4.2.2 - Classification and evolution Flashcards
Define the term ‘classification’ ?
Classification : The process by which living organisms are sorted into groups based on similar characteristics
Define the term ‘species’ ?
Species - A group of organisms with similar characteristics/ features that able to breed together and produce fertile offspring
What is the taxonomic hierarchy ?
- Domain
- Kingdom
- Phylum
- Class
- Order
- Familly
- Genus
- Species
Why do we classify organisms ?
- To identity species
- To predict characteristics
- To find evolutionary links
Explain why we classify organisms to identify species ?
By using a clearly defined system of classification, the species of an organism can easily be identified
Explain why we classify organisms to predict characteristics ?
If several members in a group have a specific characteristic, it is likely another species in the group will have the same features / characteristics
Explain why we classify organisms to find evolutionary links ?
Species in the same group probably share characteristics since they have evolved from a common ancestor
What is the binomial naming system ?
It is a universal naming system where all species are given a scientific name consisting of two parts ( the first part is the genus, the second part is the species )
What are the benefits of the binomial naming system ?
- Different areas use different names
- It is a universal naming system that ensures scientists all over the world can refer to organisms without misunderstanding
What are the five kingdoms ?
- Prokaryotae
- Protoctista
- Fungi
- Plantae
- Animalia
What are the features of Prokaryotae ?
- Unicellular
- No nucleus / membrane-bound organelles
- No visible feeding mechanism ( nutrients absorbed through cell wall and produced internally via photosynthesis )
Features of Protoctista ?
- Unicellular
- A nucleus and other membrane- bound organelles
- Some have chloroplasts
- Some sessile/ some move via cilia, flagella or amaeboid
- Nutrients are acquired by photosynthesis, ingestion of other organisms and some are parasitic
What are autotrophic feeders ?
They are organisms that are self-feeders and produce their food via photosynthesis
What are heterotrophic feeders ?
They are organisms that eats other plants or animals for energy and nutrients
Features of fungi ?
- Unicellular/ multicellular
- A nucleus, other membrane-bound organelles and cell wall made of chitin
- No chloroplasts/ chlorophyll
- No mechanisms for locomotion
- Most have a body or mycelium made. Of threads or hyphae
- Nutrients are acquired by absorption from decaying material
- Most store their food as glycogen
What are saprophytic feeders ?
They are organisms that feed on the dead and the decaying matter in the environment
Features of plantae ?
- Multicellular
- Nucleus, other membrane-bound organelles ( eg. Chloroplasts ) and cell wall made of cellulose
- Contain chloroplasts
- Most don’t move, gametes move via cilia and flagella
- Nutrients are acquired by photosynthesis
- Store food as starch
Features of animalia ?
- Multicellular
- Nucleus, other membrane-bound organelles but no cell wall made of
- No chloroplasts
- Move with aid of cilia, flagella, contractile proteins
- Nutrients are acquired by ingestion
- Food stored as glycogen
How have there been changes in the classification system ?
- Originally, organisms were classified based on observable characteristics/ phenotype ( artificial classification )
- Through study of genetics and other biological molecules, scientists now classify organisms based on their genotype
- By comparing similarities in DNA and proteins of different species, this shows evolutionary relationship
What are the 3 Domains systems ?
- Eukarya
- Archaea
- Bacteria
Features of the Eukarya domain ?
- Have 80s ribosomes
- Nucleus, membrane-bound organelles
- RNA polymerase contains 12 proteins
Features of Archaea domain ?
- Have 70s ribosomes
- RNA polymerase contains 8-10 proteins, similar to eukaryotic ribosome
Features of bacteria domain ?
- Have 70s ribosomes
- RNA polymerase contains 5 proteins
What is the six kingdom classification system ?