Classification of Living Organisms

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Classification of Living Organisms

• Unit 7, Part 1

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Classification Of Organisms

• Classification (grouping) of organisms is done in
  a general to specific method, which results in a
  unique classification for each different type of
  creature.
• From most general to most specific, organisms are
  grouped by kingdom, phylum, class, order, family,
  genus, species.

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A Little Help

• Kings (kingdom)
• Play (phylum)
• Cards (class)
• On (order)
• Fat (family)
• Green (genus)
• Stools (species)

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An Example

• Kingdom Animalia
• Phylum Chordata
• Class Mammalia
• Order Primates
• Family Hominidae
• Genus Homo
• Species sapiens

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Binomial Nomenclature

• Binomial nomenclature is a method of naming an
  organism using the last two words of its
  scientific classification, always Latin words.
• For example, the scientific name of a human is
  Homo sapiens.
• In binomial nomenclature, the name is always
  underlined or italicized and the genus name is
  capitalized while the species name is lower-case.

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• Biologists classify organisms into taxa in a
  process called taxonomy. Taxa are defined by
  their common traits. For example, animals
  belonging to the class Mammalia tend to have body
  hair, produce milk, and have live birth.

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Why Classify?

• Classification is used to bring order to the
  great diversity of species present on Earth.
• It also serves as a basis for identifying newly
  discovered and unfamiliar organisms.
• What is the importance of having the same naming
  system all over the world?
• What is the difference between a panther, a
  jaguar, and a puma? Nothing, except for their
  common names - they all have the same scientific
  name.

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Kingdoms

• Scientists currently use a 5- or 6- kingdom
  system.
• We will use the 5-kingdom system, which includes
  kingdoms Animalia, Plantae, Fungi, Protista, and
  Monera.
• Every organism fits into one of these categories,
  which are the broadest and largest of the taxa.

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Kingdom Monera

• Examples of organisms from this kingdom include
  most bacteria and some unicellular organisms.
  Bacteria like coccus, spirilium, and bacillus
  fall into this category.

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Kingdom Protista

• Organisms from this kindgom include amoeba, some
  types of algae (like red algae), and Euglena.

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Kingdom Fungi

• Organisms from this kingdom include mushrooms,
  yeast, and penicillium.

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Kindgom Plantae

• Organisms in this kingdom include trees (like
  oak and pine), succulent plants (like cactus and
  aloe), flowering plants (like roses and tulips),
  vegetable- and fruit-producing plants (like
  carrots and bananas) and grasses (like wheat and
  bamboo).

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Kingdom Animalia

• Organisms in this kingdom include all types of
  fish, all types of birds, all types of reptiles,
  all types of mammals, and all types of insects.

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Phylum

• The second part of the scientific classification
  narrows down the groups considerably.
• For humans, we fit into phylum Chordata. This
  includes all animals that have, or at one time
  during their life cycle, had, a tail bone.

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Class

• The third part of the classification is called
  Class. This step further narrows down the groups.
  As we progress down the ladder, we get more
  specific and there are more categories than the
  step before.
• Again, for humans, we belong to class to
  Mammalia. This includes all animals that have
  body hair, give birth to their young rather than
  lay eggs, and produce milk.

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Order

• This is the next most specific branch.
• Humans belong to order Primates. This includes
  all animals that have a certain size brain,
  facial structure, and specific organs.

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Family

• This step on the classification ladder breaks
  down the groups a little more.
• We belong to family Hominidae. This group
  includes animals that stand up straight, walking
  on only two legs.

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Genus

• This group is included in the scientific name of
  an organism.
• Humans belong to genus Homo. This is not the
  Greek form of the word meaning same, but the
  Latin form of the word meaning man.

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Species

• This is the most specific part of an organisms
  classification. Each type of organism fits into
  its own special niche.
• For humans, its Sapiens.
• Sapiens means thinking, therefore describing
  humans as thinking men.
• Remember, the last two parts of the
  classification make up the scientific name.

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Test Your Knowledge

• Do you what the common names of these organisms
  are?
• Canis familiaris
• Felis catus
• Ursus arctos
• Latrodectus mactans
• Gorilla gorilla

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The Answers

• Domesticated dog
• House cat
• Brown bear
• Black widow spider
• Gorilla

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Natural and Artificial Selection

• Unit 7, Part 2

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Natural v. Artificial Selection

• Natural selection is often referred to as
  survival of the fittest. This simply means that
  those organisms that are most able to survive
  under given conditions are the ones who will
  reproduce and pass on their genes.
• An example of this would be a smaller or slower
  animal being eaten by a predator while its faster
  and larger family members escape.
• Natural selection happens without human
  influence. It means that an organism with
  unsuitable characteristics will be wiped out
  naturally.

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• Artificial selection is when an organism is
  allowed to live based on its traits. This means
  that humans choose the traits that are most
  favorable to them.
• An example of this is when people breed dogs for
  certain traits.
• Another example is dating and marriage. You pick
  the person with traits that are desirable and
  ultimately, you pick which genes are passed on to
  the next generation.

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The Theory of Natural Selection

• Point 1
• In nature, there is a tendency toward
  overproduction.
• For example, mice, watermelons, ants, fish,
  dandelions, and mosquitoes are well-known
  overproducers.

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• Point 2
• Not all offspring that are produced survive.
• For example, many bacteria treated with
  antibiotics will die. Not all seeds from a
  watermelon will grow and thrive. Not all babies
  will make it through birth, or will die within
  the first year of life due to many factors.

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• Point 3
• Variations exist in any population.
• For example, some spadefoot toads mature faster
  than others. Some dogs have longer noses than
  others. Some kids have freckles or pale skin
  while others dont.

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• Point 4
• Variations are inherited.
• For example, the long fur of a cat will be passed
  on to the cats offspring. The color pattern of
  many insects are the same from generation to
  generation. A cleft chin will show up in many
  generations.

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• Point 5
• Those individuals with variations that are
  suitable for their environment will live longer
  and leave more offspring on average than will
  individuals not having the variations. Thus,
  suitable variations will tend to be passed on and
  unsuitable ones lost.
• For example, penicillin-resistant bacteria will
  survive and reproduce after treatment with this
  antibiotic.

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• Point 6
• The resulting population as a whole will change
  as it becomes better adapted to its environment.
  
• For example, mosquitoes can become resistant to
  certain pesticides or leopards with darker spots
  will become more numerous as they produce
  offspring that look like them.

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Adaptations v. Variations

• In many cases, adaptations and variations can
  lead to changes in the classification process.
• This is why sometimes, an organisms scientific
  name will change.

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• Variation and adaptation do not mean the same
  thing. Variations lead to adaptation.
• This means that a single organism may have a
  variation, but over time, the entire population
  adapts because of that variation.

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• Generally speaking, only variations that aid
  survival will be preserved by natural selection.
• For example, a hunting cat that is born with an
  albino mutation has a variation. If he is unable
  to capture prey because he does not blend in, he
  will likely starve and not pass on that gene.
  Therefore, it does not become an adaptation for
  the future population.

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• However, if a hunting cat is born with a
  variation of long claws, he may be more
  successful at his job and will survive to produce
  more offspring with long claws. That is an
  adaptation.
• The adaptation that comes from a beneficial
  variation will be a general characteristic of the
  entire population.

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Keep In Mind

• Adaptations do not arise all at once. They are
  the result of adaptive changes being passed down
  by many generations.
• Natural selection does not invent new organisms.
  It only modifies what already exists for
  posterity.

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Evolution Macro v. Micro

• Macroevolution is a term used to describe
  evolution occurring on a large scale (like one
  species changing to another).
• Microevolution refers to changes happening on a
  molecular (genetic) level, such as those changes
  that occur during natural or artificial
  selection, including mutations.

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Something to think about

• Why would it be a bad thing if all organisms of a
  certain species in a given region had no
  variations?

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Advantages of Biodiversity

• Aside from aesthetic reasons, diversity is
  important for preservation. All organisms
  interact with and rely on one another in some
  form.
• Without the vast diversity of living organisms we
  have, we could not carry out our normal
  processes, nor could any other organism.