LECTURE 1: INTRODUCTION TO TAXONOMY • Common descent – common ancestry
• Smallest distinct groupings -
A systematic zoologist has three major goals:
• Reproductive community - interbreeding
- To discover all species of animals
SPECIES DISTRIBUTION
- To reconstruct their evolutionary relationships
Geographic range
- To communicate those relationships by constructing an
- Cosmopolitan – species having very large geographic
informative taxonomic system.
ranges or worldwide distributions
TAXONOMY AND SYSTEMATICS
- Endemic – species with very restricted geographic
A formal system for naming and classifying species following the
distributions
principle of common descent.
- Range can either be continuous or disjunct.
- Recent ancestry share
- Evolutionary duration – distribution through time which is
- Common features and are grouped closer together
variable per species
- Shared features
- Taxonomic predate evolutionary biology
Classifying organisms based on studies of variation among LECTURE 2: ARCHITECTURAL PATTERNS OF
populations that reveal their evolutionary relationships.
- Needs to accommodate various alternative taxonomic ANIMALS & INTRODUCTION TO TAXONOMY
viewpoints. ORGANISMAL GRADE OF COMPLEXITY/ORGANIZATION
LINNAEUS AND TAXONOMY Protoplasmic – confined
- Aristotle (384 – 332 BC) – Greek biologist/philosopher, who among unicellular organisms
first classified organisms based on structural similarities. - all life functions are confined
- Carolus Linnaeus designed the current system of within the boundaries of a
classification. single cell.
• Published in his work, Systema Naturae, which - differentiated into organelles
used morphology to develop a classification
system of animals and plants.
LINNAEAN TAXONOMY Cellular – aggregation of cells
- Divided animal kingdom into species and gave each a that are functionally
distinctive name differentiated
• Grouped species based on shared common - division of labor
essential properties into genera, genera into
orders, and orders into classes, and so on.
• Animals are arranged in an ascending series of
groups with increased inclusiveness. Cell (Tissue) - aggregation of
- Original classification scheme: limited and but was similar cells into definite patterns
drastically altered. or layers
- Basic principle is still followed today. - organized to perform a
TAXA IN LINNAEAN SYSTEM common function
- Taxa (-on, sing.) – major animal groups at each level in the
hierarchy Tissue (Organ) – aggregation of
- Taxonomic ranks – indicate the general degree of tissues in a organ
inclusiveness per group. - organs are usually composed of more than one kind of tissue
- The seven mandatory major ranks - has a specialized function
• Kingdom, phylum, class, order, family, genus, Organ - perform a function
species producing highest level of
• Each major rank can be further subdivided into organization
smaller levels of taxa (e.g. superclass, suborder) - body function (circulation,
BINOMIAL NOMENCLATURE respiration, reproduction,
- Two words, normally in Latin digestion)
- Species name: Homo Sapiens x 1800
• Rules..? Genus name, specific epithet (= species
epithet) – never stands alone
• The same name can’t be given to two different
genera.
• Latin: precise description
• Common names: vary both culturally and BODY SYMMETRY
geographically - balance proportions, correspondents in size and shape of
• Genus: Noun parts
• Species epithet: adjective (never stands alone) 3 TYPES OF BODY SYMMETRY
WHAT IS A SPECIES? 1. Spherical symmetry – any plane passing through the
center that divides the body into mirrored halves
- Thomas Henry Huxley asked his famous question which still
- Occurs among eukaryotes (unicellular); rare among
has no clear answer. vertebrates
• There are numerous species concepts, which 2. Radial symmetry – forms that can be divided into similar
lead to numerous disagreements. halves by more than two planes passing through the
- Biologist have repeatedly used certain criteria for identifying longitudinal axis.
species
P.H.G. Clemente – 1MBIO6 1
- Tubular; bowl shaped
- Can be present on jellyfishes, hydras, urchins etc.
3. Bilateral symmetry – animals that can be divided along
sagittal planes into two mirrored portions (right & left halves)
- Associated with cephalization (connection of nervous system
to the head)
Different types of animal symmetry
Anterior – head end
DEVELOPMENT SEQUENCES OF ANIMALS
Posterior – opposite/tail end
Dorsal – back or upper side
Ventral – front or belly side
Frontal plane (coronal plane) – torso / running through anterior and
posterior axis
- Dividing an animal into right and left part
Transverse plane – cross section
- Cuts through dorsal and ventral
SEGMENTATION
- Metamerism (segmentation) is a
common feature of metazoans
•Serial repetition of body segments;
longitudinal axis
TERMINOLOGIES - Metamere or somite – contains internal
Ectoderm/Endoderm – germ layers & external structures
Proto – means start •Mobility and complexity of structure and
Tome – mouth function
Protostomes – mouth being developed first
Deutero – second
Deuterostomes – mouth develops after the anus
Mesoderm (germ layer) – dictates the body cavity or coelom of an
animal VERTEBRATE TISSUE TYPES
Pseudocoelomate – animals having a false coelom Tissue – group of similar cells
Acoelomate – animals without coelom/ having no body cavity
Coelomate – organisms having two coelom or body cavities
Diploblastic – two germ layers only (ectoderm & endoderm)
Tripoblastic - + mesoderm
METHODS OF MESODERM FORMATION
- Dictates the type of body cavity present on an animal
P.H.G. Clemente – 1MBIO6 2
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