Diversity of Living Things
Objectives:
1. Explain how multi-cellular organisms evolved from single cellular organisms
2. Differentiate between prokaryotic and eukaryotic organisms
3. Explain what taxonomy is.
4. Describe distinguishing characteristics of organisms in each of the six kingdoms
How is All Life on Earth Related?
• All of life is made up of the same
macromolecules.
(What are the 4 macromolecules of life?)
• All of life uses DNA to pass on genetic
information from one generation to the
next.
• All of life is made up of cells.
Figure 1.9 Life’s Calendar
•First cells arose about 3 billion
years ago.
•For 2 billion years, life consisted of
single cells—prokaryotes.
–These cells were in the oceans,
protected from UV radiation.
•Photosynthesis evolved about 2.5
billion years ago.
Figure 1.10 Photosynthetic Organisms Changed Earth’s Atmosphere
The first photosynthetic cells were similar to cyanobacteria.
Consequences of photosynthesis
•O2 accumulated in the atmosphere
•Aerobic (with oxygen) metabolism
began
•Ozone layer formed—allowed
organisms to live on land
Eukaryotic cells evolved from
prokaryotes.
- They contained organelles —
membrane bound compartments
with specialized functions:
• Nucleus
• Chloroplast
Diversity
• So how did the rest of Earth’s organisms get
here?
• Evolution gives rise to diversity
• Over time organisms evolve and change into
more complex organism
• I.e.: Single cell Prokaryotes  multi cell
Eukaryotes
Taxonomy: the science of identifying
and classifying all organisms - both living
and non-living.
Organisms are identified by observing
physical characteristics, behaviour and
geographic location.
• Biological classification: The grouping of organisms
in to groups/categories, based on their physical and
evolutionary characteristics or relationships.
• Carl Linnaeus is credited with devising a
naming system for all living things, called
binomial nomenclature.
– Ex. Castor (meaning Beaver) canadensis (meaning
‘from Canada’): Genus name, species name
– Both underlined or italicized to indicate that they are
Latin
• Based on the idea, that the more features
organisms have in common, they closer their
relationship
Kingdoms
• Linnaeus created a system to further group
organisms in to different levels (Tomorrow)
• The first, most general level was kingdom.
• Originally there were only two Kingdoms
– Plants and Animals
• Now-a-days there are six commonly recognized
Kingdoms
– Eubacteria, Archaebacteria, Protista, Fungi, Plantae and
Animalia
The Six Kingdoms
EUKARYOTIC
PROKARYOTIC
1. Eubacteria (Bacteria)
4. Fungi
2. Archaebacteria (Archaea)
5. Plantae
3. Protista
6. Animalia
Your Task
• In groups of 4 or 5
• Use your textbook to research and find the
required information about your given
Kingdom.
• Once you have completed your research and
filled in your table please fill in your section of
the overhead located up front.
Plenary
• Answer the following questions...
1)What Kingdoms contain Eukaryotic organisms?
2)What Kingdoms contain Prokaryotic organisms?
3)What is the major difference between Prokaryotic
and Eukaryotic organisms?
4)What distinguishes Eubacteria from Archaea?
5)What distinguishes Plants from Fungi?
Thinking...
How did Eukaryotic organisms evolve from
Prokaryotic organisms?
Homework...
• Read page 326-331
• Answer questions 2, 3, 4, 5, 6
• Read through worksheet and answer
questions.
Extra questions…
1. What is taxonomy?
2. Explain how the taxa are arranged in a hierarchy.
3. List the 6 kingdoms and three characteristics of
each.
4. Why do you think that biologists originally placed
fungi within the plant kingdom?
5. List the seven main taxonomic ranks/levels of
classification in order from most inclusive to least
inclusive.
Taxonomic Rank
Objectives:
1. Explain what the term taxonomy means.
2. State the 7 levels of taxonomic classification
Quiz
1. What Kingdoms contain single celled organisms?
2. What Kingdoms contain multi-celled organisms
3. What is the major difference between Prokaryotic
and Eukaryotic organisms?
4. Name the three ‘Domains’ and the Kingdoms in each
Domain.
Bonus:
List, in order the major levels or classification
(Start with Kingdom.).
The Seven Levels of Taxonomic Classification:
least inclusive taxon
SPECIES
GENUS
FAMILY
ORDER
CLASS
PHYLUM
most inclusive taxon
KINGDOM
King Philip Could Only Find Good Shoes
Ex:
Taxon
Kingdom
Phylum
Class
Order
Family
Genus
Species
Human
Animalia
Chordata
Mammalia
Primates
Hominidae
Homo
Homo sapiens
Bald Eagle
Animalia
Chordata
Mammalia
Carnivora
Odobenidae
Odobenus
Odobenus rosmarus
Taxonomic Levels
• Taxon: a category or level used to group or classify
organisms with certain shared characteristics.
• Ie: all species in phylum Chordata have a backbone
• Ie: all members of class Mammilia are warmblooded
• Taxonomic Rank: The levels of classification in a
hierarchy (The most basic rank is that of species, the
next most important is genus, and then family)
An example of Classification:
Human
Kingdom: Animalia
Nine-Banded Armadillo
Animalia
Phylum:
Chordata
Chordata
Class:
Mammalia
Mammalia
Order:
Primata
Xenarthra
Family:
Hominidae
Dasypodidae
Genus:
Homo
Dasypus
Species: sapiens
Name:
novemcinctus
Homo sapiens
Dasypus novemcinctus
Phylogeny and Dichotomous
Keys
Objectives:
1. Explain what phylogeny means.
2. Explain what a dichotomous key is used for and
demonstrate how to use one to identify an unknown
organism.
Quiz
• Answer the following questions...
1)What is taxonomy?
2)What does hierarchical classification mean?
3)What does binomial nomenclature mean?
Evolution
• Today scientists believe that organisms have
changed over time.
Based on Darwin’s theory of evolution, which
states that all living things have descended
from a common ancestor.
• Phylogeny: The history of the evolution of a species
or a group of organisms (evolutionary relationships)
– Speciation
– Genetic diversity
– Species diversity
Phylogeny(More on this later)
• The study of the
evolutionary
relationship between
and among species
• Often shown in the
form of a phylogenetic
tree which is a diagram
that shows the
evolutionary
relationship between
species
Common Ancestor
Very Distant Relatives
• DNA sequencing studies reveals that some genes in
archaebacteria are more closely related to human
genes and other eukaryotes than to those of
eubacteria.
Three-Domain system of classification may better
reflect the history of life.
Domain: the highest taxonomic level (above
kingdoms) – each domain is genetically distinct
Classified into three domains
Domain Eubacteria: Kingdom Eubacteria
Domain Archaea: Kingdom Archaea
Domain Eukaryotes: Kingdom Protista
Kingdom Animalia
Kingdom Plantae
Kingdom Fungi
Based on what you have learned so far,… describe the
most significant differences between the three
domains of life. Why are the Eubacteria and Archaea
difficult to distinguish?
NB: What makes something a species?
- can reproduce and produce fertile offspring
Try: dichotomous key activity (complete for homework)
These spiders look
different but are
the same species:
can reproduce and
have fertile
offspring.
So how do we classify all these
different organisms???
Dichotomous Keys
From antelopes to zebras - each type of
4.1 Life on Earth
animal is a species. There are more than
two million species.
Many more are yet to be discovered and scientists
estimate there could be up to 30 million different types of
living things!
4.1 Different species
Are these different species?
Blackbuck
Pronghorn
We can't tell without seeing if their offspring are fertile
4.2a Finding what you want
Aisle 7
Aisle 8
Aisle 9
milk and dairy
bread and cakes
fruit
Where would you find these:
strawberry yoghurt, raspberries, fruit cake, clementines
Classification key…
• A classification key can be used to help you classify an
organism based on its characteristics.
Dichotomous Key: A two-part key used to identify living
things.
The Key
1. A) Has hair
B) Doesn’t have hair
2. A) Has feathers
B) Doesn’t have
feathers
3) A) Uses gills
B) Uses lungs
4) A) Has smooth skin
B) Has scales
•
•
•
•
Mammal
Go to 2
Bird
Go to 3
•
•
•
•
Fish
Go to 4
Amphibian
Reptile
All Vertebrates
Has Hair
No Hair
Mammal
Feathers
No Feathers
Bird
Uses Gills
Fish
Smooth Skin
Amphibian
Uses Lungs
Scales
Reptile
Your Task
• Turn to page 332/333
• Complete activity
• Answer Analysis questions on page 333
• Evaluation and Synthesis: Create your own
Dichotomous Key to identify the insects shown.
H/W: Complete handout on Using a
Dichotomous Key
Plenary
1) What does phylogeny mean?
2) What are the three domains?
3) What is the classification of organisms into these
domains based on?
4) What is a taxon?
5) What are the 7 ranks of taxonomy?
6) What is the most specific taxon and how are
organisms in this group related?
7) What tool can we use to help identify or classify
organisms?