Multicellular OrganizationMulticellular Organization

I. Tissues, Organs, & Organ I. Tissues, Organs, & Organ SystemsSystems

a)a) Cells are organized into tissues (a group Cells are organized into tissues (a group of cells that carry out a specific function)of cells that carry out a specific function)

b) Types of tissues: b) Types of tissues: epithelial, connective, muscle, epithelial, connective, muscle,

nerve.nerve.

c) An organ is formed when several c) An organ is formed when several types of tissue interact to perform a types of tissue interact to perform a

specific functionspecific function

Ex: stomach (muscle, epithelial, Ex: stomach (muscle, epithelial, connective, and nerve tissue)connective, and nerve tissue)

D. An D. An organ systemorgan system is composed of a is composed of a group of organs that group of organs that perform a set of perform a set of related tasks.related tasks.

Ex: the digestive Ex: the digestive system (mouth, system (mouth, esophagus, stomach, esophagus, stomach, intestines)intestines)

E. Types of plant tissue: E. Types of plant tissue: dermal, ground, dermal, ground, vascular.vascular.

F. Types of plant organs: F. Types of plant organs: roots, stems, leaves, roots, stems, leaves, and flowers.and flowers.

II. Evolution of Multi-Cellular II. Evolution of Multi-Cellular OrganizationOrganization

Fossil records indicate the earliest Fossil records indicate the earliest cells were simple prokaryotes like cells were simple prokaryotes like present day bacteria.present day bacteria.

Organisms dependent on limited Organisms dependent on limited organic resourcesorganic resources reproduced reproduced

competition of resourcescompetition of resources cells with adaptations evolved (early cells with adaptations evolved (early eukaryotes)eukaryotes)

1.1. Definition: A Definition: A collection of collection of genetically identical genetically identical cells that live cells that live together in a closely together in a closely connected group.connected group.

2.2. Example: green alga Example: green alga VolvoxVolvox

a.a. Outer cells use Outer cells use flagella for flagella for movementmovement

b.b. Cells involved with Cells involved with reproductionreproduction

A.A. Colonial Colonial OrganizationsOrganizations

3. Unicellular organisms3. Unicellular organisms Colonial organismsColonial organisms True True multicellular organismsmulticellular organisms

4. Some believe that plants, animals, 4. Some believe that plants, animals, and fungi evolved from different and fungi evolved from different colonial organisms hundreds of colonial organisms hundreds of millions of years ago.millions of years ago.