Classification Flashcards
(42 cards)
Define classification
The act of arranging organisms into groups based on their similarities and differences
Why do we classify organisms?
To make it easier to identify them and study them
Taxonomy definition
The study of classification
How do classification systems work?
By placing organisms into a taxonomic heirarchy
What are the 8 levels of taxonomic groups? (in order)
-Domain
-Kingdom
-Phylum
-Class
-Order
-Family
-Genus
-Species
Keep Pond Clean Or Frog Gets Sick
What happens to the groups as you move down the heirarchy?
There are more groups but fewer organisms in each group
What are the 5 kingdoms in the five kingdom classification system?
- Prokaryotae
- Protoctista
- Fungi
- Plantae
- Animalia
What are the general features of the Prokaryotae group?
- Prokaryotic
- Unicellular
- No nucleus
- Less than 5 nanometers
What are the general features of the Protoctista group?
- Eukaryotic cells
- Usually live in water
- Single celled or simple multicellular organisms
General features of the Fungi group
- Eukaryotic cells
- Chitin cell wall
- Saprotrophic
- Single celled or multicellular organisms
Define saprotrophic
-Can absorb substances from dead or decaying organisms
General features of Plantae group
- Eukaryotic cells
- Multicellular
- Cell walls made of cellulose
- Can photosynthesise
- Contain chlorophyll
- Autotrophic
General features of Animalia group
- Eukaryotic
- Multicellular
- No cell walls
- Heterotrophic
What is the naming system used for classification called?
The binomial system
How does the binomial naming system work?
- The first part of the name is the genus name, and has a capital letter
- The second part of the name is the species, written with a lower case letter
- Names are always written in italics
Why is the binomial system used?
-To help avoid the confusion of using common names, e.g. over 100 different species are called raspberries
What is phylogeny?
The study of the evolutionary history of groups of organisms. Tells us who’s related to whom and how closely
What have all organisms evolved from?
A shared common ancestor
How can the relationship between organisms be shown?
Phylogenetic tree
On a phylogenetic tree, how can you tell species are closely related?
How reacently they divereged away from each other e.g. closely related species diverge away from each other most recently
Cladistics
The method of classifying organisms and taking into account phylogeny when arranging into groups
What was early classification based on?
Observational features
What is the problem with classifying based purely on observational features?
Scientists don’t always agree on the relative importance of different features and physical features alone may not show how closely related organisms are
What are the types of evidence that we now use to classify organism?
- Molecular evidence
- Embryological evidence
- Anatomical evidence
- Behavioural evidence
