4.3 Classification and Evolution Flashcards
What is the binomial system?
A system that uses the genus name and the species name to avoid confusion when naming organisms.
Define classification.
The process of placing living things into groups.
Why do we group organisms?
- For our convenience
- To make the study of living things more manageable
- To make it easier to identify organisms
- To help us see the relationships between species.
Who devised the classification system we use today to group living things?
Carl Linnaeus
How did Carl Linnaeus put living things into categories?
Linnaeus organised living things into groups according to their visible features. He created a hierarchy of ranked categories. His original classification contained five levels: Kingdom, class, order, genus and species.
Who changes Carl Linnaeus classification system and how was it changed?
Carl Woese Changed the system because he didn’t like how all bacteria was grouped together.
He introduced 3 domain above the kingdoms: Archaea, Eubacteria and Eukaryote. He also made the kingdoms 6 kingdoms: animal, plant, fungi, proctista, bacteria(eubacteria) and archaea (archaebacteria)
What is a taxonomic levels?
A hierarchy of ranked categories.
What taxonomic levels does the current classification system include, in order of hierarchy?
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What rhyme can you use to remember the taxonomic levels in the current classification system?
Kings and Princes Can Often Find Grass Snakes
(don’t forget Domain)
What is a domain?
The highest taxonomic rank which includes: Archaea, Eubacteria and Eukaryote.
What is a kingdom?
The second highest taxonomic level, ???????
What is the taxonomic level, phylum?
A major subdivision of the kingdom. A phylum containing all the groups or organisms that have the same body plan, e.g. possession of a backbone.
What is the taxonomic level, class?
A group of organisms that all possess the same general traits, e.g. the same number of legs.
What is the taxonomic level, Order?
A subversion of the class using additional information about the organism, e.g. the class mammal is divided into meat-eating animals and vegetation-eating animals.
What is the taxonomic level, family?
A group closely related genera, e.g. within the order Carnivora we might recognise the ‘dog’ family and ‘cat’ family.
What is the taxonomic level, genus?
A group of closely related species.
What is the taxonomic level, species?
The basic unit of classification. All members of the species show some variations, but are essentially the same.
Why is it quite easy to place a species into it’s domain, kingdom or phylum?
At the higher levels of the ranked system, the differences between the organisms are very great.
Why is it more complicated to place a species in a class compared to placing it in a domain or kingdom?
The differences between the classes in one phylum may not be very great. A longer description of the species may be needed.
What does bionomial mean?
‘Two names’.
What two names are used in the binomial system?
- Genus name
- Species name
How must you write the names in the binomial system?
- The binomial system is in Latin.
- The genus name always has a capital letter and the species name has a lower-case one.
- The is typed in in italics or written underlined.
Who devised the binomial system?
Carl Linnaeus.
Why do we use the binomial system to name animals?
Before the binomial system, species were identified by a common name, or a long and detailed description sometimes in Latin too. Using a common name didn’t work because:
- The same organism may have had different common names in different parts of a country.
- Different common names used in different countries.
- Translation of languages or dialects may give different names.
- The same common names may be used for different species in different parts of the world.
Why is Latin used for the binomial system?
Latin is a universal language so in whatever country, the name is the same.
When classifying organisms, why is it important to study each specimen in detail?
There may be very small differences between similar species.
Why is a spider not an insect?
A spider does not have six legs, two pairs of wings and three body sections.
What is meant by the binomial system for naming organisms?
The use of scientific names for the genus and species.
Why is a standard way of naming organisms useful?
To avoid confusion, when different organisms may be given the same common name, or the same organism may be given different common names in different areas. To overcome language differences.
What is the biological definition of a species?
A group of organisms that can freely interbreed to produce fertile offspring
What group of organisms does the biological definition for a species not work for?
It does not work for organisms that reproduce asexually, as it is very hard to apply to organisms that are known as fossils.
What is the phylogenetic definition of a species?
A group of individual organisms that are very similar in appearance, anatomy, physiology, biochemistry and genetics.
Being so similar, the members in a species occupy the same niche in an ecosystem.
In early classification systems, what were groups based on? What this system good?
Appearance and anatomy.
For many cases, this provided enough information to allow accurate classification. However, it is easy to make mistakes.
What did Aristotle classify all living things into?
Either plant or animal.
He then subdivided the animals into three groups- those that:
- live and move in water
- live and move on land
- move through the air
In the 17th centaury, what happened which meant organisms can be classified more accurately?
By the 17th centaury, scientists had microscopes help.
What are 7 points that make-up the kingdom prokaryotes (Eubacteria & Archaebacteria)?
- Have no nucleus.
- Have a loop of DNA that is not arranged in linear chromosomes.
- Have naked DNA.
- Have no membrane bound organelles.
- Have smaller ribosomes than other groups.
- Have smaller cells than eukaryotes.
- May be free living/ parasitic.
What are 6 points that make-up the kingdom protoctista?
- Are eukaryotic.
- Mostly single-celled.
- Show a wide variety of forms.
- Show a variety of plant-like and animal-like features.
- Are mostly free-living.
- Have autotrophic and heterotrophic nutrition.
What is autotrophic nutrition?
A process where the organisms produces it’s food via photosynthesis.
What is heterotrophic nutrition?
Heterotrophic nutrition is a mode of nutrition in which organisms depend upon other organisms for food to survive. They can’t make their own food.
They digest larger molecules to form smaller molecules for absorption.
What are 5 points that make-up the kingdom fungi?
- Are eukaryotic.
- Can exist as single cells or they have mycelium that consists of hyphae.
- Have walls made up of chitin.
- Have a cytoplasm that is multinucleate.
- Are mostly free-living and saprophytic.
What are 5 points that make-up the kingdom plantae?
- Are eukaryotic.
- Are multicellular.
- Have cells surrounded by cellulose cell wall.
- Are autotrophic.
- Contain chlorophyll.
What are 4 points that make-up the kingdom Animalia?
- Are eukaryotic.
- Are multicellular.
- Heterotrophic.
- Are usually able to move around.
what does saprophytic mean?
A microorganism that lives on dead or decaying matter.
What is phylogeny?
The study of the evolutionary relationships between organisms.
What is artificial classification?
A type of sorting which:
- Is based on only a few characteristics.
- Does not only reflect any evolutionary relationships.
- Provides limited information.
- Is stable.
If members of the same species are very similar, what do we regard them as?
Closely related.
What group are two closely related species put in?
A genus.
What group are two closely related genera’s be put in?
A family.
What is natural classifiation?
Natural classification groups organisms together so that the whole living world can be organised in to a series of ranked groups- a heirarchy. Natural classification:
- uses many characteristics.
- Reflects evolutionary relationships.
- Provides a lot of useful information.
- May change with advancing knowledge.
Why is natural classification that reflects real relationships between groups could be very useful?
If we want to find out more about rare or endangered species, we would not want to risk harming the individuals left. However, if we know a very similar species to provide information that is also applicable to the endangered species. This may make convervation more successful.