Biodiversity and its measures Flashcards

1
Q

What is the definition of biodiversity?

A

The variety of living organisms in an area

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2
Q

What is the definition of a species?

A

A group of similar organisms able to reproduce to give fertile offspring

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3
Q

What is the definition of a habitat?

A

The area inhabited by a species, including the physical factors and the living factors. E.g a pond

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4
Q

What are the first 3 scales that biodiversity can be measured on?

A
  1. Species diversity
  2. Genetic diversity
  3. Habitat diversity
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5
Q

For species diversity, explain the two measures.

A
  1. Species richness- This is the number of different species in an area
  2. Species evenness- This is the abundance of species in an area
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6
Q

For species diversity, how are the two measures measured?

A

Taking a random sample of a habitat and counting the population of each species and the number of species

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7
Q

What increases the species richness? Give an example

A

The higher the number of different species, for example a woodland could contain many different species of plants, insects, birds and mammals

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8
Q

What increases the species evenness?

A

The more similar the population size of each species

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9
Q

When would an ecosystem be considered diverse?

A

When the species richness and evenness are both high, giving a high biodiversity

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10
Q

What does species diversity as a measure take into account?

A

The stability and health of food chains

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11
Q

Explain what genetic diversity is

A

This is the variation of alleles within a species or a population of a species

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12
Q

Give an example of genetic diversity

A

Human blood type is determined by a gene with 3 different alleles

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13
Q

Explain what habitat diversity is

A

The number of different habitats/ ecosystems in an area

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14
Q

What makes habitat diversity the most difficult aspect of biodiversity to calculate?

A

The boundaries of habitats/ ecosystems are difficult to determine.

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15
Q

Give an example of somewhere containing many different habitats.

A

A coastal area- beaches, sand dunes, mudflats, salt marshes etc

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16
Q

How is habitat diversity affected by humans?

A

Agricultural land has larked ploughed fields making a uniform habitat

17
Q

What is genetic biodiversity?

A

It determines how easily a species is able to adapt to changes in its environment

18
Q

Why is genetic biodiversity so crucial for a species survival?

A

A species with high genetic diversity will contain a wide range of traits on which natural selection can act, therefore increasing the chance of a species adapting and surviving environmental changes, allowing evolution to occur

19
Q

What can cause the genetic diversity of a population to increase?

A
  • DNA mutation

- Gene flow from another population (breeding between populations of the same species)

20
Q

What can cause the genetic diversity of a population to decrease?

A
  • Selective breeding
  • Captive breeding
  • Genetic bottle necks (when a population is reduced to a small size due to disease, habitat destruction etc)
21
Q

Genetic diversity can be measured by genetic polymorphism. Explain how this is done and give the equation

A
  • Alleles are different versions of genes
  • Alleles of the same gene are found at the same point on a chromosome (locus)
  • polymorphism described a locus with 2 or more alleles
  • working out the proportion of polymorphic gene loci in an organism gives you a measure of genetic diversity

Proportion of polymorphic gene loci=
number of polymorphic gene loci / total number of loci

22
Q

What may happen if a population has a low genetic diversity?

A

It might not be able to adapt to a change in the environment and the whole population could be wiped out by a single event e.g a disease

23
Q

Give examples of populations where genetic diversity may be low.

A
  • Animals bred in captive breeding programmes (e.g zoos)
  • Populations of pedigree animals (e.g dogs bred to meet kennel club criteria)
  • Rare breeds
24
Q

Does a species that has a high percentage of monomorphic genes (only 1 allele) have high or low genetic diversity?

A

-low, and with a low percentage of monomorphic genes has high genetic diversity