Title: Classification of Organisms
1Classification of Organisms
2Classification of Organisms
- The study of the kinds and diversity of organisms
and their evolutionary relationships is called
systematics or taxonomy - Taxonomy is the work involved in the original
description of a species. - Systematics is the assigning of species into
evolutionary groups.
3Father of Modern Classification
- The modern classification system originated with
the work of Carolus Linnaeus - he recognized the different species could be
grouped into broader categories based on shared
characteristics - any grouping of animals that shares a particular
set of characteristics forms an assemblage called
a taxon
4Modern taxonomists use 7 taxa
- kingdom, phylum, class, order, family, genus and
species - as taxa increase organisms get more specific
5Binomial Nomenclature
- when a species is talked about only the genus and
species names are used - this is called the scientific name
- unique to each type of organism
- Required by the International Code of Zoological
Nomenclature
6Writing Scientific Names
- the genus names is always capitalized
- both names are either italicized or underlined
- leave a space in the underline between names
- ex. Homo sapien
- Felis leo
- Quercus rubra
7Kingdoms of Life
- In 1969, Robert H. Whitaker classified kingdoms
based on cellular organization and mode of
nutrition - this lead to the formation of the 5 kingdoms
85 Kingdoms of Classification
- Monera comprised of bacteria and cyanobacteria
- distinguished by being single cell prokaryotes
- Protista comprised of Amoeba, Paramecium etc.
- distinguished by being single celled eukaryotes
- Plantae multi-cellular photosynthetic eukaryotes
- plants have cell walls and are non-motile
95 Kingdoms of Classification
- Fungi multi-cellular heterotrophic eukaryotes
- fungi have cell walls and usually non-motile
- digest organic matter extra-cellularly (outside
of cell) and absorb the breakdown products - Animalia multi-cellular heterotrophic
eukaryotes - animal cells lack a cell wall and usually motile
- feed by ingesting other organisms or parts of
other organisms
10Monera prokaryote single-cell
Protista eukaryote multi-cell
Plantae eukaryote multi-cell autotrophic
Fungi eukaryote multi-cell heterotrophic,
external digestion
Animalia eukaryote multi-cell heterotrophic,
internal digestion
11DOMAINS???
- Many taxonomists have pushed the idea that the
five kingdom system isnt enough - they feel that organisms share too much
similarities and need to be grouped otherwise - the push has led to the addition of 3 domains
123 Domains
- Archae bacteria that live in extreme conditions
- Eubacteria true bacteria
- Eukarya all eukaryotic organisms
13Patterns of Organization
- Once the kingdom of an organism has been decided
other aspects of the organism must be looked at
to determine its classification - Symmetry describes how the parts of an animal
are arranged around a point or an axis
14Types of symmetry
- Asymmetry the absence of a central point or
axis around which body parts are equally
distributed - characterizes most protists and many sponges
- not known to be an adaption or advantage to
anything - organisms do not develop complex communication,
sensory, or locomotor functions
15Types of symmetry
- Radial Symmetry arrangement of body parts such
that any plane passing through the central
oral-aboral axis divides the animal into mirror
images - oral-aboral axis one point of reference is the
mouth (oral end) and a second point of reference
is the end opposite the mouth (aboral end) - often modified by the arrangement of some
structures in pairs , or in other combinations,
around the central oral-aboral axis
16Types of symmetry
- Bilateral Symmetry the arrangement of body
parts such that a single plane, passing between
upper and lower surfaces and through the
longitudinal axis of an animal, divides the
animal into right and left mirror images. - characteristic of active, crawling, or swimming
animals - tend to move in one direction, so one end is
generally more complex - Cephalization the development or formation of a
distinct head
17- Planes of symmetry are used to describe the
organisms based on the relationships of body
parts - Not all animals are easily described and can be
confusing if different people try to explain them
differently - To make it simpler some terms have been
universally adopted.
18Terms of Directions
- Aboral the end opposite the mouth
- Oral the end containing the mouth
- Anterior the head end usually the end of a
bilateral animal that meets its environment - Posterior the tail end
- Caudal toward the tail
- Cephalic toward the head
- Distal away from the point of attachment
of a structure on the body (the toes are
distal to the knee)
19Terms of Directions
- Proximal toward the point of attachment of a
structure on the body (the hip is proximal
to the knee) - Dorsal the back of an animal usually the
upper surface synonymous with posterior for
animals that walk upright - Ventral the belly of an animal usually the
lower surface synonymous with anterior for
animals that walk upright - Inferior below a point of reference (the mouth
is inferior to the nose in humans) - Superior above the point of reference (the
neck is superior to the chest) - Lateral away from the plane that divides a
bilateral animal into mirror images - Medial (median) on or near the plane that
divides a bilateral animal into mirror images
20Other Patterns of Organization
- Unicellular (Cytoplasmic) level all single
celled organisms - characteristic body plan of the Protista
- is not simple
- must provide for locomotion, food acquisition,
digestion, water and ion regulation, sensory
perception, and reproduction all in a single cell - colonies can exist, but show little signs of
interdependence, cooperation, or coordination of
function
21Other Patterns of Organization
- Diploblastic Organization simplest tissue-level
organization - tissue is derived from two embryonic layers
- Ectoderm gives rise to the epidermis, the outer
layer of the body wall - composed of epithelial and muscular cells
- Endoderm gives rise to the gastrodermis, the
tissue that lines the gut cavity - composed of digestive and muscular cells
- between the epidermis and gastrodermis is the
mesoglea, a noncellular layer - cells in each layer are functionally
interdependent
22Other Patterns of Organization
- Triploblastic Organization tissues are derived
from three embryological layers - like diploblastic, the ectoderm forms the outer
layer and the endoderm lines the gut - in between these two layers is the mesoderm
which gives rise to supportive, contractile, and
blood cells - most organisms have organ-system level of
organization
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24Triploblastic Subgroups
- Based on the presence of and what kind of body
cavity they have. -
- Body Cavity a fluid-filled space in which the
internal organs can be suspended and separated
from the body wall
25Why are Body Cavities advantageous?
- Provide more room for organ development.
- Provide more surface area for diffusion of gases,
nutrients, and wastes into and out of organs - Provide and area for storage.
- Often act as hydrostatic skeletons.
- Provide a vehicle for eliminating wastes and
reproductive products from the body - Facilitate increased body size.
26Triploblastic Subgroups
- Triploblastic Acoelemate Pattern the mesoderm
layer is a relatively solid mass of cells between
ectodermal and endodermal layers - acoelemate means without a cavity
- some of the mesodermal cells are parenchyma
loosely organized cells not specialized for a
specific function
27Triploblastic Subgroups
- Triploblastic Pseudocoelemate Pattern
- pseudocoelom a body cavity not entirely lined by
mesoderm - No muscular or connective tissues are associated
with the gut tract - No mesodermal sheet covers the inner surface of
the body wall - No membranes suspend organs in the body cavity
28Triploblastic Subgroups
- Triploblastic Coelemate Pattern
- coelem a body cavity completely surrounded by
mesoderm - peritoneum thin mesodermal sheet that lines the
inner body wall . - serosa thin mesodermal sheet that lines the
outside of visceral organs. - peritoneum and serosa are continuous and suspend
visceral organs in the body cavity. - mesentery the suspending sheets of organisms.
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30Three major groups of the Animal Kingdom
- Mesozoa includes phylum Mesozoa, or the
mesozoans - Parazoa includes phylum Porifera, or the
sponges - Eumetazoa includes all other phyla
- Eumetazoa are further divided into two groups
based on body symmetry - Radiata animals that have radial symmetry
- Bilateria animals that have bilateral symmetry
31- Bilateria animals are divided into two group
based on embryological characteristics - Comparative Embryology studies based on the
observation that embryological events may be
similar because of shared ancestry
32Two Bilateria Groups
- Protostomes include animals in the phyla
Platyhelminthes, Nematoda, Mollusca, Annelida,
Arthropoda, and others - Deuterstomes include animals in the phyla
Echinodermatat, Hemichrodata, Chordata, and
others.