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A Level Biology (Salters-Nuttfield SNAB) > Topic 4: Biodiversity and natural resources > Flashcards

Topic 4: Biodiversity and natural resources Flashcards

1
Q

What is a species?

A

A group of organisms that are able to reproduce together to produce fertile offspring. They will also have common features and be reproductively isolated.

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2
Q

What is a niche?

A

An organism role whiting its ecosystem. It’s role in the food chains and its biotic and abiotic interactions.

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3
Q

How does human activity threaten the variety of life?

A

An rapid population increase, increases the need and demand for natural resources having harmful effects on the environment damaging many habitats and therefor reducing biodiversity. Main threats include
- habitat destruction
- over exploitation
- hunting
- agriculture
- climate change

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4
Q

What is meant by the term biodiversity?

A

The number and variety of species in a specific area. It can also mean the genetic variation within a species

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5
Q

What is the definition of endemism?

A

A species that is found in only one geographical location and do not naturally occur anywhere else.

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6
Q

How can biodiversity be measured?

A
  • species richness
  • heterozygosity index
  • index of diversity
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7
Q

What is the definition of species richness?

A

Species richness is the number of species within a given areas or habitats.
Can be misleading as does not take into account the number of individuals of each species.

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8
Q

What is genetic diversity and how can it be calculated?

A

The number of different alleles in one gene pool. It can be calculated by using the heterozygosity index.

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9
Q

What is the heterozygosity index equation?

A

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

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10
Q

How to what is the equation for the index of diversity?

A

D = N(N-1) / total n (n-1)

n = total number of organism of a single species in the community
N = total no of organism in the community

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11
Q

What are the three types of adaptations?

A
  • behavioural
  • anatomical
  • physiological
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12
Q

What is an anatomical adaptation?

A

Changes to the physical characteristics of a species.
E.g. polar bears have white fur to help them camouflage with the snow and hid from prey.

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13
Q

What is a behavioural adaptation?

A

Changes to a species actions.
E.g. Cheetahs stalking there prey

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14
Q

What is a physiological adaptation?

A

Changes in the process what occur within a species.
E.g. mammals shiver when they are cold

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15
Q

What is the definition of evolution?

A

A change in allele frequency in a population over a given period of time. It occurs when two population of the same species becomes reproductively isolated.

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16
Q

What is the process of natural selection?

A
  1. There are variations within a species population (Random mutation) meaning some individuals posses different phenotypes.
  2. The difference in alleles may be advantageous to their environment.
  3. This makes them more likely to survive and reproduce passing on the advantageous allele to their offspring.
  4. This process repeats so that the advantageous alleles increase in frequency over time and generations.
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17
Q

What is the hardy-Weinberg principle?

A

The Hardy-Weinberg principle states that is certain conditions are met, the allele frequencies of a gene within a population will not change from one generation to the next.

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18
Q

What’s are the assumption of the Hardy-Weinberg principle?

A
  • mating must be random
  • no mutations
  • infinite population
  • no selectional pressures
  • geographical isolation
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19
Q

What does the Hardy-Weinberg equation show.

A

Allows for the calculation of allele and genotype frequencies within a population. And allows for predictions to be made about how these frequencies witless change in future generations.

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20
Q

What are the Hardy - Weinberg equation?

A

p + q = 1
p2 + 2pq + q2 = 1

p = dominant allele
q = recessive allele
p2 = homozygous dominant
q2 = homozygous recessive
2pq = heterozygote

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21
Q

What the different ways that reproductive isolation can take place?

A
  • seasonal changes
  • mechanical changes
  • behavioural changes
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22
Q

How can seasonal changes led to reproductive isolation?

A

When some individuals in a pop auction may develop different mating or flowering seasons becoming sexually active at different times of the year.

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23
Q

How does mechanical changes led to reproductive isolation?

A

Some individuals in a population may develop changes in their genitalia that preventing then for mating successful with the opposite sex.

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24
Q

How does behavioural changes led to reproductive isolation?

A

Some individuals in a population may develop change in courtship behaviour, meaning they can no longer attract individuals of the opposite sex for mating.

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25
Q

How does allopatric speciation occur?

A
  1. Population of organism become reproductively isolated due to geographical isolation
  2. Gene flow between populations in reduced
  3. The different population with expedient different selectional pressure making different allele more advantageous
  4. Random mutation case genetic variation within a population
  5. This mutation may give the organism an advantageous characteristic.
  6. This organism is therefor more likely to to survive and reproduce
  7. Allele passed onto offspring and frequency of allele will increase
  8. Meaning the two populations can no longer reproduce to create fertile offspring
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26
Q

What is classification?

A

Organising the variety of life (biodiversity) based on similarities in physical features and molecular similarities in DNA.

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27
Q

What is taxonomy?

A

Biological classification based on similarities in the physical features of different organisms.

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28
Q

What’s is molecular phylogeny?

A

Organising biodiversity based on molecular similarities in DNA base sequences and protein structure.

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29
Q

What are the different ranks in the taxonomic classification systems?

A

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

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30
Q

What is the binomial system?

A

It is the scientific names given to individual species. It consists of the organisms genus and species name in modern Latin.

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31
Q

Why is the binomial system good?

A

It allows for species to be universally identified across the entire globe.

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32
Q

What are the five kingdoms?

A

Prokaryotae > have prokaryotic cells which contain no nucleus
Protoctista > eukaryotic which don’t fit else where
Fungi > eukaryotic cells that have non cellulose cell walls
Plantae > multi cellular eukaryotic organism (plants)
Animalia > multicellular eukaryotic organism (animals)

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33
Q

What are the critical evaluations of new classification data?

A

Difficulty has arisen as classification using physical features have many limitations and can led to wrong classifications. Advances in genome sequences and immunology has allowed scientist to further investigate the evolutionary relationship between species leading to many species being reclassified and changes to the classification systems such as the new three domain classification system.

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34
Q

What is the three domain classification?

A

Carl Woesse proposed the three domains
Eukarya (eukaryote)
Bacteria (prokaryote)
Archaea (prokaryote)

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35
Q

What is the structure and function of a plant cell nucleus?

A

This is a double membrane organelle surrounded by a nuclear envelope containing nuclear pore for the exchange of substances.
It’s function is to store genetic information and the nucleolus. And is the site of protein synthesis (transcription) and DNA replication

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36
Q

What is the structure and function of the cell wall in a plant cell?

A

The cell wall in of plants is made up of cellulose, hemicellulose and lignin.
It’s functions is to provide structural support to the cell.

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37
Q

What is the structure and function of chloroplast is a plant cell?

A

A double membrane organelle surrounded by a double membrane containing membrane bound compartments called thylakoids which contain chlorophyll stacked to form grana.
It’s function in to perform photosynthesis and synthesis proteins needed in chloroplast replication.

38
Q

What is the structure and function of amyloplast in plants cell?

A

Small membrane bound organelle containing starch granules.
They are responsible for storing starch in plant and converting it back to glucose when the plant needs it.

39
Q

What is the structure and function of a vacuole in a plant cell?

A

The a membranous sac containing sap.
They keep the cell turgid.

40
Q

What is the structure and function of tonoplast in a plant cell?

A

Membrane layer that surrounds the vacuole.
Controls what enters and leaves the vacuole.

41
Q

What is the structure and function of plasmodesmata in a plant cell?

A

Narrow threads of cytoplasm that’s connect adjacent cells allowing substance to be transported between plant cells and cell to cell communication.

42
Q

What are the structure and function of pits in a plant cell?

A

Very thin regions within a cell wall, they line to in adjacent cells facilitating the transport of substances between cells.

43
Q

What is the structure and function of the middle lamella in a plant cell?

A

The outermost layer of the plant cell that acts like glue to stick adjacent plant cells together. It provides stability to the plant.

44
Q

What is starch?

A

Starch is a storages polysaccharide in plants. It’s a large polymer consisting of glucose monomers found in two different forms amylose and amylopectin.

45
Q

What is the structure of amylose?

A

Amylose is a form of starch made up of monomers of alpha glucose joined together in a condensation reaction forming 1,4 glycosidic bond. It’s coiled shape enables it to be more compact and maximum sense energy storage.

46
Q

What is the structure of amylopectin?

A

Amylopectin is a branched molecule comprising of 1,4 and 1,6 glycosidic bonds formed in a condensation reaction. The branched stature allows it to be hydrolysed quicker for use in cellular respiration.

47
Q

What properties make starch a good storage molecule?

A
  • compact meaning large quantities can be stored at once
  • insoluble so won’t have an osmotic effect.
48
Q

What is the structure of a cellulose molecule?

A

Cellulose is an unbranded polysaccharide consisting of long chains of B-glucose joined by 1,4 glycosidic bonds in a condensation reaction. Alternating OH groups in beta glucose are inverted meaning microfibrils can form through hydrogen bonds (also makes it very strong)

49
Q

What is the function of cellulose?

A
  • main structural component of cell walls due to its strength (hydrogen bonds)
  • high tensile strength meaning it can be stretched without breaking (withstand pressure)
  • strengthened cell wall provide structural support for plants.
50
Q

What are the physical properties of a xylem vessel?

A

Xylem are long and hollow tubes of dead cells found in the plant cells which are extremely strong. They have lignified cell walls, making them waterproof.

51
Q

What is the functions of xylem vessels?

A

Xylem vessels
- transport of water
- transport of dissolved mineral ions
From the roots of the plant to the photosynthetic part as well as they are essential for
- support

52
Q

What is a sclerenchyma fibre?

A

Long hollow plant cells that have a lignified and cellulose cell wall.

53
Q

What is the role of a sclerenchyma fibre?

A

They provide strength and supports to the plant.

54
Q

Why are xylem vessels and sclerenchyma fibres exploited for human use?

A

Both these fibres are incredible strong making them useful for human use. They are used for making ropes and certain fabrics (cotton any hemp).

55
Q

Why are xylem vessels and sclerenchyma fibres so strong?

A
  • arrangements of microfibrils in a mesh-like pattern
  • secondary thickening which results in a thick secondary cell wall developing which often contains lignin.
56
Q

What is a phloem?

A

A long elongated tube of sieve tube elements separated by sieve plates (containing pores) and are surrounded by companion cells (containing a nucleus) found in plant stems.

56
Q

What is a phloem?

A

A long elongated tube of sieve tube elements separated by sieve plates (containing pores) and are surrounded by companion cells (containing a nucleus) found in plant stems.

57
Q

What is the role of a phloem in a plant cell?

A

They are responsible for the translocation of organic solutes.

58
Q

What is a vascular bundle and it’s structure?

A

Consists of xylem vessels which are grouped together by phloem tissues. In a stem xylem vessels are always located towards the middle of the stem, while the phloem is located closer towards the outside of the stem with sclerenchyma vessel on the edge.

59
Q

What is the role of water in plants?

A

Water is important to
- maintain turgidity in the plant cells through pressure in cell vacuoles
- provides a transport medium for minerals
- regulates the temperature ensuring enzymes can function at their optimum rate

60
Q

Why is nitrogen ions important for plants?

A

Nitrogen ions are essential in synthesise of DNA and amino acids. With a nitrogen deficiency the plant will display yellow leaves and stunted growth.

61
Q

Why is calcium ions important for plants?

A

Calcium ions are used in the synthesis of calcium pectate used in cell wall growth. It also regulates proper growth and cell membrane permeability. Without them the plant will be yellow, with crinkly leaves and stunted growth.

62
Q

Why are magnesium ions essential for plants?

A

Magnesium’s is important for the production of chlorophyll which is essential for photosynthesis. Without it the plant will have yellow spots and stunted growth.

63
Q

What is a placebo?

A

An inactive substance that has a psychological benefit in the patient but no physiological impacts. They are used as a control.

64
Q

What is a blind trial?

A

When one set of patients is given the drug but the other set is given a placebo. The patient doesn’t know whether they have revived the actual drug whereas the the doctors do. It helps remove bias form the results.

65
Q

What is a double blind trial?

A

Where one set of patients is given the placebo and another set is given the actual drug. Neither the patient nor the doctor know who has received the placebo. This removes bias form the results.

66
Q

Why are drugs tested?

A
  • test for toxicity
  • test for side effects
  • test for efficacy (does it work at all or well)
  • to determine the dosage and methods of delivery.
67
Q

Who is William Withering and what did discover/test?

A

William Withering was an English scientist from 1700s. He is best known for his work using digitalis as a treatment for swelling caused by heart failure. He treated his patients with an extract made form foxgloves which contained digitalis.

68
Q

How did Whitering drug test digitalis soup?

A
  1. He isolated the active ingredients in foxgloves (digitalis)
  2. Tested on 163 unhealthy unknowing patients (blind study)
  3. He did not use a placebo
  4. He varies the dosage given to each patient
  5. Recorded findings
69
Q

How are drugs tested in the modern day pre clinical?

A
  1. Modelling the potential effect of drug using computers
  2. The drug is tested on human tissues in a laboratory
  3. The drug will then be tested in animals
70
Q

How are drugs tested in through clinical trials in the modern day?

A

The clinical trial is a series of three phases
Phase 1 = drugs are tested on a small number of healthy volunteers to determine the toxicity, side effects and safe dosage
Phase 2 = drug tested on several hundred unhealthy volunteers in a double blind study to determine efficiency, safe dosages and best method of delivery
Phase 3 > drug tested on several thousands of unhealthy patients in a double blind study to again determine efficiency, rare and frequent side effects

71
Q

What are the conditions required for bacterial growth?

A
  • sufficient supply of nutrients for respiration and growth
  • sufficient supply of oxygen for aerobic respiration
  • optimum pH and temperature in order to ensure that bacterial enzymes aren’t denatured
72
Q

What is the definition of sustainability?

A

Meeting the needs of the present generation without compromising the ability of future generations.

73
Q

Why are plant fibres sustainable?

A

Plant fibres are biodegradable meaning they can be broken down and minimise environmental pollution. This is why using plant fibres to make products such as ropes and fabric is more sustainable than using oil based plastics.
Additionally making plant based products is easier and cheaper.
C > they may not be as strong

74
Q

]What sustainable processes can starch be used in?

A

Starch can be mused to make
- bio plastics (It is more sustainable at is does not require as much fossil fuels to be burned and the crop can be replanted (renewable)0
- It can also be used or make biofuels.

75
Q

How do zoos help to conserve endangered species?

A

Zoos aim to protect the population size of endangered species and their diversity by
- scientific research
- public education
- reintroduction programmes
- captive breeding programmes

76
Q

What are reintroduction programmes used to help conserve endangered species?

A

This is where endangered species are reintroduced back into their native habitat. This can be difficult as the the individual may not have the skill set to survive in the wild.

77
Q

What are captive breeding programmes that are used to help conserve endangered species?

A

These increase the size of a species population. When zoos are doing this genetic diversity must be considered as it may be lost through interbreeding.

78
Q

How do zoos maintain genetic diversity in captive breeding programmes?

A

In order to maintain genetic diversity, zoos can perform breeding programmes in which mates are selectively picked so that individual don’t breed twice.
- Genetic testing is used
- records are keep use of stud books.
- Genetic diversity can also be increased through breeding between zoos.

79
Q

Why is interbreeding bad?

A

It is disadvantageous because the mating of closely related individuals causes interbreeding depression. As a result the offspring produced are more likely to inherit homozygous recessive genetic conditions.

80
Q

What is a seed bank?

A

Seed banks are a collection of plant samples that are conserved Incase a plant becomes extinct. The seeds are used for botanical research, habitat restoration and species reintroduction.

81
Q

What are the conditions of seed banks?

A
  • cool
  • dry
82
Q

Why are cool and dry conditions used in a seed bank?

A

It helps to increase seed longevity by
- reducing the plants biochemical (metabolism) reactions making it less likely to germinate
- reduced the growth of microorganism reduced the rate of decomposition

83
Q

Why are seeds easy to store?

A
  • take up little space meaning more sped can be stored at once
  • they are dormant and so can be stored for long periods of time
  • seeds require little maintenance
  • all seeds can be stored in similar conditions
  • reduces economic cost
84
Q

Core practical 6: how to identify different plant structure under a microscope methods?

A
  1. Extracts the vascular bundle or a section of a plant stem using forceps and place them of microscope slide
  2. Add a stain (methylene blue) to highlight structures and add a coverslip
  3. Examine under a light microscope at both low and high power
85
Q

Core practice 7: investigating plant mineral deficiencies - variables?

A

Control > species of a plant, age of plant, temperature (water bath), volume of mineral solution and length of grow period
Independent > mineral levels
Dependent > plant growth (shoot length)

86
Q

Core practice 7: investigating plant miners deficiencies - method?

A
  1. Fill four tests tubes with every mineral required by the plant except one, have one control.
  2. Place a seedling on top of each test tube that is covered with tin foil.
  3. Place the test tubes near a light source and leave them to grow
  4. Measure the change in shoot height every three days and record each height and any physical properties
87
Q

Core practical 8: determine tensile strength of plant fibres - variables?

A

Control > type of the plant fibre, age of the plant fibre, thickness, temperature and humidity
Independent > species of the plant
Dependent > mass required to break the plant fibre

88
Q

Core practical 8: determine tensile strength of plant fibres - method?

A
  1. Suspend the fibre longitudinally by a clamp and stand.
  2. Add mass slowly until the fibre breaks
  3. Calculate tensile strength (force /cross sectional area)
  4. Repeat with other species and calculate mean
89
Q

Core practical 9: investigate the anti microbial properties of plants - variables?

A

Control > species of plant, species of bacteria, age of plant, volume of extract, concentration of extract, concentration of bacteria.
Independent > species of plant and species of bacteria
Dependent > area of zone of inhibition

90
Q

Core practical 9: investigate the anti microbial properties of plants - method?

A
  1. Grow a culture of bacteria on an agar plate
  2. Place paper disc with each plant solution on agar plate
  3. Tape lid onto Petri dish, invert and place agar in incubator
  4. Measure sine of inhibition
  5. Repeat and calculate means
91
Q

What aseptic technique is used when experimenting with bacteria?

A
  • disinfect work surface before and after use
  • boil cultural medium before and after use
  • sterilise all equipment by passing them through a flame
  • work in the draught of a naked flame
  • don’t fully seal the age plate containing the bacteria samples

A Level Biology (Salters-Nuttfield SNAB) (8 decks)

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