concept map, Classification and Systematics (Levels of Taxonomic…
Classification and Systematics
represent the divergence of one taxon into two
a feature present in one or several derived members of a group, but not present in the ancestral members
all of the branches that lead from it constitute a clade.
extend from any particular point
one that does not contain all the descendants of the most common ancestor
diagram that shows evolutionary patterns by means of series of branches.
any ancestor (node) & all of the branches that lead from it
Cladograms and taxonomic categories
living descendants of those early-diverging clades
eg: angiosperms are either monocot or dicot.
species that can interbreed.
a specimen obtained from the same plant/clone as the type specimen
a single specimen that is the absolute standard for the species & its scientific name
Levels of Taxonomic Categories
genera are natural
all common ancestor are in same genus.
all species include genus
related to eachother by common ancesor.
members evolved from different ancestor
closely related species grouped together
well defined , with widespread
composed of one, several or often many genera.
level above family are order, class, division and kingdom
can be traced directly to Carolus Linnaeus
inheritance of acquired characteristics
all cells of the body produce fluids
specie refers to the money,
can interbreed with eachother.
most fundamental level of classification.
binomial system of nomenclature
every species have had both number of genus name and a species epithet
Other type of classification system.
Classification systems of fossils
to identify both its ancestors and its relatives that might have later evolved in the species.
form genera all fossils with the same basic form or structure classified together.
goal is to understand the evolution of the fossil
third type of classification used for fossil organisms.
Artificial systems of classification
follow the organic history of the organisms.
goal is to identify plant by means of obvious characters such as flower color and plant habitat.
easy to observe
only used as adjuncts to natural systems.
common ancestral group.
or homologous feature.
descended from common ancestor.
complicated by the fact that plants can resemble each other for 2 distinct reasons
they have undergone convergent evolution.
method of analyzing these photogenic evolutionary relationships
understand each of these evolutionary lines
adopted goals at the end of 19th century,
assigning plants name on the basis of phylogenetic relationships.
Natural system of classification.
scientist who specialize in classification and naming
hereditay relationships of any group of organisms
reflects the relationship.
major lines of evolution.
based on levels of evolutionary advancement
established clade of true plants
ex: protistans were placed together bc they had low lvl (low grade) of evolutionary advancement
Chapter 19:Algae and the Origin of Eukaryotic Cells
Origin of Eukaryotic Cells
In plants and algae
Flagella & Cilia
9+2 arrangement of microtubules
Origin of Mitochondria and Plastids: The Endosymbiont Theory
Revived in the 1960s
Speculated that plastids & mitochondia are prokaryotes in eukaryotes.
Found by KC Mereschkowsky
Origin of Mitochondria
Prokaryote was engulfed by a Eukaryote
Prokaryote evolved to have some eukaryotic species.
Origin of Plastids
Gave rise to diatoms, brown algae, etc.
Two flagella of different types
Gave rise to a clade containing red, and green algae
Arise similarly to mitochondria
Produced other lines of Algae
Engulfed partner would’ve been photosynthetic
Types of Cytokinesis
Several types occur in Algae
May be associated with division
Microtubules oriented parallel to the plane where the new wall will form.
Prokaryotes eventually became more complex, and became eukaryotes
Many genes contain introns
More elaborately packaged than in prokaryotes
DNA molecule carries thousands of genes
Nuclear Structure and Division
Contains most of the DNA
Typically Haploid or Diploid
Eukaryote= True Nucleus
Characteristics of Various Groups of Algae
Lines Resulted from the secondary endosymbiosis of plastids.
Body Construction in Green Algae
Cells lose flagella or never develop them
Karyokinesis occurs without cytokinesis, and giant multinucleate cells result.
aka Siphonous Body
All cells are similar
None is particularly specialized
Cells adhere loosely
Orientation of cell divisions is controlled precisely such that all new walls occur in only two planes.
Cell division occurs rapidly in all three planes
Cells are interconnected by plasmodesmata
Attaches filaments to a rock
Cells are held tightly by a middle lamella
Life Cycles of Green Algae
Specialization occurs in that only one free-living generation exists.
Alternation of Isomorphic Generations
Gametophyte & Sporophyte resemble strongly
Slight differences in Gametes
Alternation of generations between haploid and diploid
Alternation of Heteromorphic Generations
Gametophyte and Sporophye are very different
Representative Genera of Green Algae
Sister group to the embryophyte clade
Multicellular reproductive structures
Undergo cell division by means of a phragmoplast
Undergone by Haploid filaments
Grow into new filaments
Members of Genus
Monobiontic life cycle
Two anterior flagella
Motile Colonial Species
Each colony contains only a few cells
Flagella beat in coordination
Progeny cells are held together by gelatinous matrix
Dibiontic life cycle
Almost identical to
Dividing cells form sheets
Green Algae and Embryophytes
Monophyletic clade of:
Names suggested for the clade of:
Red Algae )
Occurs in cytoplasm as granules
Branched polymer of glucose
In the walls of algae
Large group of especially distinct algae
Poorly known-life Cycle
Severe Plant Pathogens:
Disease of potatoes
Cause of Irish potato famine
Disease of grapes
Most are aquatic
Diverse in structure and nutrition
Mostly sexual reproduction
Must be parasitic or saprophytic
Red Tide )
So numerous that the water is reddish
Typical spindle does not form
Almost exclusively motile and unicellular
Nuclear envelope and nucleolus persist throughout mitosis
Chromosomes are permanently condensed
The majority never have chloroplasts
Many features have undergone little change
Most are unicellular
None reproduce sexually
Brown algae and their relatives
Deposits of Siliceous Frustules
Clade of heterokont
Long tubular coenocyte
Large central vacuole
Occur mostly in fresh water
Ends of Branches
Swollen with large deposits of hydrophilic compounds
Resemble sieve tube members
Carry-out long-distance transport of carbohydrates
Some undergo meiosis
Cell walls contain cellulose and alginic acid
Almost exclusively marine
Grow in the Littoral Zone
Region between low & high tide
Constitutes up to 34% of the body weight
Almost always have flagella
Either uniflagellate or biflagellate
Do not decompose
Develop within special vesicles in the ER
Single cells covered with numerous tiny siliceous scales