10: Biodiversity Flashcards
What is a species?
The basic unit of classification
What do members of a species have in common?
They are capable of breeding to produce fertile offspring
Belong to the same gene pool
What is a gene pool?
All genes & alleles of a population
What do same species have in common?
Similar physical/biochemical
Similar immunologically (antibodies)
Occupy same ecological niche
Similar courtship behaviour
What is courtship behaviour determined by?
Genetics
Why can an animal with an odd number of chromosomes not reproduce?
Odd number of chromosomes cannot split evenly in meiosis, no gametes can form
What is a hierarchy?
Groups within larger composite groups with no overlap
What is the binomial naming system?
First generic name denotes the genus - Capital first letter
Second specific name - lowercase, if not known replaced with “sp.”
Italics in papers, underlined in exams
What is the purpose of courtship behaviour?
Recognise members of their own species Identify a mate capable of breeding Form a pair bond Synchronise mating Become able to breed
Why is recognising members of the same species important?
Ensure mating only takes place between members of the same species
To ensure fertile offspring
Why is identifying a mate capable of breeding important?
Both partners need to be sexually mature for mating
How does courtship action work?
Male carries out a “courtship action”
Female responds yes or no
No makes male give up and moves to other female
Yes makes male do a different action and after a few this will make mating occur
What is the stimulus response chain?
Male action and response by female
Yes to actions until mating occurs
All members of same species follow same chain
What does courtship include?
Chemicals
Behavioural displays
Etc.
What is taxonomy?
Theory and practice of biological classification
What is artificial classification?
Classifies organisms according to differences based on analogous characteristics
What are analogous features?
Same function but different evolutionary origin
E.g bird wing and bee wing
What is phylogenetic classification?
Based on evolutionary relationship between organisms and their ancestors
Classifies species into groups using shared features derived from ancestors
Groups in a hierarchy
What are homologous characteristics?
Same basic structure and evolution origin but may have different functions
What is the domain and what are they?
Highest taxonomic rank
Bacteria, Archaea, Eukarya
What are the taxonomic ranks?
Domain Kingdom Phylum Class Order Family Genus Species
What are the features of bacteria?
Single-celled prokaryotes Absence of membrane-bound organelles Ribosomes are smaller Cell walls contain murein No histones
What are the features of archaea?
Single-celled prokaryotes that differ from bacteria by:
Genes/protein synthesis more similar to eukaryotes
Membranes contain fatty acids and glycerol with ether bond
No murein
More complex form of RNA polymerase
What are eukarya?
Eukaryotic cells
Membrane-bound organelles
Membranes contain fatty acids and glycerol with ester bond
Not all have cell wall, those that do have no muerin
Ribosomes are large
Define biodiversity
Variety of living organisms in an area
What is species diversity?
Refers to number of different species in one community
What is a community?
All populations of different species in a habitat
What is genetic diversity?
Refers to variety of genes possessed by population of species
What is ecosystem diversity?
Refers to range of different habitats
What is local biodiversity?
Variety of different species in a small habitat
What is global biodiversity?
Variety of different species on Earth
What is species richness?
Number of different species in an area at a given time
What is the index of diversity?
Way of measuring biodiversity
“d”
What is the index of diversity equation?
d = N(N-1) / sum of n(n-1) N = number of organisms of all species n = number of organisms of one species
What do farmers do to affect crops and what is the affect of this?
Increase the amount of food that they produce
Reduces biodiversity
What are some examples of biodiversity reduction due to agriculture?
Woodland clearance Hedgerow removal Pesticides Herbicides Monoculture
How does woodland clearance and hedgerow removal affect biodiversity?
Destroys habitat for farmland
Species lose shelter and food source
Causes death and loss of biodiversity
How do pesticides and herbicides affect biodiversity?
They kill pests/weeds
Reduces biodiversity in the area
What is mono-culture and how does it affect biodiversity?
Only grow one type of plant
Single type means supports fewer organisms
What is done to balance biodiversity and agriculture?
Conservation schemes
Such as legal protection to species, or rewarding farmers for protecting biodiversity
How can evolutionary relationships/genetic diversity be investigated?
Compare observable features
Compare DNA base sequences
Comparing proteins
Compare mRNA
Why is comparing physical features done and what are the disadvantages?
Done as the features are due to DNA coding for structural proteins
But environment affects observable features
Observable characteristics are polygenic so there is continuous variation, difficult to make distinctions
What does polygenic mean?
Characteristic is caused by many different genes
Therefore many different variations
What are the two ways you can compare DNA base sequences?
DNA sequencing
DNA hybridisation
Why is comparing DNA base sequences done?
Closely related species have similar DNA sequences
After evolution initially similar sequence
Over time there will be more differences due to mutations
What is DNA sequencing?
Computers compare order of bases
Closely related species have a higher % of similar bases
What colours are given to different bases in DNA sequencing?
Adenine - green
Thymine - red
Cytosine - blue
Guanine - yellow
Why is mRNA sequences used to compare species?
mRNA copied from DNA
mRNA of a common gene can be sequenced to see how similar they are
Why is mRNA preferable to sequencing DNA?
mRNA is found in the cytoplasm
mRNA is a copy of one gene not thousands of genes like in DNA
Why is comparing proteins used to compare species?
Closely related species have similar amino acid sequences for the same protein
What are the two ways to compare proteins?
Counting similarities/differences in amino acid sequence of the same protein in different species
Immunological comparisons
What is immunological comparisons for comparing proteins?
Antibodies bind to protein to form a precipitate
Similar proteins bind to the same antibody
If antibody binds to protein in different species they are closely related
Compare amount of precipitate formed
What is inter-specific variation?
Variation between different species
What is intra-specific variation?
Variation between members of the same species
Why are samples taken?
Unrealistic to get data from the whole population of the Earth
Why is a sample not representative of a population?
Sampling bias - selection process may be biased
Chance - individuals may not be representative of the population
What can be done to increase how representative a sample is?
Large sample size - smaller probability that chance will influence it and anomalies won’t affect it
Analysis - shows whether variation is the result of chance
What is the shape of a normal distribution curve?
Symmetrical bell-shape
What is it called when a distribution curve is shifted?
Skewed curve
What are the three methods for calculating averages?
Mean - sum of values / number of values
Mode - most common value
Median - middle value of a set of values
Where is the mean, median and mode on a normal distribution curve?
Same value in the middle
What is mean used for?
Provides average value
Allows comparison of averages
What is standard deviation used for?
Measure of spread of values around the mean
Large S.D means values vary a lot
How is standard deviation shown on a graph?
Bars one standard dev. above and below
If they overlap can’t be said to be different
Why is index of diversity used instead of species richness?
Takes into account both species richness and evenness
Gives an idea of the number of each species relative to population size
Small and large populations are treated differently
