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An Evolutionary and Ecological
Main Concepts

  The field of Zoology is the study of
    It is a very broad field with many
Main Concepts

  An understanding of evolutionary
   processes is very important in zoology
   because evolution explains the family
   relationships among animals and how the
   great variety of animals arose.
Main Concepts

  An understanding of ecological principles
   is very important in zoology because it
   helps zoologists to understand the
   interrelationships among individual
   animals and groups of animals.
   Understanding ecological principles also
   helps zoologists to understand how
   human interference threatens animal
   populations and the human environment.
Zoology basics

  Plainly stated, Zoology is the study of
  One of the broadest fields in science due
   to the immense variety of animals.
    Ex. 20,000 species of described bony fish
    Ex. 300,000 species of described beetles

  Most zoologists specialize in one or more
  They may study particular functional,
   structural, or ecological aspects of one or
   more animal groups or they may choose
   to specialize in a particular group of
Table 1.1
                                               Examples of Specializations in Zoology
  Subdiscipline                                                              Description
    Anatomy         Study of the structure of entire organisms and their parts

    Cytology        Study of the structure and function of cells

    Ecology         Study of the interaction of organisms with their environment

  Embryology        Study of the development of an animal from the fertilized egg to birth of hatching

    Genetics        Study of the mechanisms of transmission of traits from parents to offspring

    Histology       Study of tissues

Molecular biology   Study of subcellular details of structure and function

  Parisitology      Study of animals that live in or on other organisms at the expense of their host

   Physiology       Study of the function of organisms and their parts

  Systematics       Study of the classification of, and the evolutionary interrelationship among, animal groups
Table 1.2

 Examples of specializations in Zoology by taxonomic categories

 Entomology                                   Study of insects

 Herpetology                                  Study of amphibians and reptiles

 Ichthyology                                  Study of fishes

 Mammalogy                                    Study of mammals

 Ornithology                                  Study of birds

 Protozoology                                 Study of protozoans
Zoology: An Evolutionary
  Organic evolution is change in the genetic
   makeup of populations of organisms over time.
  It is the source of animal diversity, and it
   explains family relationships within family
  Charles Darwin published convincing evidence
   of evolution in 1859 and proposed a
   mechanism that could explain evolutionary
   change. Since that time, many scientists have
   become convinced that evolution occurs.
Structure and Function
  Understanding how the diversity of
   animal structure and function arose is
   one of the many challenges faced by
  For example, lets take a look at the
   cichlid scale eaters of Africa.
  As you may have guessed, they eat the
   scales of other cichlids.

  They attack their prey from behind and bite a
   mouthful of scales off of their prey.
  The scales are then stacked and crushed by a
   second set of teeth and sent to the stomach
   and intestine for protein digestion.
  A scientist discovered that within a certain
   species, Perissodus microlepis, there are two
  One group has a mouth that is asymmetrically
   curved to the left, while the other group has a
   mouth that is asymmetrically curved to the
  This allows the left mouthed fish to attack on
   the the right, and the right mouth fish to attack
   on the left.
  Both of these fish are found to live in the same
  Why is it helpful for them to live near each
Animal Classification and
Evolutionary Relationships
  Evolution not only explains why animals
   appear and function as they do, but it also
   explains family relationships within the animal
  Groups of individuals are more closely related
   if they share similar DNA. (You are more
   closely related to your brothers/sisters than
   your cousins, thus you should resemble your
   brother/sister more so than your cousin.)
  Genetic studies suggest that the oldest population of
   African cichlids are found in Lakes Tanganyika and
  These fish eventually invaded African rivers and Lakes
   Victoria, Malawi and many other small lakes.
  The invasion of Lake Victoria by Lake Kivu’s cichlids is
   thought to have happened around 100,000 years ago.
  This passage was closed around 40,000 years ago.
  There are approximately 500 species of cichlid that are
   found in Lake Victoria, yet not in Lake Kivu.
  This represents one the most rapid origin of species
   that is known to man.
Karl von Linne
aka Linnaeus
  1707-1778
  Primarily remembered for collecting and
   classifying plants.
  Designed the system that we use today
   to classify animals.
Binomial nomenclature
  Uses a two-part name to describe an
  The first part indicates the genus, while the
   second part indicates the species.
  The genus name must be capitalized, while the
   species name is lowercase.
  The genus and species name are always listed
  They must be written in italics or underlined.

   Domain
   Kingdom
   Phylum
   Class
   Order
   Family
   Genus
   Species
Zoology: An Ecological
  In the 1950’s the giant Nile perch was
   introduced into Lake Victoria in an
   attempt to increase the lake’s fishery.
  This predator reduced the cichlid
   population from 99% to less that 1% of
   the total fish population and has led to
   the extinction of many cichlid species.
Lake Victoria
  The cichlids are algae eaters.
  With nothing to eat the algae, it grew,
  The decaying algae caused a depletion of
   oxygen in the water.
  Also, nile perch has to be dried, which has lead
   to fisherman cutting down many of the trees in
   the area to smoke the fish. This deforestation
   has lead to further degradation of the water in
   Lake Victoria due to runoff.
Lake Victoria

  The reduction of water quality in turn led
   to the death of more cichlid and caused
   major problems to others.
  The loss of Lake Victorian cichlids may
   be the largest extinction event of
   vertebrate species in modern human
Some Good News

 Many cichlid species are recovering.
 Nile perch population is down from 90%
  in the early 80’s to somewhere around
  50% now.
World Resources and
Endangered Animals
  There is a concern for the ecology of the
   entire world, not just Africa’s lakes.
  The problem lies mostly within
   developing nations striving to keep up
   with industrialized nations.
  The focus of our ecological concerns are:
    Global overpopulation
    Exploitation of the world’s resources

  Global overpopulation is at the root of virtually
   all environmental problems.
  92% of growth is in less developed countries.
  That’s 5 billion of the world’s 6.3 billion people.
  The rate of growth shows no signs of slowing
   with some population estimates reaching 10.4
   billion by the year 2100.
World Resources

  Human overpopulation is stressing world
  Food production is maxed out.
  Maximum oil consumption is depleting our
   fossil fuel supplies and increasing the
   greenhouse effect and global warming.
  Deforestation of the world’s forests continues
   due to a high demand for wood.
Wildlife Alert

  Tropical rainforests have been reduced
   to 44% of their former size.
  We are losing species that we do not
   even know exist, and we are missing out
   on resources that could lead to new
   medicines, foods and textiles.
Endangered vs.
  An endangered species is in imminent
   danger of extinction throughout its range.
  A threatened species is likely to become
   endangered in the near future.
  A 2003 U.S. Fish & Wildlife Service
   Survey lists 1,263 species in the U.S.
   and 1,824 foreign species as being either
   endangered or threatened.
Preservation of
endangered species
  A global system of national parks to protect
   large tracts of land and wildlife corridors that
   allow movement between natural areas.
  Protected landscapes and multiple-use areas
   that allow controlled private activity but also
   retain value as a wildlife habitat.
  Zoos and botanical gardens to save species
   whose extinction is imminent.

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