Chapter 11 - Biodiversity Flashcards
Define abiotic
Non living
Define biodiversity
Variety of living organisms present in an area
Define species
Smallest + most specific taxomic group
How can biodiversity be assessed
o The number and range of different ecosystems and habitats
o The number of species and their relative abundance
o The genetic variation within each species
What is habitat diversity
• range of different ecosystems or habitats within a particular area or region
What is species richness
number of species within an ecosystem
What is species diversity
number of different species in an ecosystems + the evenness of abundance across the different species present
What is species evenness
evenness of abundance across the different species present
What will increase the species diversity
greater the number of species in an ecosystem + more evenly distributed the number of individuals from each species
How can an ecosystem have a lot of different species but not have a high species diversity
some species may be very rare in ecosystem = does not necessarily have high species diversity
A more stable ecosystem…
high species diversity
Why does a low species diversity make an unstable ecosystem
If pathogen targets one of the species = whole population could be wiped out + ecosystem collapses
What is genetic diversity
diversity of alleles and genes in the genome of species
How to measure genetic diversity
by working out the proportion of genes that have more than one form (allele) + how many possible alleles each gene has
Why may there be genetic differences between populations of the same species
because the two populations occupy slightly different ranges in their habitat = subject to different selection pressures = affect the allele frequencies in their populations
Why is genetic diversity within a single population important
help the population adapt to, and survive, changes in the environment
Negatives of inbreeding
leads to a high proportion of individuals being homozygous (e.g. AA to aa) for many genes, resulting in lower genetic diversity
o This can mean that genetic diseases caused by recessive alleles can become more common in these populations
What is sampling
a method of investigating the abundance and distribution of species and populations
Two types of sampling
o Random
o Non-random
What is random sampling used for
to estimate the distribution and abundance of species
What is the distribution of a species
how it is spread throughout the ecosystem
What is the abundance of a species
number of individuals of that species
How to carry our random sampling - Quadrats
- Use Quadrats
- convert sampling area into grid
- use random number generator = quadrats
- record abundance / percentage cover
What are Quadrats used for
suitable for sampling plants or slow-moving animals
Other methods for sampling
- sweep nets
- pitfall traps
- pooters
- tullgreen funnel
- kick sampling
Sweep nets
large, strong nets with a fine material (very small holes) that are used to catch flying insects and insects that live in long grass by sweeping the net back and forth through the grass
Pitfall trials
cans or jars that are buried in the ground that are used to catch ground-dwelling (often nocturnal) insects and other invertebrates as they fall into the trap
Modification in pitfall
- canopy = stop trap filling with water
- newspaper / leaves = allow smaller insects to hide from predatory ones
Pooters
small plastic or glass containers with two tubes sticking out that are used to suck up small insects and other small invertebrates
first tube is placed over the insect and the second tube is used by the scientist to create suction
Tullgren funnel
funnels with a light bulb above and a container below that are used to collect invertebrates that live in leaf litter or soil.
leaf litter / soil is placed in the funnel and the light and heat forces the invertebrates to move down until they drop into the container
Kick sampling
used to catch freshwater invertebrates living in streams or rivers.
net placed on the stream-bed so that the water is flowing into it and the stream-bed just above the net is kicked
invertebrates are carried by the stream into the net
Types of non random sampling
• Opportunistic
• Stratified
• Systematic
Opportunistic
• choosing sampling locations based on various non-random factors = most convenient
Stratified sampling
• population is divided into subgroups or strata based on certain characteristic.. The subgroups are then sampled in proportion to their size or importance in the population = random within each strata
Systematic sampling
• method of sampling where every nth member of a population is selected for inclusion in the sample. The sampling interval or “n” is determined by dividing the population size by the desired sample size = random or non random? = no patterns in the data
How to do Quadrats non randomly
Using transects
How to use line transects
o Lay out a measuring tape in a straight line across the sample area
o At equal distances along the tape, record the identity of the organisms that touch the line. For example, every 2m
How to use belt transects
o Place quadrats at regular intervals along the tape and record the abundance or percentage cover of each species within each quadrat
What is species richness
measure of the number of different species within a given area
Problem with species richness
can be a misleading indicator of diversity as it does not take into account the number of individuals of each species
What is spedier evenness
• measure of the relative abundance of the different species within a given area
Why is this an example of the problems with species richness
• In the example above , Area 1 and Area 2 both contain 4 tree species
• However, Area 2 is actually dominated by one species and in fact, one of the species is very rare (only one individual)
• Although the two areas have exactly the same species richness, Area 1 has a higher species evenness (and therefore a higher overall species diversity) than Area 2
How to measure species richness
count the number of different species present.
How to measure species evenness
count the number of different species present and the number of individuals of each species
What is Simpsons index formula
You get in exam
What do all the variables mean in Simpsons index
• n = total no. of organisms for a single species
• N = total no. of organisms for all species
How to use this formula - careful where the sum of is
o Step 1: First calculate n / N for each species
o Step 2: Square each of these values
o Step 3: Add them together and subtract the total from 1
What does it mean if the Simpson index is near 1
indicate high levels of biodiversity
What does it mean if the Simpson index is near 0
low levels of biodiversity
What can the Value of D (simpsons index) Fall between
0 and 1
What is genetic diversity
genetic variation in a species
How can individuals in the same species have genetic diversity
same genes at the same loci – but maybe different alleles of each gene
What is loci
a specific linear position of a gene on a certain chromosome
Define gene pool
comprised of all the alleles of all the genes within a species
Why is there genetic differences between populations of SAME species
• Because two populations occupy slightly different ranges in their habitat and so are subject to slightly different selection pressures that affect the allele frequencies in their populations
More genetic diversity…
Larger gene pool
Why is genetic diversity within a SINGLE population important
creates a larger gene pool which can help the population adapt, and survive changes in the environment
How is genetic diversity measure
• using the proportion of polymorphic gene loci (number of loci that have two or more alleles)
• using the proportion of the population that is heterozygous for any specific gene locus
• using allele richness = number of different alleles that exist for each specific gene
What is similar about all three ways of testing genetic diversity
ALL 3 – determine whether there are multiple genes at a locus
How do you identify the alleles
phenotypes / DNA sequences / protein products
What is genetic polymorphism
occurs when there are two or more alleles present at a single loci
What is the frequency of the rarest allele
frequency greater than 1% or greater than 5%
What is a monomorphic locus
one that does not have multiple alleles = one allele
What is a polymorphic locus
one that has multiple alleles
Frequency of most common allele
frequency less than 95% or 99%
What happens if the frequency of an allele is more than 95% or 99%
other allele(s) are extremely rare and likely to disappear
The equation for calculating the proportion of polymorphic gene loci (P) is:
P = number of polymorphic gene loci ÷ total number of loci investigated
There are many different registered pedigree dog breeds that exist.
A conservationist stated that the degree of inbreeding that has occurred in some of the older breeds could be problematic as it likely reduces genetic diversity.
Scientists investigated 100 gene loci in 2 different breeds. For breed A (the older breed), 59 out of 100 gene loci were found to be polymorphic at the 0.95 level. For breed B, 87 out of 100 gene loci were found to be polymorphic at the 0.95 level.
Calculate P for both breeds and evaluate whether the results support the conservationist’s statemen
Step 1: Calculate P for breed A
P = number of polymorphic gene loci ÷ total number of loci investigated
P = 59 ÷ 100
P = 0.59
Step 2: Calculate P for breed B
P = 87 ÷ 100
P = 0.87
Step 3: Determine if results support the statement
The older breed A has a lower P value than breed B. This suggests that it has lower genetic diversity which could be caused by inbreeding. More studies would need to be carried out on a larger number of breeds in order to prove this statement true.
Limitations of the proportion of genetic loci measurement
does not illustrate the allele richness of a breed or species
What does it mean that the proportion of polymorphic gene loci does not illustrate the allele richness of a breed or species
o A study that looked at different blood proteins in dogs found that all genetic loci were polymorphic, P = 1. However, the number of alleles for each gene locus was not the same, it varied from 2 to 1
Factors effecting biodiversity
• Human population growth
• Agriculture = monoculture
• Climate change
Why is the human population growing
improved tech = abundance of food = increase birth rate
improved medicine / hygiene = decrease in death rate
What is habitat loss
plant and animals completely lose their habitats
What is habitat fragmentation
habitats are divided into small areas - populations living within these separated habitat fragments are more likely to suffer from inbreeding or local extinction
How is the human population growth destroying biodiversity
Deforestation
Destruction of coral reef = catch fishing
Hunting
What is monoculture
farms become more specialised + grow only one type of crop
What is bad about monoculture
o support much lower levels of biodiversity
What else is bad about agriculture other than monoculture / land space
• Use of fertilisers. / pesticides
Why are fertilisers bad
leach into waterways, causing eutrophication, which can lead to the death of many aquatic invertebrate and fish species
Why are pesticides bad
o kill insect pests but also kill many non-target species = bees
Why does a compromise need to be made in agriculture
Because agriculture has high yield + profit = economically viable
How is global warming decreasing biodiversity
causing many species to move towards the poles or to higher altitudes
o increasing atmospheric CO₂
Why is increasing atmospheric CO₂ bad
more CO₂ dissolving in seawater, decreasing its pH (known as ocean acidification). This is negatively affecting organisms that require calcium carbonate for shells
Why is many species to move towards the poles or to higher altitudes bad
o may not be able to compete with / out-compete species already there = decreased biodiversity
o plants – can’t move or change their distributions fast enough to adapt to increasing temperature and may go extinct
What is biodiversity made up of
o Genetic diversity
o Species diversity
o Ecosystem diversity
Reasons for maintaining biodiversity
• Ecological – protecting keystone species + maintaining genetic resource
• Economic – reducing soil depletion
• Aesthetic – protecting landscapes
What is a keystone species
have a larger impact on the ecosystem than others
What happens when a keystone species goes extinct
Ecosystem collapses
Example of a keystone species - extra
e.g – Bush elephants
• They graze in a very extreme way, knocking over and eating several species of tree
• This destruction of vegetation actually helps to maintain the ecosystem
• Elephant dung also provides a habitat for many important fungi and insect species
• When elephants were legally hunted for their ivory, their numbers reduced and scientists observed a major negative impact on the savannah
Why is maintaining biodiversity good economically
• Making medicines
• Ecotourism – jobs / source of income
• Science + technology
Reasons for + explanations table - maintaining biodiversity = no need to memorise common sense just read
Endangered
threatened with extinction
In situ
conservation carried out in the natural habitat
Examples of in situ methods
o National parks / marine parks
Ex situ
conservation outside natural habitat
Examples of ex situ
o Zoos / botanic gardens / seed banks
Characteristics of conserved areas
• Human access restricted
• Agriculture / building = regulated
• Hunting prohibited
• Ecotourism
What do zoos do
Captive breeding = so offspring can release into wild
Problems with captive breeding
reduce genetic diversity
Why are zoos bad
not all zoos can provide adequate habitats
What are botanic gardens
Plant zoos
What do botanic gardens do
o use cuttings and seeds collected from the wild to establish a population of the endangered species in captivity
How to conserve genetic material
Frozen zoos
Seed bank
Frozen zoos
store genetic material from animals (eggs, sperm, tissue samples etc) at very low temperatures so that they can be kept for a very long time
Seed bank
drying and storing seeds in a temperature controlled environment
Conservation methods - table list
4 conservation agreements
IUCN
CBD
CITES
CSS
IUCN stand for
• International Union for the Conservation of Nature
CBD stand for
• Convention on Biological Diversity
CITES stand for
Convention on International Trade in Endangered Species of Wild Flora and Fauna
CSS stand for
• Countryside Stewardship Scheme
IUCN
• Role in assessing the conservation status of animal and plant species
CBD - three goals
o The conservation of biological diversity by use of a variety of different conservation methods
o The sustainable use of biological resources
o The fair and equitable sharing of benefits arising from genetic resources
CITES - aim
to control the trade of endangered species and their associated products
CITES - categories
o Appendix I : species that are endangered and face the greatest risk of extinction
o Appendix II: species that are not currently endangered or facing extinction, but will be unless trade is closely controlled
o Appendix III: species included at request of the country that is regulating trade of the species and trying to prevent its overexploitation
How does CITES conserve
Traducing regulations
CSS
1980s = provided funding to farmers + private landowners in England who used environmental management strategies to protect + increase the natural biodiversity on their land
ESS
CSS replaced with Environmental Stewardship Scheme = 2005
