Life
Capacity for self-replication - reproduce
Capacity for self-regulation - utilize raw materials from the
environment)
Cellular discrete modules with distinct features that permit
chemical reactions
Diversity of Life on Earth
Knowledge of how many different types of life (diversity)
that exists on this planet comes from two different basic types
of evidence:
1. fossils and comparison to modern living organisms
2. chemical structure of modern and ancient DNA
Evidence from Fossils
Fossil - tangible remains or signs of an ancient organism
that died thousands or millions of years ago
Fossilization group of processes by which fossils form, nearly all are in sedimentary rocks
Preservation of Hard Parts skeletal features that are readily preserved
Preservation of Soft Parts felshy parts are preserved
Permineralization void spaces filled with minerals (calcite, quartz or chert, pyrite, etc.)
Molds three-dimensional negative imprints left in sediments of organic structures, caused by water percolating through and dissolving rocks and sediments
Impressions squashed or flattened molds
Carbonization residue of carbon after other organic materials are lost
Trace Fossils tracks, trails, burrows and other marks left by animal activity (record behavior)
Evidence from Modern and Ancient DNA
During early evolution, the DNA RNA protein system
present in all living cells became the basic blueprint for biological
information processing
Some of the complex molecules that make up RNA can be used as sensitive measures of evolutionary change. By measuring differences in the chemical structure of the macromolecules, a measure can be made of evolutionary distance between organisms
The 16S rRNA gene (show gene map) and its applications to evolution as determined by Carl Woese (Illinois Microbiology) has proven an excellent evolutionary chronometer
Structure of Life on Earth
The result of combining evidence from fossils, modern organisms,
and genetic analyses is that our modern understanding of a Universal
Tree of Life that contains 6 kingdoms (Fig. 3.6)
Bacteria (or Eubacteria) highly diverse domain, includes all known disease-causing pathogens and most of bacteria found in natural environments, capable of living in oxic environments (those containing O2) and anoxic environments (those not containing O2)
Archaea (or Archeobacteria) very specialized and less diverse domain, most are incapable of living in oxic environments
Eukarya includes all higher complex organisms, such as yeast, fungi, algae, plants, and animals, which include the following:
Plantae organisms (plants) that produce their own food via photosynthesis (autotrophs - primary producers of organic matter)
Fungi heterotrophs (consume organic matter formed by other organisms) and absorb food into cells and then digest the food inside of the cells, mostly multi-cellular
Animalia heterotrophs that digest food outside of cells and absorb the products, mostly multi-cellular
Protists assortment of simple, mostly unicellular, with groups ancestral to plants, fungi, and animals
Taxonomic Groups
Kingdom, Phylum, Class, Order, Family, Genus, Species (Fig. 3.1)
Tree of Life
Phylogeny structure of life with respect to ancestry (evolutionary history) via shared traits
Clade a cluster of species that share an ancestry
Show the 3 main branches or domains of diversity (Universal
Tree of Life figure)