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Biology Edexcel Sophie > Topic 5 Photsynthesis evolution Climate > Flashcards

Topic 5 Photsynthesis evolution Climate Flashcards

1
Q

What is an ecosystem?

A

All the organisms living in a particular area and all the non-living (abiotic) factors

Ecosystems include both living (biotic) and non-living components interacting together.

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2
Q

Define habitat.

A

The place where an organism lives, e.g. a rocky shore or a field

Habitats provide the necessary resources for organisms to thrive.

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3
Q

What is a population in ecological terms?

A

All the organisms of one species in a habitat

Population refers specifically to individuals of a single species.

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4
Q

What does community refer to in ecology?

A

All of the organisms of different species that live in the same habitat and interact with each other

Communities are made up of multiple populations.

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5
Q

Define abiotic factors.

A

The non-living features of the ecosystem, e.g. temperature and availability of water

Abiotic factors are crucial for the survival of organisms.

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6
Q

What are biotic factors?

A

The living features of the ecosystem, e.g. the presence of predators or food

Biotic factors influence population dynamics and community structure.

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7
Q

What is abundance in ecological terms?

A

The number of individuals of one species in a particular area

Abundance is synonymous with population size.

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8
Q

How does population size vary with abiotic factors?

A

Population size varies due to factors like light, water, space, temperature, and chemical composition

Ideal abiotic conditions support faster growth and reproduction.

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9
Q

What happens to population size when abiotic conditions are not ideal?

A

Organisms cannot grow as fast or reproduce successfully

This often leads to decreased population sizes due to increased energy expenditure.

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10
Q

What is interspecific competition?

A

Competition between different species for the same resources

Example: Red and grey squirrels competing for food sources.

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11
Q

What is intraspecific competition?

A

Competition within a species for the same resources

Intraspecific competition can lead to population fluctuations.

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12
Q

Define carrying capacity.

A

The maximum stable population size of a species that an ecosystem can support

Carrying capacity is influenced by resource availability.

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13
Q

What is predation?

A

Where an organism (the predator) kills and eats another organism (the prey)

Predation is a key factor in regulating population sizes.

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14
Q

How are predator and prey populations linked?

A

As prey population increases, predator population grows; as predator population increases, prey population decreases

This dynamic relationship is crucial for ecosystem balance.

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15
Q

Fill in the blank: Organisms can only exist where the abiotic factors they can survive in _______.

A

exist

This highlights the importance of abiotic conditions in habitat suitability.

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16
Q

Give an example of how abiotic factors affect distribution.

A

Some plants only grow on south-facing slopes in the northern hemisphere due to light intensity

This demonstrates the relationship between abiotic factors and organism distribution.

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17
Q

True or False: Large trees can grow in polar regions.

A

False

Large trees cannot grow in polar regions due to extremely low temperatures.

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18
Q

What is interspecific competition?

A

Competition between different species for resources.

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19
Q

Give one example of interspecific competition.

A

The grey squirrel outcompeting the native red squirrel in the UK.

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20
Q

Define the term niche.

A

The role of a species within its habitat.

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21
Q

What are the two types of interactions included in a niche?

A
  • Biotic interactions
  • Abiotic interactions
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22
Q

True or False: A niche can be occupied by more than one species.

A

False.

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23
Q

What does abundance refer to in ecology?

A

The number of individuals of one species in a particular area.

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24
Q

What is the difference between habitat and niche?

A

Habitat is where a species lives; niche is what it does in that habitat.

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25
Q

How can abiotic factors affect the abundance of organisms? Give one example.

A

Factors like temperature or moisture level can impact survival and reproduction.

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26
Q

Give two examples of abiotic factors that can affect the distribution of organisms.

A
  • Temperature
  • Soil salinity
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27
Q

What is the purpose of sampling in ecological studies?

A

To investigate the abundance and distribution of species.

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28
Q

What is random sampling?

A

Choosing sample sites without bias to accurately represent the habitat.

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29
Q

What is systematic sampling?

A

Sampling at fixed intervals, often along a line.

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30
Q

Define intraspecific competition.

A

Competition between individuals of the same species.

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31
Q

What is a frame quadrat used for?

A

To investigate immobile populations by recording species within a defined area.

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32
Q

How is percentage cover measured in a frame quadrat?

A

By counting how much of the quadrat is covered by the plant species.

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33
Q

Fill in the blank: The _______ concept explains how different species can coexist by occupying different niches.

A

[niche]

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34
Q

What is an environmental gradient?

A

A habitat that changes gradually in abiotic factors.

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35
Q

True or False: The abundance of species can be simply counted by sampling.

A

True.

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36
Q

What is the role of abiotic factors in the distribution of organisms?

A

They determine the conditions necessary for species survival.

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37
Q

What should be done when comparing different habitats during sampling?

A

Always use the same sampling technique.

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38
Q

Explain the term ‘predator-prey relationships’.

A

Interactions where predators hunt and feed on prey species.

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39
Q

What can affect the chance of survival for species in a habitat?

A

The presence of better-adapted species.

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40
Q

In terms of ecological research, what is the significance of taking multiple samples?

A

It provides a better indication of the whole habitat.

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41
Q

What is a point quadrat?

A

A horizontal bar on two legs with a series of holes at set intervals along its length.

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42
Q

How is a point quadrat used in investigating plant populations?

A

It is placed on the ground at random points, and pins are dropped through the holes to record every plant touched.

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43
Q

What should be recorded if a pin touches several overlapping plants?

A

All of them are recorded.

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44
Q

How is the percentage cover of a species calculated using point quadrats?

A

By calculating the number of pins that touch a given species as a percentage of the total number of pins dropped.

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45
Q

In what type of areas are point quadrats especially useful?

A

In areas with dense vegetation close to the ground.

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46
Q

What is the purpose of using transects in ecological studies?

A

To investigate the distribution of plant populations across an area.

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47
Q

What is a line transect?

A

A tape measure is placed along the transect, and species that touch the tape measure are recorded.

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48
Q

Describe a belt transect.

A

Data is collected along the transect line using frame quadrats placed next to each other.

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49
Q

What are interrupted transects?

A

Measurements are taken at intervals along the transect instead of investigating the whole transect.

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50
Q

What is a kite diagram used for?

A

To plot the abundance and distribution of organisms in an area.

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51
Q

How does the thickness of the kite shape in a kite diagram represent abundance?

A

The thickness shows the abundance of each organism.

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52
Q

What does the x-axis in a kite diagram represent?

A

The distance along the transect line.

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53
Q

What is climate in the context of abiotic factors?

A

The weather conditions of a region over a long period of time.

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54
Q

How is temperature measured in ecological studies?

A

Using a thermometer.

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55
Q

What device is used to measure rainfall?

A

A rain gauge with a funnel attached to a measuring cylinder.

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56
Q

How is humidity measured?

A

Using an electronic hygrometer.

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57
Q

What is the purpose of measuring oxygen availability?

A

To assess the amount of oxygen dissolved in aquatic habitats.

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58
Q

What tool measures solar input (light intensity)?

A

An electronic light sensor.

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59
Q

How is soil pH measured?

A

Using indicator liquid or electronic pH monitors.

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60
Q

Describe how moisture content of soil is measured.

A

By measuring the mass of soil before and after drying it in an oven.

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61
Q

What is relief in terms of topography?

A

How the height of the land changes across a surface.

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62
Q

How can slope angle be measured?

A

Using a clinometer.

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63
Q

What does aspect refer to in topography?

A

The direction a slope is facing.

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64
Q

Fill in the blank: The results of investigations into the abundance and distribution of organisms can be plotted on a _______.

A

kite diagram.

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65
Q

True or False: Point quadrats can only be used in fields.

A

False.

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66
Q

What is the purpose of using frame quadrats in estimating percentage cover?

A

To sample a population of plants in a specific area.

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67
Q

State two ways climatic conditions could be measured.

A
  • Temperature
  • Rainfall
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68
Q

What is succession in ecology?

A

The process of ecosystem change over time.

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69
Q

What are the two types of succession?

A
  • Primary succession
  • Secondary succession
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70
Q

What is primary succession?

A

Succession that occurs on land that has never been formed or exposed, starting with bare rock.

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71
Q

What is secondary succession?

A

Succession that occurs on land that has been disturbed but where soil remains, such as after a forest fire.

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72
Q

What are pioneer species?

A

The first species to colonize an area during succession.

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73
Q

How do pioneer species affect abiotic conditions?

A

They change abiotic conditions by dying and decomposing, which helps form soil.

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74
Q

Fill in the blank: The final stage of succession is called the _______.

A

climax community.

75
Q

What happens to biodiversity as succession progresses?

A

Biodiversity increases.

76
Q

What is a climax community?

A

The ecosystem that supports the largest and most complex community of plants and animals.

77
Q

Explain the role of lichens in primary succession.

A

Lichens grow on bare rock, break it down, and release minerals, contributing to soil formation.

78
Q

What is a plagioclimax?

A

A climax community that is artificially prevented from developing.

79
Q

How can human activities prevent succession?

A

By regularly mowing or disturbing the land, preventing larger plants from establishing.

80
Q

True or False: Secondary succession starts with bare rock.

A

False.

81
Q

What changes occur in the soil during primary succession?

A

The soil deepens and becomes richer in minerals as organic material accumulates.

82
Q

What type of succession occurs after a forest fire?

A

Secondary succession.

83
Q

Fill in the blank: The process of succession leads to an increase in _______.

A

ecosystem complexity.

84
Q

What is the relationship between succession and competition among species?

A

Different plants and animals out-compete others for dominance as conditions improve.

85
Q

What climatic factors influence the types of climax communities?

A
  • Temperature
  • Precipitation
86
Q

Describe the role of grasses in dune succession.

A

Grasses can stabilize sand and improve conditions for larger plants like shrubs.

87
Q

What happens to species composition during succession?

A

Species composition changes as new species move in and out-compete existing ones.

88
Q

What is photophosphorylation?

A

Adding phosphate to a molecule using light.

89
Q

Define photolysis.

A

The splitting of a molecule using light energy.

90
Q

What are redox reactions?

A

Reactions that involve oxidation and reduction.

91
Q

What happens during oxidation?

A

A molecule loses electrons and may lose hydrogen or gain oxygen.

92
Q

True or False: Oxidation of one molecule always involves reduction of another molecule.

A

True.

93
Q

List some biological processes that require energy in plant cells.

A
  • Photosynthesis
  • Active transport
  • DNA replication
  • Cell division
  • Protein synthesis
94
Q

List some biological processes that require energy in animal cells.

A
  • Muscle contraction
  • Maintenance of body temperature
  • Active transport
  • DNA replication
  • Cell division
  • Protein synthesis
95
Q

What is the overall equation for photosynthesis?

A

6CO₂ + 6H₂O + Energy → C₆H₁₂O₆ (glucose) + 6O₂

96
Q

How do plants store energy from photosynthesis?

A

In glucose, which is released by respiration.

97
Q

How do animals obtain glucose?

A

By eating plants or other animals.

98
Q

What is ATP?

A

Adenosine triphosphate, the immediate source of energy in a cell.

99
Q

How is ATP synthesized?

A

By the phosphorylation of ADP using energy from an energy-releasing reaction.

100
Q

What enzyme catalyzes the synthesis of ATP?

A

ATP synthase.

101
Q

What happens to ATP when it diffuses to the part of the cell that needs energy?

A

It is broken down via hydrolysis back into ADP and inorganic phosphate.

102
Q

What is the role of ATPase?

A

Catalyzes the reaction that breaks down ATP into ADP and inorganic phosphate.

103
Q

What are chloroplasts?

A

Flattened organelles found in plant cells that are the site of photosynthesis.

104
Q

What is the structure that keeps the reactants for photosynthesis close to their reaction sites?

A

Chloroplast envelope.

105
Q

What are thylakoids?

A

Fluid-filled sacs in chloroplasts that have a large surface area for light absorption.

106
Q

What are grana?

A

Stacks of thylakoids in the chloroplast.

107
Q

What are the two types of photosystems used by plants?

A
  • Photosystem I (PSI)
  • Photosystem II (PSII)
108
Q

At what wavelength does Photosystem I absorb light best?

A

700 nm.

109
Q

At what wavelength does Photosystem II absorb light best?

A

680 nm.

110
Q

What is the stroma?

A

The gel-like substance surrounding the thylakoids in chloroplasts.

111
Q

Fill in the blank: The process used to synthesize ATP from ADP is called ______.

A

phosphorylation.

112
Q

What are the two stages of photosynthesis?

A

1) Light-Dependent Reaction 2) Light-Independent Reaction (Calvin Cycle)

The Light-Dependent Reaction requires light energy, while the Light-Independent Reaction does not.

113
Q

Where does the Light-Dependent Reaction take place?

A

In the thylakoid membranes of the chloroplasts

This stage involves the absorption of light energy by photosynthetic pigments.

114
Q

What are the products of the Light-Dependent Reaction?

A
  • ATP * Reduced NADP * Oxygen

These products are used in the Light-Independent Reaction.

115
Q

What is photophosphorylation?

A

The process of making ATP from ADP and inorganic phosphate using light energy

This occurs during the Light-Dependent Reaction.

116
Q

What does the term ‘photolysis’ refer to?

A

The splitting of water into protons, electrons, and oxygen

This process occurs during the Light-Dependent Reaction.

117
Q

What is the primary role of the electron transport chain in photosynthesis?

A

To transfer excited electrons and create a proton gradient

This gradient is essential for ATP synthesis.

118
Q

What is chemiosmosis?

A

The process where the movement of H+ ions across a membrane generates ATP

This process also occurs in respiration.

119
Q

What is cyclic photophosphorylation?

A

A process that only uses PSI, where electrons are recycled back to PSI

This process produces only ATP and no reduced NADP or oxygen.

120
Q

Where does the Light-Independent Reaction (Calvin Cycle) take place?

A

In the stroma of the chloroplasts

This stage does not directly use light energy.

121
Q

What is glyceraldehyde 3-phosphate (GALP)?

A

A molecule made from CO2 and ribulose bisphosphate in the Calvin Cycle

GALP can be used to synthesize glucose and other organic substances.

122
Q

What is the role of ATP and reduced NADP in the Calvin Cycle?

A

They provide energy and hydrogen ions necessary for the cycle

These are supplied by the Light-Dependent Reaction.

123
Q

What is carbon dioxide fixation?

A

The process of incorporating carbon from CO2 into an organic molecule

This occurs during the Calvin Cycle.

124
Q

Fill in the blank: The light energy is used to add a phosphate group to ADP to form _______.

A

ATP

125
Q

True or False: Light-Dependent Reactions produce glucose directly.

A

False

Glucose is produced in the Light-Independent Reaction (Calvin Cycle).

126
Q

What is the role of RUBISCO in the Calvin cycle?

A

RUBISCO catalyses the reaction between CO2 and ribulose bisphosphate (RuBP) to form a 6-carbon compound

127
Q

What does the unstable 6-carbon compound break down into during the Calvin cycle?

A

Two molecules of a 3-carbon compound called glycerate 3-phosphate (GP)

128
Q

How many ATP molecules are required for the reduction of GP to glyceraldehyde 3-phosphate (GALP)?

A

2 x ATP

129
Q

What are the products of the Calvin cycle?

A

Glyceraldehyde 3-phosphate (GALP) and ribulose bisphosphate (RuBP)

130
Q

Which organic substances can be produced from GALP and GP?

A
  • Carbohydrates
  • Lipids
  • Amino acids
  • Nucleic acids
131
Q

Fill in the blank: The sugar in RNA (ribose) is made using _______.

A

GALP

132
Q

True or False: Five out of every six molecules of GALP produced in the Calvin cycle are used to make hexose sugars.

A

False

133
Q

What is the purpose of the DCPIP dye in the investigation of the Hill reaction?

A

DCPIP acts as an electron acceptor and gets reduced during the light-dependent reactions

134
Q

What happens to the color of DCPIP as the Hill reaction occurs?

A

DCPIP changes from blue to colorless

135
Q

How is ribulose bisphosphate (RuBP) regenerated in the Calvin cycle?

A

By using the remaining ATP produced in the light-dependent reactions

136
Q

What is the effect of CAIP on glucose production?

A

CAIP inhibits RUBISCO, which would decrease glucose production

137
Q

Where in the chloroplasts does the light-independent reaction occur?

A

In the stroma

138
Q

Describe the experimental setup for measuring the rate of the Hill reaction.

A

Use a colorimeter to measure absorbance of DCPIP in chloroplast extract exposed to light

139
Q

What is the significance of preparing negative control tubes in the Hill reaction experiment?

A

To show that the DCPIP color change occurs only due to chloroplast activity and not naturally over time

140
Q

What is the initial reactant combined with ribulose bisphosphate in the Calvin cycle?

A

CO2

141
Q

What is the outcome of the hydrolysis of ATP in the Calvin cycle?

A

It provides energy to convert GP into glyceraldehyde 3-phosphate (GALP)

142
Q

Fill in the blank: The Calvin cycle is the starting point for making all the _______ substances a plant needs.

A

organic

143
Q

What is the role of producers in an ecosystem?

A

Producers produce organic molecules using sunlight energy.

144
Q

What is biomass in the context of energy transfer?

A

Biomass is the mass of living material, representing stored energy.

145
Q

Who are primary consumers?

A

Organisms that eat producers.

146
Q

What happens to energy when organisms eat other organisms?

A

Energy is transferred through the living organisms of an ecosystem.

147
Q

What percentage of energy is typically lost at each trophic level?

A

Around 90% of the total available energy is lost.

148
Q

List some reasons why energy is lost in ecosystems.

A
  • Plants can’t use all light energy reaching their leaves
  • Some light hits non-photosynthesizing parts of plants
  • Parts of food are not eaten
  • Indigestible parts of food pass as waste.
149
Q

What is gross productivity?

A

The total energy absorbed by organisms.

150
Q

What is respiratory loss?

A

Energy lost to the environment during respiration for movement or body heat.

151
Q

Define net productivity.

A

The amount of energy available to the next trophic level.

152
Q

How is net productivity calculated?

A

Net productivity = gross productivity - respiratory loss.

153
Q

What is the formula for calculating the efficiency of energy transfer?

A

(net productivity ÷ energy received) * 100.

154
Q

Fill in the blank: Net primary productivity (NPP) is calculated using the formula NPP = _______.

A

GPP - plant respiration.

155
Q

What factors can lower net primary productivity?

A

Cold temperatures and low light availability.

156
Q

How is energy transfer between trophic levels measured?

A

By calculating the difference in net productivity between levels.

157
Q

What is dry mass and why is it used in measuring energy transfer?

A

Dry mass is the mass of organisms after removing water; it indicates stored energy.

158
Q

What ethical considerations are there when measuring the dry mass of animals?

A

Killing animals for measurement may not be ethical.

159
Q

What is a potential issue when estimating energy transfer between trophic levels?

A

Consumers may have taken in energy from other sources, complicating calculations.

160
Q

True or False: All energy in an ecosystem is efficiently transferred from one trophic level to another.

A

False.

161
Q

What is meant by ‘gross primary productivity’?

A

The total amount of energy produced by photosynthesis in plants.

162
Q

Calculate the net productivity if gross productivity is 8000 kJ/m²/yr and respiratory loss is 6000 kJ/m²/yr.

A

2000 kJ/m²/yr.

163
Q

How can one calculate the percentage efficiency of energy transfer from one trophic level to another?

A

By using the formula: (net productivity ÷ energy received) * 100.

164
Q

What is the role of producers in an ecosystem?

A

Producers produce organic molecules using sunlight energy.

165
Q

What is biomass in the context of energy transfer?

A

Biomass is the mass of living material, representing stored energy.

166
Q

Who are primary consumers?

A

Organisms that eat producers.

167
Q

What happens to energy when organisms eat other organisms?

A

Energy is transferred through the living organisms of an ecosystem.

168
Q

What percentage of energy is typically lost at each trophic level?

A

Around 90% of the total available energy is lost.

169
Q

List some reasons why energy is lost in ecosystems.

A
  • Plants can’t use all light energy reaching their leaves
  • Some light hits non-photosynthesizing parts of plants
  • Parts of food are not eaten
  • Indigestible parts of food pass as waste.
170
Q

What is gross productivity?

A

The total energy absorbed by organisms.

171
Q

What is respiratory loss?

A

Energy lost to the environment during respiration for movement or body heat.

172
Q

Define net productivity.

A

The amount of energy available to the next trophic level.

173
Q

How is net productivity calculated?

A

Net productivity = gross productivity - respiratory loss.

174
Q

What is the formula for calculating the efficiency of energy transfer?

A

(net productivity ÷ energy received) * 100.

175
Q

Fill in the blank: Net primary productivity (NPP) is calculated using the formula NPP = _______.

A

GPP - plant respiration.

176
Q

What factors can lower net primary productivity?

A

Cold temperatures and low light availability.

177
Q

How is energy transfer between trophic levels measured?

A

By calculating the difference in net productivity between levels.

178
Q

What is dry mass and why is it used in measuring energy transfer?

A

Dry mass is the mass of organisms after removing water; it indicates stored energy.

179
Q

What ethical considerations are there when measuring the dry mass of animals?

A

Killing animals for measurement may not be ethical.

180
Q

What is a potential issue when estimating energy transfer between trophic levels?

A

Consumers may have taken in energy from other sources, complicating calculations.

181
Q

True or False: All energy in an ecosystem is efficiently transferred from one trophic level to another.

A

False.

182
Q

What is meant by ‘gross primary productivity’?

A

The total amount of energy produced by photosynthesis in plants.

183
Q

Calculate the net productivity if gross productivity is 8000 kJ/m²/yr and respiratory loss is 6000 kJ/m²/yr.

A

2000 kJ/m²/yr.

184
Q

How can one calculate the percentage efficiency of energy transfer from one trophic level to another?

A

By using the formula: (net productivity ÷ energy received) * 100.

Biology Edexcel Sophie (8 decks)

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