Download Intro to Zoology

Zoology as a part of Biology
 Zoology
is the study of animals
 Characteristics of animals:
1.
2.
3.
4.
A branch of the evolutionary tree of life
Part of a large limb of eukaryotes
(organisms with nuclei in cells)
Unique in nutrition – heterotrophs (eat other
organisms and need to capture food)
Not capable of photosynthesis. Lack cell
walls.
Zoology
A
broad field with many subdisciplines
 Examples:




Cytology – structure and function of cells
Histology – tissues
Parasitology – animals that live in or on
other organisms, at the expense of the host.
Ichthyology – study of fishes
See Tables 1.1 and 1.2 in text
Zoology: An Evolutionary
Perspective
 An
understanding of evolutionary
processes allows us to explain the
family relationships among animals
and how the great variety of
animals arose.
 Evolutionary process have resulted
in an estimated 4 to 100 million
species of animals living today.
Zoology: An Evolutionary
Perspective
 Organic
evolution: change in
population of organisms over time

Source of animal diversity and explains family
relationships within animal groups
 Groups
of individuals are more closely
related if they share more of their DNA
with each other than with individuals in
other groups.
Zoology: An Ecological
Perspective
 Ecology:
study of the relationships
between organisms and their
environment.
 Two main problems of concern:


1. Global overpopulation
(Most growth in less developed countries)
2. Exploitation of world resources
(Oil production, fossil fuels, deforestation, etc)
Zoology: An Ecological
Perspective
 Solutions:



Better understanding of basic ecological
principles
Must work to prevent spread of disease,
famine, etc
Better resource management
Animal Systematics
 Goal

of animal systematics:
To arrange animals into groups that reflect
evolutionary relationships
Animal Systematics
 Phylogeny:
Also
known as evolutionary
tree. Based on
characters that vary
among species.
 Character: anything
that has a genetic
basis and can be
measured.
Patterns of Organization
Symmetry vs. Asymmetry
Symmetry: describes how
parts of an animal are
arranged around a point
or axis.
Asymmetry: absence of
a central point of axis.
Patterns of Organization
 Types
of symmetry:
1. Radial: any plane passing through the
central axis divides the animal into mirror
images.
2. Bilateral: a single plane, passing through
the longitudinal axis of an animal, divides
the animal into right and left mirror images.
Radial Symmetry
Bilateral Symmetry
Terms of Direction
 Table
7.3
 Aboral – end opposite the mouth
 Oral – end containing the mouth
 Anterior – head end
 Posterior – tail end
 Caudal – toward the tail
 Cephalic – toward the head
Terms of Direction
 Table
7.3 (cont’d)
 Distal – Away from point of attachment
 Proximal – Toward the point of
attachment
 Dorsal – Back of an animal (synonymous
with posterior for upright animals)
 Ventral – Belly of an animal
(synonymous with anterior for upright
animals)
Terms of Direction
 Table
7.3 (cont’d)
 Inferior – Below a point of reference
 Superior – Above a point of reference
 Lateral – Away from the plane that
divides a bilateral animal
 Medial – On or near the plane that
divides a bilateral animal
Other Patterns of Organization
 Unicellular
Level of Organization
 Protista
 Diploblastic
Organization
 Body parts organized into layers derived
from two tissue layers
1.
2.
Ectoderm – gives rise to epidermis
Endoderm – gives rise to gastrodermis
 Jellyfish,
Hydra
Other Patterns of Organization
 Triploblastic
 Tissues
layers
1.
2.
3.
Animals
derived from three embryonic
Ectoderm
Mesoderm – found in middle. Gives rise
to supportive, contractile, and blood
cells.
Endoderm
Other Patterns of Organization
 Triploblastic

Animals (cont’d)
Organized based on the presence or
absence of body cavity
 Body
Cavity – fluid-filled space in which
internal organs can be suspended and
separated from body wall.