biodiversity Flashcards
1
Q
What is biodiversity?
A
The variety of living organisms
present in an area
2
Q
What is the importance of biodiversity?
A
Essential in maintaining a balanced ecosystem for all organisms • All species are interconnected • In regions of reduced biodiversity, these connections may not be present, which eventually harms all the species in the ecosystem
3
Q
Describe global variations in biodiversity
A
• Tropical, moist regions (that are warm all year round) have the most biodiversity • The UK’s temperate climate (warm summers and cold winters) has less biodiversity • Very cold areas e.g. the Arctic, or very dry areas e.g. deserts, have the least biodiversity • The closer a region is to the equator, the greater the biodiversity
4
Q
What role does measuring biodiversity play in
conservation?
A
• Informs scientists of the species that are present, providing a baseline for the level of biodiversity in an area • From this information, the effects of any changes to an environment can be measured • e.g. the effect of: human activity, disease, climate change etc.
5
Q
What is an Environmental Impact Assessment (EIA)?
A
An assessment done before a major project is undertaken e.g. building a new road, or creating a new nature reserve • The assessment attempts to predict the positive and negative effects of a project on the biodiversity of that area
6
Q
What are the levels that biodiversity can be studied at?
A
- Habitat biodiversity
- Species biodiversity
- Genetic biodiversity
7
Q
What is habitat biodiversity?
A
The number of different habitats found within an area • Each habitat can support a number of different species, therefore in general, the greater the habitat biodiversity, the greater the species diversity will be in that area
8
Q
Give examples of habitat
biodiversity on a large and
small scale
A
Large • The UK is home to many habitat types e.g. meadow, woodland, streams, sand dunes, so it has a large habitat biodiversity • Antarctica is covered by an ice sheet, so has very low habitat biodiversity and very few species live here Small • A countryside that is habitat rich e.g. river, woodland, hedgerows, wild grassland, will be more species rich than a farmed countryside with large ploughed fields making up a single uniform habitat
9
Q
What us a community?
A
All the populations of living
organisms in a particular habitat
10
Q
What is species biodiversity?
A
Made up of two different components: • Species richness - the number of different species living in a particular area • Species evenness - a comparison of the number of individuals of each species living in a community
11
Q
How can an area differ in species biodiversity even if it
has the same number of species?
A
e.g. A cornfield and a grass meadow may both contain 20 species • In the cornfield, corn will make up 95% of the community, with the remaining 5% being weed plants, insects, mice and birds etc • In the grass meadow, the species will be more balanced in their populations
12
Q
What is genetic biodiversity?
A
The variety of genes that make up a species • Many genes are the same for all individuals within a species, however for many genes, alleles exist • This leads to genetic biodiversity within a species • Greater genetic biodiversity within a species allows for better adaptation to a changing environment, and is more likely to result in individuals who are resistant to disease
13
Q
What is sampling?
A
Taking measurements of a limited
number of individual organisms
present in particular area
14
Q
What can sampling be used
for?
A
To estimate the number of organisms in an area without having to count them all • Abundance - the number of individuals of a species present in an area To measure a particular characteristic of an organism • e.g. if you measure the height of a number of plants then calculate an average, your result is likely to be close to the average height of the whole crop You can use the results of a sample to make generalisations or estimates about the number of organisms, distribution of species or measured characteristic throughout the entire habitat
15
Q
What is random sampling?
A
Sampling where each individual in the population has an equal likelihood of selection e.g. to take a random sample at a grass verge: 1. Mark out a grid on the grass using two tape measures laid out at right angles 2. Use random numbers to deter the x-coordinate and the ycoordinate on your grid 3. Take a sample of each of the coordinate pairs generated
16
Q
What is non-random sampling?
A
An alternative sampling method to random sampling, where there sample is not chosen at random. It can be opportunistic, stratified or systematic
17
Q
What is opportunistic sampling?
A
• Uses organisms that are conveniently available • Weakest form of sampling as it may not be representative of the whole population
18
Q
What is stratified sampling?
A
• Some populations can be divided into a number of strata based on a particular characteristic • e.g. the population may be separated into males and females • A random sample is then taken from each of these strata proportional to its size
19
Q
What is systemic sampling?
A
• Different areas within an overall habitat are identified, which are then sampled separately • e.g. may be used to study how plant species change as you move inland from the sea • Often carried out using a line or a belt transect
20
Q
What is a line transect?
A
Involves marking a line along the ground between two poles and taking samples at specie points • This can include describing all the organisms which touch the line, or distances of samples from the line
21
Q
What is a belt transect?
A
Two parallel lines are marked, and samples are taken of the area between the two lines • Provides more information than a line transect
22
Q
Why is a sample never entirely representative of the
organisms present in a habitat?
A
Sampling bias • Selection process may be biased • e.g. you may choose to sample a particular area that has more flowers because it looks interesting • The effects can be reduce by using random sampling, where human involvement in choosing the samples is removed Chance • The organisms selected may, by chance, not be representative of the whole population • Can’t be completely removed from the process, but its effect can be minimised by using a large sample size • More individuals studied, the lower the probability that chance will affect the result; larger the sample size, more reliable the result
23
Q
Describe methods for sampling
animals
A
• A pooter is used to catch small insects • Sweep nets are used to catch insects in areas of long grass • Pitfall traps are used to catch small, crawling invertebrates e.g. beetles, spiders and slugs • Tree beating issued to take samples of invertebrates living in a tree or bush • Kick sampling is used to study the organisms living in a river
24
Q
How are plants normally sampled?
A
Using a quadrat, which can also be used to pinpoint an area in which the sample of plants should be collected • Quadrats can also be used to sample slow-moving animals e.g. limpets, barnacles, mussels and sea anemones
25
Describe the two main types of quadrat
```
Point quadrat
• Consists of a frame containing a
horizontal bar
• At set intervals along the bar, long
pins can be pushed through the
bar to reach the ground
• Each species of plant the pin
touches is recorded
Frame quadrat
• Consists of a square frame divided
into a rid of equal sections
• The type and number of species
within each section of the quadrat
is recorded
```
26
How should quadrats be used?
```
• To collect the most valid
representative sample of an area,
a random sampling technique
should be used
• To study how the presence and
distribution of organisms across
an area of land varies, the
quadrants can be place
systematically along a line or belt
transect
```
27
How is species richness measured?
A list should be compiled of each
species identified. The total number
of species can then be calculated
28
What are identification keys?
```
Images to identify the organism, or a
series of questions which classify an
organism into a particular species
based on the presence of a number
of identifiable characteristics
• Enable scientists to accurately
identify organisms
```
29
What are the 3 main ways in which frame quadrats are
| used?
```
Density
• If large individual plants can be
seen clearly count the number of
them a 1m by 1m quadrat
• This gives the density per square
metre
• This is an absolute measure, not
an estimate
Frequency
• Used where individual members of
a species are hard to count, e.g.
grass or moss
• Using the small grids within a
quadrat, count the number of
squares a particular species is
present in
• e.g if clover is present in 65 out of
100 squares, the frequency of its
occurrence is 65%
Percentage cover
• Used for speed as lots of data can
be collected quickly
• Useful when a particular species is
abundant or difficult to count ]an
estimate by eye of the area within
a quadrat that a particular plant
species covers
```
30
Why is it difficult to determine animal population sizes?
They are constantly moving through
| a habitat, and others may be hidden
31
How can animal population size be estimated?
```
Capture-Mark-Release-Recapture
1. Capture as many individuals of a
species in an area as possible
2. The organisms are marked and
then released back into the
community
3. Time is allowed for the
organisms to redistribute
themselves throughout the
habitat before another sample of
animals is collected
4. By comparing the number of
marked individuals with the
number of unmarked individuals
in the second sample, scientists
can estimate population size
The greater the number of marked
individuals captured, the smaller the
population
```
32
What are abiotic factors?
```
Non-living conditions in a habitat
• Wind speed; anemometer; ms-1
• Light intensity; light meter; lx
• Relative humidity; humidity sensor;
mgdm-3
• pH; pH probe; pH
• Temperature; temperature probe;
°C
• Oxygen content in water;
dissolved oxygen probe; mgdm-3
```
33
Why is the use of sensors to measure abiotic factors
| advantageous?
```
Many abiotic factors can be
measured quickly and accurately
• Rapid changes can be detected
• Human error in taking a reading is
reduced
• A high degree of precision can
often be achieved
• Data can be stored and tracked on
a computer
```
34
What is Simpson’s Index of
| Diversity (D)
```
A measure of biodiversity between 0
and 1 that takes into account both
species richness and species
evenness. The higher the value of
Simpson’s Index of Diversity, the
more diverse the habitat
D = 1 - Σ(n/N)2
• Σ = sum of (total)
• N = the total number of all species
• n = the total number of organisms
of a particular species
```
35
```
What are the typical habitat
features for the following
environments?
1. Low biodiversity
2. High biodiversity
```
```
Number of successful species
1. Relatively few
2. A large number
Nature of the environment
1. Stressful and/or extreme with
relatively few ecological niches
2. Relatively benign / not stressful,
with more ecological niches
Adaptation of species to
environment
1. Relatively few species live in the
habitat, often with very specific
adaptations for the environment
2. Many species live in the habitat,
often with few specific
adaptations to the environment
Type of food webs
1. Relatively simple
2. Complex
Effect of a change to the
environment on ecosystem as a
whole
1. Major effects on the ecosystem
2. Often relatively small effect
```
36
Why is it important to conserve some habitats with low
| biodiversity?
In order to conserve rare species
that may be too specialised to
survive elsewhere
37
What is the importance of
| genetic biodiversity?
```
Within a species, individuals have
very little variation within their DNA
• Differences un the alleles among
individuals of a species creates
genetic biodiversity within the
species, or within a population of
the species
• Species that contain greater
genetic biodiversity are likely to be
able to adapt to changes in their
environment
• This is because there are likely to
be some organisms within the
population that carry an
advantageous allele, which
enables them to survive in the
altered conditions
```
38
# Define the following:
1. Gene flow
2. Genetic bottleneck
3. Founder effect
```
1. Gene flow - when alleles are
transferred from one population
to another by interbreeding
2. When large numbers of a
population die prior to
reproducing, leading to reduced
biodiversity within the population
3. When a few individuals of a
species colonise a new area,
their offspring initially experience
a loss in genetic variation, and
rare alleles can become much
more common in the population
```
39
What are the factors that affect genetic biodiversity?
```
• For genetic biodiversity to
increase, the number of possible
alleles in a population must also
increase
• For genetic biodiversity to
decrease, the number of alleles in
a population must also decrease
```
40
What causes an increase in the number of possible alleles in a population?
```
• Mutation (s) in the DNA of an
organisms, creating a new allele
• Interbreeding between different
populations. When an individual
migrates from one population and
breeds with a member of another
population, alleles are transferred
between the two populations. This
is known as gene flow
```
41
What causes a decrease in the number of possible alleles in a population?
```
• Selective breeding (aka artificial
selection) where only a few
individuals within a population are
selected for their advantageous
characters are bred
• Captive breeding programmes,
where only a small number of
captive individuals of species are
available for breeding
• Rare breeds where selective
breeding has been used
historically to produce a breed
with characteristics that then
become less popular or
unfashionable, so the number of
the breed fall catastrophically
• Artificial cloning (asexual
reproduction) e.g. using cuttings to
clone a farmed plant
• Natural selection
• Genetic bottlenecks
• The founder effect
• Genetic drift, due to the random
nature of alleles being passed on
from parents to their offspring, the
frequency of occurrence of an
allele will vary
```
42
How is genetic biodiversity measured?
By measuring polymorphism.
Polymorphic genes have more than
one allele.
43
How do you calculate the proportion of genes that are
| polymorphic?
```
• The locus of a genes refers to the
position of the gene on a
chromosome
• The greater the proportion of
polymorphic gene loci, the greater
the genetic biodiversity within the
population
```
44
What influence do humans have on biodiversity?
```
• Deforestation - the permanent
removal of large areas of forest to
provide wood for building and fuel
(logging), and to create space for
roads, building and agriculture
• Agriculture - an increasing amount
of land has to be farmed in order
to feed the growing population.
This has resulted in huge amounts
of lands being cleared and
monoculture
• Climate change - release of CO2
and other pollutants into the
atmosphere from the burning of
fossil fuels is increasing global
temperature
• Pollution from industry and
agriculture e.g. chemical pollution
of waterways
• Littering - improper disposal of
waste and packaging
```
45
How does deforestation happen naturally?
e.g. As a result of forest fires caused
by lightning or extreme heat and dry
weather
46
How is deforestation caused by humans?
```
• Directly e.g. by logging
• Indirectly e.g. through acid rain,
which forms as a result of
pollutants being released into the
atmosphere
```
47
How does deforestation affect biodiversity?
```
• Directly reduces the number of
trees present in an area
• If only a specific type of tree is
felled, species diversity is reduced
• Reduces the number of animal
species present in an area as it
destroys their habitat, including
their food source and home
• Animals forced to migrate to other
areas for survival, so biodiversity
may increase in near areas
```
48
How do the techniques used in agriculture lead to a reduction in biodiversity?
```
Deforestation - Increases the area of
land available for crops and animals
Removal of hedgerows - Due to
mechanisation, removed so large
machinery can be used to plant,
fertilise and harvest crops, and
there’s more land for growing.
Reduces the number of plant
species present, and destroys the
animal habitats
Pesticides - Reduces species
diversity directly as it destroys the
pest species, and indirectly by
destroying the food source for other
organisms
Herbicides - Kill weeds, reducing
plant diversity and animal diversity
by removing a food source
Monoculture - Lowers biodiversity
as only one species of plant is
present. Few animal species
supported by only 1 type of plant, so
lower overall biodiversity levels
```
49
What were the key findings in the 2007 Intergovernmental Panel on Climate Change
(IPCC) report?
```
The warming trend over the last 50
years is nearly twice that for the
previous 100 years
• The average amount of water
vapour in the atmosphere has
increase since the 1980s over land
and ocean
• Since 1961, the average
temperature of the global ocean
down to depths of 3km has
increased
• The global average sea level rose
by an average of 1.8mm per year
from 1961-2003
• Average arctic temperatures have
increased at almost twice the
global rate in the past 100 years
```
50
If global warming continues, how will biodiversity be
| affected?
```
• Melting of polar ice caps could
lead to extinction of plant and
animal species in these regions
• Rising sea levels from melting ice
caps and the thermal expansion of
oceans could flood low-lying land,
reducing habitats. Saltwater would
flow up rivers, reducing habitats of
freshwater plants and animals
• Higher temperatures and less
rainfall would result in some plant
species (and animals) not
surviving, and xerophytes
becoming more dominant
• Insect life cycles and populations
will change. Insects are key
pollinators, so could affect the
lives of the plants it leaves behind,
causing extinction. Spread of
tropical insects could lead to the
spread of tropical diseases
```
51
What will happen if climate change is slow?
```
• Species may have time to adapt
e.g. eating a different food source
or migrating to new areas
• Loss of native species
• Other species may move into the
area
• Biodiversity would not be lost, the
species mix would simply change
```
52
What are aesthetic reasons for maintaining biodiversity?
```
• Presence of different plants and
animals in our environment
enriches our lives, e.g. relaxing in a
beach or visiting a rainforest
• Natural world provides inspiration
for people e.g. musicians and
writers
• Patients recover more rapidly from
stress and injury when they are
supported by plants and a
relatively natural environment
• Tourism
```
53
What are ecological reasons for maintaining biodiversity?
```
• All organisms are interdependent
on others for survival e.g
decomposers break down dead
material and remains, releasing
nutrients into the soil, which plants
use for healthy growth. Plants rely
on bees for pollination
• Protecting keystone species
```
54
What are keystone species?
```
Species which are essential for
maintaining biodiversity - they have
a disproportionately large effect on
their environment relative to their
abundance. When a keystone
species is removed, the habitat is
drastically changed
```
55
What are economic reasons for maintaining biodiversity?
```
• Soil erosion and desertification
may occur because of
deforestation, and lack of crops in
a course can lead to resource and
economic dependence on other
nations
• Complete loss of raw materials
(e.g. hardwood timber) will lead to
the collapse of industry in an area
• Undiscovered species in tropical
rainforests may be chemically or
medically useful
• Continuous monoculture results in
soil depletion, making the
ecosystem more fragile. Farmer
will become dependent o
expensive pesticide, herbicides
and fertilisers
• Without biodiversity, a change in
condition or disease can destroy
entire crops e.g. Irish potato
famine of 1840s led to death of 1
million people
• Highly biodiverse areas can
promote tourism
• The greater the diversity in an
ecosystem, the greater the
potential for the manufacture of
different products in the future
• Plant varieties are needed for
cross breeding, which can lead to
better characteristics.g. disease
resistance or increased yield
```
56
What positive impacts does human activity have on
| biodiversity?
```
Natural habitat is created by human
intervention and the management of
land e.g. farming, grazing, planting
of hedges, meadows, and forest
management have changed the
landscapes and ecology over
thousands of years
```
57
What is conservation?
```
The maintenance of biodiversity
• in situ conservation - within the
natural habitat
• ex situ conservation - out of the
natural habitat
```
58
How are species classified for the purpose of conservation?
```
• Extinct - no organisms of the
species exist anywhere in the
world
• Extinct in the wild - organisms of
the species only exist in captivity
• Endangered - a species that is in
danger of extinction
• Vulnerable - a species that is
considered likely to become
endangered in the near future
```
59
What is sustainable development?
Economic development that meets
the needs of people today, without
limiting the ability of future
generations to meet their needs
60
What is in situ conservation?
```
Takes place inside an organism’s
natural habitat
• Maintains genetic diversity and
evolutionary adaptation
• By allowing the endangered
species to interact with other
species, also preserves the
interdependent relationships
present in a habitat
• Interlinked species may also be
preserved
• Cheaper than ex situ conservation
• e.g. wildlife reserves and marine
conservation zones
```
61
What are the active management techniques in a
| wildlife reserve?
```
• Controlled grazing - only allowing
livestock to graze an area of land
for a certain period of time allows
species time to recover
• Restricting access - e.g. not
allowing people to visit a beach
during seal reproductive season
• Controlling poaching - creating
defences to prevent access,
issuing fines, removal of horns
• Feeding animals - so more
organisms reach reproductive age
• Reintroduction of species - adding
species to areas whose areas have
decreased significantly
• Culling or removal of invasive
species - these organisms
compete with native species for
resources
• Halting succession - as a result of
natural succession any piece of
land left alone for long enough in
the UK will develop into woodland
```
62
What is succession?
```
The progressive replacement of one
dominant type of species or
community by another in an
ecosystem, until a stable climax
community is established
```
63
How do marine conservation zones work?
```
• Lundy Island is currently the only
statutory marine reserve in
England
Marine reserves
• Preserve species-rich areas e.g.
coral reefs
• Create areas of refuge within
which population can build up and
repopulate adjacent areas
• Large areas of sea are required for
marine reserves as the large
species often move large
distances, or breed in
geographically different areas
```
64
What is ex situ conservation?
```
Involves the removal of organisms
from their natural habitat. Normally
used in addition to in situ measures,
ensuring the survival of a species
• Botanic gardens
• Seed banks
• Captive breeding programes
```
65
Describe botanic gardens
```
• Here the plants species are
actively managed to provide them
with the best resources to grow
e.g. soil nutrients, sufficient
watering and removal of pests
• 1500 botanic garden worldwide,
holding 35 000 plant species
```
66
Describe seed banks
```
A store of genetic material from
plants in the form of seeds
• Seeds are stored carefully so that
new plants can be grown in the
future
• Dried and stored at -20°C to
maintain their viability, by slowing
down the rate at which they lose
their ability to germinate
• Seed banks don’t work for all
plants - some die when dried and
frozen; seeds of most tropical
rainforest trees fall into this
category
```
67
Describe captive breeding programmes
```
Produce offspring of species in a
human-controlled environment
which are often run and managed by
zoos and aquatic centres
• Aim to create a stable, healthy
population of a species and then
gradually reintroduce the species
back into its natural habitat
• Provide the animals with shelter,
food, absence of predators and
veterinary treatment
• Artificial insemination, embryo
transfer and long-term cryogenic
storage of embryos allow new
genetic lines to be introduced
```
68
Why are some organisms born in captivity not suitable for release in the wild?
```
• Diseases - may be a loss of
resistance to local diseases in
captive-bred populations. Also
new diseases might exist in the
wild that the captive animals have
not yet developed resistance to
• Behaviour - most behaviour has to
be learned through copying or
experience
• Genetic races - the genetic makeup
of captive animals can become
so different from the original
population that the two
populations cannot interbreed
• Habitat - if only a small suitable
habitat exists, the introduction of
new individuals can lead to stress
and tension as individuals fight for
limited territory and resources
scubas food
```
69
What is the International Union for the Conservation of Nature (IUCN)?
```
• Intergovernmental organisation
that assist in securing agreements
between nations
• Publishes the Red List once a year
detailing the current conservation
status of threatened animals, so
countries can work together to
conserve these species
• Involved in the establishment of
the Convention on International
Trade in Endangered Species
(CITES)
```
70
What was The Rio Convention?
```
Historic meeting in 1992 of 172
nations resulting in new agreements
between nations
• The convention on Biological
Diversity (CBD) requires countries
to develop national strategies for
sustainable development
• The United Nations Framework
Convention on Climate Change
(UNFCCC) is an agreement
between nations to stabilise
greenhouse has concentrations
within the atmosphere
• The United Nations Convention to
Combat Desertification (UNCCD)
```
71
What is the countryside stewardship scheme?
```
Operated on a local level in England
between 1991 and 2014, with the
general aim of making conservation
a part of normal farming and land
management practice
Specific aims:
• Sustaining the beauty and
diversity of the landscape
• improving, extending and creating
wildlife habitats
• Restoring neglected land and
conserving archaeological and
historic features
• Improving opportunities for
countryside enjoyment
This scheme has now been replaced
by the Environmental Stewardship
Scheme, which operates similarly
```
