○F ORM○
classification
https://www.youtube.com/watch?v=aiC_Z8Za7wc
→ TAXONOMY - ,,system biologists use to group organisms based on similar characteristics.’’
(scientific study of naming, defining and classifying groups of biological organisms based on
shared characteristics) it’s based on a concept called homology - shared characteristics that
have been passed down from a common ancestor.
→ taxon (taxa) - a group of organisms (population or group of populations) usually
considered to be phylogenetically related, with a specific feature that distinguishes them
from other taxonomic units. The taxa include all lower-level taxa it contains
Linnaeus (is often called the Father of Taxonomy) set himself the task of devising a
METHOD to: “join the similar to the similar, and to separate the dissimilar from the
dissimilar in nature.” In other words, Linnaeus decided to devise a classification system for
living things.
Linnaeus’ system of classification used seven
major groups: empire, kingdom, class, order,
genus, species, and variety.
The two-empire system splitted the organisms
into two groups, the same way we now
classify their cells (based on having or not
having the nucleus).
Empire is no longer used, and a modern
hierarchy is:
kingdom, phylum, class,
order, family, genus, species
, In recent years a new level called the domain has been introduced above the kingdom in the
hierarchy. Classification systems were based originally on observed features, but a wider
range of evidence is now used. Molecular evidence is increasingly important as a result of
rapid advances in molecular biology. New knowledge gained from DNA studies, such as base
sequencing, is particularly important. The evidence suggests that there is a natural
evolutionary division of living organisms into three main groups or ‘domains’. These are:
Main characteristics of the three domains:
→ archea – prokaryotic cells that live in conditions that are too extreme for other forms of
life and have distinct molecular characteristics separating them from bacteria as well as from
eukaryotes. CELL WALL DOES NOT CONTAIN PEPTIDOGLYCAN AND CELL MEMBRANE USES
ETHER LINKED LIPID
→ bacteria – unicellular, prokaryotic, microscopic, lacking a nucleus and
membrane-bounded organelles, and having a plasma membrane. CELL WALL CONTAINS
PEPTIDOGLYCAN (MUREIN) AND CELL MEMBRANE USES ESTER LINKED LIPIDS
→ eukarya – their cells are larger than prokaryotic cells and have a “true” nucleus,
membrane-bound organelles, and rod-shaped chromosomes
classification
https://www.youtube.com/watch?v=aiC_Z8Za7wc
→ TAXONOMY - ,,system biologists use to group organisms based on similar characteristics.’’
(scientific study of naming, defining and classifying groups of biological organisms based on
shared characteristics) it’s based on a concept called homology - shared characteristics that
have been passed down from a common ancestor.
→ taxon (taxa) - a group of organisms (population or group of populations) usually
considered to be phylogenetically related, with a specific feature that distinguishes them
from other taxonomic units. The taxa include all lower-level taxa it contains
Linnaeus (is often called the Father of Taxonomy) set himself the task of devising a
METHOD to: “join the similar to the similar, and to separate the dissimilar from the
dissimilar in nature.” In other words, Linnaeus decided to devise a classification system for
living things.
Linnaeus’ system of classification used seven
major groups: empire, kingdom, class, order,
genus, species, and variety.
The two-empire system splitted the organisms
into two groups, the same way we now
classify their cells (based on having or not
having the nucleus).
Empire is no longer used, and a modern
hierarchy is:
kingdom, phylum, class,
order, family, genus, species
, In recent years a new level called the domain has been introduced above the kingdom in the
hierarchy. Classification systems were based originally on observed features, but a wider
range of evidence is now used. Molecular evidence is increasingly important as a result of
rapid advances in molecular biology. New knowledge gained from DNA studies, such as base
sequencing, is particularly important. The evidence suggests that there is a natural
evolutionary division of living organisms into three main groups or ‘domains’. These are:
Main characteristics of the three domains:
→ archea – prokaryotic cells that live in conditions that are too extreme for other forms of
life and have distinct molecular characteristics separating them from bacteria as well as from
eukaryotes. CELL WALL DOES NOT CONTAIN PEPTIDOGLYCAN AND CELL MEMBRANE USES
ETHER LINKED LIPID
→ bacteria – unicellular, prokaryotic, microscopic, lacking a nucleus and
membrane-bounded organelles, and having a plasma membrane. CELL WALL CONTAINS
PEPTIDOGLYCAN (MUREIN) AND CELL MEMBRANE USES ESTER LINKED LIPIDS
→ eukarya – their cells are larger than prokaryotic cells and have a “true” nucleus,
membrane-bound organelles, and rod-shaped chromosomes
