Transcript Exploring Living Things

Lab Challenge:
How will we determine the taxonomy
of the microbes we find?
Traditional Classification
Chapter 26, 27 and 28
Understanding the 3 Domain;
Kingdom System with a focus on
Bacteria and Archaea
Chapter References
 HEY!!! Let’s make this abundantly CLEAR---
when you see references to chapters,
READ THEM! They are your HOMEWORK!
 Chapter 26 and 27 (selections)
 Reading Tips - Don’t read every word. Skim
over all headings! Then, look for the parts of
reading that match your notes
 Take NOTES by making a powerpoint!
Unity: Characteristics of
Living Things
 Made of Cells
 Respond to Stimuli
 Obtains materials
 Maintain
and use energy
 Grow and
Develop
 Reproduce
Homeostasis
 Based on a
Genetic Code
 Evolve
Hierarchical
Organization
Binominal
Nomenclature:
2 word naming system
based on Genus
species
Did king philip come
over for good soup?
Shows
relationships…what
are they based on?
Diversity: How can these
characteristics show the diversity of
living things?
Focus on Bacteria
All living things are MADE of CELLS, but size,
shape, or arrangement may vary
Focus on Bacteria
Does the naming system make sense?
Gram staining
• Make up of cell structures is also a distinguishing
characteristic
• Cells with peptidoglycan in their walls stain
darker
(a) Gram-positive bacteria: peptidoglycan traps crystal violet.
Gram-positive
bacteria
(b) Gram-negative bacteria: crystal violet is easily rinsed
away, revealing red dye.
Gram-negative
bacteria
Carbohydrate portion
of lipopolysaccharide
Cell
wall
Peptidoglycan
layer
Cell
wall
Plasma
membrane
10 m
Outer
membrane
Peptidoglycan
layer
Plasma membrane
Figure 27.3
Response to environment
 Notetaking: what should you write down
about this visual slide?
Obtaining energy
 Nutrition is one
important
characteristic
that allows us to
compare.
 Into which group
do you think our
cheese microbe
will fit?
New characteristics force
changes in classification
 What was the 2
kingdom model?
 The 5 kingdom
model?
 How do the Domains
and the current 6
kingdom model
relate?
 What’s the current
debate?
Role of technology
Using Molecular Data
 In 1977, Carl Woese used
molecular data from
ribosomal RNA to classify
microbes. Previously,
microbes classification
was limited due to their
lack of identifiable
characteristics.
http://dericbownds.net/uploaded_images/microbes2.gif
 Woese’s work led to the
current three “domain”
system of classification:
Archaea, Bacteria,
Eukarya
http://aboundlessethic.com/wp-content/uploads/2007/10/treeoflife.gif
3 Domains
The 3 domains
vary in how
organisms
display the
characteristics
of living things
See Table 27.2

What’s the difference
between eubacteria and
archaebacteria?
Archaebacteria are more
closely related to eukaryotes.
 Cell walls
 Eubacteria: Material-peptidoglycan
 Archaebacteria: Other
materials
 Archaebacteria are usually
extremophiles
 Halophiles
 Thermophiles
How closely related are the
kingdoms?
Eukaryotes
 Key
Characteristic=
Nutrition
 If we use this as
the basis, are fungi
more closely
related to animals
or plants?
 Fungi:
Heterotrophic
decomposers
 Animals:
Heterotrophic
consumers
 Plants:
Photoautotrophs
Problems with using
characteristics
 Maybe cell wall
shows a better
relationship.
 Does this agree
with your previous
hypothesis?
 Plants: Cellulose
 Fungi: Chitin
(although some
have no cell wall)
 Animals: No cell
wall
Chitin vs. Cellulose
 Note: Animals do not use chitin for a
cell wall but can manufacture chitin for
an exoskeleton…what do they need to
make chitin?
What do the genes tell us?
 General consensus:
Fungi & Animals share
most recent Common
Ancestor.
 Jury is still out though…
Active Reading Activity
 Read and take
notes to answer a
question…what
information/vocab
are important to
that question!
 Section 28.1
Is the protista
kingdom
MONOPHYLETIC?
(all share a common
ancestor)
Kingdom Protista=Problem
Protists
 Are all
protists
closely
related to
eachother?
Activity
 Take the
information from
your reading &
notes and fill out
the kingdom
graphic organizer
that you did in 9th
grade!
 Discussion:
Is this
memorization?
Direction…
 Later we will look
at classification of
the animal
kingdom.
 As we go through
the year, we will
see the
importance of
understanding
classification of
plants, fungi, and
protists.