5.3 - Classification of Biodiversity

binomial system

system to classify living species, assessed and updated every 4 years at international congress

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allows for identification and comparison (can show relationship, easy to sort, group)

genus

group/class of species

hierarchy of Taxa

eukaryote classification:

species → genus → families → orders → classes → Phylum → kingdom

plant example

acris → ranunculus → ranunculacae → ranunculales → eudicotidae → angiospermophyta → plantae

animal example

sapiens → homo → hominidae → primate → mammalia → chordata → animalia

kingdoms

plants, animals, fungi, proctortista

3 domains of all organisms

eubacteria (prokaryotic, no nucleus) , archaea (prokaryotic cells, no nucleus), eukaryota (membrane bound nucleus protists, plants, fungi, animals)

bacteria

* no histones associated with DNA
* rare/absent introns
* cell walls made of peptidoglycan
* cell membrane made of glycerol-ester lipids, unbranched side chains, d-form of glycerol

histones in bacteria

absent histones associated with DNA

bacteria introns

rare or absent introns

cell walls made of peptidoglycan

bacteria cell walls

cell walls not made of peptidoglycan

archaea and eukaryota

d-form of glycerol

bacteria and eukaryote

i-form of glycerol

archaea (form of glycerol)

cell membrane with glycerol-ester lipids and unbranched side chains

bacteria, archaea and eukaryote - all domains

archaea

* proteins similar to histones bound to DNA
* introns present in some
* cell walls not made of peptidoglycan
* cell membrane - glycerol ester lipids, unbranched side chain, I-form of glycerol

eukaryote

* histones associated with DNA
* usually has introns
* cell walls not made of peptidoglycan and not always present
* cell membrane - glycerol ester lipids, unbranched side chain, d-form of glycerol

natural classification

grouping based on the way species evolved, so grouping with shared common ancestors

advantage of natural classification

easier identification

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can show evolutionary relationships and predict characteristics

disadvantage of natural classification

changes as new info is discovered, common ancestor is not always clear. sometimes group should be split up into different taxa, or unite taxa.

artificial classification

selecting unifying characteristics first, then grouping organisms accordingly

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eg. grouping bats, insects, birds together because they can all fly

advantages of artificial classification

easy to develop, and stable (unlikely to change)

disadvantages of artificial classification

doesn’t show evolutionary relationships, so are not commonly used

dichotomous keys

pairs of descriptions or a branched flowchart that identifies a species

Vertebrate phyla

bony ray-finned fish, amphibians, reptiles, birds, mammals

fish

* scales, bony plates in the skin
* gills covered by an operculum, one gill slit
* no limbs
* fins supported by rays
* egg and sperm released for external fertilisation
* remain in water throughout their life
* swim bladder containing gas for buoyancy
* don’t maintain constant body temp

amphibians

* soft moist skin permeable to water and gases
* simple lungs with small folds and moist skin for gas exchange
* tetrapods with pentadactyl limbs
* four legs when adult
* egg and sperm released, external fertilisation
* larval stage that lives in water and adult that lives on land
* eggs coated in protective jelly
* does not maintain constant body temperature

reptiles

* impermeable skin covered in scales of keratin
* lungs with extensive folding to increase the surface area
* tetrapods with pentadactyl limbs
* four legs (mostly)
* sperm passed to female for internal fertilisation
* female lays eggs with soft shells
* teeth all of one type, no living parts
* does not maintain constant body temp

birds

* skin with feathers made of keratin
* lungs with para-bronchial tubes, ventilated using air sacs
* tetrapods with pentadactyl limbs
* two legs and two wings
* sperm passed into female for internal fertilisation
* female lays eggs with hard shells
* beak but no teeth
* maintains constant body temp

mammals

* skin has follicles with hair made of keratin
* lungs with alveoli, ventilated using ribs and diaphragm
* four legs in most or two legs and two arms
* sperm passed to female for internal fertilisation
* most give birth to young and feed with milk
* teeth of different types with living core
* maintains constant body temp

egg and sperm released for external fertilisation

fish and amphibians

sperm passed into the female for internal fertilisation

reptiles, birds, and mammals

tetrapods with pentadactyl limbs

amphibians, reptiles, birds, mammals

do not maintain constant body temperature

fish, reptiles, amphibians

maintains a constant body temp

birds, mammals

animal phyla

porifera, cnidaria, platyhelminthes, mollusca, annelida, arthropoda

porifera examples

fan sponges, cup sponges

cnidaria examples

hydras, jellyfish, corals, sea anemones

platyhelminthes examples

flatworms, flukes, tapeworms

mollusca examples

bivalves, gastropods, snails, chitons, squid, octopus

annelida examples

marine bristleworms, oligochaetes, leeches

arthropoda examples

insects, arachnids, crustaceans, myriapods

porifera

* no mouth or anus
* no symmetry
* internal spicules for skeleton (needles)
* pores over the surface for draining water for filter feeding

cnidaria

* mouth only,
* radial symmetry,
* soft skeleton, but hard corals secrete CaCo3


* tentacles arranged in rings around the mouth, with stinging cells

platyhelminthes

* mouth only
* bilateral symmetry
* soft, no skeleton
* flat and thin bodies. no blood system or gas exchange system

mollusca

mouth and anus

bilateral symmetry

most have CaCo3 shell

fold in the body wall called the mantle secretes the shell. radula used for feeding

annelida

* mouth and anus
* bilateral symmetry
* skeleton is an internal cavity with fluid under pressure
* bodies made up of ring-shaped segments

anthropoda

mouth and anus

bilateral symmetry

exernal skeleton made of plates of chitin

segmented bodies and legs

animal phyla with mouth and anus

mollusca, annelida, arthropoda

animal phyla with mouth only

cnidaria and platyhelminthes

animal phyla with bilateral symmetry

platyhelminthes, mollusca, annelida, arthropoda

plant phyla

bryophyta, filicinophyta, coniferophyta, angiospermophyta

bryophyta

* mosses, liverworts, hornworts
* rhizoids but no true roots (vegetative organs)
* no xylem or phloem (vascular tissue)
* no cambium, no true trees and shrubs
* pollen not produced
* no ovaries or ovules
* no seeds
* no fruits

filicinophyta

* ferns
* roots, stems, leaves usually present (vegetative organs)
* xylem and phloem both present (vascular tissue)
* no cambium, trees, shrubs
* no pollen, ovaries, seeds, fruits

coniferophyta

* conifers
* roots, stems, leaves (vegetative organs)
* xylem and phloem (vascular tissue)
* cambium present - allows thickening of stems, roots, development into trees and shrubs
* pollen produced by male cones
* ovules produced in female cones
* seeds produced and dispersed

angiospermophyta

flowering plants

* roots, stems, leaves
* xylem and phloem
* cambium present
* pollen produced by anthers in flowers
* ovules enclosed inside ovaries in flowers
* seeds produced and dispersed
* fruits produced

plant phyla with vegetative organs and vascular tissue

filicinophyta, coniferophyta, angiospermophyta

plant phyla with no cambium

bryophyta, filicinophyta

plant phyla that doesn’t produce seeds

bryophyta, filicinophyta

vegetative organs

parts of the plant concerned with growth rather than reproduction

vasular tissue

tissues with tubular structures used for transport within the plant

cambium

cells between xylem and phloem that can produce more of these tissues