Ecosystems, populations & sustainability

What is an ecosystem?

all organisms that live in an area AND the physical factors present in the area

List biotic factors:

symbiosis, predation, competition, makind, mimicry, camouflage, disease, parasitism

How is energy lost from one trophic level to another?

• excretion

• organisms own movement

• respiration

• maintain own temp

  • Not all parts of organism eaten (bones)

What can ecological pyramids show?

number, energy, biomass

What is biomass?

total dry mass of living organisms at each trophic level

What will a pyramid of energy show?

total amount of biomass/ energy converted into new biomass

Why is energy lost from the sun to producers?

• plants don’t possess enough chlorophyll pigments to absorb all light wavelengths

• light might not fall on plant or transmitted through

• sun energy converted into heat within photosynthesis

What is the equation for calculating ecological efficiency of energy transfers?

(energy or biomass available after transfer / energy or biomass before) x 100

What is a climax community?

mature community where a habitat can be formed solely from sun source of energy

How do agricultural ecosystems increase productivity and efficiency?

prevent climax community from forming in order to favour the rapid growth of a specific plant

Why is productivity low in ecosystems?

there are limiting factors present which prevent one species from becoming dominant

Where is carbon stored?

atmosphere & oceans as CO2, vegetation as cellulose, sedimentary rocks as CaCO3, fossil fuels, soil

What are detritius?

dead organic matter

What are detritivores?

invertebrates that feed on detritius by breaking down by intracelullar digestion in order to help decomposers increase surface area

What do decomposers do?

extracecullar digestion

What are saprobionts?

decomposers that break down dead matter by extracelullar digestion

How do volcanoes release CO2?

release CO2 from CaCO3 from sedimentary rocks underground

What are the 3 types of bacteria involving Nitrogen?

nitrogen-fixing bacteria, nitrifying bacteria, denitrifiying bacteria

What are nitrogen fixing bacteria and give examples?

converts gaseous nitrogen into ammonium ions

• Azotobacter in soil

• Rhizobium in root nodules

What are nitrifying bacteria and give examples?

convert NH4+ into NO2- and NO3-

• Nitrosomonas convert NH4+ into NO2-

  • Nitrobacter convert NO2- into NO3-

What is denitrifying bacteria?

convert NO3- into N2

What are the 3 non random sampling methods?

opportunistic, stratefied, systematic

What is primary succession?

process when newly formed land with no species is colonised by pioneer species

What is deflected succession?

activity of humans causing stable community to be different than climax community

What is sustainability?

management of ecosystems taht allows economic exploitation of natural resources without running out

What are the 3 reasons for conservation?

economic (more diversity = more substances produced), ethical (co-exist with other species), social (provide enjoyment)

Name two areas which manage ecosystems?

timber production and fishing

How is timber production managed and increase biodiversity?

fast growing conifers create clearings and in situ leaving of trees attrcat species and coppicing allows more light to reach ground

How is fishing managed to protect biodiversity?

• fish quotas

• promoting trolling

• banned fishing areas

• regulate mesh and fish nets

  • limit number of boats

Name methods to conserve ecosystems:

• national and marine parks

• public engagement

• zoos

• seed banks

• botanic gardens

  • frozen zoos

Methods of controlling human effects:

decrease pollution, managing invasive species, adapting to climate change, sustainable agriculture use, restore natural habitats