Lab tomorrow.

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Eleanore Hampton
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1 Lab tomorrow Unit 1 A. The early life and the Diversification of Prokaryotes (Ch24) B. Origin and Diversification of Eukaryotes (Ch25) C. Broad Patterns of Evolution (Ch23) D. Meiosis and Sexual Life Cycles (Ch 10) March 7th WED-EXAM!

2 Figure Eukaryotes Domain Eukarya UNIVERSAL ANCESTOR Korarchaeotes Euryarchaeotes Archaea Crenarchaeotes Nanoarchaeotes Proteobacteria Chlamydias Bacteria Spirochetes Cyanobacteria Gram-positive bacteria Domain Archaea Domain Bacteria Prokaryotes

3 Figure Who are the Eukaryotes? How do they get their energy? What are some things Eukaryotic cells have that Prokaryotic cells don t have? Where are protists? COMMON ANCESTOR OF ALL LIFE Are they a good evolutionary group? Euglenozoans Forams Diatoms Ciliates Red algae Green algae Land plants Amoebas Fungi Animals Nanoarchaeotes Methanogens Thermophiles Proteobacteria (Mitochondria)* Chlamydias Spirochetes Gram-positive bacteria Cyanobacteria (Chloroplasts)* Domain Eukarya Domain Archaea Domain Bacteria

4 Figure 25.9 Major kinds of Eukaryotes? Diplomonads Parabasalids Euglenozoans Excavata Excavata 5 µm Archaeplastida 20 µm 50 µm Stramenopiles Alveolates Rhiza- rians Diatoms Brown algae Dinoflagellates Apicomplexans Ciliates Forams Cercozoans SAR clade SAR Clade 50 µm Unikonta Green algae Red algae Chlorophytes Charophytes Land plants Archaeplastida 100 µm Amoebozoans Opisthokonts Gymnamoebas Slime molds Nucleariids Fungi Choanoflagellates Animals supergroups Where are protists? Unikonta 100 µm

Figure 25.2 When did they evolve? 4.5 bya 3.5 2.5 1.5 500 mya 1.8 bya 1.5 bya 1.3 bya 1.2 bya 750 mya 635 mya 600 mya 0.5 cm 550 mya 535 mya 1 cm 20 µm (a) A 1.

5 Figure 25.2 When did they evolve? 4.5 bya mya 1.8 bya 1.5 bya 1.3 bya 1.2 bya 750 mya 635 mya 600 mya 0.5 cm 550 mya 535 mya 1 cm 20 µm (a) A 1.8-billionyear-old fossil eukaryote (b) Tappania, a 1.5-billion-year-old fossil that may represent an early alga or fungus 20 µm 25 µm 25 µm (c) Bangiomorpha, an ancient red alga (e) Bonneia, a vase-shaped eukaryote (d) Proterocladus, classified as a green alga 20 µm (f) An early member of the Ediacaran biota (g) Spriggina floundersi, an early animal with many body segments

6 What do Eukaryotes have that Prokaryotes don t have? Nucleus! Where did it come from? ORIGIN OF THE NUCLEAR ENVELOPE 1. Ancestor of the eukaryotes. Chromosomes Plasma membrane 2. Infoldings of plasma membrane surround the chromosomes. 3. Eukaryotic cell. Nucleus Endoplasmic reticulum

7 Eukaryotes also have. mitochondria and chloroplasts-endosymbiosis! Lynn Margulis

8 Figure 25.3 Cytoplasm DNA Ancestral prokaryote Plasma membrane Endoplasmic reticulum Nuclear envelope Nucleus Engulfing of aerobic bacterium Engulfing of photosynthetic bacterium Mitochondrion Mitochondrion Ancestral heterotrophic eukaryote Plastid Ancestral photosynthetic eukaryote

9 Figure 25.3 Cytoplasm DNA Ancestral prokaryote Plasma membrane Endoplasmic reticulum Nuclear envelope Nucleus Engulfing of aerobic bacterium Engulfing of photosynthetic bacterium Mitochondrion Who are these two??? Heterotrophic eukaryote? Photosynthetic eukaryote? Ancestral heterotrophic eukaryote Mitochondrion Ancestral photosynthetic eukaryote Plastid

Figure 20.21 How do we show endosymbiosis on a phylogenetic tree?

Ancestral cell populations Mitochondria Chloroplasts Fungi Plantae

10 Figure How do we show endosymbiosis on a phylogenetic tree? Whole organisms were engulfed-but genes were also being swapped HOW? Ancestral cell populations Mitochondria Chloroplasts Fungi Plantae Methanogens Thermophiles Cyanobacteria Proteobacteria Domain Eukarya Domain Domain Bacteria Archaea

11 Figure COMMON ANCESTOR OF ALL LIFE Euglenozoans Forams Diatoms Ciliates Red algae Green algae Land plants Amoebas Fungi Animals Nanoarchaeotes Methanogens Thermophiles Proteobacteria (Mitochondria)* Chlamydias Spirochetes Gram-positive bacteria Cyanobacteria (Chloroplasts)* Domain Eukarya Domain Archaea Domain Bacteria

Figure 29-16 Engulfing of a protist which itself had already engulfed a photosynthetic prokaryote Basically a Eukaryotic cell ate another Eukaryotic cell.

12 Figure Engulfing of a protist which itself had already engulfed a photosynthetic prokaryote Basically a Eukaryotic cell ate another Eukaryotic cell. Some ate a green algae and some ate a red algae. SECONDARY ENDOSYMBIOSIS Nucleus Predatory protist Photosynthetic protist Chloroplast Nucleus 1. Photosynthetic protist is engulfed. 2. Nucleus from photosynthetic protist is lost. Organelle with four membranes

13 Figure 25.4 Cyanobacterium Membranes are represented as dark lines in the cell. Red alga Secondary endosymbiosis Dinoflagellates Plastid Primary endosymbiosis Stramenopiles Nucleus Heterotrophic eukaryote One of these membranes was lost in red and green algal descendants. Secondary endosymbiosis Secondary endosymbiosis Plastid Euglenids Green alga Chlorarachniophytes

14 So again, what do Eukaryotes have so far that prokaryotes don t? Membrane enclosed nucleus Mitochondria and chloroplasts (plastids) Multiple chromosomes with linear DNA Microtubules needed to organize large genomes

15 Figure 25.9 Protists are one type of Eukaryote! Excavata 5 µm Archaeplastida 20 µm 50 µm Diplomonads Parabasalids Euglenozoans Excavata Stramenopiles Alveolates Rhiza- rians Diatoms Brown algae Dinoflagellates Apicomplexans Ciliates Forams Cercozoans SAR clade SAR Clade 50 µm Unikonta Green algae Red algae Chlorophytes Charophytes Land plants Archaeplastida 100 µm Amoebozoans Opisthokonts Gymnamoebas Slime molds Nucleariids Fungi Choanoflagellates Animals Unikonta 100 µm

16 Animals %2B2010%2Bv1-4a%2Bh-res%2BPsiW.jpg

17 Animals, plants, and fungi the three traditional kingdoms of multicellular eukaryotic life make up almost all of the visible biosphere, and they account for the majority of catalogued species on Earth [1]. The remaining eukaryotes have been assembled for convenience into the protists, a group composed of many diverse lineages, single-celled for the most part, that diverged after Archaea and Bacteria evolved but before plants, animals, or fungi appeared on Earth.

18 Basically a protist is any eukaryotic organism that is not an animal, plant or fungus. Some would say they are not a natural group, or clade, but are grouped together for convenience. Garbage group Catch-all group

19 Diversity!

20 Diversity! Today about 2 million known species (we used to say 60,000 known species) Phyla? (Chordates is one phylum) Reflects the evolutionary experimentation that occurred among the earliest eukaryotes Complex at cellular level-lots of jobs to do many Protists are exceedingly complex!

21 Where might you find them on campus? Where in you might you find them?

22 But also have resting stages so can persist in dry places too. Where do they live? Almost everywhere moist.. oceans, lakes, ponds, rivers, moist terrestrial areas bodies- in body fluids, tissues, cells (some mutualistic, some parasitic) planktonic-floating stick to rocks and other particles

23 Ecologically important! Primary consumers eat primary producers Primary producers: photosynthetic protists and bacteria

24 Some organisms are single celled and some are multicelled. Why might we be interested in the evolution of multicellularity? Why might it evolve? What might be the advantages of being multicellular?

25 Multicellularity evolved many times independently so there must be advantages. It evolved in Several protist lineages Plants Animals Fungi

26 Figure 25.5 Presumably it is sometimes great to get together with other cells. A colonial protist! What do we mean by that? What traits would need to evolve in order to be a colonial organism? How about a truly multicellular organism? What practical things would you have to be able to do?

27 More on multicellularity Need integration! Stick together Communicate Ways of moving materials around Differentiated cells are arranged in tissues Germ vs Soma-controls on mitosis and meiosis

28 What research has been done concerning the evolutionary changes that need to take place for organisms to become multicellar? Two Examples Volvox lineage Choanoflagellates and other animals

29 Figure 25.6 Volvox Lineage Chlamydomonas Gonium Ex. Volvox Lineage Why is it nice to have all this diversity in one lineage? Pandorina Volvox Outer cell wall Cytoplasm Extracellular matrix (ECM)

30 Researchers found that proteins in structures that connect cells in colonial species are similar to proteins that exist in single celled species!?! Few totally new genes..

31 Figure 25.9 Where is Volvox Group? (it is Chlorophyta) Excavata 5 µm Archaeplastida 20 µm 50 µm Diplomonads Parabasalids Euglenozoans Excavata Stramenopiles Alveolates Rhiza- rians Diatoms Brown algae Dinoflagellates Apicomplexans Ciliates Forams Cercozoans SAR clade SAR Clade 50 µm Unikonta Green algae Red algae Chlorophytes Charophytes Land plants Archaeplastida 100 µm Amoebozoans Opisthokonts Gymnamoebas Slime molds Nucleariids Fungi Choanoflagellates Animals Next ex. is a Choanoflagellate! Unikonta 100 µm

32 Figure 32-11a Choanoflagellates are sessile protists; some are colonial. Colony Choanoflagellate cell Food particles Water current

33 Figure 25.7 Choanoflagellates and animals Researchers compared genome of a single celled Choanoflagellate to animals. Why do this? p488 Individual choanoflagellate Choanoflagellates OTHER EUKARY- OTES Sponges Animals Other animals Collar cell (choanocyte)

34 Here are results Where are animals? Each color is a domain or a key part of the cadherin protein (so basically looking at one gene ). What do you notice? Is every domain same? Anything new? Choanoflagellate Hydra Fruit fly Mouse There was one small new piece-the CCD domain in the cadherin protein ( red bead ). Figure 25.8

35 The single celled Choanoflagellate had mostly the same domains for the cadherin protein that in animals is important in cell adhesion and signaling. What are they doing with cell adhesion and signaling genes when not multicellular????? Conclusion-from both of these examples?

36 To summarize 1. Compared two species in volvox lineage-single celled species vs. multicelled species (these are all protists) 2. Compared choanoflagellates (a simple colonial protist) with more complex truly multicellular animals.

2014 Pearson Education, Inc. 1

2014 Pearson Education, Inc. 1 1 4.5 bya 3.5 2.5 1.5 500 mya 1.8 bya 1.5 bya 1.3 bya 1.2 bya 750 mya 635 mya 600 mya 0.5 cm 550 mya 535 mya 1 cm 20 µm (a) A 1.8-billionyear-old fossil eukaryote (b) Tappania, a 1.5-billion-year-old fossil