1 4.5 bya 3.5 1.5 2.5 500 mya 1.8 bya 1.5 bya 1.3 bya 1.2 bya 550 750 mya 635 mya 600 mya mya 0.5 cm 535 mya 1 cm (a) A 1.8-billionyear-old fossil (b) Tappania, a 1.5-billion-year-old fossil that may represent an early alga or fungus 25 µm 25 µm (e) Bonneia, a vase-shaped (c) Bangiomorpha, (d) Proterocladus, an ancient red classified as a alga green alga (f) An early member of the Ediacaran biota (g) Spriggina floundersi, an early animal with many body segments 2 DNA prokaryote Plasma membrane Endoplasmic reticulum Nuclear envelope Nucleus heterotrophic Engulfing of aerobic bacterium Mitochondrion Mitochondrion photosynthetic Engulfing of photosynthetic bacterium Cyanobacterium 3 Membranes are represented as dark lines in the cell. Primary Nucleus Heterotrophic 1 2 3 One of these membranes was lost in red and green algal descendants. Red alga Green alga Dinoflagellates Stramenopiles Euglenids Chlorarachniophytes 4 Chlamydomonas Flagellum Outer cell wall Inner cell wall Gonium Pandorina Outer cell wall Pediastrum 5 Volvox Extracellular matrix (ECM) 6
Individual choanoflagellate OTHER EUKARY- OTES Animals Choanoflagellates Sponges Other animals Collar cell (choanocyte) Choanoflagellate Hydra Fruit fly Mouse CCD domain 7 8 Excavata 5 µm Archaeplastida Stramenopiles Alveo- Rhiza- lates rians Diplomonads Parabasalids Euglenozoans Diatoms Brown algae Dinoflagellates Apicomplexans Ciliates Forams Cercozoans Excavata SAR clade SAR Clade Unikonta 5 µm Green algae Red algae Chlorophytes Charophytes Land plants Archaeplastida 100 µm Amoebozoans Opisthokonts Gymnamoebas Slime molds Nucleariids Fungi Choanoflagellates Animals Unikonta 100 µm Undulating membrane The parabasalid parasite, Trichomonas vaginalis (colorized SEM) 9 10 0.2 µm 8 µm Euglenozoan flagellum Crystalline rod (cross section) Ring of microtubules (cross section) 9 µm Trypanosoma, the kinetoplastid that causes sleeping sickness 11 12
Blade Stipe The diatom Triceratium morlandii (colorized SEM) 40 µm Holdfast 13 14 Flagellum Alveoli Alveolate 0.2 µm 3 µm Pfiesteria shumwayae, a dinoflagellate 15 16 Contractile vacuole Cilia Oral groove Cell mouth Chromatophore Micronucleus Macronucleus Food vacuoles 5 µm 17 18
Bonnemaisonia hamifera (a) Ulva, or sea lettuce 2 cm Nori 8 mm (b) Caulerpa, an intertidal chlorophyte Multicellular chlorophytes Red algae 19 Spores 20 FERTILIZATION Emerging amoeba Fruiting bodies Solitary amoebas (feeding stage) SEXUAL REPRODUCTION Zygote (2n) Other consumers MEIOSIS ASEXUAL REPRODUCTION Herbivorous plankton Amoebas Carnivorous plankton Aggregated amoebas 600 µm Migrating aggregate 200 µm Prokaryotic producers Protistan producers Key Haploid Diploid (2n) 21 EP NP A 22 Arctic (A) NA NI North Atlantic (NA) EA Equatorial Atlantic (EA) South Atlantic (SA) North Indian (NI) South Indian (SI) North Pacific (NP) Equatorial Pacific (EP) South Pacific (SP) SI S SP SA Southern (S) 0.02 0.01 0.00 0.01 0.02 Chlorophyll change (mg/m2 yr) 2.50 1.25 0.00 1.25 2.50 Sea-surface temperature (SST) change ( C) (b) 10 µm (a) 23 24
Sporozoites Inside mosquito Inside human Liver Merozoite Liver cell Oocyst Apex MEIOSIS Zygote (2n) Merozoite Red blood cells Red blood cell 0.5 µm FERTILIZATION Gametes Gametocytes Key Haploid Diploid (2n) 25