on the wild side Flashcards
colonisation
arrival of organisms on bare land
pioneer species
first species to colonise new land
usually algae/ lichens
can germinate easily and withstand harsh conditions such as low nutrient and water availability
climax community
final community formed containing all the plant and animal species that have now colonised the land
a stable community
plagioclimax
climax communities that develop due to human intervention
stable communities
would not have developed without human intervention
deflected succession
when a community becomes stable due to human activity preventing further succession
how can humans prevent succession?
regular mowing- prevents woody plant growth
grazing- prevents new plant growth
what does photosynthesis convert light energy into?
chemical energy
where is the chemical energy that is produced in photosynthesis stored?
in the biomass of producers
what is light energy used for in photosynthesis?
photolysis of H2O
what happens to the oxygen molecule produced in photosynthesis?
it is released into the atmosphere as waste
what is stored in the bonds of glucose molecules?
chemical energy
so glucose can function as fuel for respiration
what is the equation for photosynthesis?
6CO2 + 6H2O > C6H12O6 + 6O2
what are some processed that require ATP?
anabolic processes- building new molecules from the products of digestion
activation of chemicals
movement- muscle contraction
active transport
secretion
what does the hydrolysis of ATP produce?
inorganic phosphate
a small amount of energy
what is the hydrolysis of ATP catalysed by?
ATPase
what is the chloroplast envelope?
double membrane that keeps all components needed for photosynthesis close together
the transport proteins in inner membrane control flow of molecules between stroma and cytoplasm
the inner and outer membranes are both phospholipid bilayers
what is the stroma?
gel like fluid
contains enzymes that catalyse photosynthesis
contains sugars, ribosomes, chloroplast DNA
if chloroplast has been photosynthesising, may be starch grains or lipid drops
what is chloroplast DNA?
genes that code for some proteins used in photosynthesis
what are ribosomes in chloroplasts for?
enable translation of proteins coded by chloroplast DNA
what is the thylakoid membrane?
space between 2 membranes of this double membrane called thylakoid space where conditions differ from stroma
eg protein gradient can be established between stroma and thylakoid space
small volume so protein grad develops quickly
what is a thylakoid?
flattened fluid filled sacs
each surrounded by thylakoid membrane
what are grana?
creates large sa, maximising number of photosystems and allowing max light absorption
provide more membrane area for proteins like electron carriers and ATP synthase enzymes
stacks of thylakoids
What is lamellae?
membrane channels
connect grana
ensure grana connected but distanced
what are photosystems?
each photosystem absorbs light of a different wavelength, maximising light absorption
where do light dependant reactions take place?
across the thylakoid membrane
what is photolysis?
splitting of water molecules
enabled by light energy
produces 2H+, 2e-, O
what are the products of light dependant reactions?
ATP
NADPH
(used in light independent)
what is NADP?
a coenzyme
transfers H from one molecule to another
when NADP gains H it is reduced to formNADPH
NADPH can reduce other molecules by giving away H
can oxidise by receiving
what is an electron transport chain?
electrons pass from one protein along the chain, releasing energy as they do so
what is chemiosmosis?
H+ actively pumped from low conc in stroma to high conc in thylakoid, generating a conc grad
H+ diffuse back across the thylakoid membrane into stroma via ATP synthase enzymes embedded in the membrane
movement of H+ causes ATP synthase to catalyse production of ATP from ADP and Pi
what does cyclic phosphorylation produce?
ATP
where do light independent reactions reactions occur?
stroma
what is the process of light independent reactions?
CO2 and RuBP combined
catalysed by rubisco
results in a 6C compound
unstable so splits into 2 GP (3C)
energy from ATP and H from NADPH used to reduce 2GP to form 2 GALP
5 C form GALP used to regenerate RuBP, other C used to produce glucose
what is RuBP
ribulose biphosphate
5C
what is GP
glycerate 3 phosphate
3C
what does CO2 has been fixed mean?
removed from the external environment
become part of a molecule inside plant cell
what is primary productivity?
rate at which producers convert light energy into chemical energy
what is gross primary productivity?
rate at which chemical energy is converted into carbohydrates during photosynthesis
what is net primary productivity?
rate at which energy is stored in plant biomass
what is the equation for net primary productivity?
NPP = GPP - R
what is net productivity?
rate at which energy is converted into biomass in the body of a consumer
what evidence can be used to support climate change?
atmospheric CO2
average global temp
analysing pollen grains in peat bogs
dendrochronology
how is atmospheric CO2 investigated?
analyse gas composition of bubbles formed in ancient ice cores
how is peat formed?
under waterlogged and acidic conditions, partly decomposed dead plant matter accumulates and becomes compacted under its own weight
what do light coloured rings in a tree trunk show?
fast growth during spring/ summer warmer months
what do dark coloured rings in a tree trunk show?
slow autumn growth
explain the greenhouse effect
radiation from sun hits earth
radiated back from earths surface
greenhouse gases absorb it, trapping it in earths atmosphere
why is the greenhouse effect important?
so the earth is warm enough for life
since when have CO2 levels risen to the highest?
what are some examples of carbon sinks?
trees
soils
peat bogs
oceans
what human activities have lead to the significant increase of methane levels?
intensive cattle farming
organic matter decomposing in landfill
extraction of fossil fuels from underground
why do enzymes denature?
temp too high
kinetic energy increase and vibration of enzyme put a strain on its bonds
weaker H/ ionic bonds break
tertiary structure changes
active site denatures
no longer complementary to substrate, can’t bind, cant catalyse reaction
what does Q10 calculate?
the increase in rate when the temperature increases by 10
what are biofuels made from?
recently living plants biomass eg sugar cane
what are arguments for biofuels?
cheaper than oil
carbon neutral cos release C than was recently removed from atmosphere when plants were alive (fossil fuels release C stored for millions of years)
renewable cos regrown quickly
what are arguments against biofuels?
still release CO2
land needed to grow them cld be used for food production
creating the land destroys habitats eg rainforests so bad for biodiversity
cutting down mature trees for land decreases C removal by photosynthesis
what are cons of geothermal energy?
only can be used when there’s volcanic activity close to earths surface
what are cons of solar energy?
depends on sunshine hours
what are cons of wind energy?
depends on windspeed
concern ab impact of wind turbines on birds and bats
concern ab visual impacts on landscape
what are cons of tidal energy?
only generated near coast
what are ways for humans to increase global photosynthesis rates?
stop deforestation
plant trees/ reforestation- mature trees store lots of C in biomass
evolution definition
changes in the heritable characteristics of organisms over generations
selection pressures
environmental factors that influence survival chances
steps of natural selection
- variation is present in a pop
- selection pressure affects a pop
- those w advantageous alleles are more likely to survive and reproduce
- advantageous alleles passed onto offspring
- advantageous allele frequency in pop increases
speciation definiton
development of new species from pre- existing species over time
what type of speciation is due to geographical isolation?
allopatric
what type of speciation is due to random mutations that prevent interbreeding?
sympatric
what phenotype changes could lead to sympatric speciation?
mechanical- genetalia no longer match up
behavioural- no longer attract individuals to mate w
seasonal- reproductive timings dont match
steps of speciation with natural selection
- variation present
- selection pressures act on a pop- diff between 2 isolated pops
- advantageous alleles provide some individuals w increased survival and reproduction chances- diff advantageous alleles in isolated pops
- advantageous alleles passed on
- allele frequencies change- can no longer breed to produce fertile offspring
why are fossil records evidence of evolution?
fossils have changed over millions of years
can show evidence of transitional species which shows how one species could evolve into another
why is the development of antibiotics evidence for evolution?
antibiotics is selection pressure
increase in frequency of mutated gene
why is molecular evidence evidence for evolution?
analysis of DNA/ proteins show similarities between species that indicate evolution from a common ancestor
what is the theory of evolution?
all species on earth have evolved from a single common ancestor
how does the scientific community asses new ideas?
reading scientific journals
attending scientific conferences
what does non cyclic phosphorylation produce?
ATP
NADPH
