Transcript 36 classification a

Classification
- Linnaean classification
- A taxonomic survey
- Dichotomous key
- Phylogeny
- Current technology
- Clades
Refer to chapter 19 in text.
Also 20-22, 28, 29.
Why the fancy names?
These all are
“fish” in their
own way….
What is a “fish”?
…none are
actually
fish.
Linnaean classification
- Swedish botanist ~ mid 1700s
- Devised the binomial naming system
(Genus species)
- Scala Natura: Platonic idea of nature
arrayed by graded perfection.
- Described a hierarchical classification
system, based on the sexual
structures in plants….
- His students went out on expeditions,
returning the first plants
from much of the world.
- His system was mostly morphological,
(he divided man by social habits, too)
and a bit arbitrary,
but provided the skeleton
for modern classification.
Modern taxonomy
domain
kingdom
phylum
class
order
family
genus
species
dear
King
Philip
came
over
for
great
spaghetti
Eukarya
Animalia
Chordata
Mammalia
Primate
Hominidae
Homo
sapiens
Eukarya
Plantae
Magnoliophyta
Magnoliopsida
Fagales
Fagaceae
Quercus
virginiana
←Plantae
- photosynthetic
- cellulose cell walls
- complex multicellularity
A survey – 6 Kingdoms
Protista ↓(newer: Protoctista)
- single-celled eukaryotes
- (crosses other categories)
Animalia →
- heterotrophic
- complex
multicellularity
- internal
digestion
Fungi →
- non-photosynthetic
- external digestion
- cell walls (chitin)
- multicellular (mostly)
Eubacteria ↓(bacteria)
- no membrane-bound organelles, etc.
- used to be “monera” with archaeans
← Archebacteria (archaeans)
- prokaryotic (like Eubacteria)
- includes extremophiles
Plantae
- photosynthetic
- cell walls
- complex multicellularity
- Phyla
(although in plants
gymnosperm: these are “divisions”,
not “phyla”)
pines
bryophyta:
mosses
You learned details about these in the botany unit.
filicinophyta
ferns
angiospermophyta
flowering plants
Porifera
- specialized cells,
though not true tissues
- sessile, porous
- suspension feeders
- choanocytes create
a water flow.
Animalia
- Phyla
Cnidaria
- true tissues (Eumetazoa)
- sessile or floating
- gastrovascular cavity
(one opening)
surrounded by tentacles
- cnidocytes↓: stinging cells.
Animalia
- Phyla
Platyhelminthes
- bilateral symmetry
- motile, marine
- flat, to enable diffusion
- include some nasty
parasites
- flame cells act as
primitive kidneys
Animalia
- Phyla
http://classconnection.s3.amazonaws.com/337/flashcards/85337/jpg/rotifera1330306972770.jpg
http://en.wikipedia.org/wiki/Rotifer#mediaviewer/File:Bdelloid_Rotifer.jpg
Rotifera
- microscopic, aquatic (mostly)
- ciliated corona around head
-reproduce often via parthenogenesis
(without sexual reproduction)
-alimentary (digestive) canal
http://www.zin.ru/Annrep/2000/img/13-01.gif
Their numerical dominance, often exceeding a million
individuals per square meter and accounting for about 80% of
all individual animals on earth, ... Wikipedia w source
http://www.gardeningknowhow.com/wp-content/uploads/2013/05/beneficial-nematodes.jpg
http://en.wikipedia.org/wiki/Nematode#mediaviewer/File:C_elegans_male.svg
Nematoda
- ‘roundworms’
- tubular digestive tract
with mouth and anus
- cuticle to provide structure
- about half are parasites
Mollusca
- soft body, but hard shells,
unless devolved.
- muscular foot, visceral
mass, and mantle
- marine to terrestrial
- radula: scraping mouth.
(chiton, cephalopod,
gastropod, bivalve)
Animalia
- Phyla
Annelida
- true body cavity
- segmented
Animalia
- Phyla
Arthopoda
- segmented appendages
- exoskeleton, for
protection,
muscle attachment,
water retention
Animalia
- Phyla
2 of 3 species
of animals
are arthropods
Tabulation of key features:
Por
Cnid
true tissues
No
Yes
symmetry
No
radial
body cavity
No
No
GI tract
No
GVC
segmentation No
No
exoskeleton
No
No
Plat
Yes
bilat.
No
GVC
No
No
Mol
Yes
bilat.
Yes
Yes
No
No
Ann
Yes
bilat.
Yes
Yes
Yes
No
Arth
Yes
bilat.
Yes
Yes
Yes
Yes
This leaves us on the brink of Chordata and the vertebrates.
IB holds you to no more details here.
The AP only teachers have pushed more of these chapters.
(We hit the last two text sections under human evolution.)
Phylogeny
…looking at how
structural relatedness
suggests ancestral
relatedness.
The Tree of Life image
that appeared in Darwin’s
On the Origin of Species
by Natural Selection,
1859.
..the only illustration.
Now there is much more evidence, beyond morphology
(homologous, analogous, vestigial, fossil)
to suggest ancestral relatedness,
especially molecular evidence.
Cladistics
is the updated concept of
relatedness mapping,
based heavily on DNA and RNA
Ideally it is monophyletic
(one ancestor),
but may be paraphyletic
(incomplete)
or polyphyletic
(not enough info. to be sure).
Part of the trick
is knowing which traits are derived,
and which ancestral.
http://waynesword.palomar.edu/lmexer3b.htm
A clade consists of
an ancestral species
and all identified descendents;
This cladogram is the
coolest one around:
It is based on organisms
that have had their
entire genomes
sequenced.
Green = Archaea
Purple = Bacteria
Pink = Eukarya
You are the second
to top in the pink,
between the chimp
and the
Norwegian rat.
Zoom in.
www.newworldencyclopedia.org/entry/Cladistics
Please read and follow the cladogram section in 19.2 (p342 ff).
Parsimony
is trying to find
the least complicated
path to explain the
observed relatedness.
This is the hypothetical
case on p 502-503 in
the text.
Walk through it.
The plans require 8,
9, and 10 mutation
events, respectively.
The first plan seems
most likely.
Currently there is so much information coming online,
especially with DNA/RNA evidence,
that biologists are partnering with computer scientists
to develop new presentation paradigms:
“For 25 species, there are more possible trees than
there are stars in the known universe,” Dr. Westneat said. “For 80 species,
there are more trees than there are atoms in the known universe.”2
Conventional methods provide a starting point,
and supercomputers take it from there.
Zimmer, Carl “Crunching the Data for the Tree of Life”
Science Times/ The New York Times, 2/10/2009
http://www.nytimes.com/2009/02/10/science/10tree.html
2
QUESTIONS NOT DONE…
CAN YOU FIGURE OUT YOUR OWN STUDY QUESTIONS?
binomial
Fungi
Mollusca
hierarchical classification
Plantae
radula
taxonomy
Monera
Annelida
domain
Rotifera
Arthopoda
kingdom
Nematoda
exoskeleton
phylum
phylogeny
class
morphology
order
Porifera
cladistics
family
sessile
clade
genus
choanocyte
Archaea
species
Cnidaria
Eubacteria
Protista
cnidocyte
Eukarya
Animalia
Platyhelminthes
parsimony
.
flame cell
.
Plantae
- photosynthetic
- cell walls
- complex multicellularity
- Phyla
(although in plants
gynmosperms these are “divisions”,
not “phyla”)
↓
bryophyta
↓
Vascular No
Roots No
Leaves No
Seeds No
Flowers No
Yes
Yes
Yes
No
No
↑
filicinophyta
This one is
all review…
with formal
names.
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
↑
angiospermophyta