Topic 5 Flashcards

Question

What is primary succession?

Answer 1

Primary succession = land that has been newly formed or exposed There's no soil or organic material (it’s bare rock) E.g volcano eruption or dropped sea level

Answer 2

Secondary succession = land that has been cleared of all plants, but soil remains E.g a forest fire or deforestation

Answer 3

The abiotic conditions are hostile so no soil to retain water Only pioneer species (the first species to colonise an area) can grow b/c they’re specially adapted The pioneer species changes the abiotic conditions They die and decompose = dead organic material = soil Conditions are less hostile = new organisms w/ dif. adaptations can grow They then die = more organic material = deeper and richer-in-minerals soil = larger plants can grow = more water retained New species may change it so conditions aren’t good for previous species

Answer 4

Same as primary but soil layer already present Pioneer species are larger plants At each stage, dif. plants and animals that are better-adapted move in - They out-compete the plants already there - They become the dominant species in the ecosystem - The ecosystem becomes more complex - More species = ↑ biodiversity

Answer 5

- A climax community - the ecosystem is supporting the largest and most complex community - It wont change much b/c its in a steady state

Answer 6

Bare rock → Woodland Example 1. Pioneer species colonise the rocks, E.g lichens grow on and break down rocks, releasing minerals 2. Lichens die and decompose = a thin soil 3. Soil thickens as more organic material forms 4. Other species can grow, E.g. mosses 5. Larger plants can move in b/c more water as soil deepens, E.g grass 6. Shrubs, ferns and small trees can grow, outcompeting the other species becoming the dominant species = ↑ diversity 7. The soil is deep and rich in nutrients = supports large trees = climax community

Answer 7

Dif. organisms = dif. climax communities Temperate climate = lots of water, mild temp, not much change w/ seasons Climax community = large trees Polar climate = not a lot of water, low temp, massive changes w/ season Climax community = herbs/ shrubs b/c trees can’t grow

Answer 8

- Artificially stopped succession = community is the climax community but called plagioclimax - E.g mowing a grassy field = don’t develop shrubs and trees b/c can’t establish - A longer interval b/w, the further succession can progress = ↑ diversity - The shorter the interval succession can’t progress = low diversity

Answer 9

Phosphorylation = adding phosphate to a molecule E.g ADP is phosphorylated to ATP

Answer 10

Photophosphorylation = adding phosphate to a molecule using light

Answer 11

Photolysis = the splitting of a molecule using light energy

Answer 12

Hydrolysis = the splitting of a molecule using water E.g ATP is hydrolysed to ADP

Answer 13

Redox reactions = reactions that inv. oxidation and reduction (OIL RIG) Oxidation always inv. the loss of another molecule as well

Answer 14

Photosynthesis = the process where light energy is used to break the strong bonds in H2O - The H is stored as glucose - Formed when H combines w/ COշ - Oշ is formed and released - Stored until its released by respiration

Answer 15

- An immediate source of energy in a cell

Answer 16

- During respiration, glucose broken down = energy = ATP - ATP carries energy around the cell where it’s needed Synthesised by the phosphorylation of ADP - Using energy from an energy-releasing reaction - ATP synthase catalyses this reaction It diffuses to the part that needs energy Broken down via hydrolysis back into ADP + Pi - Chemical energy is released from the phosphate bond - ATPase catalyses this - They’re both recycled so the process starts again

Answer 17

- The rate of photosynthesis is affected by the same things enzyme-controlled reactions are affected by, e.g temp - b/c it uses lots of dif. enzymes - It also relies on coenzymes - Coenzymes = a molecule that helps the function of an enzyme - They transfer a chemical group from one molecule to another - E.g NADP

Answer 18

- Takes place in thylakoid membranes - Light energy is converted into chemical energy - Light energy adds Pi to ADP to = ATP and reduced NADP (NADPH) - ATP transfers energy and NADPH transfers H to - light-independent - This process is called phosphorylation - HշO is also oxidised to Oշ - This process is called photolysis

Answer 19

STEP 1: Light energy excites electrons in chlorophyll - Light energy is absorbed by PSII - This excites electrons - The electrons move to a higher energy level - They move down the ETC to PSI STEP 2: Photolysis of water produces protons, electrons and Oշ - As electrons leave PSII they must be replaced - Light energy splits water in photolysis to replace them STEP 3: Energy from the excited electrons make ATP - Electrons lose energy as they move down ETC - Energy is used to transport protons into t- thylakoids - To have a higher conc. than the stroma - A proton gradient forms across the membrane - Protons move down their conc. gradient into stroma via ATP Synthase (enzyme) - This then makes energy for the combination of ADP and Pi to = ATP - This process is called Chemiosmosis STEP 4: The energy also generates NADPH - Light energy is absorbed by PSI = This excites electrons even more than before to an even higher energy level - The electrons are transferred to NADP with H+ from stroma to = NADPH

Answer 20

- Takes place in the stroma of chloroplasts - ATP and NADPH that are needed are made in the light-dependent stage - Also known as Carbon Dioxide Fixation b/c C from COշ is ‘fixed’ into an organic molecule

Answer 21

STEP 1: COշ is combined w/ RuBP to = GP - COշ enters the leaf through the stomata - It diffuses into the stroma of a chloroplast - It combines w/ RuBP (ribulose biphosphate) - This reaction is catalysed by RUBISCO - An unstable 6-C compound is made - This is broken down into 2x 3-C compounds, GP (glycerate 3-phosphate) STEP 2: GP is reduced to GALP - Hydrolysis of ATP makes energy to turn GP into another 3-C Compound, GALP (glyceraldehyde 3-phosphate) - This also requires H+ ions, which comes from NADPH - NADPH is recycled to NADP - 1-C from GALP is converted into other useful organic compounds - E.g glucose, which requires 6 cycles - 2x molecules of GALP can make a hexose sugar - The 5-C leftover continue in the cycle STEP 3: RuBP is regenerated - The 5-C leftover of GALP is used to regenerate RuBP - This uses the rest of the ATP produced by the light-dependent

Answer 22

The Calvin Cycle Products can make other organic substances, such as; Carbohydrates = simple sugars (e.g glucose) from - 2x GALP, and polysaccharides (e.g starch and cellulose) - Made by joining 2x hexose sugars - Glucose is v. important in respiration for energy for biological processes Lipids = made using glycerol, that's synthesised from GALP and fatty acids - Fatty acids are synthesised from GP - Amino Acids = some are made from GP - Nucleic Acids = sugar in RNA is made using GALP

Answer 23

- They’re flattened organelles in plant cells - Have a double membrane called chloroplasts envelope - Keeps reactants close to their reaction sites - Has thylakoids, which have a large SA = light energy can be absorbed - Lots of ATP synthases in thylakoid membranes - Contain photosynthetic pigments - Coloured substances to absorb light energy - Found in thylakoid membranes and attached to proteins - Protein + pigment = photosystem

Answer 24

Two photosystems = Photosystem I and Photosystem II - Photosystem I absorbs light at 700nm - Photosystem II absorbs light at 680nm - Stroma contains enzymes, sugars and organic acids required for light independent - Also contains oil droplets, which store non-carbohydrate organic material - Photosynthesis takes place in chloroplasts

Answer 25

Can be used to investigate photosynthesis - In light dependent, NADP acts as an electron acceptor - It accepts electrons and a proton to become NADPH - Oxygen is released as a byproduct This is called the Hill reaction - Can investigate it using a redox indicator dye (DCPIP) to isolate chloroplasts - The dye acts as an electron acceptor, and changes colour once oxidised - Blue → Clear 1. Cut a few leaves into pieces→to test→careful w/ sharp objects - Make sure to remove any tough stalks 2. The grind up the pieces in a blender w/ 20cm3 chilled isolation medium→preserves enzyme activity 3. Filter the liquid into a beaker w/ a funnel lined w/ muslin cloth→ to separate the solution and leaves→be careful to not spill any and slip 4. Wring the muslin cloth into the beaker→not waste any 5. Transfer to centrifuge tubes and centrifuge at high speed for 10 mins→pellet will gather at the bottom 6. Remove the liquid from the tubes (supernatant) 7. Resuspend the pellet in chilled isolation solution (leaf extract)→to act as a buffer 8. Set up 4 test tubes: A = DCPIP+Leaf extract, B= DCPIP+Buffer, C= no DCPIP+Leaf extract, X= DCPIP+Leaf extract, Y= DCPIP+Supernatant - To remember B=Buffer, C=Colour Compare, - X=Xrays in the dark, Y=You-seful/ Y you change colour - ABC are controls, X and Y are the tests 9. Place A, B, C and Y in front of a lamp, and X in the dark 10. Record how long it takes them to go from blue to green→till Oշ is produced - The faster the colour change the faster the rate of the Hill reaction - A shouldn’t change, shows chloroplasts (in supernatant) cause the changes (Blue) - If it does change then it means in blending the pellet got damaged so some ETC’s entered the leaf extract (leaf extract is the pellet)

Answer 26

B is to show that the DCPIP won’t just go colourless on its own (Blue) C is used to compare the other test tubes against to see if DCPIP goes colourless X is to show that the hill reaction needs light to work (Blue) Y is the one that should go from blue to green b/c the supernatant contains ETC and so the DCPIP can act as an electron acceptor for it (Green)

Answer 27

Energy is transferred through ecosystems - It enters an ecosystem from photosynthesis - Producers (plants)= convert sunlight energy into a form that can be used by other organisms - Store energy as biomass, energy transfer is basically biomass transfer - Ecological efficiency = net production of new biomass at each trophic level Biomass = the mass of living material Primary Consumers = organisms who eat producers Secondary Consumers = organisms who eat primary consumers Tertiary Consumers = organisms who eat secondary consumers - Each stage is called a trophic level

Answer 28

A lot (90%) of energy is wasted in biomass transfer - 60% is never taken in - Plants can’t use all the energy that reaches their leaves, so it’s reflected or passes through - The sunlight might hit parts of a plant that can’t photosynthesise (e.g bark) - Some parts of food aren’t eaten so they pass to decomposers - Decomposers = organisms that break down dead or undigested material - Some parts are indigestible so pass through organisms as waste to decomposers

Answer 29

Net productivity = the volume of energy available for the next trophic level - NPP = Gross Primary Productivity - Respiratory Loss

Answer 30

Net primary productivity = net productivity for producers

Answer 31

Calculating energy transfer efficiency = (net / energy received) x 100

Answer 32

Gross primary productivity = NPP - plant respiration

Answer 33

- Measure the dry mass of the organisms for how much energy it contains - Dry out the organisms in an oven at a low temp - Then weigh at regular intervals - Once constant, the water has been removed so this is its biomass - Do this for both organisms and work out the difference - May not work though b/c the higher trophic level might have received biomass from other organisms so it isn't accurate

Answer 34

Climate change = long-term changes in global weather patterns - Or a significant change in the weather of a region over a period of several decades - Inc. natural variations but is mostly changes caused by humans

Answer 35

Global warming = rapid ↑ in global temperature over the last century - Which causes other types of climate change

Answer 36

- Been measured using thermometers since the 1850s - Gives a reliable, short term record of global temp change

Answer 37

- Method to figure out how old a tree is using its tree rings - Most trees produce one ring per year - Ring thickness depends on the climate - When warmer the rings will be thicker b/c of better growth conditions - Cores from tree trunks can be taken and then each ring can be dated - The thickness of each ring then gives us an idea of the climate

Answer 38

- Shows how temp has changed over thousands of years - Pollen is preserved in peat bogs - Peat bogs = acidic wetland areas - Peat bogs accumulate in layers, so older preserved pollen are deeper down - Cores from peat bogs can be taken and pollen grain extracted - The pollen grains can then tell us which plant it came from - Only fully grown plants produce pollen, so the species were successful at one point - Plants in today's climate living in the past mean there was a similar climate then - Plant species vary w/ climate so preserved pollen will vary w/ time - A gradual ↑ in pollen of one species that is more successful in warmer climates show a rise in temp

Answer 39

Anthropogenic = human activity - Human activity has caused global warming by enhancing the greenhouse effect - Greenhouse effect = the effect of greenhouse gases absorbing outgoing energy, so less is lost to space - But the greenhouse effect is essential to keep the planet warm - Disputed b/c of bias scientists, how good and reliable the data is

Answer 40

COշ = global warming - Atmospheric COշ has ↑ by over 100 ppm since mid-19th century - It was stable for the previous 10 000 years - It continues to ↑ b/c of burning fossil fuels and destruction of natural sinks - Natural sinks store C as organic compounds - COշ is released when trees are burnt, or when decomposers break down the organic compounds and respire them

Answer 41

CH4 = global warming - Atmospheric CH4 conc. has more than doubled since mid-19th century - It was stable for the past 850 years - It continues to ↑ b/c more is being released - More fossil fuels are being extracted, and there are more cattle - Released from natural stores, e.g frozen ground

Answer 42

- Data can be extrapolated to form predictions about the future - These can then produce models of how the global climate might change

Answer 43

- Don’t know how much greenhouse gas emissions will change - I.e which scenario would be most accurate - Don’t know how much each scenario will cause temp to rise by - Atmospheric greenhouse gas conc. might change b/c of natural causes - There may be attempts to manage the atmospheric conc. or their success - There are complex feedback systems inv. so won’t know the exact effects on climate

Answer 44

An ↑ in temp will affect enzyme activity - It will ↑ the rate initially due to more kinetic energy - But if the temp goes too high, some bonds will break, ruining the enzyme’s shape - Active site will change shape = no enzyme-substrate complexes form - The enzymes will become denatured

Answer 45

Metabolism = chemical reactions that take place in its cells to keep it alive - Metabolic reactions are controlled by enzymes - A faster enzyme rate = develop and progress through their life cycle faster - They’re inv. in photosynthesis, so plants may grow faster and die quicker - Cyanobacteria can produce toxins and they photosynthesise - They will produce more toxins which are harmful to humans - A slow/ stopped enzyme rate = develop and progress through their life cycle slower - Above 25°C wheat develop fewer grains so yields will ↓ - The eggs of cold water fish won’t hatch as they develop at low temps

Answer 46

Species’ ideal conditions may be more common - Subtropical plankton species are being found up north b/c of warmer seas - European butterflies are being found up north b/c of warmer weather Species’ ideal conditions may become rare - Alpine plants grow in cooler conditions and so are moving further up mountains - Ice caps are melting so polar bears have smaller habitats and ↑ competition

Answer 47

- It can affect development and life cycles - Ocotillo is dormant during dry periods, so more dry periods = longer dormancy periods - It can affect distribution - ↓ rainfall = ↑ deserts, species will have to find new habitats if their original one becomes a desert

Answer 48

- It can affect development and life cycles - Red squirrels in Canada are giving birth earlier b/c of an earlier availability of food - It can affect distribution - Some swallows live in South Africa in winter, and Europe in spring and summer to breed - An earlier spring means flowers and insects are earlier than usual - When the swallows come to europe, there will be less food available - Less swallows will be born which may lead to extinction

Answer 49

1. Plant seedlings in soil trays and measure their height 2. Place the trays in incubators at dif. temps 3. Make sure other variables are the same 4. Then record the change of height 5. Calculate average growth rate using→average change / incubation period

Answer 50

1. Plant an equal no. of brine shrimp eggs in water baths of dif. temps 2. Make sure other variables are the same 3. Record the no. of hatched brine shrimp 4. Calculate average hatch rate using→no. of hatched eggs / no. of hours

Answer 51

1. Set up boiling tubes of same volume and conc. of hydrogen peroxide 2. Add the same volume of buffer solution to each→to maintain pH 3. Place a bung w/ a delivery tube in the boiling tube. Then place an upside down measuring cylinder in a trough of water. The delivery tube should go under and into the measuring cylinder 4. Then place each set up in dif. water baths which are at dif. temperatures 5. Using a pipette, add the same volume and conc. of catalase to each boiling tube before quickly reattaching the bung 6. Record how much Oշ is produced every 10s by recording how much the water in the cylinder moves down

Answer 52

Initial rate of reaction can be calculated by finding the gradient of the tangent at that point

Answer 53

Q10 = the temperature coefficient - Shows how rate changes w/ a temperature ↑ of 10℃ = rate at higher temperature rate at lower temperature - A value of 2 means the rate doubles, a value of 3 means the rate trebles - Most enzyme-controlled reactions have a Q10 of ~2

Answer 54

- Absorbed by plants during photosynthesis = C compounds in plant tissues - Passed onto animals from eating plants and to decomposers from dead organic matter - Returned to the atmosphere from respiration - C compounds can be turned into fossil fuels - Combustion of fossil fuels releases COշ into the atmosphere - To reduce conc. of COշ, volume going into the atmosphere needs to ↓ - Or the volume being taken out of the atmosphere needs to ↑

Answer 55

- Produced from biomass (material that is or was previously living) - Often from crops so can be replanted = a sustainable resource - They’re burnt to release energy, producing COշ - No net ↑ in atmospheric COշ conc. - Volume produced = volume taken in during growing

Answer 56

- Planting new trees in existing forests that have shrunk - More trees = more COշ removed from atmosphere - COշ becomes C compounds and is stored in the plant tissues - Less C in atmosphere so less C for global warming

Answer 57

- Farmers will support b/c gov will fund the farming of the crops - Drivers will support b/c price of biofuels is lower than oil-based - Consumers will oppose b/c less farmland for food so ↑ food costs - Conservationists will oppose b/c forests will have to be cleared for space

Answer 58

- Manufacturers will support b/c their sales will ↑ - Environmentalists will support b/c electricity produced w/o COշ - Local will oppose b/c they’re ugly - Bird conservationists will oppose b/c many birds killed by them

Answer 59

Evolution = changes in allele frequency in a population over time

Answer 60

1. Individuals w/n a pop. vary b/c of dif. alleles 2. The dif. alleles are due to gene mutation 3. This means some individuals are better adapted than others 4. Individual w/ an allele that ↑ the chance of survival is more likely to survive (intraspecific competition), reproduce and pass on the allele 5. A greater proportion of the next gen. will inherit the beneficial allele 6. Meaning they are also more likely to survive and reproduce

Answer 61

Geographical Speciation = Allopatric Speciation - They will experience dif. conditions - Dif. selection pressures = dif. changes - b/c of natural selection - Allele frequency changes = diff. in the gene pool = changes in phenotypic frequencies - Eventually, the dif. pops will become genetically distinct - The two pops won’t be able to breed and produce fertile offspring - They’ve been reproductively isolated = separate species

Answer 62

- Seasonal diff. = dif. flowering/ mating/ sexually active seasons - Mechanical diff. = dif. genitalia preventing mating - Behavioural diff. = courtship rituals that aren’t attractive to others

Answer 63

- Random mutations occurring w/n a population - Lead to reproductive isolation - E.g polyploidy = ↑ no. of chromosomes

Answer 64

- Uses DNA technology to determine base sequence of an organism’s genome and functions of its genes - Scientists can make comparisons b/w organisms DNA - Theory of evolution = all organisms evolved from shared common ancestors - The more closely related species the earlier the diversion - b/c less time for changes in DNA sequence

Answer 65

The study of proteins - The sequence of amino acids is coded by the DNA sequence - Related organisms = similar DNA sequences = similar amino acid sequences - The more similar proteins = the more recent divergence

Answer 66

Peer Review = before their work can be published - Other scientists in that area review the work - They check the work is valid and supports the conclusions - Makes sure the experiment was carried out to a high standard Scientific journal = academic magazines where they publish articles - Share new ideas, experiments, evidence, theories and conclusions - Can repeat experiments using same methods to get the same results - Replicated results means the evidence is reliable Scientific Conferences = meetings to discuss each others work - Present their work w/ a lecture or poster presentation - Other scientists can ask questions and discuss their work - An easy way for the latest theories to be shared and discussed

Topic 5 Flashcards

(90 cards)