classifying living things. scientists identify, define, and name species of organisms a species is...
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Classifying Living Things
Classifying Living Things
Scientists identify, define, and name species of organisms
A species is a group of organisms that share similar physical features, are genetically similar, and can reproduce with one another to produce a viable offspring.
Why this is important Accurately names organisms Prevents duplicated names Prevents misnomers (E.g. starfish & jellyfish arent’
fish) Universal language (latin) To show evolutionary relationships
Taxonomy
An organism is a living thing that is capable of reproducing, responding to stimuli, and growth.
All organisms in the world can be classified into a grouping system known as Taxonomy.
Taxonomy was initially created by Carl Linnaeus.
Taxonomy
How many species are there?
About 1.4 million have been identified
Nearly 2/3 are insects
Scientists estimate 10-100 million (meaning most aren’t even discovered yet)
Thought Experiment
Imagine you were in charge of naming all living organisms. How might you divide these organisms?
Taxonomy
Was created by examining physical and structural features : The more features in common, the closer
the ancestral relationship Binomial nomenclature is the system
used to name every organism.
E.g. Canis lupus (Grey Wolf)
Binomial Nomenclature
Binomial nomenclature is usually based on a characteristic of the organism E.g. Castor canadensis
(i.e. it is from Canada)
The first word Castor is known as the genus name and the second word canadensis is known as the species name.
*Note that the genus name is always capitalized while the species is not. Also the entire name is italicized.*
Levels of Classification
The Genus and Species names are part of the 8 ranks
The image on the left shows the different levels of classification (i.e. ranks)
If two organisms have the same genus name they are more similar than two organisms with the same phylum name Dearest King Philip Came Over For
Good Spaghetti
Levels of Classification
Taxon
Side Note: Taxon (Plural = Taxa) is a specific rank for organisms
I.e.Rank = KingdomTaxa = Animalia
E.g. Human Classification
Common Name: HumansScientific Name: Homo sapiens
Classification Level Classification NameKingdom AnimaliaPhylum ChordataClass MammaliaOrder PrimatesFamily HominidaeGenus HomoSpecies sapiens
The common name is often used to name a species.
The Kingdom level is the most general while the Species is most specific
Which two organisms are most closely related?
Classification Level Humans Grey Wolf Brown Bear
Kingdom Animalia Animalia Animalia
Phylum Chordata Chordata Chordata
Class Mammalia Mammalia Mammalia
Order Primates Carnivora Carnivora
Family Hominidae Caninae Ursidae
Genus Homo Canis Ursus
Species sapiens lupus arctos
Levels of Classification
There are 3 Domains and 6 KingdomsThe Domain: First level of
Classification This level breaks down living organisms
into the major categories of:1. Bacteria
2. Archaea
3. Eukarya Eukaryotes
Prokaryotes
Do not have a nucleus Do not have well defined organelles E.g. Bacteria and Archaea
Eukaryotes
Have a nucleus Have well defined membrane-bound
organelles
The Kingdom Taxa
The six Kingdom system is commonly used: bacteria, Archaea, Protista, Fungi, Plantae, Animalia
The Other Taxa
Taxa for the Grey Wolf (Canis lupus)
What Makes a Species a Species Lions and tigers can reproduce together
and make a liger or tigon. Why then are they considered different species?
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What Makes a Species a Species Recall: A species is a group of organisms
that look similar and can can interbreed under natural conditions to produce fertile offspring.
In other words, their children can grow and reproduce.
Ligers and tigons cannot reproduce
Video of Liger
https://www.youtube.com/watch?v=1zOWYj59BXI
Homework
Read pages 10-30#2-6 (p.13); Activity 1.1 (p.13); #2-3, 6-7, 9-10 (p.16); #9,11(p.19); #1-2, 4-7, 9 (p.30)