diversity and classification C Flashcards
what is a species
A group of organisms that can (interbreed to) produce fertile offspring
Suggest why 2 different species are unable to produce fertile offspring
-Different species have different chromosome numbers → offspring may have odd chromosome number
-So homologous pairs cannot form → meiosis cannot occur to produce gametes
what is a hierarchy
-smaller groups placed within larger groups
-no overlap between each group
groups are called…
taxa
state the hierarchy
-domain
-kingdom
-phylum
-class
-order
-family
-genus
-species
How is each species universally identified?
A binomial consisting of the name of its genus and species, eg. Homo sapiens
Suggest an advantage of binomial naming
Universal so no confusion as many organisms have more than one common name
what is phylogenetic classification
-arranges species into groups in the above hierarchy based on evolutionary relationships
-shows how closely related species are by looking at common ancestors
what is courtship behaviour
-behaviour that organisms carry out to attract a mate
-specific to a particular species
-can be used to classify species
Explain why courtship behaviour is a necessary precursor to successful
mating
● Allows recognition of members of same species → so fertile offspring produced
● Allows recognition / attraction of opposite sex
● Stimulates / synchronises mating / production / release of gametes
● Indicates sexual maturity / fertility
● Establishes a pair bond to raise young
what are simple courtship behaviours
-releasing a chemical
-using sound
-visual displays
what are complex courtship behaviours
-dancing
-building
two ways to classify using DNA/ Proteins
-Genome sequencing=
. Compare the order of base sequence of whole genome of different species
. Higher % match = more closely related e.g. humans and chimps = 96%
-Immunology=
. tertiary structure of protein tells us about sequence of DNA
.If same antibody binds to a specific antigen then it is closely related
how are gene technologies used to assess genetic diversity ?
comparing the base sequence of DNA,base sequence of mRNA or amino acid sequence of the proteins encoded by DNA and mRNA
what are the advantages of using gene technologies rather than traditional methods to assess genetic diversity in a population?
-give more accurate estimates of genetic diversity and make comparisons of genetic diversity easier to carry out
what is biodiversity
● Variety of living organisms (species, genetic and ecosystem diversity)
● Can relate to a range of habitats, from a small local habitat to the Earth
What is a community?
All populations of different species that live in an area.
what is a habitat?
is the place where an organism lives e.g. field
What is species richness?
A measure of the number of different species in a community
What does an index of diversity do?
Describes the relationship between:
1. The number of species in a community (species richness)
2. The number of individuals in each species (population size
Suggest why index of diversity is more useful than species richness
● Also takes into account number of individuals in each species
● So takes into account that some species may be present in small or high numbers
Describe how index of diversity values can be interpreted
● High → many species present (high species richness) and species evenly represented
● Low → habitat dominated by one / a few species
Explain how some farming techniques reduce biodiversity
*Removal of woodland and hedgerows, monoculture, use of herbicides to kill weeds=
● Reduces variety of plants
● So fewer habitats and niches
● And less variety of food sources
*use of pesticides=
●Predator population of pest decreases
Explain the balance between conservation and farming
● Conservation required to increase biodiversity
● But when implemented on farms, yields can be reduced, reducing profit for farmers
= Eg. by reducing land area for crop growth, increasing competition, increasing pest population
● To offset loss, financial incentives / grants are offered
How can genetic diversity within or between species be measured?
● Comparing frequency of measurable or observable characteristics
● Comparing base sequence of DNA
● Comparing base sequence of mRNA
● Comparing amino acid sequence of a specific protein encoded by DNA and mRNA
Explain how comparing DNA, mRNA and amino acid sequences can indicate
relationships between organisms within a species and between species
● More differences in sequences → more distantly related / earlier common ancestor
● As mutations (change in DNA base sequences) build up over time
● More mutations cause more changes in amino acid sequences
Explain the key considerations in quantitative investigations of variation
within a species
● Collect data from random samples (use a random number generator) → removes bias
● Use large sample size (or sample until stable running mean) → representative of whole population
● Ethical sampling (where applicable) → must not harm organism / allow release unchanged
● Calculate a mean value of collected data and standard deviation of that mean
● Interpret mean values and their standard deviations (S.D
