Diversity of Living Things

Objectives:1. Explain how multi-cellular organisms evolved from single cellular organisms

2. Differentiate between prokaryotic and eukaryotic organisms3. 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

1. Eubacteria (Bacteria)

2. Archaebacteria (Archaea)

3. Protista

4. Fungi

5. Plantae

6. Animalia

PROKARYOTIC

EUKARYOTIC

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 organisms3. 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:

KINGDOM

PHYLUM

CLASS

ORDER

FAMILY

GENUS

SPECIES

most inclusive taxon

least inclusive taxon

King Philip Could Only Find Good Shoes

Ex: Taxon Human Bald EagleKingdom Animalia AnimaliaPhylum Chordata ChordataClass Mammalia MammaliaOrder Primates CarnivoraFamily Hominidae OdobenidaeGenus Homo OdobenusSpecies Homo sapiens 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 warm-

blooded• 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 Nine-Banded Armadillo Kingdom: Animalia Animalia

Phylum: Chordata Chordata

Class: Mammalia Mammalia

Order: Primata Xenarthra

Family: Hominidae Dasypodidae

Genus: Homo Dasypus

Species: sapiens novemcinctus

Name: 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

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?

Domain Eubacteria: Kingdom Eubacteria

Domain Archaea: Kingdom Archaea

Domain Eukaryotes: Kingdom Protista

Kingdom Animalia Kingdom Plantae Kingdom Fungi

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

4.1 Life on EarthFrom antelopes to zebras - each type of animal is a species. There are more than

two million species.

Many more are yet to be discovered and scientistsestimate there could be up to 30 million different types of

living things!

Are these different species?

We can't tell without seeing if their offspring are fertile

4.1 Different species

Blackbuck Pronghorn

4.2a Finding what you want

Aisle 7

milk and dairy

Aisle 8

bread and cakes

Aisle 9

fruit

Where would you find these:

strawberry yoghurt, raspberries, fruit cake, clementines

Sorting things into groups is

classification

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 hairB) Doesn’t have hair

2. A) Has feathersB) Doesn’t have feathers

3) A) Uses gillsB) Uses lungs

4) A) Has smooth skinB) Has scales

• Mammal• Go to 2• Bird• Go to 3

• Fish• Go to 4• Amphibian• Reptile

All Vertebrates

Has Hair No Hair

Feathers

No Feather

sUses Gills

Uses Lungs

Smooth Skin

Scales

Mammal

Bird

Fish

Amphibian 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

Plenary1) 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?