Classification and Biodiversity Flashcards
What is classification?
The organisation of living organisms according to their shared similarities.
What is taxonomy?
The study of the principles genuine classification.
This is dynamic
What is heriachy?
A large group of items are split into smaller and smaller groups.
What is phylogenetic?
The organisms are grouped to reflect evolutionary relatedness.
Why do we classify?
To make the study of living organisms more manageable.
To support the ideas of evolution.
To allow scientist to communicate with each other.
What is phylogenetic hierarchy?
It’s the modern classification system in which they are classified based on their phylogeny evolutionary relatedness of organisms) each node represents the most common ancestor of the descendants.
Give me the phylogenetic hierarchy?
Kingdom LARGEST phylum class order family genus species SMALLEST
What happens as you go down the hierarchy?
The organisms have a closer relation they share a few common features with the same kingdom but many similarities in the same genus.
What is a species?
A group of organisms that can interbreed under natural conditions to produce fertile offspring
When writing Latin names of a species what has to happen?
The genius name is always capitalised and the species name is always lowercase.
What are the five kingdoms?
Animalia, fungi, Plantae, Protoctista, Prokaryotae.
What are the three domains?
Bacteria (true bacteria)
Archaea (extremophile prokaryotes)
Eukaryota (all eukaryotic organisms).
What does the organisms of each domain share?
A distinct unique pattern of ribosomal RNA which establishes that close evolutionary relationship
What is the problems with the classification system?
It places divisions on evolutionary trends which are continuous.
It has to be a compromise between accurate representation of evolutionary trends/relatedness and what is convenient (grouping ‘similar’ organisms together).
New discoveries may require new groups to be set up.
What features are used to group organisms?
Similar morphology - structure of organism
biochemical methods - molecules within structure i.e DNA, protein sequence, RNA structure and cell wall biochemistry.
fossil records - gives time scale
What are homologous structures?
Evolved from the same original structure for different functions e.g pentadactyl limb in vertebrates. They suggest shared ancestry and divergent evolution.
What are analogous structures?
Same function but evolved from a different origin, so have separate evolution structures. They have similar external forms, but different internal structure and development.
No evolutionary relationship i.e wings on birds and insects. Indicates convergent evolution.
How is biochemical method used when classifying organisms?
Certain molecules are compared with different species to see how similar/dissimilar the structures are. These methods can help minimise classification mistakes due to convergent evolution.
How is DNA hybridisation used to determine evolutionary relatedness?
Single DNA strands from two different species are joined together to form hybrid double helices.
The resulting hybrid DNA is heated and the temperature is recorded for which it becomes a single strand. The temperature relates to a number of hydrogen bonds form between complementary base pairs.
What is the degree of hybridisation proportional to?
Degree of similarity between the DNA molecules of two species.
What does the temperature recorded indicate?
If the species are closely related then the temperature of separation would be close to 86 due to sharing my base pairs.If they aren’t closely related they won’t show many common DNA sequences so have fewer complementary base pairs and a temperature of separation would be less than 86.
What other sequence can be used to identify related organisms?
The protein cytochrome for respiration. Closely related organisms will have similar amino acid sequences in the protein.
What does biochemical method to help reduce?
Mistakes made in classification due to convergent evolution.
How does genetic fingerprinting and enzyme studies help show relatedness?
It doesn’t rely on morphological convergences. It measures the proportion of DNA of proteins share between species to estimate relatedness, DNA fragments of proteins are usually displayed is bands on electrophoresis gel.
