What were the earliest organisms?
Prokaryotes
Prokaryote
cells that lack true nuclei
What are the two groups of prokaryotes?
Bacteria and Archaea
Eukaryotes
Cells that are composed of one or more cells that contain true nuclei and other organelles
When did the first animals live?
In the late-PreCambian seas
Spontaneous Generation
The belief that life could regularly arise from non-living matter
Biogenesis
The theory that life only comes from the reproduction of preexisting life. This was proven by Louis Pasteur in 1862.
Four-stage hypothesis for the Origin of Life
1) the abiotic synthesis of organic monomers 2)abiotic synthesis of polymers 3)Formation of Pre-cells 4)Origin of Self-Replicating Molecules
Stage 1: The abiotic synthesis of organic monomers
Synthesis of of small organic molecules, such as amino acid and nucleotide monomers.
Stage 2: Abiotic synthesis of polymers
The joining of these small molecules into macromolecules including proteins and nucleic acid
Stage 3: Formation of Pre- Cells
the packaging of all these molecules into pre-cells, droplets with membranes that maintained an internal chemistry different from the surroundings
Stage 4: Origin of Self-replicating molecules
The origin of self-replicating molecules that eventually made inheritance possible
Cocci
spherical prokaryotic cells
Cocci can occur in clusters such as staphlococci
Cocci in chains are called streptococci
Bacilli
Rod-shaped prokaryotic cells
How do some prokaryotes move?
Flagella
biofilm
Prokaryotes attatched to a surface in a highly organized film ex. dental plaque
Binary Fission
the reproduction process used by prokaryotes in which they divide their DNA almost continuously and divide again and again
Endospore
thick-coated protective cell produced within the prokaryotic cell when the prokaryote is exposed to unfavorable conditions
phototrophs
species that obtain energy from light
chemotrophs
species that obtain energy from environmental chemicals
archaea
meaning ancient refers to the antiquity of this groups origin from the earliest cells
extremophiles
meaning lovers of the extreme, some archaea live in extreme conditions such as very salty lakes, very hot lakes, or extremely cold places
Pathogens
Bacteria and other organisms that cause disease
Exotoxins
are proteins that bacterial cells secrete into their environment
Endotoxins
are chemical componets of the outer membrane of certain bacteria. Symptoms: fever, aches, and sometimes a dangerous drop in blood pressure (septic shock)
Bioremediation
the use of orgnanisms to remove pollutants form water, air, or soil
Protists
all eukaryotes that are not fungi, animals, or plants.
Symbiosis
is a close association between organisms of tow or more species
endosymbiosis
refers to one species living in side another host species
Parasite
derives its nutrition from a living host, which is harmed by the interaction
Protozoans
Protists that live primarily by ingesting foods
Amoebas
characterized by their great flexibility in their body shape and the absence of permanent organelles for locomotion
pseudopodia
temporary extensions of the cell
Cilliates
Protozoans named for their hair- like structures called cilia, which provide movement for the protist and sweep food into its mouth