Topic 5 Flashcards
What is a biosphere
A part of the earth and its atmosphere that is inhabited by living organisms
What are biotic factors and give example
Living factors
Competition,predation ,mutualism
What are abiotic factors and give examples
Non living factors
Climate
Pollution
Topography
Solar energy input
What is a habitat
A distinct set of conditions where an organisms lives and several populations of organisms live there
What is meant by ecosystem
An area with a distinct set of features that affects where an organism lives
What is a population
A group of interbreeding individuals from the same species
What is a community
Various populations sharing a habitat or ecosystems
What is a niche
The role of an organism in its environment
Ie if It’s a predator or prey
What does topography mean
It includes things like altitude,drainage
What are edaphic factors
They are connected with soil,mineral concentration
What is abundance
In a certain area it’s the number of individuals of a single species
What is Distribution
This is the location of a particular species in your area of investigation
Why is it important that sampling is random
In order to avoid biases
When is non random sampling used
When there is a high variation in abiotic features or distribution in a habitat
What is systematic sampling
When samples are taken along a line at fixed intervals
I.e. Quadrats are placed along a transect
How are frame quadrats used in an investigation
An area could be selected and using a randon number generator co ordinates can be selected and this is where the quadrat is placed
Plant species is percentage cover is measured by how much the quadrat covers it
How are point quadrats used
They are placed on the group with the pins going through holes
And every plant that touches the pin is recorded
Percentage cover is measure by calculating the amount of pins that touch a given species
How are interrupted transects used
Measurements are taken at intervals i.e. Placing the quadrat down at every 5 m
How are lone transects used
along a transect a tape measure is placed and the species that touch the tape measure are recorded
What is succession
When a community started by organisms changes over time
What are the two types of successions
Primary and secondary succession
Distinguish between primary and secondary succession
Primary succession occurs in newly formed habitats where there hasn’t been a community
Secondary succession occurs on bare soil where a existing community had been previously
In primary succession what are the pioneer species and why are they crucial
They are species like algae and lichens and are the first organisms to colonise bare rock
They are the only species that are capable of coping with the extreme temperature lack of soil,water,nutrients
What 2 things occur in the pioneer phase of succession
The pioneer species begin to break up the rock surface which enables some organic material to build up in the spaces marking the beginnings of soil
They change the conditions in the habitat which enables it to be suitable for other species
As succession continues what does the development or Moss spores cause (Stage 2)
It allows the build up of more organic matter called hummus in the soil meaning water can be held up meaning seeds begin to germinate and survive
As succession continues in primary succession what do improving conditions in the habitat enable
(Stage 2)
It allows for large taller plant species to colonise and they compete with plant species
What happens when larger plant species compete with existing in plant species in primary succession (stage2)
They end up winning and replace the existing community
In primary succession what eventually occurs in the community as succession continues (last stage)
The community is dominated by trees and it results in a stable climax community
What is the dominant species of the community in primary succession
The species that exerts an overriding influence over the rest of the plant,mircrobe and animal species
And it has the highest abundance
What is meant by co- dominance
When several species share the role as the dominant one
What is a climax community
It means the ecosystem is supporting the largest and most complex community of plants and animals and is stable
It’s the final stage of succession
What is secondary succession and where does it occur
It’s when a community begins to develop on bare soil that has been occupied by a previous community
For pioneer species give some adaptations of seed dispersal (start of secondary succession)
Wind dispersal
Rapid growth
Animals
Abundant seed population
What is deflected succession
When a community is only remaining stable due to human activity preventing succession from running its course
Give some comparisons between primary and secondary succession
Primary- takes a longer time to complete
Secondary- takes less time to complete
Primary- it occurs in an area that’s lifeless or barren
Secondary-takes place on an area that was previously inhabited
Primary-soil is absent at the beginning of primary succession and environment isn’t suitable for life
Secondary -soil is present at the beginning of secondary succession and some of previous occupants remain
Primary -No hummus in the beginning as soil is absent
Secondary-hummus is present from the beginning by decomposition of previous occupants
What is primary productivity
The rate energy is incorporated into organic molecules in ecosystem
What are autotrophs
Organisms that can make their own organic compounds from inorganic compounds they are producers
What is meant by some primary producers being photosynthetic
Means they gain energy from sunlight
What is meant by chemosythetic autrophs
They make organic molecules from energy that’s is released from chemical reactions
What are hetrophs
These are organisms that can’t synthesis food for themselfves so rely on other organisms to gain food
What is meant by photolysis
This is the splitting of water into hydrogen and oxygen from energy from sunlight
What are the uses of glucose in a plant
Can be converts into starch
Used to make cellulose
Fats
Amino acids
What are the two main stages in photosynthesis
Light dependant reactions
Light independent reactions
What is reduction and what is oxidation
Reduction is gaining of electrons
Oxidation loss of electrons
What is the site of photosynthesis in a plant and where is it located
Cholorplast and it’s located in the palisade mesophyll
Name the parts of the chloroplast and their functions
Thylakoids membrane-system of fluid filled sacs which has proteins and electron carriers in the memebranes that are involved in LDR
Starch gran-stores the products of photosynthesis
Granum-stacks of thylakoids joined together
Stroma-a fluid that surrounds the thylakoids and contains enzymes needed to carry out light independent reactions
Inner membrane-contains transports molecules that regulate passage of substances in and out of chloroplast
DNA loop- contains genes for proteins of chloroplast
Outer membrane is permeable for molecules I
What are the two types of chlorophyll called
PS1 PSII
Describe stages in LDR when light is first absorbed by PS1 and PS 11 chlorophyll
1 cholorphyll molecules are in an exited state as light energy raises two electrons in each cholophyll molecule to a higher level
- After leaving the excited state electrons go along a series of electron carrier molecules this forms an electron transport chain which is embedded in thylakoid membrane
- .psII chlorophyll, its electrons as they pass from carrier to carrier, lose energy in a series of oxidation and reductions,
- PS1 cholophyll loses its electrons and they are replaced by electrons from PSII chlorophyll
What is the energy that the electrons lose in PSII chlorophyll used for
It’s used in photophosphotylation which is the synthesis of ATP
Describe the remaining stages in LDR from photolysis
5.The electrons from the PSII have to be replaced for electron flow to continue
6 in the thylakoids space photolysis occurs which produces electrons,oxygen gas and hydrogen ions and they replace the electrons lost from PSII chlorophyll meaning its not got a charge
7 reduced Nadp forms from electrons from the PS1 chlorophyll combing with Co enzyme NAdp and hydrogen ions from water
What are the Reduced Nadp and ATP used for
They are used in the light independent reactions
What is ATP
It’s an energy transferring molecule and it has a adenine base,5-base ribose and 3 phosphate groups
Describe how ATP releases energy
ADP first forms in which the third phosphate is removed and becomes hydrated with water molecules forming bonds
The formation of theses bonds between water and phosphate causes a lot of energy to be released which drives reactions
What enzyme catalysed the breakdown of ATP into ADP
Atpase
What is phosphorylation
The synthesis of ATP by adding an inorganic phosphate to ADP
Where does the L I R take place and what does it use
It takes place in the storma and it used reduced Nadp and ATP
What is the Calvin cycle and what molecule is made
It fixes carbon in organic molecules and GAlp is made
Where does the light independent reaction take place and what is used in the reaction
It takes placed in the stroma of chloroplasts ATP and reduced Nadp are used
What is the GAlp used for
To make glucose
Describe each stage of the Calvin cycle
The 6CO2 combines with RUBp and the reaction is catalysed with the enzyme Rubisco
- the 6- carbon compound that is formed breaks down to form 2-3 Carbon molecules called Glycerate3-phosphate
- this 3-carbon compound is reduced to form Galp
The reduced Nadp from the light dependant reaction provides the hydrogen for the reduction of GP into GAlp
While ATP provides the energy for this reaction
- 2 out of every 12 Galps formed are involved in the making of hexose this is converted to other organic compounds
- 10/12 Galps are used in the recreation of RUBp and ATP is used in the phosphorylation forming RUBP
What can the glucose be used for
Used in making starch and cellulose
Can be used In Respiration
Can be used to make amino acids
Used to make sucrose
What are autotrophs
They are produced and can make their own food via photosynthesis
What are heterotrophs
They are organisms that obtain energy(organic matter) by ingesting material from organisms
What are primary consumers
These are herbivores that consume plant material
What are secondary consumers
These are carnivores they feed on primary carnivores
What are tertiary consumers
They are top of the food chain and feed on other consumers
What are decomposes
They feed on dead remains of organisms and animals faces
What are detritvores
They feed on dead organic matter called detritus and they primary civsynwrs
Give reasons as to why not all energy is passed into trophic level
Some food pass as waste so energy is lost
Some energy is lost by respiration which energy is used for movement or body heat
Not all light energy is used by plant lost photosynthesis or reflected
What is GPP
The rate at which energy is by an ecosystem absorbed into organic molecules
What is net primary productivity
The amount of energy available to the next trophic level
How is NPP calculated
Gross productivity-respiratory loss
What pieces of evidence is their for climate change
Dendrochronology
Temperature records
Pollen in peat bogs
Rain fall patterns
What is dendrochronology
The study of tree rings
What is peat
It’s formed when organic matter decays,it’s remains of dead plants in which pollen grand are well preserved
What is trophic level
The position of a species in a food chain
Give reasons as to why pollen from peat is useful when studying climate change
Peat is resistant to decay due to our layer
We get a large sample as it’s produced in vast amounts by plants
Peat forms in layers so the deeper it is the older the peat we can find it’s she
Plant species have a certain type of pollen so we can identify the plant species from the peat
What is the green house effect
When gases in the earths atomsphere absorb energy that reflected from the surface of the earth hence warming it up
Give examples of greenhouse gases
Oxygen Water Co2 Methane Nitrous oxide
Why is climate change such a controversial issue
Scientific methods can’t prove theories only disprove them
Not many people believe in climate change
Scientific evidence is sometimes biased
Data sets used in making predictions are limited
What is extrapolation
Is the extending of a line in order to make assumptions
What does extrapolation allow us to assume
That present trends shown will continue
We have enough data to establish a trend accurately
What factors affect climate change
Green house gases
Changes in suns radiation
The fraction of earth covered with ice and snow
What problems are their with climate models
Limited data
Limited knowledge
Failure to take into account all climate change factors
Limiting in computing resources
Changing trends in factors
What are the two categories for changes that can be attributed to climate change
Changing distribution of species
Altered development and life cycle
How can change in distribution of species be caused by climate change
Some species may become more dominant as they can cope better with the new conditions and some may lose out
Crop yield may reduce Due to spread of pests and disease
What other factors change as a result of global warming
Changing rainfall patterns seasonal cycles
Life cycle
Describe how ATP works to produce energy
A phosphate is removed from the ATP forming ADP and the phosphate is hydrated in water it forms bond and this releases a lot of energy to drive reactions in cells
What is evolution
Change in allele frequency in a population over time and it occurs as a result of natural selection
Describe the stages in natural selection
Gene mutation causes different allele which means individuals in a population vary as they have different alleles
This means individuals are adapted to their environments than others selection pressures act on the population
Individuals with this allele are more likely to survive as it increases their chances of survival It means they can reproduce and pass on their gene
It means the greater proportion of the next generation are going to inherit the beneficial allele
They in turn are more likely to survive reproduce and their genes are passed in meaning the frequency of the beneficial allele increases from generation to generation
Give some examples of evidence for evolution
DNA molecular clocks
DNA hybridisation
DNA profiling
Dans and protein sequencing
Describe what happens in DNA hybridisation
DNA hybrid is made by mixing different strands of DNA
It’s then heated to see how long it takes to denature,DNA relatedness is measured by seeing the temperature needed to denature the hybrid
The more similar base sequences of the two species the higher the temperature needed for them to denature
What is speciation
The formation of new species as a result of isolation
State the two types of speciation and the difference between them
Allopatric and sympatric
Allopatric is when the populations are geographically isolated
Sympatric this is when the two populations are reproductively isolated e without a geographical barrier
What is meant by niche
The role an organism that plays in its environment
What is carbon fixation
That inorganic carbon from carbon dioxide is incorporated into organic molecules initially GO
What is the carbon cycle
The movement of carbon between organisms and the atmosphere
How is carbon absorbed from the atmosphere
It’s absorbed by plants when they carry out photosynthesis
How is the carbon passed on from plants
When they are eaten and digested by animals
State ways the carbon returns to the atmosphere
By respiration of organisms
By decomposes respiration on dead organisms
By combustion when we burn fossil fuels
State ways we can prevent an net overall increase in carbon emissions
Reforestation
Using biofuels as they are carbon neutral
What is carbon fixation
The first stage of the carbon cycle in which Co2 is combined with RuBP
What is meant by genetic diversity in a gene pool
The variety of alleles in a gene pool
