Transcript Taxonomy

TAXONOMY
Domains and Kingdoms
What are we learning today?
Benchmarks
 SC.912.L.15.6 – Discuss
distinguishing
characteristics of the
domains and kingdoms of
living organisms. (AA)
 15.4—Describe how and
why organisms are
hierarchically classified
and based on evolutionary
relationships.
Learning Objectives
 I will classify organisms
based on the
distinguishing
characteristics of the
domains and kingdoms
of living organisms.
 I will describe how and
why organisms are
hierarchically classified
and based on
evolutionary
relationships.
WHY DO WE ORGANIZE THINGS?
Classify, or organize, the following terms into groups.
Montana
Miami
Canada
Illinois
Hialeah
Haiti
France
Alaska
Alabama
Hawaii
Little Haiti
Asia
Dade
North America
Mexico United States
Palm Beach
Aventura
Africa
El Portal
Monroe
South America
Florida
Broward
Europe
Martin
WHAT IS THE ESSENTIAL QUESTION?
Try to imagine the problems faced by the biologists of several hundred
years ago as they tried to find patterns in the vast diversity of life.
What are some similarities that you might use to try to put the
following organisms into related groups?
Why do biologists classify?
 Biologists have
identified and
named about
2 million
species so far.
 Scientists estimate
that there are about
8 million additional
species yet to be
discovered.
 Taxonomy is the discipline where scientists classify and
assign each organism a universally accepted name.
How Has Classification Changed Since the 1700’s?
1753 – Linnaeus
introduced his
two-kingdom
system which
included Plantae
and Animalia
1700
1938 – American
Biologist Herbert
Copeland argued
that all prokaryotes
deserved their own
kingdom, Monera
1800
1866 – German biologist
Ernst Haeckel proposes
moving all single-celled
organisms to the Kingdom
Protista
1900
1977 – Research
by Carl Woese led
scientists to split
Monera into two
kingdoms:
Eubacteria and
Archaeabacteria
2000
1959 – American ecologist
Robert Whittaker proposed
that fungi should be placed in
their own kingdom because
of how they feed
We Classify Organisms into Kingdoms
Based on 4 Criteria…
• 1. Is its body made up of 1 cell or many
cells?
• 2. Does its cell(s) have a nucleus or not?
• 3. Does the organism make its own food or
is it a consumer?
• 4. Does it have any other special
characteristics that set it apart from other
organisms?
WHAT ARE THE DIFFERENT TYPES OF
CELLS?
• The cell is the basic structural and functional unit of all
known living organisms.
• It is the smallest unit of life that is classified as a living
thing.
• Organisms can be classified as unicellular (its whole
body is a single cell; includes bacteria, protista, some
fungi)
• Or multicellular (many cells make up its body; includes
some fungi, all plants and all animals)
WHAT ARE PROKARYOTES AND EUKARYOTES?

Cells fall into two broad
categories, depending on
whether they contain a
nucleus

Eukaryotes are cells that
contain a nucleus and
membrane-bound organelles


Eu- means true
-karyote means nucleus
Prokaryotes are cells
that DO NOT contain a nucleus or membrane-bound
organelles. THESE WERE THE FIRST LIVING THINGS!

Pro- means before
-karyote means nucleus
HOW ARE PROKARYOTES AND EUKARYOTES
SIMILAR?

Both eukaryotes and
prokaryotes have

a cell membrane

genetic material
(DNA)

ribosomes

cytoplasm
HOW DO PROKARYOTES AND
EUKARYOTES DIFFER?
Prokaryotes
Eukaryotes

Nucleus is absent

Nucleus is present

No membrane-bound
organelles

Many membrane-bound
organelles

Most 1-10 um in size

Many 2-1000 um in size

Evolved 3.5 billion years
ago FIRST LIVING
THINGS

Evolved 1.5 billion years
ago MORE RECENT

All other kingdoms
(animal, plant, fungi, and
protist)

Only bacteria and
archaeabacteria
WHAT IS THE THREE-DOMAIN SYSTEM?
• The domain is the largest
category of classification.
• The three domains are:
Eukarya, Bacteria, and
Archaea.
SUMMARY OF CHARACTERISTICS OF THE SIX KINGDOMS
WHICH VERY IMPORTANT CHARACTERISTIC IS MISSING??
WHAT MAKES UP THE KINGDOM
ARCHAEABACTERIA?
• Corresponds to the domain
Archae.
• Unicellular and prokaryotic
organisms live in some of the
most extreme environments
on our planet.
• Many of these bacteria can
survive only in the absence
of oxygen.
WHAT IS THE KINGDOM EUBACTERIA?
• Corresponds to the domain bacteria.
• Members are unicellular and
prokaryotic.
• Cells have a thick, rigid cell wall
containing peptidoglycan.
• Ecologically diverse, ranging from
free-living soil organisms to deadly
parasites.
• Some need O2, other are killed by it.
WHAT MAKES UP THE DOMAIN EUKARYA?
• Consists of all organisms that have a nucleus.
• Composed of protists, fungi, plants, and animals.
Animals-Like Protists
• Some protozoans have
properties of both plants
and animals.
• Live in water, soil, and in
the bodies of animals.
• Most are harmless, but a
few cause disease.
• Have different methods of
moving:
• Flagellum
• Cilia
• Pseudopods
Plant-Like Protists
• Algae are plant-like because
they do photosynthesis.
• Simpler than plants
• Live in lakes, streams,
rivers, ponds, oceans.
• Algae is autotrophic.
• Food source for many
aquatic organisms– form the
base of the food web
WHAT IS IN THE KINGDOM FUNGI?
WHAT ARE THE CHARACTERISTICS OF
THE KINGDOM FUNGI?
• Eukaryotic
• Heterotrophs
• Cell wall with chitin
• Most feed on dead or decaying
organic matter.
• Fungi secrete digestive
enzymes into their food source,
before absorbing the smaller
food molecules into their bodies.
• Most multicellular, some are
unicellular
WHAT IS THE KINGDOM FUNGI?
• Fungi release special
chemicals on dead plant
and animal matter.
• These chemicals break
down, or decompose,
the dead matter.
• This decomposed matter
is later absorbed by the
fungus or the soil.
WHAT ORGANISMS ARE IN THE KINGDOM
PLANTAE?
What organisms are in the Kingdom
Plantae?
• Trees, grasses, ferns, and
mosses.
• Nonmotile, meaning they
can not move from place to
place.
• They are photosynthetic
autotrophs.
• Multicellular
• Cell walls contain cellulose
WHAT MAKES UP THE KINGDOM ANIMALIA?
WHAT ARE THE CHARACTERISTICS OF
THE KINGDOM ANIMALIA?
• Eukaryote
• Multicellular
• Heterotroph
• No cell wall or chloroplasts
What is the three-domain system?
 All organisms evolved from cells that formed over 3 b.y.a.
 Domain Archaea corresponds to the Kingdom
Archaebacteria
 Domain Bacteria corresponds to the Kingdom Eubacteria
 Domain Eukaria includes the Kingdoms Protista, Fungi,
Plantae, and Animalia
Topic 9: Day 2
 SC.912.L.15.5 – Explain the
reasons for changes in how
organisms are classified.
TAXONOMY
AND CLADISTICS
What are we learning today?
Benchmarks
 SC.912.L.15.4 –
Describe how and why
organisms
are hierarchically
classified and based on
evolutionary
relationships.
 SC.912.L.15.5 – Explain
the reasons for changes
in how organisms are
classified.
Learning Objectives
 Explain the difference between
evolutionary classification and
Linnaean classification.
 Analyze a cladogram to
recognize the concepts of
common ancestry and degrees of
evolutionary relationship.
 Describe how DNA and RNA can
help scientists determine
evolutionary relationships
How will you classify the following
organisms?
How are Linnaean and evolutionary
classification different?
 Linnaeus grouped species into
larger taxa, mainly according to
visible similarities and
differences.
 This approach can cause
problems.
 The goal of evolutionary biology
is to group species into larger
categories that reflect lines of
evolutionary descent, rather
than overall similarities and differences.
 Inspired by Darwin’s ideas about descent with
modification
What is cladistic analysis?
 Modern evolutionary classification uses a method called
cladistic analysis.
 Cladistic analysis
identifies and
considers only those
characteristics of
organisms that are
evolutionary
innovations.
 Traits that appear in recent parts of a lineage but not in its
older members are called derived characters.
 Derived characters can be used to construct a cladogram, a
diagram that shows the evolutionary relationships among a
group of organisms.
How can I read a cladogram?
 A speciation event, in which an ancestral lineage branches
into two new lineages, is the basis for each branch point, or
node. Each node represents the last point at which the new
lineages shared a common ancestor.
 The bottom, or “root,” of the tree represents the common
ancestor shared by all organisms on the cladogram.
How can I read a cladogram?
 A cladogram’s branching
patterns indicate
degrees of relatedness
among organisms.
 Because lineages 3 and
4 share a common
ancestor more recently
with each other than
they do with lineage 2, you know that lineages 3 and 4 are
more closely related to each other than they are with
lineage 2.
 Likewise, lineages 2, 3, and 4 are more closely related, in
terms on ancestry, with each other than any of them is to
lineage 1.
Collaborative Activity: Construct a Cladogram
Purpose: In this activity, you will fill in a cladogram for
methods of transportation.
Problem Statement: How can methods of transportation be
organized using a cladogram?
Collaborative Activity: Construct a Cladogram
Purpose: In this activity, you will construct a cladogram to
classify a group of animals. (Pag. 520)
Hair
Legs
Backbone
Collaborative Activity: Interpreting a
Cladogram
This cladogram shows
the evolutionary
history of cats.
1. What are the
derived characters
in this cladogram?
2. Is hair a derived
character of
mammals?
3. Is amniotic egg a derived character of mammals?
4. For which clade is retractable claws a derived character?
5. Why is four limbs a derived character for clade tetrapoda,
but a primitive character for all the other clades?
How are DNA sequences used in
classification?
 Similarities in DNA can be
used to help determine
classification and
evolutionary relationships.
 The more similar the DNA
sequences of two species,
the more recently they
share a common ancestor, and the more closely they are
related in evolutionary terms.
 The more two species have diverged from one another, or
changed in comparison to one another during evolution, the
less similar their DNA will be.
How are DNA sequences used in
classification?
1. According to the figure,
which species is most
closely related to red
pandas?
2. Biologists had previously
classified giant pandas
together with raccoons
and red pandas. What
did DNA analysis reveal
about giant pandas and bears?
DNA evidence suggests that that the giant panda shares a
common ancestor with bears than with either red pandas
or raccoons.
What is the essential question?
The Linnaean classification
system is based solely on
physical characteristics. How
has the classification of
organisms changed since
Linnaeus developed his
taxonomy system?
In your answer:
 explain how cladistics differs
from Linnaean taxonomy. (5 pts.)
 explain how new technologies in molecular biology and
DNA research have affected the Linnaean classification
system. (5 pts.)