biodiversity Flashcards
(215 cards)
1
Q
How do scientists calculate the proportion of polymorphic gene loci (P)?
A
P = number of polymorphic gene loci ÷ total number of loci investigated.
2
Q
What does a higher P value indicate?
A
Greater genetic diversity in the population.
3
Q
What is a limitation of using P to assess genetic diversity?
A
It does not show allele richness or the number of alleles per gene locus.
4
Q
What method is useful for investigating allozymes?
A
Comparing amino acid sequences of proteins.
5
Q
What are allozymes?
A
Slightly different forms of the same enzyme, each coded by a different allele.
6
Q
Why might comparing amino acid sequences not show all genetic differences?
A
Because the genetic code is degenerate, different DNA sequences can code for the same amino acid sequence.
7
Q
What is now the most common method used to assess genetic diversity?
A
Comparing DNA base sequences.
8
Q
What types of DNA do scientists focus on when comparing sequences?
A
Specific sequences in nuclear DNA and mitochondrial DNA (mtDNA).
9
Q
What has caused exponential human population growth in the last 150 years?
A
Improved technology, medicine, hygiene, and healthcare leading to higher birth rates and lower death rates.
10
Q
How does human population growth affect biodiversity?
A
It increases the demand for natural resources, leading to environmental damage and reduced biodiversity.
11
Q
What conflict exists due to human population growth?
A
A conflict between meeting human needs and conserving biodiversity.
12
Q
What are the five main human-related factors affecting biodiversity today?
A
Habitat destruction, overexploitation, hunting, agriculture, and climate change.
13
Q
What is habitat loss?
A
When natural environments are destroyed and organisms lose their living spaces entirely.
14
Q
What is habitat fragmentation?
A
When habitats are broken into smaller, isolated sections, increasing the risk of inbreeding and local extinctions.
15
Q
Why is deforestation particularly harmful to biodiversity?
A
Forests often contain the highest levels of biodiversity, and their loss removes critical habitats.
16
Q
How are marine habitats being destroyed by humans?
A
Through practices like dynamite fishing and trawling, which damage coral reefs and sea beds.
17
Q
What is overexploitation?
A
Using natural resources faster than they can be replaced.
18
Q
Give two examples of overexploitation.
A
Unsustainable deforestation and overfishing.
19
Q
How does overfishing affect marine ecosystems?
A
It reduces fish populations and harms organisms that rely on those fish, like marine mammals and seabirds.
20
Q
Why is hunting a threat to biodiversity?
A
It removes animals from the wild faster than their populations can recover.
21
Q
What is bush meat, and where is it commonly hunted?
A
Meat from wild animals hunted in developing countries, including primates and reptiles.
22
Q
What major changes in agriculture occurred after WWII?
A
Specialisation in one crop or livestock (monoculture), larger fields, drained wetlands, and increased use of fertilisers and pesticides.
23
Q
What is monoculture and how does it affect biodiversity?
A
Growing one type of crop, which supports far less biodiversity than varied natural habitats.
24
Q
Why are hedgerows important for biodiversity?
A
They provide habitats for insects, small mammals, and birds.
25
How do fertilisers harm aquatic ecosystems?
They cause eutrophication, which depletes oxygen and kills aquatic life.
26
How do pesticides affect biodiversity?
They kill both pests and non-target species like bees, reducing insect biodiversity.
27
Why are bumblebees important to biodiversity and agriculture?
They are essential pollinators for wildflowers and crops.
28
What is causing the decline of bumblebee populations?
Habitat loss due to monocultures and hedgerow removal, and exposure to pesticides.
29
Why is it difficult to balance biodiversity and profit in farming?
Conservation practices can lower yields, increase costs, and reduce profits in a competitive market.
30
How does climate change impact biodiversity?
It alters habitats too quickly for many species to adapt, potentially causing extinctions.
31
How are species responding to global warming?
By moving to higher altitudes or latitudes, which may disrupt existing ecosystems.
32
Why can't some species adapt or migrate due to climate change?
Plants and some animals may not be mobile or fast enough to respond to temperature changes.
33
What is ocean acidification and what causes it?
More CO₂ dissolving in seawater, lowering its pH, which harms organisms like plankton and corals.
34
What is coral bleaching and why is it happening more often?
Corals lose essential symbiotic organisms due to heat stress; increased sea temperatures from global warming are making this more frequent.
35
Why is it important to maintain biodiversity?
It impacts humans and all other species on Earth and supports ecological stability, the economy, aesthetics, social well-being, moral responsibility, environmental health, and agriculture.
36
What is an ecological reason for maintaining biodiversity?
A more diverse ecosystem is better able to adapt and survive environmental changes or threats.
37
How does biodiversity affect ecosystem stability?
High biodiversity allows some species to survive changes like climate shifts, ensuring the ecosystem continues to function.
38
Give an example of how biodiversity helps an ecosystem adapt to climate change.
If a lake warms due to climate change, some fish may die, but others can survive and keep the ecosystem going.
39
What is a keystone species?
A species that has a disproportionately large impact on its ecosystem relative to its abundance.
40
Give an example of a keystone species and its impact.
Bush elephants in the African savannah knock over trees and eat vegetation, which helps maintain the savannah ecosystem and supports fungi and insect species via their dung.
41
What happened when elephant numbers decreased due to hunting?
The savannah ecosystem was negatively affected due to the loss of their unique ecological role.
42
What are economic reasons for maintaining biodiversity?
Nature provides valuable resources like medicines, tourism income, and scientific and technological discoveries.
43
Give an example of a medicine sourced from nature.
Paclitaxel, a cancer-fighting drug, comes from Pacific and Himalayan Yew trees.
44
Why is the Himalayan Yew under threat?
It is overharvested for fuel and medicine, reducing its population.
45
Why should we protect species for future medicines?
Many drugs come from nature, so other undiscovered species may hold new treatments.
46
How does ecotourism relate to biodiversity?
Wildlife and natural parks attract tourists, boosting the economy and creating jobs.
47
What is an aesthetic reason for maintaining biodiversity?
Nature's beauty brings humans joy and inspires artists, musicians, and poets.
48
What are social reasons for maintaining biodiversity?
Natural environments allow people to enjoy activities together like birdwatching, walking, and climbing.
49
What is the risk if we lose natural environments?
We lose the social benefits and community activities they support.
50
What are moral or ethical reasons for maintaining biodiversity?
Many believe humans have a responsibility to prevent species extinction caused by human activities.
51
Why do humans have a greater responsibility to protect biodiversity?
As the most intelligent species, we have the ability and duty to protect other organisms.
52
What are environmental reasons for maintaining biodiversity?
Diverse ecosystems provide services like absorbing CO₂, recycling nutrients, and supporting the water cycle.
53
How do plants help fight climate change?
They absorb carbon dioxide and reduce the greenhouse effect.
54
What do microorganisms do in ecosystems?
They break down organic waste and recycle nutrients.
55
How do plants support the water cycle?
Through transpiration, they help produce rainfall and maintain water availability.
56
Why are fungi and bacteria important in ecosystems?
They recycle nutrients into the soil, promoting plant growth.
57
How do plants support food chains?
They are producers, supplying energy directly and indirectly to humans through food.
58
What are agricultural reasons for maintaining biodiversity?
Wild crop relatives provide genetic diversity needed to resist diseases and adapt to disasters.
59
Why are wild relatives of crops important?
They can offer useful alleles (e.g., for disease resistance) that can save cultivated crops.
60
What risk comes from using only one species in agriculture?
Low genetic diversity increases vulnerability to diseases.
61
Give an example of crop biodiversity from the Andes.
Over 100 species of wild potatoes grow in the Andes and are used to introduce disease-resistance genes into farmed potatoes.
62
What is an endangered species?
A species that is at risk of extinction.
63
What is in situ conservation?
Protecting species in their natural habitat.
64
What are examples of in situ conservation?
National parks and marine parks.
65
What is ex situ conservation?
Protecting species outside of their natural habitat.
66
What are examples of ex situ conservation?
Zoos and botanic gardens.
67
What is the role of national parks in conservation?
They protect wildlife and habitats with strict regulations and controlled human access.
68
How are activities controlled in national parks?
Industrial development is limited, and hunting is restricted or banned.
69
What are marine parks?
Protected water areas that conserve endangered marine ecosystems and species.
70
What do marine parks prevent?
Overfishing and pollution.
71
Why is public engagement important in conservation?
It raises awareness, boosts tourism income, and encourages community support.
72
How do parks benefit local communities?
They provide jobs and can fund health and education improvements.
73
How are the Galapagos Islands protected?
Large areas are national and marine parks with limited human access and fishing bans.
74
What conservation efforts happen on the Galapagos Islands?
Invasive species like rats and goats are removed, alien plants are destroyed, and giant tortoises are reintroduced.
75
How do zoos help conservation?
They run captive breeding programmes, support research, and educate the public.
76
What is the goal of captive breeding programmes?
To breed animals in captivity and reintroduce them into the wild.
77
What can scientists learn from zoos?
They study animal genetics, behaviour, and habitat needs.
78
What are some problems with zoos?
Small populations reduce genetic diversity, some animals won't breed in captivity, and not all zoos meet animals' needs.
79
Give a success story from a zoo breeding programme.
The oryx was saved from extinction and reintroduced into the wild.
80
Give a failure example from zoo conservation.
Despite 60+ years of panda breeding programmes, no pandas have been reintroduced into the wild.
81
What are botanic gardens?
Places that conserve endangered plants using seeds and cuttings collected from the wild.
82
How do botanic gardens increase plant numbers?
Through tissue culturing and cloning to produce many plants from a few samples.
83
What research happens in botanic gardens?
Scientists study plant growth and reproduction to grow plants in captivity or find new habitats.
84
How do botanic gardens help conservation awareness?
They educate the public about endangered plants and global conservation efforts.
85
What is a frozen zoo?
A facility that stores animal genetic material like eggs, sperm, and tissue at very low temperatures for long-term conservation.
86
What temperature do frozen zoos use?
-196°C, allowing material to be preserved for decades.
87
Why collect samples from different individuals in frozen zoos?
To maintain the genetic diversity of the species.
88
What future use do frozen zoos have?
Stored genetic material could be used to breed and reintroduce extinct species using IVF and genetic engineering.
89
What is a seed bank?
A facility that stores plant seeds in a temperature-controlled environment to preserve plant diversity.
90
Why collect seeds from different sites?
To maintain the gene pool of the plant species.
91
What happens when stored seeds age?
They are grown into plants, and new seeds are harvested and stored.
92
Where is the most famous seed bank located?
The Svalbard Global Seed Vault in Norway, located in the Arctic Circle.
93
How many plant species are stored at Svalbard?
Almost 1 million.
94
Why do organisations send seeds to Svalbard?
To preserve crop plant diversity in case of disaster.
95
Why can't some seeds be frozen?
Plants like coffee and cocoa have seeds that don't survive freezing, so successive generations must be grown or cloned.
96
What is the key message from examiner tips about conservation?
Conservation efforts are pointless if there's no habitat left—protecting whole ecosystems is essential for species survival.
97
Which ecosystems are especially important and under threat?
Tropical rainforests and coral reefs—they have high biodiversity but face threats from development, pollution, and exploitation.
98
Why is international cooperation essential for conservation?
Because protecting species worldwide requires agreements and action between multiple countries.
99
What is the IUCN?
The International Union for the Conservation of Nature, a global authority on the state of nature and how to safeguard it.
100
What does the IUCN do?
It assesses the conservation status of plant and animal species worldwide.
101
What is the IUCN Red List of Threatened Species™?
A public list showing species at risk of extinction, based on IUCN data.
102
How do scientists decide which category a species falls into in the IUCN system?
They use data and modelling to estimate population size, risks, and threats.
103
Why is the IUCN classification system updated regularly?
Because species' conservation status can change due to new threats or improvements in population size.
104
What does CBD stand for?
The Convention on Biological Diversity.
105
When and where was the CBD signed?
At the Earth Summit in Rio de Janeiro, Brazil in 1992.
106
What are the three main goals of the CBD?
Conservation of biological diversity, sustainable use of biological resources, and fair sharing of benefits from genetic resources.
107
What do countries that signed the CBD agree to do?
Create and implement national strategies for biodiversity conservation and promote international cooperation.
108
What does CITES stand for?
The Convention on International Trade in Endangered Species of Wild Flora and Fauna.
109
What is CITES overall aim?
To ensure that international trade in specimens of wildlife does not threaten their survival.
110
Why are CITES listings reviewed continuously?
To add new species and update the status of existing ones as needed.
111
What is a concern about the effectiveness of CITES?
Making trade illegal can increase a species' market value, encouraging illegal trade.
112
What is the CSS?
The Countryside Stewardship Scheme, a program from the 1980s that paid farmers and landowners in England to protect biodiversity.
113
What replaced the CSS in 2005?
The Environmental Stewardship Scheme (ESS).
114
What did farmers and landowners have to do to qualify for the CSS?
Protect wildlife habitats, manage land traditionally, conserve natural/historic features, preserve traditional crops/livestock, and educate the public about the countryside.
115
Why was the CSS important for biodiversity?
It gave financial support to landowners using eco-friendly practices to enhance and protect local biodiversity.
116
What is biodiversity?
Biodiversity is the variation that exists within and between all forms of life.
117
At what three levels can biodiversity be assessed?
1. Ecosystem or habitat diversity 2. Species diversity 3. Genetic diversity.
118
Why is biodiversity important for ecosystems?
It increases the resilience of ecosystems, helping them resist changes in the environment.
119
What is ecosystem/habitat diversity?
It's the range of different ecosystems or habitats within a particular area or region.
120
What does a large number of different habitats in an area suggest?
It suggests high biodiversity, as seen in coral reefs with many microhabitats and niches.
121
What does having only one or two habitat types in an area suggest?
It suggests low biodiversity, like in sandy deserts with uniform conditions.
122
What is species richness and evenness?
Species richness is the number of different species within an ecosystem. Species evenness is the relative abundance of individuals across the different species in an ecosystem.
123
What is species diversity?
It refers to both the number of species (species richness) and how evenly individuals are distributed among those species (species evenness).
124
How does species diversity affect ecosystem stability?
Higher species diversity usually makes ecosystems more stable and resilient to change.
125
An example of low species diversity and its risk:
Florida pine forests: dominated by few tree species - a disease targeting one species could collapse the whole ecosystem.
126
What is genetic diversity?
Genetic biodiversity is the variation between individuals belonging to the same species.
127
What causes genetic differences between populations of the same species?
Different selection pressures in slightly different habitats affect allele frequencies.
128
Can genetic diversity exist within a single population?
Yes, individuals in the same population can have a range of different alleles.
129
Why is genetic diversity important?
It allows populations to adapt to and survive environmental changes, whether biotic (like predators, pathogens) or abiotic (like temperature, rainfall).
130
What happens to genetic diversity in small or isolated populations?
It is reduced due to inbreeding, leading to more individuals being homozygous, which increases risk of genetic diseases from recessive alleles.
131
Why are recessive genetic diseases more common in inbred populations?
Inbreeding increases the chance of inheriting two copies of the harmful recessive allele (aa).
132
Why do we use sampling to determine biodiversity?
It is impossible to count every organism in large, complex ecosystems, so sampling gives an estimate of biodiversity.
133
What does sampling measure?
1. Distribution - where organisms live in a habitat; 2. Abundance - how many organisms are present.
134
Why is sample size important in sampling?
Larger sample sizes reduce the effects of chance and increase accuracy.
135
What are the two main types of sampling?
Random and non-random sampling.
136
How is a random sampling site selected?
Use a grid system and generate two random numbers as coordinates to place the sample site.
137
When is random sampling most appropriate?
When the area is uniform or has no clear pattern of species distribution.
138
Random Sampling: Advantage and Disadvantage
✅ Avoids bias as every individual has an equal chance of being selected ❌ May not cover all areas of the habitat equally, leading to underrepresentation of some species.
139
What is opportunistic sampling?
Choosing sample sites based on convenience or accessibility - least reliable and most biased.
140
Opportunistic Sampling: Advantage and Disadvantage
✅ Quick and easy, uses data that is readily available ❌ Highly biased as it depends on the observer's choice, which may not represent the whole population.
141
What is stratified sampling?
Dividing the habitat into sections and sampling proportionally to the area each habitat type covers.
142
Stratified Sampling: Advantage and Disadvantage
✅ Ensures all different areas or groups are represented, increasing accuracy ❌ Requires prior knowledge of the population and can be time-consuming to set up.
143
What is systematic sampling?
Sampling along a gradient or pattern in habitat conditions, e.g. up a hill or away from a river.
144
Systematic Sampling: Advantage and Disadvantage
✅ Good for detecting patterns or changes across a gradient (e.g., along a transect) ❌ May miss species not found exactly at the chosen intervals or points.
145
What tool is used in systematic sampling?
A transect (a line across a habitat where samples are taken).
146
What is a quadrat?
A square frame used to sample plants or slow-moving animals in a specific area.
147
What sizes can quadrats be?
Small (1 m²) for herbaceous plants or limpets; large (400 m²) for trees.
148
How can quadrats be used in sampling?
Randomly placed or along a transect line to measure species presence, abundance, or percentage cover.
149
What is percentage cover in quadrat sampling?
An estimate of how much of the quadrat area is occupied by a species, used when individuals are hard to count.
150
What are sweep nets used for?
Catching flying insects or those on vegetation by sweeping the net through grass or branches.
151
What are pitfall traps used for?
Sampling ground-dwelling invertebrates - small containers buried in the ground that insects fall into.
152
What is the purpose of a lid on a pitfall trap?
To prevent rainwater from filling the trap.
153
What is a pooter?
A small container with two tubes used to suck up small invertebrates for viewing and identification.
154
How is a pooter used?
One tube is placed over the insect, the other is used to suck, pulling the insect into the container.
155
What is a transect?
A line across a habitat used to study how species distribution and abundance change with abiotic factors.
156
Give examples of where a transect might be placed
Up a slope, at right angles to a river, across a field edge.
157
What is a line transect?
A measuring tape is laid out and organisms touching the line are recorded at regular intervals.
158
What is a belt transect?
A measuring tape is laid out and quadrats are placed at intervals or continuously along it to record species in each quadrat.
159
What is the purpose of using a random number generator in sampling?
To avoid sampling bias and ensure the sample is representative by selecting coordinates randomly rather than subjectively choosing convenient or attractive areas.
160
Why is it important to study a large enough area during biodiversity sampling?
To ensure the results are representative of the entire habitat or ecosystem being studied.
161
What is the first step when choosing sampling sites?
Mark a grid over a map or scaled drawing of the area and label the coordinates.
162
How is population density calculated using quadrats?
Place the quadrat at random coordinates, count individuals in each quadrat, calculate the mean per quadrat using a running mean, then multiply this mean by the number of quadrats that fit into the total area.
163
What is a running mean and why is it used?
It's a way of calculating the average number of individuals as more quadrats are sampled—used until the mean stabilises to ensure the sample is representative.
164
How do you calculate the estimated population size of a species using population density?
Divide the total area by the area of one quadrat to get the number of quadrats in the habitat, then multiply by the mean number of individuals per quadrat.
165
How is percentage cover calculated using a quadrat?
Place a 100-square grid quadrat at random coordinates, count the number of squares the species covers more than half of, and that number equals the percentage cover.
166
Why should the same person estimate percentage cover in all quadrats?
Because percentage cover is subjective and having one person estimate controls for variation in judgment.
167
What is species frequency?
A measure of how often a species appears across sampled quadrats, expressed as a percentage.
168
How do you calculate species frequency?
Count how many quadrats contain the species, divide by the total number of quadrats sampled, and multiply by 100.
169
What does population density tell you about a species?
It tells you how many individuals of that species there are per unit area.
170
How is population density calculated from multiple quadrats?
Add the number of individuals found in all quadrats, divide by the total area of the quadrats used.
171
What should you do if individual organisms are too small or too numerous to count?
Estimate their abundance using percentage cover or species frequency instead.
172
What does a high percentage cover and low frequency suggest about a species' distribution?
That the species exists in clusters or groups in specific preferred parts of the habitat.
173
Why is it helpful to use both frequency and percentage cover together?
Together they provide a clearer picture of how common a species is and how it is distributed.
174
What types of organisms can quadrats and transects be used for?
Immobile species like plants and slow-moving animals.
175
What is a limitation of using species frequency?
It shows how common a species is but doesn't give information on the actual number of individuals or population size.
176
What method is used to estimate population size of mobile animals?
The mark-release-recapture method.
177
Describe the first step of the mark-release-recapture method.
Capture as many individuals as possible from a species, count them, mark them in a way that doesn't harm or affect them, then release them back into the habitat.
178
What is done after marking and releasing individuals in the mark-release-recapture method?
Allow time for them to mix randomly back into the population, then collect a second large sample and count how many are marked.
179
What is the formula for estimating population size using mark-release-recapture?
N = (n1 × n2) ÷ m2, where N is population size, n1 is number marked in first sample, n2 is number in second sample, and m2 is number of marked individuals recaptured.
180
What assumptions must be made in the mark-release-recapture method?
Marked individuals must mix fully back into the population, marking must not affect survival or visibility, marks must stay on, and population size must stay constant during the study.
181
Why must the marked individuals mix fully back into the population?
To ensure the second sample is representative of the whole population, making the estimate more accurate.
182
Why should the mark not affect an organism's survival or behaviour?
To prevent bias in the second sample—if marks increase predation or affect movement, the results will be inaccurate.
183
Why must the population size remain stable during a mark-release-recapture study?
Because births, deaths, immigration, or emigration would affect the accuracy of the population size estimate.
184
What are the two key components of species diversity?
Species richness and species evenness.
185
What is species richness?
A measure of the number of different species within a given area.
186
What does a greater species richness indicate about an area?
That it has a higher number of different species and is therefore more diverse.
187
Why can species richness be a misleading indicator of biodiversity?
Because it doesn't take into account the number of individuals of each species.
188
What is species evenness?
A measure of the relative abundance of different species in a given area.
189
What does high species evenness indicate?
That all species in the area have similar population sizes, showing a balanced ecosystem.
190
How can two areas have the same species richness but different biodiversity levels?
If one area has more even distribution of individuals across species (higher species evenness), it will have higher overall biodiversity.
191
Why is it better to use an index of diversity like Simpson's Index instead of just species richness?
Because Simpson's Index considers both species richness and evenness, giving a more accurate measure of biodiversity.
192
How do you measure species richness?
By counting the number of different species present in a given area.
193
How do you measure species evenness?
By recording the number of different species and the number of individuals of each species.
194
What is Simpson's Index of Diversity used for?
To quantify biodiversity by taking into account both species richness and species evenness.
195
What is the formula for Simpson's Index of Diversity (D)?
D = 1 - Σ(n/N)², where n is the number of individuals of a species and N is the total number of individuals of all species.
196
What is the first step in calculating Simpson's Index?
Calculate n ÷ N for each species.
197
What is the second step in calculating Simpson's Index?
Square each n ÷ N value.
198
What is the third step in calculating Simpson's Index?
Add together the squared values and subtract the total from 1.
199
What does a Simpson's Index value close to 1 mean?
There is high biodiversity in the area.
200
What is genetic diversity within a species?
The genetic variation that exists within a species.
201
Do individuals of the same species have the same genes and alleles?
They have the same genes at the same loci, but may have different alleles for each gene.
202
What is a gene pool?
All the alleles of all the genes within a species.
203
How can genetic differences exist between populations of the same species?
Different populations may face different selection pressures, affecting allele frequencies and increasing genetic diversity.
204
Why is genetic diversity within a population important?
It creates a larger gene pool which helps the population adapt to and survive environmental changes.
205
What are examples of biotic factors that can affect genetic diversity?
New predators, pathogens, and competition with other species.
206
What are examples of abiotic factors that can affect genetic diversity?
Temperature, humidity, and rainfall.
207
What are the main ways to assess genetic diversity?
Proportion of polymorphic gene loci, proportion of the population heterozygous at specific loci, and allele richness.
208
What is allele richness?
The number of different alleles that exist for specific genes.
209
What do all methods of assessing genetic diversity involve?
Determining whether multiple alleles exist at a gene locus.
210
When can phenotypes be used to assess genetic diversity?
When different alleles produce observable differences in an individual's traits.
211
How can scientists assess genetic diversity when phenotypes do not show allele differences?
By examining and comparing DNA sequences or protein products of alleles.
212
What is genetic polymorphism?
When there are two or more alleles present at a single locus.
213
What is a monomorphic locus?
A gene locus with only one allele.
214
What is a polymorphic locus?
A gene locus with multiple alleles.
215
What is the significance of the frequency of the most common allele in a population?
If it's above 99%, other alleles are very rare and likely to disappear, indicating low genetic diversity.
