The 3 Domains Flashcards
What are classification systems now based on?
Observable features along with other evidence
What are the 4 pieces of evidence that led to the creation of the 3 domain system?
-Molecular
-Embryological
-Anatomical
-Behavioural
What is molecular evidence and how did this help the creation of the 3 domain system?
-Is the similarities in proteins and DNA
-Can compare how DNA is stored and sequence of DNA bases as well as sequence of amino acids in proteins
What is embryological evidence?
Similarities in the early stages of an organisms development
What is anatomical evidence?
Similarities in structure and function of body parts
What is behavioural evidence?
Similarities in behaviour and social organisation
What did the 3 Domain System replace?
5 Kingdom Classification System
In the 3 domain system, what happens to the organisms that were in the Kingdom of Prokayotae?
Are separated into 2 domains-archaea and bacteria
Why was the 3 domain system proposed?
Due to differences between organisms in kingdom prokaryotae
What are the 3 differences that caused the 3 domain system to be proposed?
-Molecular
-Cell Membrane
-Ribosomal
What were the molecular differences?
-RNA polymerase is different in bacteria and archaea
-Archaea have histones similar to those in eukarya
What were the cell membrane differences?
-Bonds of lipids in cell membrane of bacteria and archae are different
-Development and composition of flagellae are also different
What were the ribosome differences?
-Eukarya have 80S ribosomes
-Archaea have 70S ribosomes as well as bacteria
What do most scientists agree on about archaea and bacteria?
That they evolved seperatly and that archaea is more closely related to eukarya
