some examples of density dependent factors (effect carrying capacity)?
Accumulation of toxic waste, Disease, Parasitism, Food supply
What is a density independent factor (with examples)?
Effects all animals and plants no matter what population size/density (freezing,flood,fire - sudden changes in an abiotic factor)
what are fluctuations in the size of a population called?
population oscillations - usually consequence of weather patterns
what is intraspecific competition?
competition between individuals of the same species
what is interspecific competition?
competition between individuals of different species
In an ecological pyramid why do the numbers in the food chain decrease when the chain goes up?
Because energy is converted/lost in respiration, movement, chemical reactions, investment in reproduction, egestion and sound
what is a carnivore?
eats meat
what is a herbivore?
eats vegetable matter
what is an omnivore?
eats both meat and vegetable matter
what is a saprotroph?
feed from something dead or decaying
what is a decomposer?
organisms like some bacteria and fungi involved in the decomposition process
what is a producer?
generally a photosynthesising plant but could be chemosynthetic bacteria
what is a consumer?
an organism that cannot synthesise its own food and is obliged to eat something else to obtain nutrients
what is a predator?
an organism that actively hunts and kills its food
what is a parasite?
an organism that passively obtains nutrients from a host over a relatively long time period
what is succession?
the change in structure and species composition of a community over time
what is a community?
all the living organism in an ecosystem
what is primary succession?
introduction of plants/animals into areas that have not previously been colonised
what is secondary succession?
occurs on an area which has previously had vegetation on it, natural interuption
what is a sere?
a stage in succession
what is a climatic climax?
stable and in equilibrium with climatic conditions
in Britain = mixed deciduous woodland
what is a disclimax?
a deflected climax community, often caused by land management, grazing burning, mowing, research coppicing with standards, deforestation
When can a quadrat be used?
if a habitat is uniform
When can a transect be used?
if the habitat is not uniform (e.g. with a gradient)
What are the types of transect?
line or belt transect
What is abundance?
the number of individuals of one given species in a given area
How can plants be recorded?
in density/m^2 (actual number counted)
in percentage cover
What is random sampling?
when you make no conscious decision about where samples are taken. Use random coordinates within a defined sample area.
What is systematic sampling?
You decide where to take samples and take them at regular intervals within the area
How can percentage cover be recorded?
estimatation, trying to give rough idea of what it would be if pushed together
How do you avoid bias in sampling?
generate a random sample, forming grid and coordinates and randomly selecting coordinates
How do you measure abundance of mobile organisms?
capture-mark-remark experiments
kick sampling in a stream and counting aquatic invertabrates
