C2: Classification and biodiversity Flashcards
Define classification
Putting items into groups
Name the heriarchy of taxons in order
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
How do scientists classify organisms
Based on their evolutionary history (phylogenetics)
Define phylogenetic
Reflects evolutionary relatedness
Name the three domains
Bacteria (or Eubacteria) which are the true bacteria.
The Archaea (or Archaeabacteria) include the extremophile prokaryotes.
Eukaryota which include all eukaryotic organisms i.e. animals, plants, fungi and protoctista.
What do the organisms of each domain share
a distinctive, unique pattern of ribosomal RNA, which establishes their close evolutionary relationship
Define extremophiles
Extremophiles exist in a wide variety of environmental conditions including extremes of temperature, pH, salinity and pressure
Name the five kindoms
Prokaryotae, Protoctista, Plantae, Fungi, Animalia
Describe Prokaryotae
Composed of prokaryotic cells, which lack a
nuclear envelope and membrane-bound organelles (the cell wall does not contain cellulose or chitin)
Describe Plantae
multicellular eukaryotes, photosynthetic, cellulose cell wall
Describe Animalia
nervous co-ordination; multicellular eukaryotes, no cell wall, heterotrophic
Describe Fungi
Heterotrophic eukaryotes, cell walls of chitin, most have filaments called hyphae; reproduce by spores.
Describe protoctista
Mainly single cell eukaryotes, no tissue
differentiation
How to assess the relatedness of organisms using physical features
provide an example
The presence of Homologous structures - which have a similar arrangement of component parts and similar developmental origin but different functions.
eg:the pentadactyl limb in vertebrates(human arm,bat wing and whale flipper)
What type of evolution is the pentadactyl limb
Divergent evolution
Define divergent evolution
A common ancestral structure has evolved and performs different functions resulting in homologous structures (mostly)
Define Analogous structures
Have a corresponding function and similar shape, but have a different developmental origin are not suitable to classify organisms
Define Convergent evolution
Structures evolve similar properties but have different developmental origins resulting in analogous structures.
Other than physical features what can also help assess relatedness
Genetic evidence like DNA sequences and amino acid sequences
What is the benefit of using genetic profiling for species relatedness
can reduce the mistakes made in classification due to convergent evolution or sexual dimorphism
Define a species
A group of organisms that can interbreed to produce fertile offspring
What is the use of the binomial naming system
Its unambiguous - so one name for one species cannot be misinterpreted
It is universal - based on latin and used all over the world
Allows closely related species to be identified as they share Half a name
How to use the binomial naming system
The Genus is the first word and has a capital letter
the species name comes second and is lowercase
( it is written in full the first time of writing then it can be abbreviated
when handwriting it should be underlined )
(NOT IMPORTANT)
Define Biodiversity
the number of species and the number of individuals of each species in a given environment.
Describe the two aspects of biodiversity
species richness - how many different species
species evenness - The number of individuals of each species living together in a community
What factors affect biodiversity
Environmental (eg: light intensity)
Genetic (eg: succession and natural selection)
Human Influence (eg: deforestation, climate change, habitat destruction, overfishing and land misuse)
Why are biodiversity hotspots around the equator and tropics
High light intensity all year ensures high energy input into the ecosystem, which means the ecosystem can support a large species richness and evennessa
How can biodiversity be assessed in a habitat
Spearmanβs diversity index
What is the formula for spearmans diversity index
βπ(πβ1)
D= 1β ββββββββββββββββ
π(πβ1)
What range must the simpsons diversity index be between
describe what a greater value means
0 - 1
the greater the value the greater the samples diversity
How can biodiversity be assessed within a species
At a genetic level by looking at the variety of alleles in the gene pool of a population ( the proportion of polymorphic loci across the genome)
By determining the:
Number of alleles at a locus
Proportion of the population that have a particular allele
Define polymorphism
The occurrence of more than one phenotype in a population that cannot be accounted for by mutation alone.
Describe how polymorphism occurs
results from the presence of multiple alleles for the same gene in a gene pool.
Describe the molecular assessment of biodiversity
Use genetic fingerprinting /profiling (same) to determine differences in introns;
small one base differences are SNPs (single nucleotide polymorphism)
Longer regions (20-40 base sequences) that are repeated many times are STRs (short tandem repeats)
The more differences the greater the biodiversity
Define natural selection
The gradual process in which inherited characteristics become more or less common in a population, in response to the environment determining the breeding success of individuals possessing those characteristics
Describe the process of natural selection in 7 stages
Mutation occurs
Mutation is expressed in phenotype so there is a change in physical appearance or behaviour
This variation is a selective advantage (competitive advantage) and outcompetes others during the intra-specific competition for resources
So they are most adapted to the environment and survive better
So they can more successfully reproduce
passing on advantageous alleles to offspring
allele frequency increases in future generations
Name three different types of adaptations
Anatomical
Physiological
Behavioural
