SYSTEMATICS AND PHYLOGENY. Upon first glance, one would probably classify this as a…________, but…

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