Chapter 10 - Biodiversity Flashcards
What is classification?
The organisation of living organisms into groups
What will all members of a species have in common?
They can breed to produce fertile offspring
What is the name given to the current system of naming organisms?
The binomial system
What did Linnaeus do?
Devised a universal system of naming organisms
What languages are the names of organisms written in?
Greek or Latin
What is the first name of an organism?
The generic name, or the genus
What is the second name of an organism?
The specific name, or the species
What are the three rules that apply when writing the names of organisms?
1) Must be underlined if handwritten
2) The first letter of the genus should be a capital letter
3) If the species is unknown, it can be written as sp
What is biodiversity?
The variety of living organisms in an area
What is a habitat?
The place where an organism lives
What is a community?
All the populations of different species in a habitat
How can members of the same species identify each other?
They resemble each other, either biochemically or physically
What are the four main advantages of courtship?
Members of the same species can recognise each other
Organisms identify a mate capable of breeding
Organisms form a pair bond
Synchronise mating
What must a prospective mate be?
Mature and fertile
Why is it important to ensure mating only occurs between members of the same species?
So that fertile offspring are produced
Why is it important to synchronise mating?
To ensure the maximum probability of the sperm and egg meeting is achieved
What do males use courtship for?
To determine if the female is receptive to mating because females only release eggs at certain times
What is taxonomy?
The science of classification
What will organisms of the same species exhibit?
Similar courting behaviour
What is artificial classification?
Based on physical characteristics and their functions rather than evolutionary origins
What is phylogenetic classification?
Based upon the evolutionary relationships. It divides organisms into groups using shared features they have received from ancestors and arranges these groups into a hierarchy
What is a hierarchy?
A group contained within a larger group but with no overlap
What does the first point on a phylogenetic tree show?
A common ancestor of all family members
What do the branches on a phylogenetic tree show?
Another common ancestor from which a different group diverged
How to tell if two species on a phylogenetic tree are closely related
They diverged away from each other recently
What is each group in taxonomy called?
A taxon
What is phylogeny?
The study of the evolutionary history of groups of organisms
What are the three domains?
Archaea, bacteria and eukarya
Characteristics of domain archaea
Newly discovered cell types included
1 kingdom - the archaebacteria
How do archaea differ from bacteria?
Their genes and protein synthesis mechanisms are closer to that of eukaryotes
No murein in cell walls
A more complex form of RNA polymerase
Characteristics of domain bacteria
1 kingdom - the eubacteria
What are eukarya?
A group of organisms made up of multiple eukaryotic cells
What are phyla?
The largest groups in each kingdom
Characteristics of Eukarya
Membrane-bound organelles
No murein in cell walls (if applicable)
Larger ribosomes than bacteria and archaea
Membranes containing fatty acid chains attached to glycerol by ether linkages
Characteristics of domain eukarya
4 kingdoms - protista, animalia, plantae and fungi
What is species diversity?
The number of individuals of each species in a community
What is genetic diversity?
The range of alleles in a community
What is ecosystem diversity?
The range of different habitats
What is species richness?
The number of different species in a particular area at a given time
What is local biodiversity?
The variety of different species in a small habitat
What is global biodiversity?
The variety of species on earth
What is ecosystem diversity?
The range of different habitats within one particular area
What impact does agriculture have on biodiversity?
Natural ecosystems develop from complex communities
Agricultural ecosystems are controlled by humans
Farmers select the most productive crops
The number of species and number of alleles they possess decreases
For economic reasons, the yield must be large
Any one area can only support a certain amount of biomass
If most of an area is taken up by a crop, there is little room for anything else
These organisms must outcompete the crop for nutrients, light and space, which rarely occurs
Direct practises which have reduced biodiversity (4)
Removal of hedgerows
Creating monocultures
Filling ponds and draining marsh and other wetland
Overgrazing of land
Why has the overgrazing of land reduced biodiversity?
It prevents the regeneration of woodland
Why have monocultures reduced biodiversity?
Fewer organisms can be supported
Why has hedgerow and woodland removal reduced biodiversity?
Species lose habitats and food sources
Ways in which food production has increased (4)
Genetic modification
Use of pesticides and herbicides
Changes in farm practices
Technology
Why do pesticides reduce biodiversity?
Not only does it kill the insect themselves, but it also removes a food source for the food chain
Indirect practices which have reduced biodiversity (3)
Use of pesticides and inorganic fertilisers
The absence of crop rotation
Escape of effluent from silage stores into water sources
How has the EU helped maintain biodiversity?
Offering farmers grants to return to a natural meadow
3 examples of conservation schemes
Legal protection for endangered species
Creating protected areas which restrict further development
Environmental Stewardship Scheme encourages farmers to conserve biodiversity
How are people trying to maintain biodiversity? (5)
Maintain and create hedgerows and ponds
Leave wet corners of fields
Reduce the use of pesticides and inorganic fertilisers
Use nitrogen-fixing crops to improve soil fertility rather than fertilisers
Create natural meadows and replant native trees
How can observable characteristics help to classify organisms?
Characteristics are influenced by the genes an organism has, so organisms with similar characteristics have similar DNA
Why are there limitations with using observable characteristics to help us classify organisms?
Lots of characteristics are either influenced by environmental factors or by a number of genes
How can comparing mRNA sequences help us to classify organisms?
mRNA is coded for by DNA by complementary base pairing, so by comparing two strings of mRNA, we can also compare two sequences of DNA
How can amino acids help us to classify organisms?
A sequence of amino acids is coded for by mRNA, so also DNA. This means that we can compare the amino acid sequence for the same protein in two species and count the number of similarities or difference in order to see how similar they are
How can proteins be used to test the similarity between two organisms?
If two proteins, and therefore two organisms are similar, they will bind to the same antibody, so you can test to see how well two proteins bind to the same antibody
How can DNA be used to test the similarity between two organisms?
Modern technology has allowed us to determine the entire base sequence of an organism’s DNA. We can compare the DNA of members of one species to that of members of another species in order to see how similar they are. Closely related species will have a higher percentage of similarity in their DA base order
When a species gives rise to another species through evolution, how would we expect their DNA to differ?
Initially, it would be very similar. However, over time, mutations would develop and the nucleotide sequence in the new species would change over time
Problems with DNA sequencing to classify organisms
Not all DNA is functional and codes for proteins
What does a percentage similarity table show you?
How similar two organisms area - if two are very similar, the percentage will be higher
How can you tell that two organisms are very similar by looking at their DNA?
The more similarities between the sequences, the more similar the two are
How can antibodies and antigens be used to compare organisms?
Serum albumin from species A is injected into species B
Series B produces antibodies complementary to the antigens in the albumin of species A
Serum from species B is mixed with serum from species C
The antibodies in serum C respond to their corresponding antigens in serum B
These antibodies form a precipitate
The more precipitate that forms, the closer two species are related
What is interspecific variation?
When one species differs from another
What is intraspecific variation?
When organisms in the same species differ from each other
What is variation?
The differences that exist between individuals
What two factors is variation caused by?
Genetics and the environment
What are the two reasons that a sample might not be representative?
Sampling bias
Chance
Method of random sampling
1) Divide the study area into a grid of numbered lines
2) Use a random number generator to obtain a series of coordinates
3) Take samples at the intersections of these coordinated
How to minimise the chances of our data not being representative
Use a larger sample size
Analyse the data collected
Why does using a larger sample size reduce the chances of our data not being representative?
Anomalies will have less influence over the result
The data is more reliable
What is a skewed distribution curve?
When it is shifted slightly to one side
How to calculate the mean?
Total of all values / number of values
What is the mode?
The most common value
What is a normal distribution curve?
A bell-shaped curve that is symmetrical about the mean
What is the median?
The middle value
Why is the mean useful?
You can easily compare one sample with another
Why is the mean not very useful?
It gives you no information about the range of the data values
What is standard deviation?
How much the values in a single sample vary
How to find standard deviation from a graph?
It is the point where the curve changes from being convex to concave
How much of the data lies between one standard deviation?
68%
How much of the data lies between two standard deviations?
95%
When there is no information on the number of significant figures to use, what should you do?
Use the same number as the data given to you in the question
How to calculate standard deviation
See flashcard
How to draw error bars on a graph
They extend one SD above and below the mean
