Transcript 4-3 Multicellular Organization

4-3 Multicellular Organization
4-3 Objectives
• Distinguish between tissues, organs and
organ systems.
• Describe the features of a colonial
organism.
Tissues, Organs, and Organ
Systems
• Most multicellular organisms are
organized into tissues.
• Tissues- groups of cells that carry out a
specific function.
Tissues, Organs, and Organ
Systems
• Ex: epithelial tissue, connective tissue,
muscle tissue.
Blood Tissue
•
Human Red Blood Cells, Platelets and T-lymphocyte (erythocytes = red; platelets = yellow; T-lymphocyte = light green) (SEM x 9,900). This image is
copyright Dennis Kunkel at www.DennisKunkel.com, used with permission.
Tissues, Organs, and Organ
Systems (cont.)
• Organ- several types of tissues that
interact to perform a specific function.
Tissues, Organs, and Organ
Systems (cont.)
• Ex: stomach
contains epithelial,
muscle, nervous
and connective
tissue
Tissues, Organs, and Organ
Systems (cont.)
• Organ system – group of organs that work
together to perform a set of related tasks.
• Systems interact to carry out life
processes.
Tissues, Organs, and Organ
Systems (cont.)
• Digestive system
includes, mouth,
esophagus,
stomach,
intestines, etc.
Tissues, Organs and Organ
Systems (cont.)
• Plant cells include parenchyma,
sclerenchyma, collenchyma, xylem, and
phloem cells.
• Plant tissues include dermal, ground, and
vascular tissue.
• Plant organs include flowers, stems,
leaves, and roots.
• Plant organ systems include shoots and
roots.
Evolution of Multicellular
Organisms
• Colonial Organizations
– Colonies- temporary groups of eukaryotic
cells of the same kind
– Colonial organism – a collection of genetically
identical cells that live together in a connected
group.
Evolution of Multicellular
Organisms
• Individual cells of a colonial organism may
have specific functions.
• Ex: Outside cells of Volvox colonies have
flagella that propel the colony through the
water.
Evolution of Multicellular
Organisms
• Volvox exhibits specialization but lacks
tissues and organs; therefore it is a
unicellular colony and not a multicellular
organism.
Volvox
Evolution of Multicellular
Organisms
• Research indicates that multicellular
organisms evolved from colonial
organisms.