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Diversity of Living Things. Objectives: Explain how multi-cellular organisms evolved from single cellular organisms Differentiate between prokaryotic and eukaryotic organisms Explain what taxonomy is. Describe distinguishing characteristics of organisms in each of the six kingdoms.
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Diversity of Living Things Objectives: Explain how multi-cellular organisms evolved from single cellular organisms Differentiate between prokaryotic and eukaryotic organisms Explain what taxonomy is. 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.
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.
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 • Eubacteria (Bacteria) • Archaebacteria (Archaea) • Protista • Fungi • Plantae • 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... • What Kingdoms contain Eukaryotic organisms? • What Kingdoms contain Prokaryotic organisms? • What is the major difference between Prokaryotic and Eukaryotic organisms? • What distinguishes Eubacteria from Archaea? • 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… • What is taxonomy? • Explain how the taxa are arranged in a hierarchy. • List the 6 kingdoms and three characteristics of each. • Why do you think that biologists originally placed fungi within the plant kingdom? • List the seven main taxonomic ranks/levels of classification in order from most inclusive to least inclusive.
Taxonomic Rank Objectives: Explain what the term taxonomy means. 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? • 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 KINGDOM most inclusive taxon
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: HumanNine-Banded Armadillo Kingdom: Animalia Animalia Phylum: Chordata Chordata Class: Mammalia Mammalia Order: Primata Xenarthra Family: Hominidae Dasypodidae Genus: HomoDasypus Species: sapiensnovemcinctus Name: Homo sapiensDasypus 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... What is taxonomy? What does hierarchical classification mean? 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) Common Ancestor 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
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 animal is a species. There are more than two million species. 4.1 Life on Earth 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 milk and dairy Aisle 8 bread and cakes Aisle 9 fruit Sorting things into groups isclassification 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.
A) Has hair B) Doesn’t have hair 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 The Key
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
Plenary • What does phylogeny mean? • What are the three domains? • What is the classification of organisms into these domains based on? • What is a taxon? • What are the 7 ranks of taxonomy? • What is the most specific taxon and how are organisms in this group related? • What tool can we use to help identify or classify organisms?