figure 20.un01
DESCRIPTION
Which of these trees is not like the others…. B. A. D. Figure 20.UN01. B. C. D. C. C. B. A. A. D. (a). (c). (b). Figure 24.18. Domain Eukarya. Eukaryotes. Korarchaeotes. Euryarchaeotes. Archaea. Domain Archaea. Crenarchaeotes. UNIVERSAL ANCESTOR. Nanoarchaeotes. - PowerPoint PPT PresentationTRANSCRIPT
Figure 20.UN01
A
B
C
D
(a)
D
C
B
A
(c)
B
D
C
A
(b)
Which of these trees is not like the others…..
Figure 24.18
UNIVERSALANCESTOR
Do
main
Eu
karya
Gram-positivebacteria
Cyanobacteria
Spirochetes
Chlamydias
Proteobacteria
Nanoarchaeotes
Crenarchaeotes
Euryarchaeotes
Korarchaeotes
Eukaryotes
Do
main
Arch
aeaD
om
ain B
acteria
Archaea
Bacteria
Prokaryotes
Who are the Eukaryotes?
How do they get their energy?
Which lineages are good monophyletic groups?
When did they evolve? GO back to your timeline….
Fossils 1.8bya (but lipids made by Euk. around 2.7 bya)
Multicellularity?
600mya
Protists-ARE ONE type of Eukaryote!DIVERSITYMany are important ocean photosynthesizers! p500
Parasitic protists
•Trichomonas•Giardia- beavers•Malaria p501
Figure 20.20
Forams
Ciliates
Euglenozoans
Diatoms
COMMONANCESTOR OF ALL LIFE
Land plants
Animals
Amoebas
Fungi
Red algae
Chlamydias
Green algae
(Mitochondria)*
Methanogens
Proteobacteria
Nanoarchaeotes
Thermophiles
Do
ma
in E
uk
arya
Gram-positivebacteria
(Chloroplasts)*
Spirochetes
Cyanobacteria
Do
ma
in B
acteria
Do
ma
inA
rch
aea
Plasma membrane
Chromosomes
1. Ancestor of theeukaryotes.
2. Infoldings ofplasma membranesurround thechromosomes.
Endoplasmicreticulum
3. Eukaryotic cell.
Nucleus
ORIGIN OF THE NUCLEAR ENVELOPEEukaryotes have a Nucleus
Where did it come from?
Eukaryotes also have mitochondria and chloroplasts-Endosymbiosis!
Lynn Margulis
Figure 25.3
CytoplasmDNA
Nucleus
Engulfingof aerobicbacterium
Engulfingof photo-syntheticbacterium
Mitochondrion
Mito-chondrion
Plastid
Plasmamembrane
Endoplasmicreticulum
Nuclearenvelope
Ancestralprokaryote
Ancestralheterotrophiceukaryote
Ancestralphotosyntheticeukaryote
Figure 25.3
CytoplasmDNA
Nucleus
Engulfingof aerobicbacterium
Engulfingof photo-syntheticbacterium
Mitochondrion
Mito-chondrion
Plastid
Plasmamembrane
Endoplasmicreticulum
Nuclearenvelope
Ancestralprokaryote
Ancestralheterotrophiceukaryote
Ancestralphotosyntheticeukaryote
Figure 20.21
Cyanobacteria
Proteobacteria
Thermophiles
Do
main
Eu
karyaD
om
ain B
acteriaD
om
ainA
rchaea
Fungi
Plantae
Ch
loro
plasts
Mito
cho
nd
ria
MethanogensAncestral cellpopulations
How do we show endosymbiosis on a phylogenetic tree?
So sometimes whole organisms were engulfed-but genes were also being swapped
HOW?
Figure 29-16SECONDARY ENDOSYMBIOSIS
Nucleus
Predatory protist
Photosynthetic protist
Chloroplast
Nucleus
1. Photosynthetic protist is engulfed.
2. Nucleus from photosynthetic protist is lost.
Organelle with four membranes
1 23 4
Engulfing of a protist that already engulfed a photosynthetic prokaryote
Some ate a green algae and some ate a red algae.
Figure 25.4
Cyano-bacterium
Membranesare representedas dark lines inthe cell.
Red alga
Primaryendo-
symbiosis
1 2 3
NucleusHeterotrophiceukaryote
One of thesemembraneswas lost inred andgreen algaldescendants.
Greenalga
Secondaryendo-
symbiosis
Secondaryendo-
symbiosis
Plastid
Euglenids
Chlorarachniophytes
Stramenopiles
Plastid
Secondaryendo-
symbiosis
Dinoflagellates
Figure 25.5
When did multicellularity evolve?What traits would need to evolve in order to be a multicellular organism? What would you have to be able to do?
Many protists are multicellular!This is a colonial protist with rigid cell walls-what do we mean by colonial?
More on multicellularity…integration!
•Stick together
•Communicate
•Ways of moving materials around
•Germ vs Soma-controls on mitosis and meiosis
•Differentiated cells are arranged in tissues
•Genes regulated so that even though all cells contain all the animals genes, particular genes are active only in particular cells at certain times during a lifetime
•These things require changes in controls over developmental processes and changes in gene expression rather than new cellular structures or genes not present in unicellular organisms!
Multicellularity evolved many times
Ex Algae (“protists”), Plants, Fungi and Animals
Figure 25.6Flagellum
Cytoplasm
Outer cell wall
Inner cell wall
Outer cell wall
Cytoplasm
Extracellular matrix (ECM)
Chlamydomonas
Gonium
Pandorina
Volvox
Few totally new genes…..
Figure 25.7
Individualchoanoflagellate
Choano-flagellates
Otheranimals
Collar cell(choanocyte)
Sponges
An
imals
OTHEREUKARY-OTES
What do we know? Multicellularity in animals…
Figure 32-11a
Choanoflagellates are sessile protists; some are colonial.
Choanoflagellate cell
Colony
Water current
Foodparticles
Genome of a single celled choanoflagellate vs animals
Many protein domains in common (domain is a key part or functional region of a protein)
Choanoflagellate had the same domains that in animals are important in cell adhesion and signaling.
So evolution of multicellularity involved the “co-opting” of existing genes that had been used for other purposes
As well as one small new piece the CCD domain in the cadherin protein
Figure 25.8
Hydra
Mouse
“CCD” domain
Choano-flagellate
Fruitfly
Text goes over taxonomy of protists…which we will skip.
And then text goes over functional importance..
Protists-ARE ONE type of Eukaryote!DIVERSITYMany are important ocean photosynthesizers! p500
Parasitic protists
•Trichomonas•Giardia- beavers•Malaria p501
Development is obviously only important in multicellular organisms
How do we get such diversity of morphology?
Small changes in development can yield big differences in shape or morphology. See P 449-CH23
Two kinds of developmental changes
1. Homeotic mutations affect placement and number of body parts
(typically Hox mutations)
Numbers of legsExpression of a particular Hox gene suppresses the formation of legs in fruit flies (and presumably all insects) but not brine shrimp(Pinpointed the exact amino acid changes)
Hox gene 6 Hox gene 7 Hox gene 8
About 400 mya
Drosophila Artemia
Ubx
What is going on here?
2. Heterochronic (allometric) changes or mutations
These affect the timing or rate of development of different body parts (rate of mitosis)
parts pulled and stretched at different rates to make “new” morphologies…
Figure 23.16
Chimpanzee infant Chimpanzee adult
Chimpanzee adultChimpanzee fetus
Human adultHuman fetus
Heterochrony…paedomorphosis..Some species of salamander retain juvenile characteristics (external gills) into sexual maturity
Sticklebacks-Ex from text…
Lakes with predators-make spinesNo predators-no spines
What is genetic basis of this evolutionary change?
Change in nucleotide sequence OR change in how the gene is expressed or regulated
Thoughts on which is more risky?? Easier??
Change in way gene is regulated…
Pleiotropic effects of gene can be controlled (turn off spine production but other functions of gene on other parts of body retained)