A Level Biology Paper 1 > Biodiversity > Flashcards

Biodiversity Flashcards

(43 cards)

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1
Q

Define biodiversity

A

The number of species and the number of individuals of each species in any one community

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2
Q

Define species richness

A

The number of different species in a community

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3
Q

Define community

A

All the individuals of all the species living together in the same area at the same time

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4
Q

Define species

A

Group of similar organisms/organisms with similar features that can reproduce to produce fertile offspring

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5
Q

Define genetic diversity

A

Difference in DNA/base sequence/alleles/genes

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6
Q

Define niche

A
  • An organisms role in the ecosystem/community
  • Describes what the species is like, where it occurs, how it behaves, how it interacts with other species and how it responds to the environment
  • No 2 species share the same niche over a long period of time due to interspecific competition
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7
Q

Define habitat

A

A place where an organism normally lives within an ecosystem, characterised by abiotic and biotic factors

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8
Q

What is diversity index?

A

A measure of the number of species present and the number of individuals in each species.

Never less than 1

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9
Q

What is the formula for diversity index?

A

Sum of n(n-1)

Where N=Total number of organisms of all species
And n=Total number of organisms of each species

Always greater than 1

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10
Q

Why is index of diversity more useful than species richness?

A
  • Index of diversity also measures number of individuals in a species
  • Some species may be present in high or low numbers
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11
Q

Advantages of using index of biodiversity rather than an indicator species?

A
  • You don’t need to identify each species

- Index considers the number of organisms of each species

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12
Q

What does a high diversity mean for the environment?

A

More stable the ecosystem is
Less likely a disease or climate change will affect every organism
Continue to exist

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13
Q

What does a low diversity mean for the environment?

A

Less stable the ecosystem is

A few organisms dying or species dying would have a severe negative effect on the ecosystem

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14
Q

Economic arguments for maintaining biodiversity?

A
  • Medical/pharmaceutical products can be obtained from living organisms
  • Commercial uses like wool from sheep
  • Tourism
  • Agriculture
  • Saving local forest communities
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15
Q

Economic arguments for maintaining biodiversity?

A
  • Medical/pharmaceutical products can be obtained from living organisms
  • Commercial uses like wool from sheep
  • Tourism
  • Agriculture
  • Saving local forest communities
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16
Q

How can you ensure index of biodiversity is representative of habitat?

A
  • Random sample
  • Large sample
  • Continue sampling until running mean
  • Enough samples to carry out statistical tests if necessary
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17
Q

Classification Vs Taxonomy?

A

Classification is the grouping of organisms, taxonomy is the theory and practice of classification that involves naming and grouping organisms according to shared characteristics and evolutionary history to allow identification and comparison.

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18
Q

Define hierarchy

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A

Groups within groups

With no overlap

19
Q

What is a phylogenetic group?

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A

Groups according to evolutionary history/links/relationships/common ancestry

20
Q

Advantages and disadvantages of planting hedges on a farm

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A

Advantages

  • Greater biodiversity so increase in predators of pests meaning more yield and less need for pesticides
  • Increase in pollinators meaning more yield and income
  • May attract more tourists so more income

Disadvantages

  • Reduced land area for crops so lower yield and income
  • Greater biodiversity means increase in pest population so less yield and more need for pesticides
  • Increased interspecific competition means less yield
21
Q

How does natural selection produce changes in a species?

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A
  • Variation between members of population due to mutations
  • Predation/disease/competition results in differential selection
  • Those with advantageous alleles survive and reproduce and pass on alleles to offspring
  • Those without advantageous alleles die out and less likely to reproduce
  • Creating a change in frequency of allele over time
22
Q

How can comparing biological molecules in two species be used to find out if they are closely related?

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A
  • Compare DNA/sequence of bases/DNA hydration/separate DNA strands by breaking hydrogen bonds/mix DNA of different species/compare same protein/compare sequence of amino acids
  • Greater the similarity the closer related they are/more recently they shared a common ancestor
23
Q

Why can comparing base sequences of genes provide more information than comparing amino acid sequence in classification?

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A
  • More bases than amino acids/longer base sequence
  • Introns and exons in base sequence of DNA but amino acid only takes into account exons because introns spliced out
  • Degenerate DNA code means some amino acids may be coded for by different base sequence/triplets
24
Q

How can analysing protein structure help to investigate evolution relationships between species?

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A
  • Amino acid sequence/primary structure
  • Closer the sequence means closer the relationship
  • Protein structure comes from DNA triplets
  • So similar amino acid sequence means similar DNA so likely closely related
25
Describe the process leading to reduction in genetic biodiversity
- Reduced variety in alleles causes founder effect - A few individuals from population become isolated/form colonies - Genetic bottleneck causes significant fall in size of population - Selective breading - Artificial selection
26
Effect of farming on species diversity
- Decrease in variety of plant species - Fewer habitats/niches - Decrease in variety of food so fewer food sources# - Farming uses machinery and pesticides so kills organisms and reduces diversity
27
What is a genetic bottleneck?
Drop in population caused by many organisms killed by an event (earthquake) resulting in reduced genetic diversity and variation in alleles, meaning some species can become entirely extinct
28
Ethical arguments for maintaining biodiversity
- Prevents extinction | - Saves organisms for future generations
29
How does courtship increase probability of successful mating?
- Attracts the same species - Attracts a mate of opposite sex - Indication of sexual maturity/fertility - Stimulates release of gametes - Forms a pair bond
30
Explain the binomial system
- Naming system of species consisting of two word scientific name - Usually universal and based on Latin or Greek names telling you about a characteristic of species - Genus + Species - First word starts with a capital, all underlined and in italics
31
What are the 8 levels of Taxa?
``` Domain - Delicious Kingdom - King Phylum - Prawn Class - Curry Order - Or Family - Fatty Genus - Greasy Species - Sausages ``` Can only belong to one taxa No overlap in groups
32
Explain the highest Taxonomic rank of organisms
Domain Archaea: Single celled prokaryotes, resemble bacteria but differ because genes and protein synthesis is similar to eukaryotes, no murein cell wall, more complex RNA polymerase Bacteria: Single celled prokaryotes with no membrane bound organelles, smaller 70s ribosomes, murein cell walls, no histones and circular DNA Eukarya: Unicellular or multicellular organisms that have a nucleus enclosed in a membrane and belong to one of 4 kingdoms
33
What are the 4 kingdoms?
Animalia Fungi Plantae Protista
34
What happens as you move down the levels in hierarchy?
Fewer and fewer organisms in each group until you reach species in which contains only one type of organism
35
What is phylogenetics?
The study of patterns in evolutionary history
36
What is courtship behaviour?
- Attracts a mate of the correct species and sex and is important to ensure reproductive success. - Genetically determined so organisms more closely related display similar patterns of courtship behaviour.
37
Give some examples of courtship behaviour?
- Fireflies give off pulses of light, each species has specific patterns of pulses - Birds have displays showing off their colourful plumage, each species displaying different colours of plumage and patterns of movement - Male butterflies release chemicals, different for each species
38
Give the modern classification methods
1. Frequency of measurable observable characteristics 2. The base sequence of DNA 3. The base sequence of mRNA 4. The amino acid sequence of protein encoded by DNA and mRNA
39
Why can it be difficult to decide which species an organism belongs to?
Can't always observe their reproductive behaviour or tell if offspring is fertile because they are: 1. Extinct 2. Reproducing asexually 3. Practical and ethical issues
40
Compare modern and previous classification methods
Originally classification methods were based on observable features but lead to mistakes since some species look similar but have no recent common ancestry. Now we use genetic and molecular evidence to classify relationships between organisms for grouping
41
Explain immunological comparisons
- Antibodies are proteins with complementary binding sites to antigen which stimulates their production by B cells - Clump together as solid precipitate out of a solution - If antibodies made in response to one species protein are able to bind to the protein for another species and clump, they shared an ancestor more recently
42
Eukarya
Protctista Fungi Plantae Animalia
43
Phylogenetic tree
Diagram showing evolutionary descent Living organisms at the tips if branches Ancestral species in the branches and trunks Brach points resemble common ancestors
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