5.3 Classification Flashcards
what is the binomial system of nomenclature?
the formation system why which all living species are classified (taxonomy)
why is the binomial system useful? (4)
- allows for identification and comparison of organisms based on recognised characteristics
- allows all organisms to be named according to a globally recognised scheme
- shows how closely related organisms are, allowing for the prediction of evolutionary linked
- makes it easier to collect, sort and group info about orgniasms
how does the binomial system designate a scientific name?
1st part - Genus
2nd part - species
what 3 domains are living things classified in?
- Eukarya - eukaryotic organisms that contain a membrane-bound nucleus (protist, plants, fungi & animals)
- Archae - prokaryotic cells lack nucleus and consist of the extremophiles
- eubacteria - prokaryotic cells lacking a nucleus and consist of the common pathogenic forms
why did the 2 prokaryotic domains once consist only as a single kingdom?
biochemical differenced between the 2 groups which warranted their reclassification into separate domains
what is taxonomy?
science involved with classifying groups of organisms on the bases of shared characteristics
state the hierarchy of taxa?
Kingdom
Phylum
Class
Order
Family
Genus
Species
what domain do all plants and animal species belong to and why?
eukarya
- they are composed of eukaryotic cells
what are the 3 main schemes of classification used to identify living organisms?
artificial classification
natural classification
phylogenetic classification
what is artificial classification?
the arbitrarily selecting unifying characteristics first and the grouping organisms accordingly
what are 2 advantages of artificial classification?
easy to develop
relatively stable
what is the main disadvantage of artificial classification?
- they do not generally show the evolutionary relationship
eg. if organisms were classified according to the presence of fins then whales would be fish
what is natural classification?
involves grouping organisms based on similarities first then identifying shared characteristics
what do all members of a particular group share according to natural classification? (3)
- all members would have a common ancestor
- species of the same genus would have a common genus ancestor and be more closely related than species of the same order
- so organisms that share a lower taxa share all higher taxa
what are 3 advantages of natural classification?
- it identifies traits based on grouping rather than assigning groups based on traits
- which show evolutionary relationships
- can predict characteristics shared by species within a group
what is a disadvantage of natural classification?
they are highly mutable- tend to change as new information is discovered
- groups may be separated into genera if new evidence suggests they evolved from different ancestral species
what is an example of a species which was originally classified as something and then reclassified into different genera?
figworts (based on DNA comparison)
what is an example of a species that is grouped into a shared taxon when new evidence suggests more recent common ancestry?
- homininae sub-family as created to include gorillas and chimpanzees when it was deduced that they shared more common ancestry wth humans that with other great apes
what is phylogenic classification?
organisms who share a grater level of homology in their DNA or amino acid sequence are expected to be more closely related
what are the 3 key recognition features of Bryophyta and 2 examples?
- no vascularisation (eg. phloem and xylem)
- no ‘true’ leaves, roots or stems (anchored by rhizoid(like root))
- reproduce by releasing spores from sporangia (reproductive stalks)
- examples. mosses and liverworts
what are the 3 key recognition features of Filicinophyta and an example?
- has vascularisation (eg. phloem and xylem)
- have leaves, roots and stems (leaves are pinnate,large fronds divided into leaflets)
- reproduce by releasing spores from clusters called sori
- eg. ferns
what are the 3 key recognition features of Corniferophyta and 2 examples?
- has vascularisation
- has leaves, roots and stems (leaves are needle like&waxy and stems are woody)
- reproduce by non-motile gametes (seeds) which are found in cones
- eg. pine trees and conifers
what are the 3 key recognition features of angiospermaphyta and 2 examples?
- has vascularisation
- has leaves, roots and stems
- reproduce by seeds produced in ovules within flowers (seeds may develop in fruit)
- eg. include all flowering plants and grasses
what is the kingdom of Animalia sub-divided into?
invertebrates
vertebrates
what are examples of invertebrate phyla? (6)
porifera, cnidaria, platyhemintha, annelida, mollusca, arthropoda
what are the 3 key recognition features of platyhelmintha and 2 examples?
- have bilateral symmetry
- have mouth but no anus
- have flattened body shape to increase SA:Vol ratio (may be parasitic)
- eg. tapeworms and planaria
what are the 3 key recognition features of annelida and 2 examples?
- have bilateral symmetry
- have separate mouth and anus
- body composed of ringed segments with specialisation of segments
- eg. earthworms and leeches
what are the 3 key recognition features of mollusca and 2 examples?
- have bilateral symmetry
- have separate mouth and anus
- body composed of a visceral mass, a muscular foot and a mantle (also shell)
- eg. snails, slugs, octopi , squid and bivalves
what are the 3 key recognition features of arthropoda and 5 examples?
- have bilateral symmetry
- have separate mouth and anus
- have jointed body sections/appendages and have a hard exoskeleton (chitin)
- eg. insets, crustaceans, spider, scorpions and centipedes
what phylum do all vertebrates belong to?
chordata
what are the 3 key recognition features of arthropoda and 5 examples?
- have bilateral symmetry
- have separate mouth and anus
- have jointed body sections/appendages and have a hard exoskeleton (chitin)
- eg. insets, crustaceans, spider, scorpions and centipedes
what are the 3 key recognition features of chordata and 5 examples?
- have bilateral symmetry
- have separate anus and mouth
- have notochord and a hollow dorsal nerve tube for at least some period of their life cycle
-eg. mammals, birds, reptiles, amphibians and fish
what key features in an embryonic state that may persist into adulthood do chordata have? (5)
- notochord, hollow dorsal neutral tube, pharyngeal slits, post-anal tail
what will occur in some chordates whcih forms a protective backbone?
develop a spine (vetrebrata)
what are 5 examples of vertebrata?
- fish, amphibian, reptiles, birds, mammals
what are the characteristics of fish? (4)
- covered in scales and made out of bony plated in the skin
- reproduce via external fertilisation
- breathe through gills that are covered with an operculum
- does not maintain a constant internal body temperature(ectothermic)
what are the characteristics of amphibians?(4)
- moist skin permeable to gases and water
- reproduce via external fertilisation
- can breathe through skin but also have lungs
- do not maintain a constant internal body temperature
what are the characteristics of reptiles? (4)
- covered in scales made out of keratin
- reproduce via internal fertilisation and females lay eggs with short shells
- breathe through lungs that have extensive folding
- do not maintain a constant internal body temperature (ectothermic)
what are the characteristics of birds? (4)
- covered in feathers (keratin)
- reproduce via internal fertilisation with hard shells
- breathe through lungs with parabronchial tubes
- maintain a constant internal body temperature (endothermic)
what are the characteristics of mammals? (4)
- skin has follicles which produce hair made out of keratin
- reproduce via internal fertilisation and female feed young with milk from mammary glands
- breathe through lungs with alveoli
- maintain a constant internal body temperature (endothermic)
what is a dichotomous key?
method of identification whereby groups of organisms are divided into 2 categories
what is it preferable to use to identify specimens when identifying dichotomous keys? (3)
immutable features
- size, colouration and behavioural patterns may all vary amount individuals and across lifetimes
- physical structures and biological processes make for better characteristics
