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AEBA > Biodiversity & Natural resources > Flashcards

Biodiversity & Natural resources Flashcards

1
Q

Describe a cell wall

A

A rigid structure that surrounds plant cells. It’s made mainly of the carbohydrate cellulose.

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2
Q

What is the function of a cell wall?

A

Supports plant cells.

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3
Q

Describe the middle lamella.

A

The outermost layer of the cell

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4
Q

What is the function of the middle lamella ?

A

This layer acts as an adhesive, sticking adjacent plant cells together. It gives the plant stability.

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5
Q

Describe the plasmodesmata

A

Channels in the cell walls that link adjacent cells together.

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6
Q

What is the function of the plasmodesmata?

A

Allow transport of substances and communication between cells.

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7
Q

Describe pits

A

Regions of the cell wall where the wall is very thin. They’re arranged in pairs — the pit in one cell is lined up with the pit in the adjacent cell.

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8
Q

What is the function of pits

A

Allow transport of substances between cells.

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9
Q

Describe a chloroplast

A

A small, flattened structure. It’s surrounded by a double membrane, and also has membranes inside called thylakoid membranes.

These membranes are stacked up in some parts of the chloroplast to form grana. Grana are linked together by lamellae — thin, flat pieces of thylakoid membrane.

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10
Q

What is the function of a chloroplast?

A

The site where photosynthesis takes place. Some parts of photosynthesis happen in the grana, and other parts happen in the stroma (a thick fluid found in chloroplasts).

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11
Q

Describe an amyloplast

A

A small organelle enclosed by a membrane. They contain starch granules.

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12
Q

What is the function of an amyloplast?

A

Storage of starch grains. They also convert starch back to glucose for release when the plant requires it.

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13
Q

Describe a vacuole and tonoplast

A

The vacuole is a compartment surrounded by a membrane called the tonoplast.

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14
Q

What is the function of a vacuole and tonoplast?

A

The vacuole contains the cell sap, which is made up of water, enzymes, minerals and waste products. Vacuoles keep the cells turgid — this stops plants wilting. They’re also involved in the breakdown and isolation of unwanted chemicals in the cell. The tonoplast controls what enters and leaves the vacuole.

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15
Q

What are the structural isomers of glucose ?

A

Alpha and beta

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16
Q

How do the structural isomers of glucose differ?

A

Position of -OH group . Bottom is alpha , top is beta

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17
Q

Describe cellulose

A

A polysaccharide made of thousands of B glucose monomers arranged in single unbranched chain bonded by stable 1-4 glycosidic bond

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18
Q

In plants cellulose makes up the bulk of cell wall, what does this provide?

A

Strength required to maintain the cells shape

Support for the plant stem or trunk

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19
Q

Describe the structure of cellulose

A

Every other glucose molecules rotates 180 so that the -OH group on each molecule are adjacent to one another

Condensation reaction between them links the 2 molecules

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20
Q

What feature of cellulose gives rise to its great tensile strength ?

A

Hydrogen bonds between the chain

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21
Q

Describe how 2 betas glucose molecules must be positioned relative to each other for a condensation to take place between them

A

One molecule will be rotated 180 so two -oh. Groups lie alongside and cant react

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22
Q

Explain why the bond between each pair of glucose molecules in cellulose is called 1-4 glycosidic bond

A

It links the -oh group on the carbon 1 of one glucose with he -oh group of carbon 4 of another

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23
Q

Describe the structure of a cellulose molecule and compare it to starch

A

Cellulose is a linear molecule consisting of up to several thousand of B glucose molecules bonded by a 1-4 glycosidic bond

Starch is composed of two main molecules: amylose which forms a helix and a branched molecule called amylopectin. Amylose consists of A glucose monomers bonded by 1-4 glycosidic bonds. Amylopectin also consists of a glucose monomers but also 1,6 glycosidic bonds which causes it to branch

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24
Q

Explain the purpose of cellulose and starch in plant cells

A

Cellulose has a structural role, providing strength and support to plant cells.

Starch provides plants with a means of storing energy.

Glucose molecules are stored inside amyloplast in a compact form which can be easily hydrolysed to be released as an energy source when required

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25
Q

Explain why wood has such a high strength to weight ratio

A

The lattice structures of the cells in the wood provide a low density structure while the cellulose provides strength

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26
Q

Explain the reason for cellulose possessing such a high tensile strength

A

Cellulite’s microfibrils are composed of molecules that posses strong intermolecular bonds as well as having strong hydrogen bonding between cellulose molecules

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27
Q

Roughly how many glucose units does cellulose contain ?

A

Each cellulose chain contains between 1000-10000 glucose units - all contained in a straight chain

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28
Q

How is the cell wall arranged?

A

Contains cellulose microfibrils in a net like arrangement

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29
Q

Microfibrils are bundles of about

A

60-70 cellulose molecules wound in a helical arrangement around the cell.

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30
Q

How is the rope like structure of microfibrils held together?

A

Held together with polysaccharide glue hemicellulose + pectin

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31
Q

What are the properties of cellulose?

A

Insoluable - no osmotic effect

Strong + sturdy - prevents cell from bursting when turgid

Flexible - allow changes in osmotic pressure

Structural component

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32
Q

What is the function of xylem vessels ?

A

is to transport water and mineral ions up the plant, and provide support.

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33
Q

Describe the xylem vessel

A

They’re very long, tube-like structures formed from dead cells, joined end to end.

The tubes are found together in bundles.
The cells are longer than they are wide, they have a hollow lumen (they contain no cytoplasm) and have no end walls.

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34
Q

Why does having a uninterrupted tube beneficial for the xylem vessel?

A

allowing water and mineral ions to pass up through the middle easily.

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35
Q

What is the role of lignin in the xylem vessel?

A

Walls of the xylem lined with a waterproof polymer - lignin

Structural support - spiral thickening around wall of the vessel - strength, rigid + upright

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36
Q

Describe the movement of water up the stem in a xylem

A

Water travels up the xylem via cohesion tension

As the water from mesophyll evaporates into airspaces, a transpiration pull is created, more water is needed for leaves

Water diffuses into roots via osmosis - down the water gradient , water potential at bottom is low hence water is pulled up

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37
Q

Describe cohesion tension theory

A

H20 molecules from hydrogen bonds between one another stick

Water forms continuous unbroken dumn

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38
Q

What is the function of phloem tissues?

A

is to transport organic solutes (mainly sugars like sucrose) from where they’re made in the plant to where they’re needed.- translocation

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39
Q

Describe sieve tube elements

A

Living cells that form the tube for transporting organic substances

Contains cytoplasm but no nucleus

Wall made of cellulose

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40
Q

Describe companion cells

A

Connected to sieve tube elements via plasmodesmata

Provides energy required for active transport

Allow cytoplasm to be shared and has a nucleus

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41
Q

Describe sieve plates

A

Either end of sieve tube element

Has large pores that allow sap to move through sieve tube

Allow sugars to be transported through phloem

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42
Q

What is translocation ?

A

Translocation is the process where sugars produced in photosynthesis is transported from the leaves to other parts of a plant

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43
Q

Describe mass flow in translocation

A
  1. Active transport used to actively load solutes from companion into sieve tube at source
  2. At the sink end, solutes are removed from phloem to be used up
  3. Results in pressure gradient from source to sink - sink gradient pushes solutes along
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44
Q

During translocation, what type of cell is sucrose actively transported to?

A

Companion cells

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45
Q

Where is sucrose unloaded ?

A

At the sink cells

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46
Q

What type of gradient is there from source to sink?

A

From source to sink

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47
Q

Discuss the structural and functional differences between xylem and phloem (3)

A

Xylem is a dead issue whereas phloem is alive.

Xylem transports water and dissolved minerals around the plant

Phloem conducts dissolved sugar around the plant from it place of production to where it is required

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48
Q

Describe a way in which xylem is strengthened in mature plant

A

Strengthened by having hard fibre cells and spiral thickening of the vessel walls

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49
Q

Explain the purpose of the holes in the sieve plate at the ends of each sieve tube cells

A

The perforations of sieve planet enables the sugar solution to pass through and along the sieve tubes

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50
Q

Name the cell type in the phloem that actually conducts the sugar solution

A

The sieve tube

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51
Q

Describe the purpose of the companion cells in the phloem tissue

A

The companion cell keeps the sieve tube cell alive and controls its activity

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52
Q

What is a sclerenchyma?

A

is a non-living tissue in plants which provides strength and support.

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53
Q

What type of tissue is sclerenchyma ?

A

Simple tissue

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54
Q

Describe the structure of sclerenchyma

A

Sclerenchyma cells walls are lignified as well as containing cellulose and hemicellulose. This makes the walls thicker.

Mature sclerenchyma cells are dead.

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55
Q

What are the two main types of sclerenchyma and how do they differ ?

A

Fibres and sclereids

Sclerenchyma fibres are longer, and are usually found in bundles in plants. -Sclereids are star-shaped, and they have very thick cell walls. Sclereids are responsible for the gritty texture in fruits like pears.

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56
Q

What are the functions of sclerenchyma ?

A

Sclerenchyma supports and strengthens the plant.

Sclerenchyma is found in many plants, and in most parts of the plant. Sclerenchyma fibres tend to be associated with the vascular bundles

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57
Q

What are the different uses of plants? 4

A

Provide oxygen via photosynthesis

Source of food and metabolic energy for nearly all consumers

Provides raw materials from which innumerable other products are made

As technology has improved, more plant compound identified and no. Of product derived from it

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58
Q

Uses of plants in manufacturing

A

Car tyres, latex gloves rubber made from plant extracts

Essential oils + plant based pesticides

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59
Q

Uses of plants in fuels

A

Biofuels

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60
Q

Uses of plants in clothings and textiles

A

Fibres produced into range of materials - linen

Properties of fibre depend upon type

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61
Q

Uses of plants in plastics

A

Plant fibres - fibres e.g dialysis tubes + sellotape

Food packaging - fully biodegradeable

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62
Q

Uses of plants as shelters

A

Provides wood to build structures

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63
Q

Uses of plants in medicine

A

Rich source for pharmaceuticals - modern medicine , aspirin from willow bark

Recreational usage

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64
Q

Uses of plants as paper

A

Made by digesting wood pulp with sulphates

Can be recycled into paper products

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65
Q

Uses of plants as food

A

Plant tissue provide energy for almost all living life

Selective breeding has reproduced veg + fruit many times larger and more nutritious

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66
Q

Sustainability is

A

Avoidance of the depletion natural resources in order to maintain an ecological balance

Ability to repurpose
Reusability

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67
Q

Explain why plant based plastics provide an environmentally friendly solution to the problem of plastic pollution

A

Plastics from plant materials do not use fossil fuels as the base material. PLA products can be broken down and reused to make new bioplastics. The CO2 produced from the bioplastics manufacture is absorbed by plant. The net levels of C02 produced is very low and will reduce greenhouse gases.

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68
Q

Describe some of the disadvantages of manufacturing PLA products

A

PLA is produced from the useful starchy parts of the plant, and so diverts food crops and land use into plastic production. It could result in food shortages. Composted PLA gives off methane - potent green house gas

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69
Q

What are the role of water?

A

Solvent

Thermal properties

Cell turgidity

Acts as a reactant

Water transcription

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70
Q

Water as solvent?

A

Water is used in plants to transport dissolved substances in the xylem and phloem around the plant.

Water in plant cells provides an aqueous environment for reactions to take place, as well as taking part in reactions itself.

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71
Q

Thermal properties of water plants?

A

Water is able to maintain a reasonably stable temperature independent of its surroundings

This helps plants to maintain a reasonably constant internal temperature.

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72
Q

Cell turgidity in relation to role of water ?

A

Water keeps plant cells turgid.

Turgidity is important for supporting the plant.

If cells are not turgid enough, then the plant loses turgor pressure and wilts.

73
Q

Water as a reactant plants ?

A

Water is needed as a reactant in photosynthesis.

Photosynthesis is vital for plants so they can produce sugars to use in respiration.

74
Q

Water in transpiration?

A

Water molecules form hydrogen bonds with each other, so water is very cohesive.

Tension is the formation of hydrogen bonds between water molecules and the sides of the xylem vessel elements, and also helps to push up water.

75
Q

How do Plant synthesis their own proteins and lipids?

A

By incorporating nutrients obtained from the soil

76
Q

What factors affect a plants availability of mineral ions?

A

Depends on soil texture which affect permeability of the soil

77
Q

For the mineral ion nitrogen , what is its sources?

A

Rocks slowly dissolved via rain falls

78
Q

For the mineral ion potassium , what is its sources?

A

Artificial fertilisers

79
Q

For the mineral ion magnesium , what is its sources?

A

Dissolved in soil solution

80
Q

For the mineral ion phosphorus , what is its sources?

A

Natural fertilises - faeces and decay of dead animals and plant

81
Q

For the mineral ion sulfur, what is its sources?

A

Rainfall and fertiliser

82
Q

For the mineral ion calcium , what is its sources?

A

Typically within other compounds

83
Q

Why do plants require nitrogen mineral ion?

A

Components of a.a protein for growth of plant

84
Q

Why do plants require potassium mineral ion?

A

Involved in osmosis and ion balance , opening and closing of stomata , activator of enzymes in respiration

85
Q

Why do plants require magnesium mineral ion?

A

Part of chlorophyll molecules, activator of enzymes

86
Q

Why do plants require phosphorus mineral ion?

A

Component of energy carrying phosphate compounds ATP / ADP nuclei acids, coenzymes and phospholipids

87
Q

Why do plants require sulphur mineral ion?

A

Component of cell wall, enzyme co factor

88
Q

How to identify symptoms of nitrogen Deficiency ?

A

Poor plan growth

Pale green or yellow

Delayed flowering

Older leaves foliage

89
Q

How to identify symptoms of potassium Deficiency ?

A

Leaves curled at the tips

Appear brown and scorched

Have yellow edges prone to frost damage

90
Q

How to identify symptoms of magnesium Deficiency ?

A

Pale yellow and spotted

Flower production affected

Fruit is small

91
Q

How to identify symptoms of phosphorus Deficiency ?

A

Poor growth

Blueish purple leaves

If too low flowering can be afected

92
Q

How to identify symptoms of. Sulfur Deficiency ?

A

Younger leaves affected

Small plant , lower crop yield

Pale green or yellow

93
Q

How to identify symptoms of calcium Deficiency ?

A

Stunted growth

Leaves curl

Develop spots if fruit and bitter taste

94
Q

Suggest why chemical analysis is sometimes required to identify which nutrients is deficient

A

Some mineral deficiency present with similar symptoms. So physical symptoms can be inconclusive for diagnosing mineral deficiency

Chemical analysis provides provides quantitative results for each nutrients test and identifies which is deficient .

95
Q

You have set up a lab experiment to demonstrate the effect of nitrogen deficiency on tomato plants. Explain why you need a control for the experiment + describe an appropriate control

A

A control ensures that the responses obtained from the treatment groups are due to thes factors being tested an not the result of other variables and factors

Using a solution containing all of the essential nutrients

96
Q

In the past, how was drugs tested ?

A

Through trial and error - less scientifically

97
Q

Describe William Withering’s digitalis soup

A

William Withering was a scientist in the 1700s. He discovered that an extract of foxgloves could be used to treat dropsy (swelling brought about by heart failure). This extract contained the drug digitalis.

Withering made a chance observation — a patient suffering from dropsy made a good recovery after being treated with a traditional remedy containing foxgloves. Withering knew foxgloves were poisonous, so he started testing different versions of the remedy with different concentrations of digitalis

Too much digitalis poisoned his patients, while too little had no effect.

It was through this crude method of trial and error that he discovered the right amount to give to a patient.

98
Q

How does modern drug testing differ from historic ?

A

They are more rigorous + controlled.

Before a drug is tried on any live subjects, computers are used to model the potential effects

Tests are also carried out on human tissues in a lab, then they’re tested on live animals before clinical trials are carried out on humans.

99
Q

During new drug trials, what are the stages of testing it must undergo?

A

Phase 1 — This involves testing a new drug on a small group of healthy individuals. It’s done to find out things like safe dosage, if there are any side effects, and how the body reacts to the drug.

Phase 2 — If a drug passes Phase 1 it will then be tested on a larger group of people (this time patients) to see how well the drug actually works.

Phase 3 — During this phase the drug is compared to existing treatments.
It involves testing the drug on hundreds, or even thousands, of patients.
Using a large sample size makes the results of the test more reliable.
Patients are randomly split into two groups — one group receives the new treatment and the other group receives the existing treatment. This allows scientists to tell if the new drug is any better than existing drugs.

100
Q

How can the results of clinical trials be more valid?

A

Using placebo and double blind study design

101
Q

How is the placebo effect incorporated in trials?

A

In Phase 2 clinical trials the patients are split into two groups. One group is given the drug and the other is given a placebo — an inactive substance that looks exactly like the drug but doesn’t actually do anything. Patients often show a placebo effect — where they show some improvement because they believe that they’re receiving treatment. Giving half the patients a placebo allows researchers to see if the drug actually works (if it improves patients more than the placebo does).

102
Q

How is the double blind study I cooperated into the trials?

A

Phase 2 and 3 clinical trials are usually double blind — neither the patients nor the doctors know who’s been given the new drug and who’s been given the placebo (or old drug).

This reduces bias in the results because the attitudes of the patients and doctors can’t affect the results. E.g. if a doctor knows someone has received the real drug, they may think they’ve improved more than they actually have —but if they don’t know this can’t happen.

103
Q

To test antimicrobial properties, what conditions of the bacteria do we need in order for it to survive and reproduce?

A

Bacteria need a source of nutrients so they can respire and grow.

If they rely on aerobic respiration, they’ll need a supply of oxygen too.

The temperature and pH of the environment are also important — if either of these factors is too high or too low it can affect enzyme activity, meaning metabolic processes (e.g. respiration) can’t take place normally.

104
Q

How do we prevent contamination of microbial cultures?

A

Using aseptic techniques

105
Q

Why is it necessary to use aseptic techniques?

A

This is important because contamination can affect the growth of the microorganism that you’re working with.

106
Q

What are the key ways in which aseptic techniques are included? (6)

A

Close windows and doors to prevent draughts disturbing the air.

Regularly disinfect work surfaces to minimise contamination.

Work near a Bunsen flame. Hot air rises, so any microbes in the air should be drawn away from your culture.

Sterilise the wire inoculation loop before and after each use by passing it through a hot Bunsen burner flame for 5 seconds. This will kill any microbes on the loop.

Briefly flame the neck of the glass container of broth just after it’s opened and just before it’s closed- — this causes air to move out of the container, preventing unwanted organisms from falling in.

Sterilise all glassware before and after use, e.g. in an autoclave (a machine which steams equipment at high pressure).

107
Q

What is meant by plants having antimicrobial properties and why is this beneficial?

A

they kill or inhibit the growth of microorganisms, which is why they’re useful components of drugs.

108
Q

What is biodiversity ?

A

Measure of how varied an ecosystem is. The complexity of a biological community.

109
Q

Is biodiversity distributed evenly on earth?

A

No, it is consistently richer in the tropics and concentrated more in some areas than others

110
Q

What is genetic diversity?

A

Measures how many variations there are in the genetic code between individuals of a particular species or between different species

111
Q

What is species diversity?

A

Measure of how many different species are present in an area + how many individuals of s species there are

112
Q

What is habitat diversity?

A

Measure of how many different habitat are present in an area

113
Q

Distinguish between species diversity and genetic diversity.

A

Species diversity refers to the number of different species within an area, while genetic diversity describes the diversity of genes within a particular species.

114
Q

Explain the importance of species diversity and genetic diversity in regards to total biodiversity.

A

Biodiversity is defined as the measure of all genes,species and ecosystems in a region, so both genetic and species diversity are important in determining a region’s total biodiversity.

115
Q

How is the total biodiversity often threatened?

A

The loss of one component.

116
Q

What are biological hotspots?

A

Regions of the world that have a particularly high level of biodiversity but are threatened with destruction

117
Q

What is a species ?

A

A group of organisms that

  • Share common morphological, physiological and behavioural characteristics
  • Can interbreed + produce fertile offspring
118
Q

What is a hybrid?

A

Different species that interbreed it produce an infertile offspring

119
Q

What does an ecosystem rely on?

A

The interdependence of organisms to maintain sustainability and stability

120
Q

What does loss of species result in?

A

Serious unpredictable and possible irreversible changes

121
Q

Distinguish between the two measures of biodiversity: species richness and species evenness.

A

Species richness measures the number of species within an ecosystem whereas Species evenness describes how equally the species are distributed within an ecosystem.

122
Q

Explain why it is important to consider both species richness and species evenness.

A

Both measures are important when considering species conservation.

Species richness could give an indication of ecosystem stability and therefore how at-risk particular species may be.

Species evenness provides an indication of the species distribution - a limited distribution or a distribution individuals are widely separated may indicate that the species are at risk.

123
Q

Explain why high biodiversity is generally associated with a greater ecosystem diversity.

A

High biodiversity systems have greater number of biotic interactions operating to buffer them against change.With a large number of species involved, ecosystem processes (nutrient recycling), are more efficient and less inclined to disrupt.

124
Q

How do you calculate Simpson’s index for finite populations?

A

CHECK CGP

125
Q

What is Endemism ?

A

is when a species is unique to a single place (isn’t naturally found anywhere else in

126
Q

How do we estimate samples of a population ?

A

Choose an area to sample — a small area within the habitat being studied.

To avoid bias in your results, the sample should be random. For example, if you were investigating the species of plants in a field you could pick random sample sites by dividing the field into a grid and using a random number generator to select coordinates.

Count the number of individuals of each species in the sample area. How you do this depends on what you’re counting

Repeat the process — take as many samples as possible. This gives a better indication of the whole habitat.

Use the results to estimate the total number of individuals or the total number of different species

127
Q

Why do individuals of the same species differ?

A

because they have different alleles

128
Q

What is gene pool?

A

is the complete set of alleles in a species (or population).

129
Q

The greater the variety of alleles

A

the greater the genetic diversity

130
Q

When measuring the genetic diversity of a species , what can you look at?

A

Phenotype and Genotype

131
Q

What does heterozygosity index measure ?

A

You can measure genetic diversity within a species

132
Q

What is the formula to work out the heterozygosity ?

A

H = number of heterozygotes / number of individuals in the population

133
Q

What is a niche?

A

Ecological term thats define how an organism feeds, where it lives , and how it behaves in relation to other organisms in a habitat

134
Q

Species have evolved to…

A

Occupy a specific niche

135
Q

What meant by adaptations to a niche?

A

Every species has evolved for a specific role

Natural selection has selected traits that can help species survive and reproduce in their niche

136
Q

What are the 3 types of adaptation?

A
  • BEHAVIOURAL
    PHYSIOLOGICAL
    ANATOMICAL
137
Q

What is behavioural adaption?

A

Ways an organism acts that increase its chance of survival.

138
Q

What is anatomical adaptation?

A

Processes inside an organism’s body that increase its chance of survival.

139
Q

What is physiological adaptation?

A

Structural features of an organism’s body that increase its chance of survival.

140
Q

The adaptive feature that evolves in species are the result of ?

A

Result of selection pressures on them through the course of their evolution

141
Q

What is ecological niche?

A

Describe the functional position of a species in an ecosystem

142
Q

What is natural selection ?

A

the process that leads to evolution in a population. In order to understand how this process functions

143
Q

Random mutation?

A

Mutations are changes in the gene sequence of DNA.

Random mutations can arise spontaneously.

New mutations can result in new alleles of a gene

144
Q

Inheritance in natural selection?

A

When an individual reproduces, their offspring will inherit half of their genes.

When an individual with an advantageous mutation reproduces, the allele is inherited by their offspring.

145
Q

Change in allele frequency in natural selections?

A

Individuals in the next generation who have the advantageous mutation are also more likely to reproduce and pass on the allele.

Over many generations, the new allele will increase in frequency in the population.

The change in allele frequency over time is called evolution.

146
Q

Most mutations are harmful because

A

they alter the normal functioning of a gene.

147
Q

Some mutations are beneficial. Individuals with beneficial mutations are

A

more likely to survive and reproduce.

148
Q

What is Allele frequency?

A

How often an allele occurs in a population

149
Q

What is evolution?

A

The frequency of an allele in a population changes over time

150
Q

The allele frequencies of a population can be calculated using and used to see ?

A

the Hardy-Weinberg equations

and used to see if the population is changing over time

151
Q

What does the Hardy-Weinberg Principle Predict?

A

Allele Frequencies Won’t Change from one generation to the next.

152
Q

When is the Hardy-Weinberg Principle Predictions true?

A

only true under certain conditions — it has to be a large population where there’s no immigration, emigration, mutations or natural selection.

153
Q

If the allele frequencies do change between generations in a large population , what does this indicate?

A

then immigration, emigration, natural selection or mutations have happened.

154
Q

Working out HWP to predict allele frequency ?

A

P+Q=1

Where: p = the frequency of the dominant allele q = the frequency of the recessive allele

The total frequency of all possible alleles for a characteristic in a certain population is 1.0. So the frequencies of the individual alleles (e.g. the dominant one and the recessive one) must add up to 1.0.

155
Q

Using HWP to predict Genotype and Phenotype Frequency?

A

p2 + 2pq + q2 = 1

Where: p2 = the frequency of the homozygous dominant genotype 2pq = the frequency of the heterozygous genotype
q2 = the frequency of the homozygous recessive genotype

The total frequency of all possible genotypes for one characteristic in a certain population is 1.0. So the frequencies of the individual genotypes must add up to 1.0.

156
Q

Reproductive isolation ?

A

Reproductively isolated populations can accumulate changes in their genetics, further isolating them and potentially leading to the formation of a new species.

157
Q

What are the different ways in which populations can become reproductively isolated?

A

Physical barriers can reproductively isolate populations, like the formation of a river.

Behavioural barriers can also reproductively isolate populations, like a change in mating call.

Incompatibility of genitals is a type of mechanical barrier which can reproductively isolate populations.

Temporal barriers, like emerging to mate in either spring or in autumn, is another way that populations can become reproductively isolated.

158
Q

When a population becomes reproductively isolated, any mutations that occur will ?

A

accumulate in their group, but will not happen in the other group it has split from (unless the mutation happens independently).

This means that reproductively isolated populations will become increasingly different as they accumulate genetic changes.

159
Q

Geographical isolation can lead to ?

A

SPECIATION

160
Q

Geographical isolation happens when?

A

when a physical barrier divides a population of a species — floods, volcanic
eruptions and earthquakes can all cause barriers that isolate some individuals from the main population.

161
Q

Speciation happens because ?

A

The environment is different on each side, different characteristics will become more common due to natural selection (because there are different selection pressures)

162
Q

As different characteristics will be advantageous on each side, it leads to

A

the allele frequencies will change in each population,

163
Q

What is taxonomy ?

A

the science of classification. It involves naming organisms and organising them into groups based on their similarities and differences.

164
Q

How is biodiversity preserved through conservation?

A

In places like zoos and seed banks - they help species that are endangered get out of the woods, or back into the woods.

165
Q

What causes a reduction in global biodiversity in relation to species?

A

The extinction of a species, or the loss of genetic diversity within a species

166
Q

Why are species at risk of extinction?

A

Because of low population or threatened habitat

167
Q

What does conversation involve?

A

the protection and management of endangered species.

168
Q

What are the advantages of using seed banks to store seeds?

A

It’s cheaper to store seeds than to store fully grown plants.

Larger numbers of seeds can be stored than grown plants because they need less space.

Less labour is required to look after seeds than plants.

Seeds can be stored anywhere, as long as it’s cool and dry. Plants would need the conditions from their original habitat.

Seeds are less likely to be damaged by disease, natural disaster or vandalism than plants.

169
Q

What are the disadvantages of using seed banks to store seeds?

A

Testing the seeds for viability can be expensive and time-consuming.

It would be too expensive to store all types of seed and regularly test them all for viability.

It may be difficult to collect seeds from some plants as they may grow in remote locations.

170
Q

Describe the work that seed banks involves?

A

CrEating the cool, dry conditions needed for storage. This means seeds cab be stored for a long time

Testing seeds for viability (the ability to grow into plants) Seeds are planted, grown and new seeds are harvested to put back into stage

171
Q

What programmes does the zoo have to help endangered species?

A

CAPTIVE BREEDING

172
Q

How does captive breeding work?

A

Species that are endangered, or already extinct in the wild, can be bred together in zoos to help increase their numbers, e.g. pandas are bred in captivity because their numbers are critically low in the wild.

173
Q

What are some problems with captive breeding programmes?

A

Animals can have problems breeding outside their natural habitat, which can be hard to recreate in a zoo. For example, pandas do not reproduce as successfully in captivity as they do in the wild.

Many people think it’s cruel to keep animals in captivity, even if it’s done to prevent them becoming extinct.

174
Q

What are the benefits of reintroducing plants and animals into the wild?

A

The reintroduction of plants grown from seedbanks or animals bred in zoos can increase their numbers in the wild, helping to conserve their numbers or bring them back from the brink of extinction.

This could also help organisms that rely on these plants or animals for food, or as part of their habitat.

The reintroduction of plants and animals also contributes to restoring habitats that have been lost, e.g. rainforests that have been cut down.

175
Q

What are some problems with reintroducing organisms to the wild?

A

Reintroduced organisms could bring new diseases to habitats, harming other organisms living there.

Reintroduced animals may not behave as they would if they’d been raised in the wild.

176
Q

How do seed banks contribute to scientific research?

A

Scientists can study how plant species can be successfully grown from seeds. This is useful for reintroducing them to the wild.

Seedbanks can be used to grow endangered plants for use in medical research, as new crops or for new materials. This means we don’t have to remove endangered plants from the wild.

A disadvantage is that only studying plants from seeds in a seedbank limits the data to small, interbred populations. So the information gained may not be representative of wild plants.

177
Q

How do zoos contribute to scientific research?

A

Research in zoos increases knowledge about the behaviour, physiology and nutritional needs of animals. This can contribute to conservation efforts in the wild.

Zoos can carry out research that’s not possible for some species in the wild, e.g. nutritional or reproductive studies.

A disadvantage is that animals in captivity may act differently to those in the wild.

178
Q

How do zoos and seed banks help to educate people about conserving biodiversity?

A

Educating people about endangered species and reduced biodiversity helps to raise public awareness and
interest in conserving biodiversity:

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