10.1 Species and Taxonomy Flashcards
Define classification:
the organisation of living organisms into groups based on accepted principles
What defines a species?
Capability of breeding together to produce living, fertile offspring
What are the two names in the binomial system?
- The generic name denotes the genus a plant belongs to (similar to a surname)
- The specific name denoted the species
Rules that apply to the binomial system:
- Names are in italics or underlined to indicate scientific nature
- Generic name starts with a capital, specific name does not
- if specific name is not known, ‘sp’ can be written
How does courtship enable maximum chances for survival?
By enabling individuals to:
- Recognise members of their own species
- Identify a mate that is capable of breeding
- Form a pair bond
- Synchronise mating, to ensure highest chance of sperm and egg meeting
- become able to breed by inducing a physiological state that allows it to occur
The difference between classification and taxonomy:
Classification is the grouping of organisms whereas the theory and practice of biological classification is called taxonomy
What are the two main types of biological classification?
- Artificial classification
2. Phylogenetic classification
What is Artificial Classification?
This involves dividing organisms according to differences that are useful at the time. Analogous characteristics that have the same function but different evolutionary origins
What is Phylogenetic classification?
This is based on evolutionary relationships, and classifies species according to shared features derived from their ancestors. It also arranges groups into a hierarchy in which groups are contained within larger composite groups with no overlap. Phylogenetic classification is also partly based on homologous characteristics, e.g. the arm of a human and front leg of a horse
What does Delicious King Philippa Can Order Fun Guys Seductively stand for?
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
What is a taxon?
Each group within a phylogenetic classification
What are taxonomic ranks?
Heirarchical order in phylogenetic classification
Three types of domain:
Bacteria, Archaea (prokaryotes) and Eukarya
What features do bacteria have?
- Single celled prokaryotes
- Absence of membrane bound organelles
- Unicellular
- Ribosomes are smaller than in eukaryotes (70S)
- Cell wall present and made of murein
- Single loop of naked nucleic acid DNA but no histones
How do Archaea differ from bacteria?
- Their genes and protein synthesis are similar to eukaryotes
- their membranes contain fatty acid chains attached to glycerol by ether linkages
- No murein in cell walls
- More complex form of RNA polymerase
Main features of Eukarya:
- Cells possess membrane bound organelle
- Membranes containing fatty acids attached to glycerol by ester bonds
- Not all possess cell walls, those that do have no murein
- Ribosomes are larger than in Bacteria and Archaea (80S)
Outline the main structure of the Eukarya domain:
Divided into four kingdoms: Protoctista, Fungi, Plantae, Animalia Within each kingdom, the largest groups are known as phyla. Organisms in each phylum have bodies very different to organisms in other phylum. Diversity in each phylum allows class division. Each class is divided into orders of organisms that have additional features in common. Then we have families where the differences become less obvious and genera . Each genera is divided into species eventually. DKPCOFS
What is phylogeny?
The evolutionary relationship between organisms. The phylogeny of an organism represents the evolutionary branch that led up to it. This information is usually represented in a phylogenetic tree with the oldest at the bottom and recent ones branching upwards.
Why is there difficulty in defining species?
- Species change and evolve over time
- Within a species there can be considerable variation (e.g. artificial selection in dogs)
- many species are extinct and have left no fossil record
- some species rarely/never reproduce sexually
- geographical isolation might mean members of the species never get the chance to interbreed
- Some types of organisms are sterile
