5.3 Flashcards
What is the history of the binomial system? Why was it developed?
It’s a system for naming organisms that is universal among biologists. It was developed so that there’s no confusion or misunderstanding if different species have the same name. It was agreed upon and developed at a series of congresses.
Describe the binomial system of nomenclature:
Consists of:
Genus name - group of species sharing characteristics
Species name - distinguishes from genus
Begins with capital letter (genus) and ends with lowercase (species)
Always in italics
Can be abbreviated after one use
Explain what happens to species when they’re discovered
They are given scientific names using the binomial system
Outline how taxonomists classify species using hierarchy of taxa
Taxa form a hierarchy as each taxon includes taxa from the level below. Going up the hierarchy, the taxa include larger and larger numbers of species, which share fewer and fewer characteristics.
What are the three domains of classification?
Bacteria, Archaea, Eukaryota
What molecules gave scientists the idea that there are two distinct groups of prokaryotes?
The base sequence of rRNA is different in Archaea compared to Bacteria
Where are Archaeans found? Can you give some examples of Achaean’s?
In a broad range of habitats (often extreme) eg. ocean surface, water with very high salt concentration or high temperatures, cattle intestines
Methanogens: Methanococcus
Extremophiles: Thermococcus
Are viruses classified in the three domains?
No, they have too few characteristics of logger to be classified as living organisms eg. no metabolism, only reproduce inside living host cell
What are the principal taxa for classifying eukaryotes? What are the kingdoms?
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
Animalia- multicellular, no cell walls, mitochondria, heterotrophic, store carbohydrates as glycogen
Plantae- multicellular, cell walls made of cellulose, mitochondria, autotrophic, store carbohydrates as starch
Fungi- unicellular (yeast) or multicellular, cell walls made of chitin, mitochondria, saprotrophic, store carbohydrates as glycogen
Protictista- unicellular (usually), cell walls may or may not be present, mitochondria, various ways of nutrition, store carbohydrates as starch or glycogen
Classify one plant and one animal species from domain to species
Animal: Plant: Eukaryote Eukaryote Animalia Plantae Chordata Angiospermophyta Mammalia Eudicot Primate Rosales Hominidae Rosaceae Homo Rosa sapien canina
In natural classification, what do the genus and accompanying higher taxa of all the species consist of?
The genus and accompanying higher taxa consist of all the species that have evolved from one common ancestor. We would expect members of a natural group, evolved from a common ancestor, to share many characteristics.
Classifying animals such as bats and birds together isn’t appropriate because flight evolved separately in them and they don’t share a common ancestor
What are the features of Bacteria?
Histones associated with DNA are absent
Presence of introns is absent - rare
Structure of cell walls made of peptidoglycan
What are the features of Archaea?
Histones associated with DNA - proteins similar to histones bound to DNA
presence of introns are present in some genes
Structure of cell walls not made of peptidoglycan
What are the features of Eukaryota?
Histones associated with DNA are present
Presence of introns is frequent
Structure of cell walls aren’t made of peptidoglycan and aren’t always present
Why do taxonomists sometimes reclassify groups of species?
When new evidence shows that a previous taxon contains species that have evolved from different ancestral species -
the group should be split in two or more different tax’s
OR
when species in different tax’s are found to be closely related- the taxa can be united into one species and can be moved from one genus to another
