Cellular Organization

• Organisms range in composition from unicellular microorganisms to multicellular organisms.



• In multicellular organisms, large groups of cells work together to form systems of tissues and organs that are specialized and aid the organism in carrying out its life processes of growth, reproduction, gas exchange, metabolism, and response.

• Multicellular organisms exhibit a hierarchy of cellular organization allowing for a division of labor when carrying out life processes
• A key concept in science is that form fits function.
• In multicellular organisms, cells have specialized shapes that enable them to perform specific roles within the organism

You should be able to:
• explain the relationship among cells, tissue, organs, and organ systems 
• differentiate among common examples of unicellular and multicellular organisms and how they perform various life functions, 
•  provide evidence to support the idea that a cell's form fits its function within a multicellular organism (see image)

Classification

• Classification is useful in explaining relationships and organizing objects or processes into groups.
• Classification relies on careful observation of patterns of similarities and differences.
• Biological classification (taxonomy) uses a systematic method to name, organize, and show relationships among species.
• Any grouping of organisms into domains or kingdoms is based on several factors, including
  • the presence or absence of cellular structures, such as the nucleus, mitochondria, or a cell wall;
  • whether the organisms exist as single cells or are multicellular; and
  • how the organisms get their food
• The current biological classification system groups organisms into three domains: Archaea, Bacteria, and Eukarya
• As living things are investigated, new attributes (physical and chemical) are revealed that affect the relationships and taxonomic group into which an organism is placed.
• Information about the physical features and activities of living things are organized into a hierarchy of increasing specificity. 
• The levels in this hierarchy include domain, kingdom, phylum, class, order, family, genus, and species

• Classifications at one scale may not be valid at a different scale. For example, classification of organisms based on physical traits may not be the same as those based on DNA sequences.
• A group of similar-looking organisms that can interbreed under natural conditions and produce offspring that are capable of reproduction defines a species which are differentiated using binomial nomenclature

• categorize organisms into the three domains: Archaea, Bacteria, and Eukarya
• categorize examples of four kingdoms of Eukarya: protists, fungi, plants, and animals
• categorize organisms as representative of major animal phyla and plant divisions (see images above)
• recognize scientific names as part of a binomial nomenclature
• define what makes a species