Introduce Zoology

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• Welcome
• Introduce Zoology
• Syllabus
• Lecture
• Evolution, and Zoology
• Theory of Evolution by Natural Selection
• Origin of Species
• Properties of Life Origins of Life
• Prokaryotic and Eukaryotic
• Levels of organization
• Cell division and inheritance

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• Biology is the study of Life
• Single cell to multicellular organisms

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• Cell is the basic unit of life
• Unique plant cell and animal cell

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• Zoology- zoon, animal logos, to study
• is the study of Animals
• Is one of the broadest fields in all of science
• Variety of animals
• Complexity of and the processes

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• Specializations in Zoology
• Anatomy
• Ecology
• Genetics
• Parasitology
• Physiology
• Entomology-
• Ichthyology-

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• Ichthyologist-
• work to understand structure, function, ecology
  and evolution of fishes
• Studies have uncovered an amazing diversity of
  fishes
• Cichlid (sick-lid)- freshwater fishes
• 1000 species in Africa
• 300 in South America
• 3 in India
• 1 in North America

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Animal classification and Evolutionary
Relationship

• Evolution not only explanation why animals appear
  and function as they do
• It explains family relationships
• i.e cichlid species
• Groups share more of their DNA
• Thus resemble each other
• Genetic studies suggest
• Oldest African cichlid found in Lakes Tanganyika
  and Kivu
• These fish invades rivers, lakes Malawi, Victoria
  and others
• Most rapid known origin of species of any animal
  groups

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• Members of this group
• Variety of color patterns
• Habitats
• Body forms
• Feeding habits

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Binomial nomenclature

• Karl von Linne also known as Carolus Linnaeus
• (1707-1778)
• Named and classified plants into hierarchy of
  relatedness
• Binomial Nomenclature- systematic way of naming
  organisms-
• Two part name describes each kind of organism
• First part- indicates the genus
• Second part indicates the species to which the
  organism belongs.
• i.e. Perissodus microlepis
• Field of taxonomy Gk. taxis, arrange, put in
  order nomos, law.

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Figure 1.4
Hierarchy of Relatedness
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• Eretmodus
• Nip algae with chisel-like teeth

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• Tanganicodus
• Insect pickers

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• Perissodus
• Scale eaters

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• Brood their young
• Dogtooth cichlid

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The Fontosa
Body form
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An Evolutionary Perspective

• Share a common evolutionary past and evolutionary
  forces that influence their history
• Resulted in 4 to 100 million species of animals
• Understand evolutionary process to understand
• What it is
• How it originated

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• Evolutionary concepts hold the key to
  understanding
• why animals look and act
• Habitat
• Characteristics

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Ecological Perspective

• Ecology- (Gr. okois, house logos, to study)
• Study of the relationships between organisms and
  their environment
• Human dependence on animals (food, medicine,
  clothing)
• Humans upset the delicate ecological balances
  that has evolved

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In the 1950s in an attempt to increase the
lakes fishery

• Nile perch introduced into Lake Victoria
• Reduced cichlid population from 99 to lt1
• Most cichlid feed on algae, the algae grew
• Algae died and decayed
• Lake depleted of oxygen
• Introduced nonnative plant (water hyacinth)
• Water hyacinth has overgrown and resulted in
  further habitat loss
• Darwins nitemare
• Fishhead video Nile perch

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• The Darwinian revolution challenged traditional
  views of a young Earth inhabited by unchanging
  species
• In order to understand why Darwins ideas were
  revolutionary
• We need to examine his views in the context of
  other Western ideas about Earth and its life

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• The historical context of Darwins life and ideas

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Lamarcks Theory of Evolution

• Lamarck hypothesized that species evolve
• Through use and disuse and the inheritance of
  acquired traits
• Environmental changes generate new needs
• These needs determine the use or disuse of some
  organs
• Such organs develop or are diminished
• The acquired characters are hereditary
• But the mechanisms he proposed are unsupported by
  evidence

functions create organs and heredity determines
the change in offspring
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Fossils, Cuvier, and Catastrophism

• The study of fossils
• Helped to lay the groundwork for Darwins ideas
• Fossils are remains or traces of organisms from
  the past
• Usually found in sedimentary rock, which appears
  in layers or strata

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• Darwins interest in the geographic distribution
  of species
• Was kindled by the Beagles stop at the Galápagos
  Islands near the equator west of South America

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Darwins Focus on Adaptation

• As Darwin reassessed all that he had observed
  during the voyage of the Beagle
• He began to perceive adaptation to the
  environment and the origin of new species as
  closely related processes

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• From studies made years after Darwins voyage
• Biologists have concluded that this is indeed
  what happened to the Galápagos finches

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• In 1844, Darwin wrote a long essay on the origin
  of species and natural selection
• But he was reluctant to introduce his theory
  publicly, anticipating the uproar it would cause
• In June 1858 Darwin received a manuscript from
  Alfred Russell Wallace
• Who had developed a theory of natural selection
  similar to Darwins
• Darwin quickly finished The Origin of Species
• And published it the next year

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Evolutionary Processes

• Organic evolution- change in the genetic makeup
  of populations over time.
• Source of animal diversity
• Explains family relationships within animal
  groups
• Charles Darwin
• Published The Origin of Species- evidence of
  evolution in 1859
• Proposed a mechanism
• Understanding diversity of animal structure and
  function arose is one of the many challenges
• i.e cichlid scale eaters of Africa

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Resistance to the Idea of Evolution

• The Origin of Species
• Focused biologists attention on the great
  diversity of organisms
• Shook the deepest roots of Western culture
• Challenged a worldview that had been prevalent
  for centuries

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• Darwin made two major points in his book
• He presented evidence that the many species of
  organisms presently inhabiting the Earth are
  descendants of ancestral species
• He proposed a mechanism for the evolutionary
  process, natural selection

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Descent with Modification

• The phrase descent with modification
• Summarized Darwins perception of the unity of
  life
• States that all organisms are related through
  descent from an ancestor that lived in the remote
  past

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• In the Darwinian view, the history of life is
  like a tree
• With multiple branchings from a common trunk to
  the tips of the youngest twigs that represent the
  diversity of living organisms

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phylogenetic tree (Gk. phylon, stock, tribe
genus, birth, origin)
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Natural Selection and Adaptation

• Evolutionary biologist Ernst Mayr
• Has dissected the logic of Darwins theory into
  three inferences based on five observations

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• Observation 1 For any species, population sizes
  would increase exponentially
• If all individuals that are born reproduced
  successfully

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• Observation 2 Nonetheless, populations tend to
  be stable in size
• Except for seasonal fluctuations
• Observation 3 Resources are limited
• Inference 1 Production of more individuals than
  the environment can support
• Leads to a struggle for existence among
  individuals of a population, with only a fraction
  of their offspring surviving

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• Observation 4 Members of a population vary
  extensively in their characteristics
• No two individuals are exactly alike

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• Observation 5 Much of this variation is
  heritable
• Inference 2 Survival depends in part on
  inherited traits
• Individuals whose inherited traits give them a
  high probability of surviving and reproducing are
  likely to leave more offspring than other
  individuals

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• Inference 3 This unequal ability of individuals
  to survive and reproduce
• Will lead to a gradual change in a population,
  with favorable characteristics accumulating over
  generations

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Artificial Selection

• In the process of artificial selection
• Humans have modified other species over many
  generations by selecting and breeding individuals
  that possess desired traits

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Summary of Natural Selection

• Natural selection is differential success in
  reproduction
• That results from the interaction between
  individuals that vary in heritable traits and
  their environment

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• Natural selection can produce an increase over
  time
• In the adaptation of organisms to their
  environment

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• If an environment changes over time
• Natural selection may result in adaptation to
  these new conditions

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• Darwins theory explains a wide range of
  observations
• Darwins theory of evolution
• Continues to be tested by how effectively it can
  account for additional observations and
  experimental outcomes

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Homology, Biogeography, and the Fossil Record

• Evolutionary theory
• Provides a cohesive explanation for many kinds of
  observations
• We will explore these key questions
• What is homology?
• How do we identify anatomical homologies?
• What do genes do? How do genes control other
  genes to build complex structures like eyes?
• How can genes be homologous?

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Anatomical Homologies

• Homologous structures between organisms
• Are anatomical resemblances that represent
  variations on a structural theme that was present
  in a common ancestor

Homology Is similarity resulting from common
ancestry
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• Comparative embryology
• Reveals additional anatomical homologies not
  visible in adult organisms

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• Vestigial organs
• Are some of the most intriguing homologous
  structures
• Are remnants of structures that served important
  functions in the organisms ancestors

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Molecular Homologies

• Biologists also observe homologies among
  organisms at the molecular level
• Such as genes that are shared among organisms
  inherited from a common ancestor

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Homologies and the Tree of Life

• The Darwinian concept of an evolutionary tree of
  life
• Can explain the homologies that researchers have
  observed

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• Anatomical resemblances among species
• Are generally reflected in their molecules, their
  genes, and their gene products

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Biogeography

• Darwins observations of the geographic
  distribution of species, biogeography
• Formed an important part of his theory of
  evolution

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• Some similar mammals that have adapted to similar
  environments
• Have evolved independently from different
  ancestors

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The Fossil Record

• The succession of forms observed in the fossil
  record
• Is consistent with other inferences about the
  major branches of descent in the tree of life

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• The Darwinian view of life
• Predicts that evolutionary transitions should
  leave signs in the fossil record
• Paleontologists
• Have discovered fossils of many such transitional
  forms

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• What Is Theoretical about the Darwinian View of
  Life?
• In science, a theory
• Accounts for many observations and data and
  attempts to explain and integrate a great variety
  of phenomena