SYSTEMATICS AND
PHYLOGENY
Upon first glance, one would probably classify this as a…________, but…
Organizing Life
3
• ____________________ is the branch of biology concerned with identifying, naming, and classifying organisms.
Remember?...Gray Wolf: ________________-Eukarya, _______________-Animalia, _______________-Chordata, ______________-Mammalia, _______________-Carnivora, _______________-Canidae, _______________-Canus, _______________-lupus
Some describe the groups as being “_____________________” because one group exists within another group.
What are taxa?
Species:Pantherapardus
Genus: Panthera
Family: Felidae
Order: Carnivora
Class: Mammalia
Phylum: Chordata
Kingdom: Animalia
ArchaeaDomain: EukaryaBacteria
Think of your “global” address
Taxonomy’s Binomial System
5
First word is the __________________
The second word is the _______________ ___________________: This refers to one species (of potentially many) within its genus
In the mid-eighteenth century, Carolus Linnaeus developed the binomial system of nomenclature to classify organisms
A species is referred to by the full binomial name (Genus + species) Genus name can be used alone to refer to a group of related species
What do the Genus and species actually specify?
IMPORTANT-
7
Lilium canadense Lilium bulbiferum
What is the difference in these fish?
Jellyfish
Crawfish
Silverfish
-Common names vary both locally and globally-Languages vary-Similar to the need for the metric system of measurements
Why are scientific names needed?
8
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
(All): © Sylvia S. Mader
_____________ is an analytical branch of biology that relies on ____________________________________________________ to determine evolutionary history and relationships –also known as _____________
Classification lists the unique characters of each taxon and is intended to reflect phylogeny, but…
Each branching point is a divergence from a ______________ ______________It represents an organism that gives rise to two new groups. It is also called a ________
It is often represented as a ___________________________: A diagram indicating lines of descent
Deciphering evolutionary history
9
Two types of characters used to construct a tree are:
__________________characters:Present in some members of a group, but absent in the common ancestorThese traits “were not seen previously”
_________________ characters:
Present in all members of a group and present in the common ancestor (ancestral traits)
Salamander
Leopard
Turtle
Lamprey
Tuna
Lancelet When inferring evolutionary relationships, it is useful to know in which clade a shared derived character first appeared
Species
Canislupus
Pantherapardus
Taxideataxus
Lutra lutra
Canislatrans
Order Family
Genus
Carn
ivor
a
Felid
ae
Mu
ste
lida
eC
an
idae
Can
isLu
tra
Taxid
ea
Pan
ther
a TAXA
ALL THESE SPECIES ARE
HERE
THIS IS THE
OF ALL SPECIES PICTURED HERE
Species
Canislupus
Pantherapardus
Taxideataxus
Lutra lutra
Canislatrans
Order Family
Genus
Carn
ivor
a
Felid
ae
Mu
ste
lida
eC
an
idae
Can
isLu
tra
Taxid
ea
Pan
ther
a
Weakness of basic phylogenetic tree:
Can’t be sure otter evolved before wolf
Also, sister taxa do not mean one came from another!
Your groups will be called a _____________________________ and they represent a common ancestor and all of its descendant lineages.
Biologists can construct _______________________________ to visually represent the derived characteristics of your clade.
chim
panz
ee
dog
finch
croc
odile
lizar
d
frog
tuna lanc
elet
(out
grou
p)
Species
Trai
ts
mammary glands
gizzard
epidermal scales
amniotic egg
four limbs
vertebrae
hair
ingroup
notochord inembryo
How do we know that the construction of a phylogenetic tree is the best hypothesis of phylogeny?
One way is through ___________________. This is a method that uses shared and derived traits to hypothesize evolutionary history. This will usually consider the simplest solution, __________________________________, in the evolutionary
history of your groups of organisms being studied.
We’ll always need to select an __________________________: a species from an evolutionary heritage that diverged before the lineage we are studying – called the __________________________________
Fig. 19.6
vertebrae
four limbs
feathers
gizzard
hair, mammary glands
long canine teeth
enlarged brain
chimpanzee
tuna
frog
lizard
crocodile
finch
terrier
lancelet (outgroup)
common ancestor
epidermalscales
Amnioticegg
commonancestor
1. A __________ is a _______________
group. It consists of an ancestral
species and ALL of its descendants.
A A A
BBB
C C C
DDD
E E E
FFF
G G G
Group IIIGroup II
Group I
CLADES VS. GROUPS
2. A ________________ group consists of an ancestral species and some, but not all of its descendants
3. A __________________
group includes taxa with different
ancestors.
common ancestor
A
B
C
D
E
F
H
I
G
A
B
C
D
E
F
H
I
G
A
B
C
D
E
F
H
I
G
CLADE OR NOT?
Drosophila
Lancelet
Zebrafish
Frog
Human
Chicken
Mouse
In some trees, the length of a branch can reflect the number of genetic changes that have taken place in a particular DNA sequence in that lineage
Which species has gone
through the most genetic
change?
542 mya
251 mya
Human
15%
Tree 1: Tree 2:
Comparison of possible trees
15% 15%
5%
5%
10%
25%20%
40%
40%
30%0
0
0
Percentage differences between sequences
Human Mushroom
Mushroom
Tulip
Tulip
What is maximum parsimony?
What is maximum likelyhood?
Remember that phylogenetic tree are _____________. As new information is found, these hypotheses can be _____________ or ________________. The best hypotheses for phylogenetic trees fit the most data: morphological, molecular, and fossil. This has been applied to infer features of dinosaurs from birds like me.
_________________• _______________ structures:
Bones in the forelimbs of mammals
_______________• Genes or other DNA
sequences are also homologous if they are descended from a common ancestor
20
Beware the analogous
What kind of data allows us to infer
phylogenic information?
__________________ evolution results in this
______________: Good, but incomplete. It is often difficult to determine the phylogeny of a fossil. Typically, hard parts are mineralized. Soft tissued organisms tend to decay before they are buried.
22
Watch TED-ed: How to fossilize yourself
Analagous scenarios can also exist in molecular data:
Coincidences: Molecularhomoplasies
24
Molecular Data• ___________________ Comparisons– Systematics assumes:
• Two species with similar base-pair sequences are assumed to be closely related
• Two species with differing base-pair sequences are assumed to be only distantly related
• Mitochondrial DNA (mtDNA) often looked at as well because mutation rate is 10x that of DNA
• ______________ Comparisons– Immunological techniques
• Degree of cross reaction used to judge relationship– Amino acid sequencing
• Similar sequence in same protein indicates close relationship (cytochrome C)
• Molecular _____________–We use non-adaptive nucleotide sequence
mutations (neutral)– Assumed constant rate of mutation over time– Fossil record + matching mutation rate =
increased strength in hypothesis
Embryology and Development can reveals homologies
Vertebrate(modern bony fish)
anus
anus
Echinoderm(sea star)
Anus develops fromblastopore in both
Adultsea star
Similar embryos
blastopore
Both organisms end up developing an anus form from the blastopore.
Later the echinoderm becomes radially symmetrical
A Three Domain System
26
Basis for placement into a kingdom:
Historically, scientists (after Aristotle’s time) grouped organisms into two kingdoms, plants and animalsIn the late 1800’s a third kingdom, the protists, was added.In 1969, the five kingdom idea was brought forth.
Tree of Life Showing The
Three Domains
common ancestor
animalsfungi
plants
cyanobacteria
protists protists
heterotrophicbacteria
In the 1970’s the idea of domains based on __________became the prominent idea on how to classify organisms
Three-Domain System
28
Sequencing of rRNA suggests all organisms evolved along three distinct lineages: Domain Bacteria Traits:
Domain Archaea
Domain Eukarya
29
How these domains differ from one another
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