Biology Unit 4

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  • Created by: Sacha
  • Created on: 10-06-13 18:54
Ecology is the study of the life-supporting layer of land, known as the _____?
Biosphere
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Define the term 'ecosystem'?
A self contained functional unit consisting of all of the interacting biotic and abiotic features in a specific area
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Which two major processes within an ecosystem must be considered?
The flow of energy through the system and the cycling of elements within the system
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Define the term 'population'?
A group of individuals of the same species that occupy the same habitat at the same time
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Define the term 'community'?
All of the organisms of all the species that live in an area at the same time, interacting with each other
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Define the term 'habitat'?
The place where a community of organisms lives
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To study a habitat, it is often necessary to count the number of individuals of a species in a given space. This is known as ______?
Abundance
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What are the two types of quadrat?
Point and frame quadrats
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What are the two types of transect?
Line and belt transect
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Complete this sentence: Systematic sampling is more suitable when ______
There is some form of transition in the communities of plants and animals
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In which two ways can abundance be measured?
Frequency and percentage cover
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What is the formula to estimate population size?
(total number of individuals in the first sample) x (total number of individuals in the second sample) / number of marked individuals recaptured
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Which 4 abiotic factors affect population size?
Temperature, light, pH and water/humidity
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This type of competition occurs when individuals of the same species compete for resources
Intraspecific
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This type of competition occurs when individuals of different species compete for resources
Interspecific
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What is meant by the 'competitive exclusion principle'?
No two species can occupy the same niche indefinitely when resources are limiting
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Define 'predation'?
One organism is consumed by the other
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Aside from predation, name two other factors that may influence population size?
Disease and climate
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These periodic popuation decreases create what is known as __________?
Selection pressure
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What is meant by 'selection pressure'?
Only those who are able to escape predators/withstand disease or adverse climate survive to reproduce
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Which two major events have caused an explosion in the human population?
The development of agriculture and the development of manufacturing and trade that created the industrial revolution
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What is the formula for calculating population growth?
(Births + immigration) - (deaths + emigration)
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What is the formula for calculating percentage population growth?
(Population change during period / population at the start of the period) x 100
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What is the formula to calculate birth rate?
(number of births per year / total population in the same year) x 1000
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What is the formula to calculate death rate?
(number of deaths per year / total population in the same year) x 1000
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What is meant by the term 'demographic transition'?
A change in society from low life expectancy and high birth rates to one with long life expectancy and low birth rates
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What is meant by 'energy'?
The ability to do work
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What is meant by the term 'activation energy' in relation to ATP?
Bonds between phosphate groups are unstable and so are broken easily
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What is the full name of ATP?
Adenosine triphosphate
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What are the two components of ATP?
Adenosine diphosphate (ADP) + Pi (inorganic phosphate)
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The type of ATP synthesis that takes place during photosynthesis in chlorophyll-containing plant cells is called _____?
Photophosphorylation
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The type of ATP synthesis that takes place in the mitochondria of cells during the electron transport chain is called ______?
Oxidative phosphorylation
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The type of ATP synthesis that takes place in cells when phosphate groups are transferred from donor molecules to ADP to make ATP is called ______?
Substrate-level phosphorylation
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Why is ATP sometimes referred to as the 'immediate energy source' of the cell?
The instability of the phosphate bonds means that it is broken down very quickly and easily
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Why is ATP a better immediate energy source than glucose?
Each ATP molecule releases less energy than glucose molecules, meaning that less heat is released, which could denature cells and enzymes and ATP is broken down in one reaction (hydrolysis), releasing energy immediately
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Name three adaptations of the leaf for photosynthesis?
Large surface area that collects as much sunlight as possible / arrangement of leaves that minimises overlapping, so no leaf shadows another / thin, so the diffusion distance is short
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How are the grana adapted for photosynthesis?
Thylakoids increase the surface area for the attachment of chlorophyll, electron carriers and enzymes
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How is the stroma adapted for photosynthesis?
Contains enzymes needed
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What are the products of the light-dependent reaction?
Oxygen, ATP and reduced NADP
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What are the products of the light-independent reaction?
Sugars (Glucose) and other organic molecules
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The splitting of water in H+ ions and OH- ions during photosynthesis is known as _____?
Photolysis
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Name three limiting factors of photosynthesis?
Light intensity, carbon dioxide concentration and temperature
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What is produced during aerobic respiration?
CO2, water and ATP
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What is produced during anaerobic respiration?
Lactate/ethanol, CO2 (in plants) and little ATP
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Briefly describe what happens during glycolysis?
Glucose molecule is split into 2 3-carbon pyruvate molecules
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Briefly describe what happens during the link reaction?
Pyruvate is split into CO2 and a 2-carbon molecule called acetylco-A
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Briefly describe what happens during Krebs cycle?
Acetylco-A is introduced into a cycle of oxidation-reduction reactions that yield some ATP and a large number of electrons
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Briefly describe what happens during the electron transport chain?
Electrons are used to synthesise ATP, producing water as a by-product
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How is ethanol produced in plants and some microorganisms during anaerobic respiration?
Pyruvate loses a CO2 molecule and accepts hydrogen from reduced NAD to produce ethanol
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How is lactate produced in animals during anaerobic respiration?
Pyruvate takes up 2 hydrogen atoms from reduced NAD to form lactate
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What is meant by the term 'consumers'?
Organisms that obtain their energy by feeding on other organisms rather than using the energy of sunlight directly
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What is meant by the term 'decomposers'?
A group of organisms that break down dead producers and consumers into simple components, releasing valuable minerals and elements in a form that can be absorbed plants
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What is the name given to each stage in a food chain?
Trophic level
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Name one reason why not all of the Sun's energy is converted to organic matter by plants?
Over 90% of the Sun's energy is reflected back into space by clouds and dust
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What is the formula used to calculate net production (rate at which plants store energy)?
gross production - respiratory losses
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Name two reasons why only a little amount of energy is transferred across trophic levels
Some of the organism is not eaten / Some energy is lost as heat from respiration
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What is the formula used to calculate energy transfer?
(energy available after transfer) / (energy available before transfer) x 100
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Name a problem with using pyramids of number?
No account taken of size - one giant tree is the same size as one greenfly on the pyramid
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Name one problem with using pyramids of biomass?
Only shows organisms present at a particular time - seasonal differences are not shown
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Why is a pyramid of energy the most accurate representation of energy flow through a food chain?
Two organisms of equal mass may store different amounts of energy - e.g 1g of fat stores 2x as much energy as 1g of carbohydrate
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What is meant by the term 'agricultural ecosystem'?
An ecosystem made up largely of domesticated animals and plants used to produce food for mankind
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The ideal pesticide should...?
Be specific to the pest in question, biodegrade to harmless chemicals in the soil, be cost-effective and not accumulate
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Name one advantage of using a biological control?
The pests cannot become resistant
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Name one disadvantage of using a biological control?
Do not act as quickly, so yield may continue to decrease for some time
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Name one advantage of using a chemical pesticide?
Kills pests quickly
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Name one disadvantage of using a chemical pesticide?
Must be reapplied, making it expensive
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Name one way in which pests affect productivity?
Many pests carry diseases which can render the animals/crops damaged or unfit for human consumption
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What is the purpose of the greenhouse effect process?
Maintains the average temperature of 17 degrees C on Earth
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What does an organic fertiliser consist of?
Dead/decaying remains of plants and animal waste, e.g manure and bone meal
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What does an inorganic fertiliser consist of?
Minerals mined from rocks and deposits and blended to give the appropriate balance for a particular crop
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What is meant by 'leaching'?
Rain water dissolves soluble nutrients such as nitrates and carry them deep into soil. They then find their way into streams/rivers/lakes, where they can be harmful to humans (e.g prevention of efficent oxygen transport in babies)
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What is meant by eutrophication?
Increased amount of nitrates leads to an algal bloom, killing plants below. Dead plants leads to growth of saprobiotic algae. This leads to increased O2 demand. O2 is then in demand for aerobic organisms, e.g fish, which then die.
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What is the name given to the first species to colonise an inhospitable environment?
Pioneer species
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What is meant by the term 'genotype'?
The genetic constitution of an organism
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What is meant by the term 'phenotype'?
The observable characteristics of an organism
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If both alleles are the same (e.g both code for dominant brown eyes), this is known as _______?
Homozygous dominant
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What is meant by the term 'co-dominance'?
Both alleles contribute to the phenotype, e.g one red and one white allele in snapdragons results in a pink colour found in the phenotype.
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Other cards in this set

Card 2

Front

Define the term 'ecosystem'?

Back

A self contained functional unit consisting of all of the interacting biotic and abiotic features in a specific area

Card 3

Front

Which two major processes within an ecosystem must be considered?

Back

Preview of the front of card 3

Card 4

Front

Define the term 'population'?

Back

Preview of the front of card 4

Card 5

Front

Define the term 'community'?

Back

Preview of the front of card 5
View more cards

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