Organizing Lifes Diversity

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Organizing Lifes Diversity
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Classification

• To attempt to make sense out of all the living
  things on the earth scientists have tried to
  organize them into like groups.
• This attempt has been termed CLASSIFICATION

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Taxonomy
The branch of biology that groups and names
organisms. Scientist who do this are called
taxonomists.
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Aristotle

• The Greek philosopher ARISTOTLE (384-322 B.C.)
  developed the first widely accepted biological
  classification system.

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• Considered the Father of Taxonomy.
• Aristotle classified all the organisms he knew
  about in to 2 groups

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• Plants
• Herbs, Shrubs, Trees
• Animals
• Air, Land, Water

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• It was useful but did not group organisms
  according to their evolutionary history.
• Bats, Bees, Birds all classed together.
• Are chickens land or air animals?
• Duck air or water animals?

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Linnaeus

• (1707 1778)
• Carolus Linnaeus developed a classification
  system that replaced Aristotles because it was
  more useful.
• We still use it today.

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• Linnaeus based his system on physical and
  structural similarities of organisms.
• The groupings revealed the relationships of
  organisms.

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• Bats fly like birds but have hair and produce
  milk for their young so they are classified as
  mammals rather than birds.

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Binomial Nomenclature

• Linnaeus used a 2 word naming system to name each
  organism he classified.
• The system is called Binomial Nomenclature

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• The first name identifies the genus of the
  organism. The first letter of the name is ALWAYS
  capitalized.
• The second name identifies the species, usually
  descriptive, it does not contain capitols.

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• The scientific name of a species is always 2
  names.
• Example Humans have the scientific name of Homo
  sapiens.
• Notice the name is italicized. If you are
  writing the name by hand underline it.

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• Homo is the genus.
• Genus means a group of similar organisms.
• Sapiens means wise
• Wise is the descriptive name.

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• All scientific names are Latin names or Latinized
  names.
• Latin is a language that is not longer in use so
  it does not change, making it great for naming
  organisms.

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• The reason we do not use common names like sea
  horse is that they can be misleading.
• A sea horse is a fish not a horse.

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• The house sparrow (America)
• The gorrion (Spain)
• The musch (Holland)
• The hussparf (Sweden)
• Same Bird different name.
• Can get confusing.

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Taxonomy Today

• Expanding on Linnaeuss work taxononists try to
  identify natural relationships of organisms.

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• They use External, internal, geographical
  distribution and chemical makeup to reveal
  possible evolutionary relationships.

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Helps find Relationships

• Birds have hollow bones, some dinosaurs have
  hollow bones too. This suggests that birds and
  dinosaurs might be more closely related than
  reptiles and dinosaurs.

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Helps Poison Control

• The folks at Poison Control have a list of all
  toxic substances.

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• If a kid eats a berry from a plant you can call
  poison control and describe the plant and because
  taxonomist have classified all poisonous plants
  they can let you know if what the kid ate is
  poisonous.

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Taxonomy and the Economy

• If a taxonomist knows a certain pine tree has a
  chemical in its bark that makes a good
  disinfectant related trees might also.

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How Living things are Classified

• Biologists group organisms, then subdivide the
  groups into smaller groups, each smaller group is
  more similar than the previous group.
• Each group is called a taxon.(plural, taxa)

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7 taxa are used today.

• Listed from broadest to narrowest.
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

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See page 459 in text.

• Kingdom is a taxon of similar phyla.
• Phylum is a taxon of similar classes.
• Class is a taxon of similar families.
• Family is a taxon of similar genera.
• Genus is a taxon of similar species.

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• A species is a group of organisms that can mate
  with one another to produce fertile offspring but
  cannot mate successfully with members of another
  group.

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• PSL 17-1 page 457 1-4.
• SA 17.1 page 459 1-5.

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The Six Kingdoms

• How do scientist determine how organisms are
  related and what taxon to place them into?
• Its no easy task.

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• Sometimes an organism is classed one way then
  years later after more research is done
  taxonomists move the organism to another taxon.

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5 ways to determine relations
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Structural similarities

• All cats have retractable claws, fore limbs with
  5 toes and hind limbs with 4 toes.
• Lynx and bobcats have 28 teeth
• Cougars have 30 as well as all other lions.

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Breeding Behavior

• Two species of frog Hyla versicolor and H.
  chrysoscelis.
• Both look similar
• Both live in the same area
• Both eat the same foods

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• Hyla versicolor makes a different sound during
  mating season than Hyla chrysoscelis therefore
  they only attract mates from their own group.

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Geographical distribution

• The wide variety of finches found on the
  Galapagos islands suggests that they may have a
  common ancestor that lived in South America and
  flew to the islands.

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• Once there the finches spread into different
  niches and evolved into many distinct species.

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Chromosome comparisons

• Organisms that have chromosomes that are almost
  identical are probably more related than organism
  with vastly different chromosomes.

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• Brussel sprouts, cauliflower, cabbage, kale and
  broccoli have almost identical chromosomes.
  Suggesting a close relationship.

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Biochemistry

• Closely related species have similar DNA
  sequences and, therefore similar proteins.
• In general the more inherited nucleotide
  sequences that two species share the more closely
  related they are.

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• BIO chem Lab. Amino acid sequences.

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Phylogeny

• The evolutionary history of a species.
• Species that share a common ancestor also share
  an evolutionary history.

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Cladistics

• Assumes that as groups of organisms diverge (grow
  apart) and evolve from a common ancestor they
  retain some unique inherited characteristics.

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Cladogram

• A model of the phylogeny of a species.
• Shows a probable phylogeny of a group of
  organisms from ancestral groups.

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Fanlike Model

• Help you find relationships between modern and
  extinct species.
• May communicate the time organisms became
  extinct, or relative number of species in a group.

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• Mini Lab 17-2 Page 467
• Fill out Six Kingdom content frame. With Teacher.

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Assignment

• SA 17.2 Page 473 1-5.
• CA17 page 477 1-25.
• Vocabulary (ALL) Page 477
• LAB Making a Dichotomous key.