Ecosystems Flashcards

Question

What is a pyramid of biomass?

Answer 1

Area of each bar is proportional to the dry mass of all organisms at that trophies level (gm^-2)

Answer 2

Put organisms in an oven to evaporate any moisture to obtain the dry mass

Answer 3

Ecological efficiency = biomass of higher trophic level / biomass of lower trophic level X 100

Answer 4

The rate at which energy passes through each trophic level

Answer 5

Rate at which plants concert light energy to chemical energy | insufficient as only about 1/8th of the suns energy enters the food chain.

Answer 6

NPP = GPP - Respiratory losses

Answer 7

Light levels - plant earlier (longer for growing season) Water availability- irrigation Temperature- greenhouses Nutrients- crop rotations / fertilisers Biotic factors- protection from pests diseases and competition

Answer 8

N= I-(F+R) ``` Harvest animals before adulthood Selective breeding Protection against disease and pests Reduced movement Control temperature ``` (Balance between ethics and efficiency)

Answer 9

Plants need mineral ions (nitrates) Mass food production removes naturally occurring mineral ions form the soil and so it is important to replenish the soil to prevent it inhibiting plant growth.

Answer 10

Dead and decaying remains of plants an animals | Animal wastes Slurry manure bone meals

Answer 11

Minerals mined from rocks and converted into different forms and mixed (nitrogen phosphorus and potassium)

Answer 12

Reduced species diversity: Fertilisers provide nutrients and therefore those species which grow faster will use up the nutrients and out compete other species Leaching: Nitrogen containing compounds could be washed into bodies of water (water pollution) Eutrophication

Answer 13

By the leaching of artificial and some organic fertilisers Most lakes have relatively low nitrate concentrations and thereforeI limits the amount of algal growth

Answer 14

1. When the nitrate content in water rises (due to leaching) algae can begin to grow rapidly 2. Algae grow mostly at the waters surface creating an algal bloom 3. This prevents sunlight from reaching lower surfaces of the water and therefore plants cannot photosynthesise and die 4. This allows saprobiontic populations to grow and feed of the dead material. The saprobionts will respire and reduce the O2 availability in the water 5. Lack of O2 causes aerobic organisms to die and increase the nitrate concentrations in the water 6. Less competition for anaerobic organisms and their numbers rise releasing more nitrates and toxic waste into the waters

Answer 15

Gradual directional changes which happen in a habitat or community over time

Answer 16

The change to an environment which was previously uninhabited

Answer 17

From damaged but previously colonised environments

Answer 18

1. Algae and lichen ( pioneer species) begin to live on the bare rock 2. The erosion of the rock and build up of dead material caused by the pioneer species leads to some nutrients build up 3. This build up of nutrients can start a soil and causes the environment to become less hostile enabling larger organisms to be supported and can now grow 4. These larger organisms increase the habitats and niches available to organisms allowing more to grow and reproduce 5. These organisms can replace the pioneer species (their numbers are reduced) and this process keeps repeating 6. Over time the biodiversity will increase producing more complex food webs and increasing biomass 7. Eventually a final stable community will be established called the climax community

Answer 19

Causes the environment to become less hostile so more habitats and niches can form This leads to increased biodiversity and therefore the production of more complex food webs increasing the overall biomass

Answer 20

Usually algae or lichen The first organisms to inhabit an area

Answer 21

Have tolerance to extreme conditions Can reproduce asexually Widespread germination Photosynthesisers (photoautotrophs)

Answer 22

Agriculture can pause succession mid way causing a sub climate community to become established A plagioclimax (caused by human intervention)

Answer 23

Keeping species and habitats as they are now by limiting the human affects on the ecosystem

Answer 24

Active process which aims to maintain or improve biodiversity of an ecosystem

Answer 25

Our exploitation- food/ sport / commerce Habitat destruction- agriculture / resource Pollution Urbanisation Introduction of invasive species

Answer 26

Raise carrying capacity by providing extra food Restrict individuals by fencing Control predators poachers and disease National parks Green belts Zoos SSSI

Answer 27

Ethics: Every species is important and has its place Social and economical: Biodiversity harbours future potential Tourism / recreation Natural predation acts as pest control

Answer 28

Timber production Fisheries (fish stocks) Agriculture

Answer 29

The mechanism by which evolution occurs

Answer 30

Fossils: New species are often similar to previous species which died out Biological molecules: Certain molecules are found throughout the living world (DNA) Two closely related species will have separated recently and so their biological molecules are likely to be similar

Answer 31

1. Offspring generally appear similar to parents 2. No two individuals are identical 3. Organisms have the ability to produce large numbers of offspring 4. Populations in nature remain fairly stable Conclusions: Better adapted individuals out compete others and overtime changes give rise to a new species

Answer 32

1. Mutations create alternative versions of a gene (allele frequencies change) 2. This creates genetic variation between the individuals of a species (intraspecific variation) 3. A selection pressure in the environment favours the survival of the individual with the more advantageous characteristics 4. These selected individuals survive and reproduce 5. The pass on their characteristics to their offspring via inheritance 6. The next generation I’ll have a higher proportion of individuals with the successful characteristics 7. Overtime the group of organisms becomes better adapted to the environment 8. Leads to evolution

Answer 33

Stabilising- environment is unchanged and favours the intermediate phenotype Directional- changing environments cause s gradual shift in the optimum phenotypes Disruptive- changing environments favours the extreme phenotypes

Answer 34

When allele frequencies change overtime due not to selection pressures but simple due to mutation genetic bottlenecking or the founder effect

Answer 35

A sharp reduction in the size of population due to environmental events (eg earthquakes floods disease)

Answer 36

The loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population.

Answer 37

When 2 populations of the same species become so genetically different they can no longer interbreed to produce fertile offspring and 2 new species are formed

Answer 38

Geographical barriers cause allopatric speciation Reproductive barriers cause sympatric speciation

Answer 39

``` Floods Volcanoes Human intervention Rivers Mountains ```

Answer 40

Behavioural differences Physiological differences Genetically difference Biochemically different

Answer 41

1. Mutation in a gene pool 2. An isolation barrier occurs (allopatric or sympatric) 3. Natural selection and selection pressures occur 4. Allele frequency changes 5. Overtime the two isolated populations can no longer interbreed 6. 2 new species arise

Answer 42

Ammonification nitrification nitrogen fixation denitrification (each stage involves saprobiontic organisms)

Answer 43

The production of ammonia from organic nitrogen containing compounds. saprobiontic bacteria feed on decaying material releasing ammonia which then forms ammonium ions in the soil enabling nitrogen to return to the non living component of the ecosystem.

Answer 44

Nirtifying bacteria convert ammonium ions to nitrite ions and then to nitrate ions. This is an oxidation reaction which releases energy. These nitrate ions can then be assimilated by plants and up-taken for the production of amino acids, proteins, growth etc.

Answer 45

The process by which Nitrogen gas is converted into nitrogen containing compounds. this is carried out by saprobiontic organisms.

Answer 46

when denitrifying bacteria convert soil nitrates into nitrogen gas which is then returned to the atmosphere and the process repeats.

Answer 47

The movement of phosphorus (phosphate ions) between rocks, bodies of water, animals and plants. This is an important cycle as phosphorus is an important biological element for ATP and phospholipids therefore essential for life.

Answer 48

A fungi that can act as extensions onto roots of plants to increase their surface area form more efficient and greater up take of nutrients and water.

Answer 49

One where both the plant and fungi benefit from each other. eg. Mycorrhizae will provide the plant with better water and inorganic ion up-take and in return be provided with sugars and amino acids from the plant.