P1 | Taxonomy and Classification (LECTURE) Flashcards
the science of classifying living
things
- involves 3 structure & interrelated categories
Taxonomy
What is the meaning of the Greek words ‘taxes’ and ‘nomos’?
taxes: arrangement
nomos: law
is the assignment of scientific
names to the various taxonomic categories and
individual organisms.
- Nomenclature
attempts the orderly
arrangement of organisms into a hierarchy of taxa
(categories).
- based on their similarities or relationships
- Classification
is the process of discovering and recording the traits or organisms so that they may be
recognized or named and placed in an overall
taxonomic scheme.
- Identification
- a Swedish botanist
- laid down the basic rules for classification and established taxonomic categories, or taxa
- also known as Linnaeus
Carl von Linné (1701-1778)
How are animals classified?
- Species (species)
- Genus (genera)
- Family (Families)
- Order (orders)
- Class (classes)
- Phylum (Phyla)
- Kingdom (Kingdoms)
- Domain (Domains)
“Whittaker’s tree”
- based on structural similarities and differences, such as prokaryotic and eukaryotic cellular organization, and the way
these organisms obtained their nutrition.
Robert Whittaker
devised a Three-Domain System of Classification
Carl R. Woese
two domains of procaryotes
- Archaea and Bacteria
- Eucarya or Eukarya (includes all eucaryotic organisms.
first living cells
Ancestral Cell Line
Domain Bacteria
- Cyanobacteria
- Chlamydias Spirochetes
- Gram-positive bacteria
- Endospore producers
- Gram-negative bacteria
Domain Archaea
- Methane producers
- Prokaryotes that live in extreme salt
- Prokaryotes that live in extreme heat
Domain Eukarya
- Eukaryotes
(plants, animals, fungi, protozoa)
provides the accepted labels by which organisms are universally recognized.
International Code of Nomenclature of Bacteria
(ICNB) or the Bacteriological Code (BC)
Binomial system of nomenclature
every organism is assigned a genus and a species of Latin or Greek derivation.
Each organism has a scientific “label” consisting
of two parts:
1. Genus - the first letter is always CAPITALIZED
2. Species - first letter is always lower case.
- printed in italics or underlined in script
relate to an organism’s genetic
makeup, including the nature of the organism’s genes and constituent nucleic acids
Genotypic characteristics
are based on features beyond the genetic level and include both readily observable characteristics and characteristics that may require extensive analytic procedures to be detected
Phenotypic characteristics
Comparison of Prokaryotic and Eukaryotic Cell Organization
Typical Size for Prokaryote and Eukaryote
(Prokaryote)
0.4-2 μm in diameter
0.5-5 μm in length
(Eukaryote)
10-100 μm in diameter
> 10 μm in length
Nucleus characteristic for Prokaryote
No nuclear membrane; nucleoid region of the cytosol
Nucleus characteristic for Eukaryote
Classic membrane-bound nucleus
Genome location for Prokaryote
attached to the mesosome (plasma membrane) in the nucleoid, at the mesosome
Genome location for Eukaryote
In the nucleus
Chromosomal DNA for Prokaryote
Circular; complexed with RNA
Chromosomal DNA for Eukaryote
Linear; complexed with basic histones and other proteins
Genome: extrachromosomal circular DNA for Prokaryote
Plasmids, small circular molecule of DNA containing accessory information; most commonly found in gram-negative bacteria; each carries genes for its own replication; can confer resistance to antibiotics
Genome: extrachromosomal circular DNA for Eukaryote
In mitochondria and chloroplasts
Reproduction for Prokaryote
Asexual (binary fission)
Reproduction for Eukaryote
Sexual and Asexual
Membrane bound organelles for prokaryote
(present, absent, all, absent in all, present in some, etc.)
absent
Membrane bound organelles for Eukaryote
(present, absent, all, absent in all, present in some, etc.)
all
Golgi bodies for prokaryote
(present, absent, all, absent in all, present in some, etc.)
absent in all
Golgi bodies for Eukaryotes
(present, absent, all, absent in all, present in some, etc.)
present in some
Lysosomes for prokaryotes
(present, absent, all, absent in all, present in some, etc.)
absent in all
Lysosomes for Eukaryotes
(present, absent, all, absent in all, present in some, etc.)
present in some; contain hydrolytic enzymes
Endoplasmic reticulum for prokaryotes
(present, absent, all, absent in all, present in some, etc.)
absent in all
Endoplasmic reticulum for Eukaryotes
(present, absent, all, absent in all, present in some, etc.)
Present in all; lipid synthesis, transport
Mitochondria for prokaryotes
(present, absent, all, absent in all, present in some, etc.)
absent in all
Mitochondria for Eukaryotes
(present, absent, all, absent in all, present in some, etc.)
present in most
Nucleus for prokaryotes
(present, absent, all, absent in all, present in some, etc.)
absent in all
Nucleus for Eukaryotes
(present, absent, all, absent in all, present in some, etc.)
present in all
Chloroplasts for photosynthesis (prokaryotes)
(present, absent, all, absent in all, present in some, etc.)
absent in all
Chloroplasts for photosynthesis (Eukaryotes)
present in algae and plants
Ribosomes; site of protein synthesis (non-membranous)
(Prokaryotes)
Present in all
Ribosomes; site of protein synthesis (non-membranous)
(Eukaryotes)
(present, absent, all, absent in all, present in some, etc.)
Present in all
Sterols in cytoplasmic membrane for prokaryotes
(present, absent, all, absent in all, present in some, etc.)
absent in mycoplasma spp.
Sterols in cytoplasmic membrane for Eukaryotes
(present, absent, all, absent in all, present in some, etc.)
present
Plasma membrane
(prokaryotes)
lacks carbohydrates
Plasma membrane
(eukaryotes)
also contains glycolipids and glycoproteins
Cell wall, if present
(prokaryotes)
peptidoglycan in most bacteria
peptidoglycan - can be seen in the cell wall of prokaryote
Cell wall, if present
(Eukaryotes)
cellulose, phenolic polymers, lignin (plants), chitin (fungi), other glycans (algae)
Glycocalyx
(prokaryotes)
(present, absent, all, absent in all, present in some, etc.)
present in most as an organized capsule or unorganized slime layer
Glycocalyx
(Eukaryotes)
(present, absent, all, absent in all, present in some, etc.)
present; some animal cells
Cilia
(prokaryotes)
(present, absent, all, absent in all, present in some, etc.)
absent
Cilia
(Eukaryotes)
(present, absent, all, absent in all, present in some, etc.)
present; see description of flagella
Flagella, if present
(prokaryotes)
simple flagella; composed of polymers of flagellin; movement by rotary action at the base; spirochetes have MTs.
(+) motile
(-) non-motile
Flagella, if present
(Eukaryotes)
Complex cilia or flagella; composed of MTs and polymers of tubulin with dynein connecting MTs; movement sliding microtubules
Pili and fimbriae
(prokaryotes)
(present, absent, all, absent in all, present in some, etc.)
present
Pili and fimbriae
(Eukaryotes)
(present, absent, all, absent in all, present in some, etc.)
Absent