4.2.2 - Classification and Evolution Flashcards
What is phylogenetic classification?
It arranges species into groups according to their evolutionary origins and relationships. It tells us how closely related species are and how recent their shared common ancestors are.
What is the order of the taxonomic hierachy from the largest taxon to the smallest?
- Domanin
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What is the binomial system of naming species?
First name is genus and second name is species
What is the advantage of the binomial system of naming species?
It is universal so the name is the same in every country and it can give an indication as to how closely related the animals are.
What are the 5 kingdoms?
- Prokaryotae
- Protoctista
- Fungi
- Plantae
- Animalia
What is prokaryotae?
- Unicellular
- No membrane bound organelles
- Small ribosomes
- Ring of DNA with no associated proteins
- Has no feeding system instead it absorbs nutrients across its surface or some photosynthesise
What is protoctista?
- Unicellular
- Does have a nucleus and membrane bound organelles
- Sometimes have chloroplasts and some have cilia or flagella for movement
- Nutrients are absorbed either by photosynthesis, ingestion of other organisms or some are parasites
What is fungi?
- Can be unicellular or multicellular
- Have a nucleus and membrane bound organelles
- No chloroplasts
- Cannot move
- Have a body made of threads or hyphae
- Nutrients can be absorbed from dead or decaying matter
- Food can be stored as glycogen
What is plantae?
- Multicellular
- Have a nucleus and membrane bound organelles
- Have chloroplasts
- Don’t move
- Nutrients are absorbed by photosynthesis and food is stored as starch
What is animalia?
- Multicellular
- Have a nucleus and membrane bound organelles
- No chloroplasts
- Can move using cilia, flagella or muscles
- Nutrients are obtained by ingestion and food can be stored as glycogen
What did classification used to be based on?
It was based on observable characteristics which can be misleading as members of the same species can look very different if they live in different habitats with very different environment conditions. Members of different species can also look very similar if they share a habitat and are exposed to very similar environmental conditions.
What evidence has led to new classification systems?
- DNA base sequence of organisms for common genes can now be compared as a measure of how closely related organisms are. The more closely related the species the higher the degree of similarity in the base sequences
- The sequence of amino acids in a polypeptide chain of proteins can also be compared because this sequence is determined by the sequence of DNA bases
What are the 3 domains?
- Bacteria
- Archaea
- Eukarya
What is bacteria?
- Have different membranes to archaea
What is archaea?
- Often inhabit extreme conditions because they have adaptations in their cell membranes to withstand high temperature, pH and salt concentrations
- Very small in size, similar to bacteria or mitochondria