Transcript The Classification of living organisms

The Classification of
living organisms
R. Llopis-Garcia
A2 Biology
Speciation
Natural selection provides a mechanism by
which NEW populations of a species can
arise.......
 But at what point these new populations
can be consider a new species?


Well how would you define “species”?....
The concept of species

The Institute of Biology define species as...
“AN INTERBREEDING GROUP WHICH
PRODUCES VIABLE AND FERTILE
OFFSPRING WHICH SHARE A
COMMON ANCESTRY AND ARE
SIMILAR IN ANATOMY AND
BIOCHEMISTRY”
Can you name the species?
Homo
sapiens
Can you name the species?
Phanther
a leo
Can you name the species?
Felis
domesticus
Can you name the species?
Mules are not a species!
If
two groups cannot
interbreed to produce fertile
and viable offspring, they
must be different species!!!
Reproductive isolation
Is a period where the populations are
prevented from interbreeding
 During that period, genetic differences
between the populations can increase due
to mutation and selection.
 Eventually, the two populations are unable
to interbreed and have become distinc
species!!!

How reproductive isolation
arise?

2 main types:
1.ALLOPATRIC
SPECIATION
2.SYMPATRIC
SPECIATION
ALLOPATRIC SPECIATION

Geopraphycal isolation occurs when the
two populations are PHYSICALLY
separated.
Examples......
Sympatric speciation

1)
2)
3)
Does not involve physical separation (the
2 population may inhabit the same area).
Reproductive isolation can arise in
different ways:
Seasonal isolation
Temporal isolation
Behavioural isolation
Seasonal isolation
Members of the
two population
reproduce at
different times of
the year.
 Can you think of
an example?

Temporal isolation
Members of the
two populations
reproduce at
different times of
the day.
 Can you think of
an example?

Behavioural isolation
Members of the
two populations
have different
courtship patterns.
 Can you think of
an example?

TAXONOMY
Taxonomy
is that
branch of biology
dealing with the
identification and
naming of organisms.
classification

Linneus attempted to
pigeon-hole (or classify)
all known species of his
time (1753). Linnean
hierarchical classification
was based on the
premise that the species
was the smallest unit,
and that each species (or
taxon) nested within a
higher category.
example
Kingdom Animalia
Phylum Chordata
Class Mammalia
Order Primates
Family Hominidae
Genus Homo
species sapiens
The Kingdoms of Life

Living things are classified into 5
kingdoms:
1.
Kingdom Prokaryote
Kingdom Protoctista
Kingdom Fungi
Kingdom Plantae
Kingdom Animalia
2.
3.
4.
5.
Kingdom Prokaryote
 Also
called MONERA
 All organism in this kingdom are
unicellular or filamentous
 The cells lack true nuclei
 Cells have no membrane bound
organelles
 Cell walls are not made of cellulose
Blue green bacteria
Bacteria reproducing
cyanobacteria
Prokaryotae
Cell structure
•Prokaryotic
•unicellular or colonial
Cell wall
•Present (Peptidoglycans)
Nutrition
•Autotrophic
(chemosynthesis/photosynthesis)
Other notes
• Contains only the bacteria
• About 10,000 known species
Prokaryotae Phyla
Cyanobacteria
•Unicellular or colonies
•Possible origin of plants
•Aquatic
•Often produce ‘blooms’population explosions of
millions of cyanobacteria
•Plantlike photosynthesis
Prokaryotae Phyla
Proteobacteria
•Purple bacteria
•often flagellated and found in pond sediments
•Chemoautotrophic
•Free-living/symbiotic species (eg Rizobium)
•Play key role in chemical cycles of ecosystems
•Chemoheterotrophic
•Include intestinal bacteria (eg Salmonella)
•Mostly rod-shaped
•Often pathogenic
Prokaryotae Phyla
Spirochetes
•Helical chemoheterotrophs
•Free-living species and
pathogens
Borrelia burgdoferi
(casues Lyme disease)
•Corkscrew-like
movements due to intenal
flagella like filaments
Prokaryotae Phyla
Gram-positive bacteria
•Mostly chemoheterotrophs
•Include mycolpasmas (often
pathogenic) smallest of all
known cells (0.10-0.25m)
Clostridium botulinium
•Some photosynthetic
•Includes soil bacteria that
resemble fungi
•Includes actinomycetes,
important sources of antibiotics
Microplasma pneumoniae
Streptomyces sp.
Prokaryotae Phyla
Chlamydias
•Intracellur parasites of animals •Lack peptidoglycan in
cell walls
•Obtain ATP from host cells
Chalmydia trachomatis
Most common cause of blindness in the world
and also of the sexually transmitted disease
Kingdom Protoctis
 Very
diverse group
 In this group if the can not fit
in any other group (dump
bin)
 All eukaryotes
 Some heterotroph, some light
autotroph
amoeba
Ephidium sp
Paramecium, a typical ciliate
Algae
Dinoflagellate, Peridinium sp
Red algae
Brown algae
Cell structure
Protoctista
•Eukaryotic
•Unicellular, colonial and multicellular forms
Cell wall
•Sometimes present (Polysaccharides)
Nutrition
•Autotrophic
•Hetorotrophic
Other notes
• Classed here if they can’t be placed in any other kingdom
therefore are the most diverse group (30 phyla)
• About 100,000 known species
Protoctista (Continued)
Among the protoctists are:
•Unicellular
•Multicellular: cells arranged in filaments
•Multicellular: cells arranged in ball like colonies
•Mulicellular: cells arranged into tissues
They can behave like:
•Animals
•Plants
Or can be:
•Slime moulds
•Protozoa
•Algae
Protoctista (Continued)
Pond weed, Spyrogyra spfilamentous protoctist
Euglena sp, freshwater species,plantlike and animal-like
Bladder wrack, Fucus vesiculosusphotosynthetic multicellular protoctist
Fruiting structure (sporangium) of a
slime mould
Kingdom Fungi
Common features:
 A non cellulose cell wall
 Non photosynthetic
 Eukaryotes (filaments or hyphae
often multinucleated)
 Secrete enzymes to digest organic
matter

SEM image of a bread mold fruiting
structure, Rhizopus stolonifer
Amanita phalloides is the most
poisionous of all mushrooms
lichens
Cell structure
Fungi
•Eukaryotic
•Mostly multicellular but some unicellular (eg yeast)
Cell wall
•Present (Chitin)
Nutrition
•Heterotrophic
Other notes
• Most made of mass of thread like filaments called hyphae.
• Lack cilia and flagella at all life cycle stages
• Reproduce by forming spores, produced by mitosis
• About 100,000 known species
Fungi Phyla
Chytridiomycota
•Absorptive mode of nutrition
•Some are unicellular but most
form hyphae (multicellular)
•Mainly aquatic, some parasites,
some saprobes
•Most primitive form of fungi,
possibly evolving from protists
with flagella
•Only fungi with flagella
Chytridium sp.
Branched hyphae
Fungi Phyla
Zygomycota
Bread mold, Rizopus stolonifer
•Zygote fungi
•Mostly terrestrial, living in soil or
decaying matter
•Includes the mycorrhizae,
mutualistic associations with
plant roots
•Some can aim their spores and
shoot them up to 2m to aid
dispersion
hyphae
Sporangial
fruiting structure
Fungi Phyla
Adcomycota
•Over 60,000 species
•Sac fungi- produce spores in
saclike asci
Brewers yeast
•Produce huge numbers of asexual
spores for reproduction
•Marine, terrestrial and freshwater
•Unicellular yeast to elaborate cup
fungi and morels
Cookeina sulcipes
•Include many plant pathogens
•Half live sybiotically with algae
as lichens
Morchella esculenta
Fungi Phyla
Basidiomycota
•25,000 species
•Includes mushrooms, puffballs
and shelf fungi
•Important decomposers of wood
and plant material
Sulphur shelf fungus
•Includes some destructive plant
parasites
•Can reproduce sexually by
producing elaborate fruiting
bodies- basidiocarps, the sources
of sexual spores
Common mushroom
Gills lined with basidia
Kingdom Plantae
 All
plants:
 Are multicellular
 Have eukaryote cells with a
CELLULOSE cell wall
 Are photosynthetic
Flowering plants, the angiosperms, were
the last of the seed plant groups to evolve,
appearing over 140 million years ago during
the later part of the of the Age of Dinosaurs
(the beginning of the Cretaceous, 140
million years ago). All flowering plants
produce flowers.
Cell structure
Plantae
•Eukaryotic
•Multicellular
Cell wall
•Present (Cellulose)
Nutrition
•Autotrophic (photosynthesis using cholorplasts)
Other notes
• About 350,000 known species
• Develop from multicellular embryos
• Complex lifecycle that involves 2 different types of adult, one
haploid and one diploid.
Plantae Phyla
Mosses
•Bryophytes
•Gametophyte is the common
generation
•Mass of many plants growing
together
•Absorbs/retains rain water
Sphagnum squarrosum
•Grip with rhizoids
•Peat mosses take up 3% of Earths
terrestrial surface!
Peat moss
Plantae Phyla
Liverworts
•Bryophytes
•Gametophyte is the common
generation
•Most species found in tropical
forests
•Bodies often divided into
lobes
•Can reproduce asexually
from bundles of cells called
gemmae
Marchantia polymorpha
gemmaa cups
Plantae Phyla
Ferns
•Vascular seedless plants
•Sporophyte (diploid generation)
is the larger and more complex
generation
Lady fern: Athyrium filix-femina
•More common in relatively damp
habitats
•Leaves called fronds, divided
into leaflets
•12,000 species
fronds
Plantae Phyla
Conifers
•Vascular seed plants
Pine cone
•Bear their seeds ‘naked’ on
surface of sporophytes
•Reproductive structure is the
cone
•Contains pines, firs, spruces,
larches and cedars among others
•Most are large trees
•Nearly all evergreen
•Dominate vast forested regions of
northern hemisphere
Redwood forest
Plantae Phyla
Flowering Plants
•Angiosperms
Orchid
•Most diverse & widespread
group of plants (250,000 species)
•Monocots (eg palms, grasses,
grain crops, orchids)
•Dicots (eg roses, peas, maples,
buttercups, sunflowers, and oaks)
•Flower is reproductive structure
•Fruits (mature ovaries) with
seeds (mature ovules) encased in
ripen ovary. Eg pea pod/peas
Sunflower
Kingdom Animalia
All animals:
 Are multicellular
 Have eukaryotic cells with NO cell wall
 Develop from a blastocyst (a hollow ball of
cells)
Most animals:
-ingest their food into a digestive system
-are motile

Hydra
The Class Gastropoda
The Class Cephalopoda
Phylum Annelida: Segmented
Worms
Phylum Arthropoda: Segmented
Bodies with Segmented
Appendages
Jumping Spider, Plaexippus paykulli
The Class Insecta
Fruit Fly, Drosophila melanogaster
Phylum Chordata
Class Chondrichthyes:
Cartilaginous Fish
Class Osteichthyes, the Bony
Fish
Class Amphibia: Animals Move
Ashore
Class Reptilia: Reproducton
Without Water
Class Aves: Birds of a Feather
Class Mammalia: Got Milk?
Class Mammalia contains around 5000
species placed in 26 orders (usually). The
three unifying mammalian characteristics
are:
 hair
 the presence of three middle ear bones
 the production of milk by mammary
glands

Mammalian Adaptations
Mammals developed several adaptations that help
explain their success.
Teeth are specialized for cutting, shearing or
grinding;
thick enamel helps prevent teeth from wearing out.
Mammals are capable of rapid locomotion.
Brain sizes are larger per pound of body weight
than most other animals'.
Mammals have more efficient control over their
body temperatures than do birds.
Hair provides insulation.
Mammary glands provide milk to nourish the young.
Subclass Metatheria: Marsupials
Subclass Eutheria
And…….
Cell structure
Animalia
•Eukaryotic
•Multicellular
Cell wall
•Absent
Nutrition
• Heterotrophic
• Involves a digestive cavity
Other notes
• Develop from embryos that at some stage formed a blastula
• Have nervous and hormonal control systems
• About 35 phyla
Animalia Phyla
Proifera (Sponges)
•Closest to the protists
Elephant ear
sponge
•Sessile with porous bodies
through which water is pumped
and food is filtered.
•9000 species, all aquatic, only
100 freshwater species
•No specialised organs or tissues
•Mostly hermaphrodites
•Capable of regeneration
Purple tube sponge
Animalia Phyla
Cnidaria (Jellyfish, Corals, Anemones)
•10,000 species
•Radially symmetrical
Jellyfish:
medusa form
•Gastrovascular cavity (central
digestive compartment)
•2 body types: polyp (anchored)
medusa (free floating)
•Carnivores, using tentacles to capture
prey
•Muscles and nerves occur in their
simplest forms
Tube coral:
poly form
Animalia Phyla
Platyhelminthes (Flatworms)
•Aceolomates (have no body cavity)
Pseudoceros ferrugineus:
free living
•Bilateral symmetry, dorsoventrally
flattened
•20,000 species (including tapeworms
and flukes)
•Free-living and parasitic species
ranging from microscopic to 20
metres in length
•Primitive brains
•Opening to body cavity serves as
mouth and anus!
Tapeworm: parasitic
Animalia Phyla
Nematoda (Roundworms)
Phasmarhabditis sp. Lives in soil
•Cylindrical body, tapered tail and
blunt head
•90,000 species known
•1mm to 1 metre in size
•Complete digestive tract (separate
mouth and anus)
•No circulatory system
•Parasitic and free-living types
•Usually sexual reproduction
Typical nematode
Animalia Phyla
Mollusca (Clams, snails, octopuses, squid, slugs)
Edible snail
•150,000 diverse species
•Muscular foot for movement
•Visceral mass (containing most of the
internal organs)
•Mantle (fold of tissue that drapes over
the visceral mass and often secretes a
shell)
Foot
Visceral mass
•Many feed using radula to scrape up
food
•Many have separate sexes but many
are hermaphrodites
Oval squid, sepioteuthis lessoniana
Animalia Phyla
Annelida (segmented worms)
•15,000 species including earthworms
and leeches
•1mm to 3 metres in length
•Segements called metameres each
contain a cluster of nerve cells and
excretory organs
Earthworm, Lumbricus terrestris
•Ventral nerve, blood vessels and
digestive tract pass though the
segments
•Earthworms are hermaphrodites but
can cross-fertilise
Tube fanworm
Animalia Phyla
Arthropoda (crustaceans, insects, spiders)
•1 million species, most successful
phyla
•Regional segmentation (head, thorax,
abdomen)
•Jointed appendages
Hawaiian lobster, Enoplometopus
occidentalis
•Exoskeleton (layers of protein and
chitin)
•Bilaterally symmetrical
•Open circulatory systems (with
hemolymph)
•Variety of gas exchange organs
Trilobite, Modocia centralis
a fossil Arthropod
Animalia Phyla
Echinodermata (sea stars, sea urchins)
Pink sea star
•6,000 species
•Radially symmetrical when fully
grown
•Almost all marine species
Sea urchins
•Sessile or slow moving
•Endoskeleton of hard calcareous
plates covered by thin skin
•Water vascular system (network of
hydraulic canals) branching into tube
feet that function in locomotion,
feeding and gas exchange
Leopard sea cucumber
Animalia Phyla
Chordata (lancelets, tunicates, vertebrates)
Sea squirt (tunicate)
•4 distinguishing features (often only
in embryonic development)
• Hollow dorsal nerve cord
• Notocord (flexible rod between
digestive tube & nerve cord)
Lancelet
• Pharyngeal Slits (gill slits)
• Post anal tail
•Vertebrates include fish,
amphibians, reptiles birds and
mammals
•Includes Homo sapiens
Human foetus
Complete the classification….
Kingdom:
 Phylum:
 Class:
 Order:
 Family:
 Genus:
 Specie:
Felis lynx








K: Animalia
P: Chordata
C: Mammalian
O: Carnivora
F: Felidae
G: Felis
S: Felis lynx
Find in the internet the
classification of the following
animals
The end