Chapter 10 - Biodiversity Flashcards
Community
The populations of living organisms in a habitat
Biodiversity
The number and variety of living organisms in a particular area
Three components of biodiversity
Species biodiversity
Genetic biodiversity
Ecosystem/habitat biodiversity
What is ecosystem biodiversity
The range of different habitats found in an area
What can the ecosystem biodiversity tell us about an area
An area with a rich ecosystem diversity, means that there is a wide range of habitats. This also tells that the area will also have a wide range of species as each habitat will support a variety of species of plants fungi animals and microorganisms
What is the species biodiversity
The number of different species and the number of individuals within each species within any one community
(Simple: the number of different species living in a certain area)
Two components that make up species biodiversity
Species richness
Species evenness
What is the species richness
The number of different species in a particular area at a given time
What is the species evenness
It compares how many individuals of each species there are in each community
What is the genetic biodiversity
The variety of genes that is possessed by an individual that make up a population of a species
(Simple: variety of genes and alleles within a species)
What can genetic biodiversity tell us about a species
Species with a high level of genetic biodiversity means that they have a greater number of alleles and genes so are more likely to survive, as they are better at adapting to environmental change and is more likely to survive if a new pathogen or disease is introduced to the population
What are monomorphic genes
Where there is only one version of a gene
What are polymorphic genes
Genes with different alleles
Factors affecting biodiversity
- large human population
- human activity
- fossil fuels
How does a large population of humans affect biodiversity
- feeding a large population of humans requires intensive farming methods that can reduce the biodiversity in an area, as farms contain monocultures
- monoculture may contain pesticides to kill insects reducing levels of biodiversity
- farms also dig up hedgerows, which contain rich levels of biodiversity of plants and animals for monoculture, so when hedgerows are destroyed the number of plants and animals reduce
- in some countries forests are cleared for monocultures to be grown
How does human activity reduce biodiversity
- human activity requires a great deal of space which leads to the destruction of forests
- deforestation may be used for fuel and for resources to make settlements and furniture
How does fossil fuels lead to a reduction in biodiversity
- burning fossil fuels can increase co2 emissions which can lead to climate change and global warming
- global warming can cause ice caps to melt resulting in the loss of habitats,leading to the extinction of animals and plants. Can also lead to an increase in global sea levels, resulting into flooding and the destruction of low lying habitats
- rising sea temperatures can cause the death of marine organisms and alter the distribution of fish
- an increase in global temperatures will lead to more droughts and many plants cannot survive under drought conditions, affecting the distribution of plants in habitats and the distribution of animals which depend on plants for food
What is the binomial system
A universal naming system for organisms
Rules of binomial system
First name is the Genus and the second name is the Species
The genus gets a capital letter the species does not
When it is handwritten it is underlined
When it is printed it is printed in italics
Advantages of binomial system
It tells us how closely related organisms are
Why do different species look similar
- they live in a similar environment
- have similar selection pressures
- similar alleles will have the selective advantage
- produces similar proteins and therefore have similar characteristics
What is classification
The organisation of living organisms into groups
What is a hierarchy
- smaller groups arranged within larger groups
- no overlap between groups
Levels of Classification of taxonomy
1) Domain
2) kingdom
3) phylum
4) class
5) order
6) family
7) genus
8) species
Do Kangaroos prefer curry or fried green sprouts
Each group is called a taxa
Why do we use classification
- to help us understand relationships between organisms and keep track of changes
- it is universal so any global scientist can understand it
Why can we not classify species on physical looks
As some species that are the same can look completely different and species that are different can look identical
Methods to compare genetic diversity (classification methods)
- DNA sequence
- mRNA sequence
- Amino acid sequence
- Immunological (which is comparing similarity in self antibody shape)
Two types of classification
- artificial classification
- phylogenetic classification
What is phylogenetic classification
A classification system based on the evolutionary links between organisms and their ancestors
Why can’t you use observable characteristics to identify genetic diversity
- As large number of the characteristics are polygenic (coded by more than one gene) so you can’t distinguish each gene from one another
- characteristics can be modified by the environment so differences may be environmental and not from alleles
What is the process of comparison from DNA bases to identify gene diversity
- it involves reading DNA bases through DNA sequencing
- it is done through a machine by tagging each nucleotide base with different coloured fluorescent dye, producing a pattern of coloured bands
- the pattern are analysed and compared to other species to determine how diverse they are
How can we use DNA sequencing for phylogenetic classification
- this technique can determine the evolutionary relationship between species
- if mutations have occurred then the sequence of nucleotide bases will change overtime sowhen the new species will reproduce more they will have more differences in their DNA, so will be more distant to the original species
- So species that are more closely related to each other should show more similarities in their DNA than species that are more distantly related
why can we use mRNA bases to identify gene diversity and what are the problems of this
As mRNA strands are complementary to strands of DNA we can measure the DNA diversity and therefore genetic diversity by comparing mRNA strands
However it only gives you a sequence of exons and not introns
How is comparison from amino acid sequence used to identify gene diversity
- the genetic diversity is determined by comparing the amino acid sequence of the proteins
- the more similar the amino acid sequence is between two species the more closely related they are
- the comparison is done by counting either the number of similarities or differences in each sequence
How is comparison from immunological used to identify gene diversity
- pure albumin samples, which is a protein found in many species all with different antigens depending on the species, are injected into a rabbit which then produces antibodies for the specific type of albumin
- the antibodies are then extracted and then mixed with different albumin samples resulting in precipitates (antibody antigen complexes) to form which are then weighed
- the heavier the precipitate the more closely related the species are
Why do we use amino acid sequence to find genetic diversity and not just DNA sequence or mRNA base
- it’s easier to find and isolate proteins from cell
What is courtship behaviour used for
- Successful mating between organisms from the same species
- Species recognition
What are courtship rituals
A sequence of actions which is unique to each species, which helps animals identify their own species to reproduce with
What is involved in courtship rituals
- a sequence of dance moves, sounds, display of colourful feathers or fighting, release of pheromones performed by the male
- the female will observe the courtship ritual and decide if they want to mate with the male
Why are courtship rituals/behaviors important
To ensure successful sexual reproduction
- to enable them to recognise their own species
- to synchronise mating behaviour
To ensure survival of the offspring
- to choose a strong healthy mate
- to form a pair bond
How can courtship rituals explain if they are related
- the more similar a courtship sequence is between different species the more closely related the species are
What are species
A group of organisms that can interbreed and produce living fertile offspring
What is artificial classification
When organisms are divided according to their analogous characteristics (characteristics with the same function but do not have the same evolutionary origin e.g colour, size, number of legs)
What is taxonomy
The study if phylogenetic groups and their positions in hierarchical order (their taxonomic ranks)
What are the three domains
Bacteria
Archea
Eukarya
Bacteria features
- they have an absence of membrane bound organelles
- unicellular
- ribosomes are smaller than eukaryotic cells
- cell walls are present and made of murein
- single loop of DNA made out of nucleic acid but no histones
Archaea features
- genes and protein synthesis is similar to eukaryotic
- membranes contain fatty acid attached to glycerol by ether linkages
- no murein in in their cell walls
- more complex form of RNA polymerase than bacteria
Eukarya features
- posses membrane bound organelles
- they have membranes containing fatty acid chains attached to glycerol by ESTER linkages
- the eukaryotes cells that do containcell walls do not have murein
- ribosome is larger than Bacteria and archea
What are the 4 kingdoms in the Eukarya domain
Protoctista
Fungi
Plantae
Animalistic
Feature of phylogenetic classification
- based on the evolutionary relationships between organisms and their ancestors
- classifies species into groups using shared features derived from their ancestors
- arranges the groups into hierarchy
What does it mean to have a high species diversity index
The higher the species diversity index the more stable an ecosystem is and the less affected it is by change due them having a higher species richness
Farming practices that directly removes habitats and reduces species diversity
- removal of hedgerows and plants - destroy habitat for animals
- monocultures - reduces diversity of plant species and attracts the same species of insects
- filling in ponds and draining wetlands
- overgrazing woodland areas, preventing the regeneration of woodlands
- selective breeding- causes you to narrow down the gene pool and reduce species diversity
Farming practices that indirectly removes habitats and reduce species diversity
- use of pesticides - kills beneficial insects
- use of fertilisers - leads to eutrophication
- effluent (liquid) from silage (fermented grass) and slurry (poo and water spread onto the farmland) - leading to eutrophication
- absence of crops or intercropping
Conservation techniques used to increase species and habitat diversity
- plant hedges rather than erect fences as field boundaries
- plant native trees on lands with low species diversity than in species rich areas
- use organic instead of inorganic fertilisers
- leave the cutting of field edges until after flowering when seeds have dispersed
- reduce the use of pesticides by using a biological control or GM organisms that are resistant to pests
Farming practices that increased food production
- use of fertilisers and pesticides
- removal of habitats increasing farm size
How can agricultural ecosystem reduce biodiversity
As farmers will select species with particular qualities that will make them profit and as a result the number of species and the genetic variety of alleles they provide will be reduced to a few species who obtain the desired characteristics
What is interspecific variation
Variation between different species
What is intraspecific variation
Variation within members of the same species
Why might samples/ measurements not be representative
- sampling bias - selection process may be bias either deliberately or unintentionally
- chance - individuals chosen may not be representative
Ways to reduce bias
- random sampling by dividing an area into a grid with number and using a random generator to select a square to sample
Ways to minimise chance
- using a larger sampling size - the more individual selected the smaller the probability that chance will influence the result and less anomalies will be present
- analyse the data collecting - by doing statistical tests to see if any variation observed is due to chance or some other cause
Features of normal distribution curve
- mean median and mode are the same
- distribution is single peaked
- curve never touches the x axis
- the height on the normal distribution curve is at the mean
Biggest to smallest value in negative skewness in a distribution curve
Mode > median > mean
Biggest to smallest value in positive skewness in a distribution curve
mean > median > mode
What does the mean measure on a distribution curve
The maximum height of the curve
Pros and cons of the mean
Pros
- useful when comparing one sample with another
Cons
- does not provide any information about the range of values in the sample
What does the standard deviation measure on a distribution curve
The width of the curve
Pros of standard deviation
Pros
- Gives an indication of the range of values either side of the mean
- takes into account of all values
know how to do Simpson index of diversity
