Biodiversity Flashcards
1
Q
What is biodiversity?
A
- range + variation of genes, species + habitats in a particular area
- relates to NO° + range of diff ecosystems + habitats on entire planet as well as NO° of species + their relative abundance in a small local habitat
2
Q
What is the definition of ecosystem?
A
- all living + non living components of a particular area
3
Q
Why is biodiversity important?
A
- allows ecosystems to resist changes in the envi.
4
Q
What is ecosystem or habitat diversity + what does it show?
A
- range of diff. ecosystems or habitats within a particular area or region
- large NO° of diff. habitats = high biodiversity
5
Q
What is an example of a habitat w high biodiversity?
A
- coral reef: v. complex w lots of microhabitats + niches to be exploited
6
Q
What is a niche?
A
- all conditions + resources required for an organism to survive + reproduce
7
Q
How can a mix of diff. species existing in an area be measured to indicate lvls of biodiversity?
A
- species richness
- species diversity
8
Q
What is species richness?
A
- measure of the NO° of diff. species within a community
9
Q
What is a community?
A
- multiple populations of diff. species living + interacting in same area
10
Q
What is species diversity?
A
- NO° of diff. species in a community + evenness of abundance (NO° of individuals) across diff. species in an area
11
Q
How is the NO° of species in an ecosystem related to distribution of organisms in each species?
A
- greater NO° of species = more evenly distributed NO° of organisms among each species is: greater species diversity
12
Q
Why are ecosystems w high species diversity usually more stable?
A
- bc they’re more resilient to envi. changes
13
Q
Why is maintaining biodiversity beneficial?
A
- ecological: biodiversity inc. stability of ecosystems
- environmental: organisms provide essential envi. services (e.g. water cycle)
- economic: many organisms contribute to medicine, ecotourism, science + tech
- agri: genetically diverse wild species can rescue crops from catastrophe
14
Q
What is the index of diversity?
A
- a measurement describing relationship between NO° of species in a community + NO° of individuals in each species
15
Q
What is the formula for index of diversity?
A
- d = N(N - 1)/Σn(n - 1)
- n = total NO° of organisms in 1 species
- N = total NO° of organisms
- Σ = sum of
16
Q
What does the index of diversity show?
A
- larger the NO° = higher the level of diversity
- value ranges from 0 - 1
17
Q
How do farming techniques reduce biodiversity?
A
- destruction of hedgerows, which provides habitat for insects + small birds + animals, to make fields bigger to accommodate machinery
- selective breeding, which ensures desirable characteristics from selected organisms are expressed in future generations, narrows down gene pool, dec. biodiversity
- monocultures, which involve growing only 1 plant species, dec. biodiversity as attracts same insects that feed on it
- filling in ponds + draining wetlands to provide more arable land
18
Q
How have compromises between conservation + farming been made?
A
- agreements to remove only a certain NO° of hedgerows
- only selectively breeding in certain areas + to particular species
- crop rotations for monocultures
- produce from organic farms (no use of fertilisers + pesticides) are favoured = benefits biodiversity
19
Q
What are individuals of the same species similar in?
A
- behaviour
- morphology (structural)
- physiology (metabolic)
20
Q
What is genetic isolation?
A
- when 2 groups are reproductively isolated so don’t interchange genes when producing offspring
- leads to each group evolving independently due to changes in allele frequencies
21
Q
What is the definition of genetic diversity?
A
- NO° of diff. alleles of genes amongst all individuals in a pop. of 1 species
22
Q
How can genetic diversity within + between species be measured by?
A
- frequency of measurable or observable characteristics
- nucleotide base sequence of DNA
- nucleotide base sequence of mRNA
- AA sequence of proteins
23
Q
How can the frequency of measurable or observable characteristics be use to identify genetic diversity within or between species?
A
- quickest but least reliable method (not precise to look at only 1 characteristic)
- used successfully to classify organisms into taxonomic hierarchy before DNA sequencing
- useful is species have unique characteristics
- measurable characteristics give better understanding of similarities + differences between species
24
Q
What are examples of measurable + observable characteristics?
A
measurable:
- NO° of legs
- NO° of seeds in a berry
- NO° of petals
- NO° of leaf indentations
observable:
- colour
- patterns of fur/scales/feathers
- habitat
- presence of hair/wings/fins
25
How can the **base sequence of DNA** be used to identify **genetic diversity** within or between species?
- **DNA extracted** from nuclei of cells from an organism
- which is **processed, analysed** + the **base sequence is obtained**
- which is **compared** to that of other organisms = determines evolutionary relationships
- **more similarities** in base sequence = **more closely related** + separated into diff. species **more recently**
26
What can **DNA sequence analysis + comparison** be used for?
- to create **family trees** showing evolutionary relationships **between** species
27
Why is analysing DNA from **mitochondria** important?
- bc **zygote** only contains mitochondria from **egg** (none from sperm) so only **maternal** mitochondrial DNA is present in a zygote
28
How can the **base sequence of mRNA** be used to identify **genetic diversity** within or between organisms?
- **mRNA extracted** from **cytoplasm** of cells (easier bc usually **multiple copies**)
- which is used as a **template to produce cDNA** (complementary DNA) = same as template strand of DNA
- 1st strand used to **produce 2nd cDNA strand** = same as coding strand of DNA
- cDNA only contains **coding regions** of gene (**no introns**)
29
How can the **AA sequence of proteins** be used to identify **genetic diversity** within or between species?
- **proteins extracted** from cell (easier than DNA)
- **sequence of AAs** of same protein is **compared** between individuals
- AA sequences of proteins **evolve much slower than DNA** so closely related species have **same** AA sequence
30
What is **sampling**?
- method of investigating **abundance + distribution** of species + populations
31
What are the 2 diff. **types** of sampling?
- random
- systematic
32
What is the reason for **sampling**?
- more **time efficient** + **accurate**
33
How do you ensure **sampling** is **accurate**?
- **random** sampling in **uniform** areas: eliminates **bias**
- **line transects** to examine a **change over distance**
- **large** NO° of samples (30+)
34
How to **decide** what sampling type to use?
- fast moving organisms = **mark-release-recapture** method
- slow/non moving organisms = sampling using **quadrat**
- uniform distribution = **random sampling**
- uneven distribution = **line transect**
35
What are the diff. **types** of **quadrat**?
- **open** or **divided** into 100 squares
36
Describe the **method** used for **random sampling**.
- lie **2 tape measures** at a **right angle** to create a **gridded square** (big enough to get representative estimate of area)
- use a **random** NO° generator to generate **2 coordinates**
- place quadrat + **collect data** (e.g. NO° of organisms)
- **repeat** (30x) + **calculate mean**
37
What are the diff. **methods** to estimate the **abundance** of a species?
- **local frequency**: % of squares in quadrat w species present
- **density**: NO° of 1 species in a given area
- **% cover**: proportion of ground occupied by species
38
What are the advantages + disadvantages of using **local frequency** to estimate the abundance of species?
Advantages:
- **quick** to sample large area
- useful is **difficult to identify** organism or **too many** to count
Disadvantages:
- **poor accuracy**: doesn’t consider **overlapping plants** or **size of plants**
39
What are the advantages + disadvantages of using **density** to estimate the abundance of species?
Advantages:
- **more accurate** if plant easily distinguishable + not too many
- used to estimate **species richness**
Disadvantages:
- more **time consuming**
40
What are the advantages + disadvantages of using **% cover** to estimate the abundance of species?
Advantages:
- **quicker** than density
- useful is **difficult to identify** organism of **too many** to count
Disadvantages:
- **subjective** limiting accuracy
- doesn’t consider **overlapping plants** or **size of plants**
41
What is **standard deviation**?
- measure of the **spread or dispersion** of data around mean
- **small** standard deviation = results **close to mean** (less variation)
- **large** standard deviation = results **more spread out**
42
What does the **overlap** of standard deviation of different data sets show?
- that the results are **not. sig. diff.**
- no overlap = results are sig. diff.
43
How do you calculate the **mean**?
- mean = sum of all measurements/NO° of measurements
44
What is the definition of a **gene pool**?
- collection of **genes** within an interbreeding population
- (sum of all alleles of 1 species or a pop.)
45
What can cause the **gene pool** in a species population to **change** over time?
- natural selection
- genetic drift
- the founder effect
46
What is the definition of **evolution**?
- formation of new species from pre-existing species over time, due to changes to gene pools from generation to generation
47
What can be sequenced + used to show **evolutionary relationships** between species?
- DNA found in the **nucleus, mitochondria + chloroplasts** of cells
