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Introduction to General Zoology
General Zoology (Far Eastern University)
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Zoology Lecture (Chapter 1 and 2)
organisms over time.
Zoology
(Gr. zoon,
animals.
logos, to study) is the study of
DNA structure- zoologists use to study the genetic
relationships among animals
Medical Zoology
Deals with the complexity of animal behavior,
heredity, evolution, species variation and comparative
studies of embryos (embryology).
1. Deals with the involvement of transmission of
diseases acquired through vectors.
2. This includes medically significant species
from arthropoda, insecta, and other species of
invertebrates.
3. Toxin excretion, physical contact of other
species that would be detrimental for humans.
4. Other impact of magnified role of other
species to humans.
Vectors- living organism that transmits an
infectious agent from an infected animal to a human
or another animal.
Zoology: Outlined History
▪ Pre-dates early records of animal figures on
illustrations (3000 B.C. or earlier).
▪ Interest early man as for animal serve as
essential source of food and ultimately for
survival.
A derived study. Deeply-rooted on the principles and
laws of chemistry, physics and deals with the
complexity of animal behavior, heredity, evolution,
species variation and comparative studies of embryos
(embryology) and loosely on Geological science.
Zoology is different from:
-
Animal Science: Agriculture-based approach.
Veterinary Medicine: Animal management
and healthcare (industrial, agricultural,
economic).
Zoology is:
•
•
•
•
•
Morphological – the structure of an animal
Phylogenetic
Structural (comparative and homogenous)
Evolutionary- study of fossil
Taxonomical
and
Systematics-based
approach- naming
Organic evolution (Latin word evolutus, unroll)
-is change in the genetic makeup of populations of
▪ Major civilizations adapted their awareness to
animal anatomy through fusion in culture and
religion.
▪ The earliest known factual description of
animal anatomy is a course on dissection of
livestock
(Mesopotamian
valley
and
Babylonian transcripts).
ARISTOTLE: a gross-extensive attempts to classify
animal diversity as documented during the early 300
B.C. (hindered by religious biases).
GALEN: fused the works of the early works and
synthesized his own work on the dissection of apes.
DA VINCI: first to incorporate human dissections to
the collection of dissection of animals.
VESALIUS: contests the works of Galen as the
standard reference of anatomical studies due to the
strong groundings on animal dissections.
WALLACE: Darwin’s intellectual equal. Proposes
the direct relationship of decline in food supply is
relative to the increase in human population growth.
DARWIN: The intellectual giant of Evolution. Made
famous by his works ‘on the origin of species’ and the
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descent of man. He provides the synergistic
development of animal and plant anatomy as well
as their morphology in adapting to certain biological
change.
domain toward species, one is looking at groups
derived from more recent ancestors and a smaller
subset of more closely related animals.
HUXLEY: Made an elaborate study on the evolution
of vertebrate skull. An interest that arises from his
belief of intelligence is centralized on the head region.
BAER: follows a different approach by relating
comparative anatomy as early as during embryo
development.
HAECKEL: Biogenetic law. Focuses on the arising
of specialized organs from a proliferating germ layers.
Germ Layer- adult tissue type
•
Ectoderm, endoderm, mesoderm
With the discoveries of EM (electron microscopy), a
new avenue of discipline opens for Zoology to
provide
an
comprehensive
explanation
on
evolutionary relationships aside from physical
evidence.
Classification of Organisms
Systematics or taxonomy
•
Study of the kinds and diversity of
organisms and of the evolutionary
relationships among them.
Nomenclature
Binomial system of nomenclature.
International Code of Zoological Nomenclature.
• No two animals have the same binomial.
• Every animal has only one correct name.
• The genus of an animal begins with a capital letter,
the species epithet begins with a lowercase letter, and
the entire scientific name is italicized or underlined
because it is derived from Latin or is latinized.
In zoological nomenclature, the specific name (also
specific epithet or species epithet) is the second part
(the second name) within the scientific name of a
species (a binomen). The first part of the name of a
species is the name of the genus or the generic
name.
Phylogeny
Molecular Approaches to Animal Systematics
Gr. phylon, race + geneia, origin.
• A description of the evolutionary history of a group
of organisms and is usually depicted using tree
diagrams.
Relatedness of animals reflected in proteins and DNA.
Phylogenetic tree- diagram that represents
evolutionary relationships among organisms.
Domains and Kingdoms
A Taxonomic Hierarchy
Taxon
Any grouping of animals that shares a particular set
of characteristics.
Taxonomic categories
• Hierarchically arranged (broader to specific).
• Domain, kingdom, phylum, class, order, family,
genus,
species.
• As one moves down through the hierarchy from
• Nuclear and mitochondrial DNA.
• Ribosomal RNA.
Ribosomal RNA studies.
•Distant evolutionary relationships.
• Evolutionary conservation results in very slow rates
of change (evolutionary conservation).
Animals also have extragenic D N A that does not
code for protein.
• Comprises a large portion of animal genomes.
• Can change without harming the animal, not
conserved evolutionarily.
• A number of D N A analysis techniques (e.g.,
microsatellites and amplified fragment length
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polymorphisms [A F L P]) can be used to examine
this DNA and investigate phylogenetic changes.
• A commonly used database is maintained by the
National Center for Biotechnology Information
(NCBI).
Animal Systematics
Goal
Animals into groups that reflect evolutionary
relationships.
Other Patterns of Organization
•Monophyletic group- single ancestral species and
all descendants.
Unicellular (cytoplasmic) level of organizationstand-alone organisms
•Polyphyletic groups – do not include the most
recent common ancestor of all members of the group.
•Paraphyletic groups – include some, but not all,
descendants of a most recent common ancestor.
• Protists (unicellular).
• Sponges (cell aggregate).
Evolutionary systematics.
• Traditional approach.
• Homologies useful in classification.
• Phylogenetic trees depict relationships, time, and
abundance.
Phylogenetic Species Concept- define species based
on common phylogenetic history.
Symmetry
-how parts of an animal are arranged around a point or
axis.
• Asymmetry – the absence of a central point or axis
around which body parts are equally distributed.
• Radial symmetry – the arrangement of body parts
such that any plane passing through the central oralaboral axis divides the animal into mirror images.
• Bilateral symmetry – the arrangement of body parts
such that a single plane, passing between the upper
and lower surfaces and through the longitudinal axis
of an animal, divides the animal into right and left
mirror images.
Diploblastic organization
• Ectoderm (outer cellular layer).
• Endoderm (inner cellular layer).
• Mesoglea (middle, noncellular).
Triploblastic Organization
• Mesoderm
• Third tissue later, composed of cells, found between
ectoderm and endoderm.
• Supportive, contractile, and blood cells.
Body cavities
• Organ development.
• Surface area for diffusion of gases, nutrients, wastes.
• Storage.
• Hydrostatic skeletons.
• Elimination of wastes and reproductive products.
• Facilitate increased body size.
Triploblastic Body Plans
a) Triploblastic acoelomate.
• Mesoderm forms solid mass
b) Triploblastic pseudocoelomate.
• Body cavity not entirely lined by mesoderm.
• Gut is not associated with muscle or connective
tissue.
c) Triploblastic coelomate.
• Body cavity completely surrounded by mesoderm.
• Mesenteries suspend visceral structures in body
cavity.
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