Topic 5 Flashcards
Ecosystem
Distinctive features affecting organism living there abiotic (non-living)/biotic (living)
Abiotic factors (physical/chemical)
Climate- temperature
Solar energy- light can affect animal behaviour and photosynthesis
Pollution
O2 concentration
Biotic factors
Completion- either interspecific (between species) or intraspecific (within species)
Diseases
Predation
Succession
Change in species over time
Primary succession- starts in new habitat where no species been before
Secondary succession- occurs where existing species have been cleared
Pioneer species (adaptations)
A species that colonises area first
Adaptations: -rapid growth
-short life cycle
-can be spread by wind
Deflected succession
Human activity preventing succession from running its course
What are autotrophs
Organisms that make their own organic compounds from inorganic compounds
Photosynthesis
6CO2 + 6H20———>C6H12O6 + 6O2
In photosynthesis energy from light break C02 and water bonds, so products are at a higher energy than reactants (act as energy store)
Photolysis of water
Occurs in granum ,it’s the splitting of OH bonds with light energy into O and H
Uses of glucose in plants
Used in aerobic respiration to release energy and C02 and glucose can be stored as starch or cellulose
Light dependant reaction
-Uses energy from light and H+ from photolysis of water to produce NADPH, ATP and O2 (waste product). O2 used in respiration or release. Occurs in thykloid membrane.
1)Light raises two electrons in chlorophyll to higher energy level (chlorophyll excited)
2)electrons leave chlorophyll via ETC
3)Photolysis of water to produce O2, electrons and H+ ions
4)Electrons move across ETC
5)Photophoshorylation to produce ATP
6)Reduction of NADP
Light independent reaction
Occurs in stroma. Uses ATP are NADPH from LDR to reduce C02 to carbohydrates (glucose)
1)RuBP combines with C02 in Carbon fixation catalysed by RUBISCO
2)Unstable 6 carbon formed breaks down into two molecules of GP
3)NADPH and ATP are used to reduce two GP molecules into GALP
4)2/12 GALP used to make 6-carbon sugar (hexose) which is converted into their compounds (lipids,amino acids)
5)the 10/12 GALP involved to recreate RuBP with ATP (phosphorylation/adding inorganic phosphate) so process can repeats
Structure of Chloroplast
Stroma- has enzymes needed for LIDR
DNA loop- contains genes for some proteins
Starch grain- stores product of photosynthesis
Granum- stack of thylakoids
Inner membrane- contains transporter molecules, inner/outer membrane form envelope
Outer membrane- freely preamble to C02 and H20
Thykaloid space- has enzymes for photolysis
Thykaloid membranes- system of flattens sacs, includes photosynthetic pigment chlorophyll and electrons involved in LDR
Role of ATP
-Energy carrier molecule
-Moves energy from energy yeilding to energy requiring reactions
-ATP is a nucleotide consisting of Adenine, Ribose and 3 phosphate group. When 3rd group removed ADP is formed and group becomes hydrated forming bonds with water. ATPase catalyses ATP—>ADP
-ATP+inorganic phosphate = ATP (ATP has higher energy in water than ADP)
Uses of glucose produced in Calvin cycle
Respiration
Make sucrose to be transported via phloem
Polymerases to form cellulose
Used to make lipids/proteins
Heterotrophs
Organisms obtaining energy as organic matter by ingesting material from other organisms
Detritivores
Primary consumers feeding on dead organic material
Gross primary productivity and Net primary productivity
—>GPP- rate of which energy is incorporated into organisms by ecosystem
—>NPP-rate of which energy is transferred into molecules making up new plant biomass
NPP=GPP-R (respiration)
What evidence is there for climate change
Temperature record
Peat bogs
Dendrochronology
Peat bogs
Pollen from peat bogs is useful as:
-pollen has outer layer resistant to decay
-plant produce large amount of pollen
-each plant species have distinctive pollen type
-peat forms layers the deeper the older, carbon 14 dating allows age to be determined
Tree ring analysis
Each year new xylem vessel produced by cell division, wider vessels in summer/spring and narrower in winter/autumn (little growth)
Green house effect
Sun radiates energy and some absorbed by earth and some reflected as infrared radiation. Some energy absorbed by greenhouse gases in atmosphere warming it up
Factors affecting global warming
-Increased C02
-other green house gases (methane)
-cloud cover
-degree of reflection
-changes in sun radiation
Darwin’s theory’s
-Organism produce more offspring that can survive and reproduce so as populations grow their is a struggle for existence due to environmental factors
-there are huge amounts of variation in species so species with best adaptions will survive (selective adv) and natural selection is occurring
How can variation occur in populations
alleles can arise through random mutations creating variation
Molecular evidence for DNA
—>DNA hybridisation- heat DNA from both sets to separate strands. Mix two strands to make a hybrid and complementary bases will occur (not all). Heat hybrid to separate stands the higher the temp the more closely related.
—>DNA profiling- using restriction enzymes to cut DNA at specific sequences to provide fragments which can be visualised on profiles. If mutation occurs enzyme can’t cut DNA
—>DNA/protein sequncing- comparing base sequences few differences show close relationships
—>Molecular clock- PCR to produce DNA copies allowing quick determination of sequences, as species evolve they mutate randomly becoming genetically different. Molecular change on clock used to pinpoint evolution events.
Speciation
Formation of new species
Allopatric speciation- occurs when there is geographical isolation
Sympatric speciation- populations become reproductively isolated
Role of microbes in carbon cycle
They recycle plant biomass via respiration and release C02
Other factors affecting C02
-Volcanos release C02
-Increase of acid rain in areas C02
-War, water holds lees C02 (sea water)
How to maintain C02 balance
Reforestation
Use of sustainable resources
Controversial: -wind farms produce energy affecting C02
-production of biofueL can reuse C02
