Unit 5.3: Classification of biodiversity

Essential idea

Species are named and classified using an internationally agreed system — binomial system

• combination if genus + species name

• ensure that despite different languages, it can be identified easily

  • latin or classical greek cause unchanging languages

• newly discovered organisms can be classified

• recognized genealogical relationships between organisms

genus

a group of species that share common characteristics but may not be able to interbreed.

• e.g. Macropus or big foot for kangaroos with big hind legs

• capital letter, written first, italics/underlined

• abbreviated after used 1 in text

species

a group of organisms in the same genus that are able to interbreed to produce fertile offspring

• lowercase letter, written second, italics/underlined

subspecies

• Organisms placed in the same species and subspecies are able to interbreed to have fertile offspring

• e.g. Macropus giganteus giganteus and the Macropus giganteus tasmaniensis

• Both eastern gray kangaroo, able to interbreed but not often because geographically isolated

taxonomy

• science branch concerned with classification of living organisms

  • virus is not

• dear king philip came over for good soup

• each higher level includes larger group of organisms — hierarchy of taxa

• more taxa shared, more in common

• only sharing species level taxa can interbreed

• eukaryotes: species → genus → family → order → class → phylum → kingdom

evolution of domain classification

• before DNA sequences: divided into prokaryotes (aka monera) and eukaryotes

• in 1977 using DNA sequencing, Carl Woese:

  • prokaryotes had 2 separate ancestors

  • THUS: 3 lines of living things/three domains namely bacteria (eubacteria), archea, and eukaryota

(Eu)bacteria

• histones: absent

• cell membrane: glycero-esters of lipids, D-form of glycerol

• cell wall: peptidoglycan

• lacking nucleus

• usually disease causing or pathogenic

archea

• histones: present in some species

• cell membrane: glycerol-ether lipids, L-form of glycerol

• cell wall: not made of peptidoglycan

• usually no nucleus and in extreme conditions

eukaryota

• histones: present

• cell membrane: Glycerol ester lipids, D-form of glycerol

• cell wall: Not made of peptidoglycan, sometimes absent

• with nucleus

phylogenetic tree

further kingdoms of 3 domains

(picture)

• domain eukaryota’s kingdoms: protoctista, fungi, plantae, animalia

natural classification

genus & higher taxa consist of species evolving from one common ancestral species

• allows prediction of characteristics shared

• allows classification of newly discovered

• artificial classification: organisms grouped by basic characteristics not showing evolutionary relationships — e.g. with wings

Blue Whale classification

• domain: eukaryota

• kingdom: animalia

• phylum: chordata

• class: mammalia

• order: cetacea

• family: Balaenopteridae

• genus: Balaenoptera

• species: musculus

garlic classification

• domain: eukaryota

• kingdom: plantae

• phylum: Magnoliophyta

• class: Liliopsida

• order: Asparagales

• family: Amaryllidaceae

• genus: Allium

• species: sativum

If organisms A, B and C belong to the same class but to different orders, and if organisms D, E and F belong to the same order but to different families, which of the following pairs of organisms would be expected to be the most similar?

D & F

• Class is a higher taxon of many orders. So if organism D, E and F belong to an order they would share more characteristics than organisms A, B or C that share the same class.

• lower taxa share more characteristics as more groups are added the higher taxa

dichotomous key

series of paired opposing statements which guide the user to the identity (or allows the classification) of an item or organism.

• yes or no questions and direction

• allows narrowing down to genus then species

Kindom Platae’s four phyla:

bryophytes, filicinophytes, coniferophytes and angiospermophytes

Bryophytes

• mosses, liverworts, hornworts

• non-flowering

• 1-10cm tall

• grow closely in clumps or mats in damp & shady

• no vascular tissue → small because can’t transport water throughout, absorbs from surroundings

• produce sporangia — spore capsules above plant on thin stalks

  • when saturated → released & settle in soil → form gametophyte → combine forming zygote → develop into sporangia

• no roots, have rhizoids — thin thread-like outgrowths holding them into soil. not for absorption

• not “true leaves” (no vascular tissue) but has chlorophyll & contain photosynthesis

• help make soil fertile, prevent flooding, pioneer species

vascular tissue

transports water and sugars throughout the plant.

• types: xylem & phloem

rhizoids

small root-like structures that help bryophytes to attach to the soil.

xylem

type of vascular tissue composed of non-living cells that transport water.

phloem

type of vascular tissue that transports sugars throughout the plant.

Filicinophytes

• ferns & horsetails

• shallow roots

• leaves develop in fronds (large divided leaf) / pinnate leaves (divided into leaflets)

• primitive vascular system with xylem & phloem

• small tree-like form but no woody stems

• spores produced in clusters (sori) on underside of fronds

  • burst & release to soil

  • with right conditions → produce gametophyte called prothallus → zygote after fertilization

Coniferophytes

• aka conifers

• gymnosperms — seeds not enclosed in ovary

  • cone-bearing seed trees with vascular tissues

• wood & needle-like leaves with thick waxy cuticle

• monoecious plants — produce male & female reproductive structurs/cones on same plant

• sexual reproduction be releasing pollen from male cones → carried by wind to female cones → stick to ovules where fertilization occurs → form seeds

• essential producers & provide shelters

• cedars, douglas fir, cypress, redwoord, spruce, and yew

angiospermophytes

• flowering

  • classified into monocotyledons or dicotyledons

• vascular tissue

• developed roots, stems & leaves — varying structure

• huge diversity in this phylum — small to massive

• fruit trees & crop plants like wheat, cabbage

• stem may be woody in shrubs & trees

• reproduction: transfer of pollen grains from anthers to stigma of carpels → fertilization of ovules in ovary → ovules form seeds, ovary maybe form fruit

  • fruit help disperse seeds once ripen and fall to the ground or eaten

• producers, often forming mutualistic relationships

animal kingdom phyla:

porifera, cnidaria, platyhelminthes, annelida, mollusca, arthropoda and chordata.

• one way to separate: symmetry

  • bilateral symmetry

  • radial symmetry (symmetrical along multiple planes stemming from center)

  • no symmetry

porifera

• sponges

• full of pores & channels allowing water circulaiton

• no mouth or anus

• filter water for plankton as food without dogestive system

• no nervous or circulatory system but may form skeleton of calcium carbonate or silic

• asymmetrical

• can sexually or asexually produce

  • typically hermaphroditic — produce male & female gametes

  • during spawning: release only egg or sperm at one time → fertilized by mixing with other gamete from another individual (genetic variation) → embryo formed → larva develops → settles on ocean bottom & attaches

  • OR budding: grow, break off, attaches elsewhere

cnidaria

• hydras, jellyfish, corals, sea anemones

• mouth, no anus as digestive system

• feeding: single opening into body cavity where digestion & waste disposal occurs

• simple nervous stem of ganglia (decentralized nerve net)

• no circualtory system

• maintain shape with hydrostatic skeleton — including musclar cavity filled with water

• 2 basic body forms:

  • swimming medusae — gelatinous umbrella-shaped bells with trailing tentacles

  • sensile (attached to rocks/substrates) polyps

  • both radial symmetry, mouths surrounded by tentacles bearing cnidocytes (specialized cells mainly to capture prey)

• reproductive: sexual & asexual

  • asexual: medusa form buds off cnidarian

  • sexual: medusa makes egg & sperm with other cnidarians → fertilization → zygote → blastula → planula → settles as polyp (?)

platyhelminthes

• flatworms

• simple digestive system

  • mouth attached to pharynx and gastrovascular cavity, no anus

• absorb nutrients from environment or directly feeding using pharynx

  • flattened body shape increases SA:V for absorption

• often parasites inside animals or in water

• nervous systems possess brain connected to ganglia, some with eyespots (detects light)

• hydrostatic skeleton to keep shape & move

• bilateral symmetry

• three tissue layers

• no body cavity

• hermaphrodites

  • sexually by injecting sperm sells into another

  • asexually through budding, if cut both can regenerate into new individual

annelida

• segmented worms and leeches

• complete digestive system: mouth, pharynx, esophagus, gizzard, intestine, anus

• gizzard to mash food before entering rest of digestive

• closed circulatory system w/ blood vessels carrying nutrients & oxygen

• nervous systems: brain attached to nerve cords running along length & connect to ganglia

• hydrostatic skeleton — using water surrounded by muscles for shape & movement

• bilateral symmetry, ringed segments (some specialized)

• marine, tidal zones, hydrothermal vents, freshwater, moist terrestrial

• e.g. earthworms

• for soil aeration

• hermaphrodites

  • but w/ diff sexes

  • budding

mollusca

• 85k+ species

• snails, slugs, octopus, oysters, mussels

• mouth & anus with radula (raspy tongue-like)

• 3 common features:

  • mantle with cavity for breathing & excretion

  • radula

  • simple nervous system

• open circulatory system — blood pumped from heart to surrounding tissues

• bilateral symmetry

• some with calcareous shell (mostly calcium carbonate) formed & repaired by mantle

• aquatic & terrestrial

• recyclers of nutrients or indicators

• most have separate sexes & sexual reproduction

• some hermaphrodites

• others asexually through parthenogenesis (female egg develpps into clone without fertilization)

arthropoda

• largest animal phylum — insects, crustaceans, spiders, scorpions, etc

• developed digestive system: mouth, pharynx, esophagus, stomach, colon and anus — feed in many ways since variety

• nervous system: brain attached to nerve cords & ganglia

• open circulatory system

• exoskeleton of chitin (carbohydrate)

• when growing → shed exoskeleton → form new aka moulting

  • vulnerable phase

  • exoskeleton limits size

• bilateral symmetry

• jointed appendages (legs) & segmented bodies

• found in most ecosystems

• part of food chain, decomposers and often form mutualistic relationships

• most terrestrial arthoprods reproduce sexually with internal fertilization

• aquatic athroprods usually reproduce externally

• some asexually — parthenogenesis

chordata

• posses notochord — cartilaginous rod supporting nerve cord

• hollow dorsal nerve cord

• mammals, fish, amphibians, reptiles, birds, Tunicata (sea squirts) and Cephalochordata (the lancelets)

• ingest food, developed digestive system w/ separate mouth & anus

• nervous system main characteristic to categorize in this phylum

• closed circulatory system — heart & blood vessels transporting nutrients & oxygen

• all bilateral symmetry

• most internal skeleton for support & movement

• diverse group in both terrestrial & aquatic

• commonly known as vertebrates

• largest class: Osteichthyes or the bony fish

• reproduce many diff ways

  • sexually, asexually (budding or parthenogenesis)

which animal phyla have bilateral symmetry

• Platyhelmintha

• Annelida

• Mollusca

• arthropoda

• chordata

Porifera none, cnidaria radial

number of gut openings for animal phyla

• porifera: 0

• cnidaria & platyhelmintha: 1

• annelida, mollusca, arthopoda, chordata: 2

segmentation of animal kingdom phyla

• porifera, cnidaria, platyhelmintha: none

• annelida, arthopoda, chordata: yes

• mollusca: non-visible

vertebraes

• subphylum of chordata

• characterised by vertebral column/backbone supporting spinal cord

• subdivided into 7 classes

• five types of vertebrates: fish, amphibians, reptiles, birds and mammals

fish

• 3 classes: jawless fish, cartilaginous fish, and bony ray-finned fish

• fish: animal with scales covering & protecting body

• lack limbs with digits

• live entirely in water

• cold blooded/ectotherma — don’t maintain own body temp

• hearts: 2 chambers

• bony ray-finned: largest of 3, fins supported with spines, gills covered by operculum, gill slit, swim bladder (contain gasses for buoyancy)

• external fertilization

• don’t usually care for offspring after hatching

amphibia

• frogs, newts, salamanders

• thin wet skin

• habitat variety: terrestrial (land-living), arboreal (in trees) or freshwater aquatic

• ectothermic

• heart: 3 chambers

• skin as secondary respiratory surface (breathe through skin)

• rudimentary lung sacs allowing gas exchange

• larval stage: gills for gas exchange since in water

• 4 limbs with digits

• many eggs coated in jelly for protection

• eggs laid → external fertilization → hatch & leave offspring for most

  • poison dart frogs carry offspring

reptilia

• turtles, corcodiles, snakes, lizards

• scales of keratin

• adapted to living on land

• many have 4 limbs with digits

• ectothermic/cold-blooded — regulate temp using external sources (sun baking)

• heart: 3 chambers

• developed lungs (help land-living)

• reproduce through internal fertilization, lay soft shell eggs, don’t usually parent

  • crocodiles do for short time

aves (birds)

• hawks, sparrows, flamingos

• covered with developed scales aka feathers of keratin

• many environments

• endothermic/warm-blooded - regulate own temp

  • help live in more diverse habitats

• heart: 4 chambers

• 4 pentadactyl limbs: 2 legs, 2 wings

  • most wings for flying

• lungs for air ventilation

• need many oxygen cause much energy for flying

• internal fertilization & lay eggs

• care for young: feeding & nesting

mammalia

• platypus, bears, cats, humans

• skin covered in hair (follicles) or fur

• skin also has sweat glands

• habitat on land and in water

• warm-blooded/endothermic

• breathing through lungs

• heart: 4 chambers

• four pentactyl limbs

• middle ear bones & mammary female glands

• mostly give birth to live young (5 lay eggs(

• internal fertilization

• parent offspring for most development