What Is a Species

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What Is a Species?

• A population or group of populations whose
  members have the ability to breed with one
  another in nature and produce fertile offspring.

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Microevolution refers to change in the allele
frequencies within a population. Macroevolution
These changes include -the origin of
different species, -the extinction of species,
and -the evolution of major new features of
living things, such as wings or flowers.
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Speciation

• The origin of new species is known as
• speciation

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Geographic Isolation and Speciation

• Geologic processes constantly change and
  rearrange Earth's features.
• This change can separate different populations of
  one species.
• Ex A mountain range may gradually emerge, slowly
  splitting a population of organisms that cannot
  cross it.
• Separation of populations as a result of
  geographic change or dispersal to geographically
  isolated places is called geographic isolation.

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What Is Taxonomy?

• Classification of living things is called
  "Taxonomy."
• This is when scientists put organisms into groups
  when they have things in common.
• The first groups they use are the Kingdoms.
• There are five kingdoms

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-Animal Kingdom -Plant Kingdom -Fungi
Kingdom -Protist Kingdom -Moneran Kingdom Now
represented by 2 kingdoms
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Each Kingdom is then split into smaller groups,
called Phyla. Each Phylum is split into smaller
groups called Classes, Each Class is split into
Orders, Each Order is split into Families, Each
Family is split into Genera, Each Genus is split
into Species.
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As each group is split into smaller groups, the
organisms are more and more alike.
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A Five-Kingdom Scheme

• It places prokaryotes such as bacteria in the
  kingdom Monera.
• Organisms of the other four kingdoms all consist
  of eukaryotic cells.
• The kingdoms for plants, fungi, and animals
  consist of multicellular eukaryotes.

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The Linnaean System of Classification

• The system of classification most widely used in
  biology dates back to Swedish botanist Carolus
  Linnaeus (17071778).
• The system has two main characteristicsa
  two-part Latin name for each species and a
  hierarchy, or ordering, of species into broader
  and broader groups.

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Scientists from around the world agreed to use
the ancient language of Latin to give organisms,
and their groups, names. Sometimes a group will
have a "Common Name" and a fancy, scientific
Latin name. For example, there is a Family of
frogs called "Ranidae" (Scientific Latin name).
This Family's common English name is "Tree
Frogs."
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Every Species gets a fancy scientific Latin name.
A Bullfrog is also known as "Rana catesbeiana."
A White-tailed Deer is known as "Odocoileus
virginianus. A Monarch butterfly is known as
"Danaus plexipus."
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One thing that makes it easier to understand all
these names is to know that a Species always has
a first and a last name The first name is also
the name of the Genus group that Species is in.
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So the Monarch butterfly is known as Danaus
plexipus and it is in the Danaus genus. Notice
that the first name of a Species is always
capitalized, while the second name is not.
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Species are classified into groups within groups.
A diagram that reflects such hypotheses of
evolutionary relationships has a branching
pattern called a phylogenetic tree -The diagram's
name comes from the word phylogeny, meaning
"evolutionary history.
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Three Domains

• In the last decade, molecular data and cladistics
  have led to a reevaluation of the five-kingdom
  system.
• A three-domain system as one alternative to the
  five-kingdom system.
• A domain is a taxonomic category above the
  kingdom level. T

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This newer scheme recognizes three basic groups
two domains of prokaryotesthe Bacteria and the
Archaeaand one domain of eukaryotes, the
Eukarya. The Bacteria and the Archaea differ in
a number of way. What is most important to
understand here is that classifying Earth's
diverse species of life is a work in progress.