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Unformatted text preview: ellularity • Point out some important organisms Chromalveolates Cryptophyte clade not shown 3˚ 2˚ Endosymbio(c events leading to chloroplasts (probably not all of them) 2˚ Plantae Excavates Unikonts Rhizaria Opisthokonts Amoebozoans 2˚ 1˚ see LIFE 9th ed. Fig. 27.1 Endosymbio(c event leading to mitochondria Mul(cellularity Unikonts Chromalveolates see LIFE 9th ed. Fig. 27.1 Plantae Excavates Rhizaria Opisthokonts Amoebozoans two strange terms • unikonts – “one” + “pole” ﬂagellum – Consists of the opisthokonts plus the amoebazoans • opisthokonts (“behind”+”pole”[ﬂagellum]) – i.e. suggests that the ﬂagellum is used for propulsion Diatoms Chromalveolates Plantae Excavates Rhizaria Unikonts Opisthokonts Amoebozoans see LIFE 9th ed. Fig. 27.1 Abundant in the oceans, and fresh water Cell walls contain silicon, preserve well as fossils Foraminiferans Chromalveolates Plantae Excavates Rhizaria Unikonts Opisthokonts Amoebozoans see LIFE 9th ed. Fig. 27.1 Calcium carbonate shells Abundant in oceans Cause of limestone deposits in Earth’s crust Dinoﬂagellates Chromalveolates Plantae Excavates Rhizaria Unikonts Opisthokonts Amoebozoans see LIFE 9th ed. Fig. 27.1 Photosynthesizers, vital primary producers in the oceans Unicellular, with two ﬂagella, one in each groove Some are symbionts of corals Trypanosomes Chromalveolates Plantae Excavates Rhizaria Unikonts Opisthokonts Amoebozoans see LIFE 9th ed. Fig. 27.1 see LIFE 9th ed. Table 27.2 Plasmodium, the malaria parasite Chromalveolates Plantae Excavates Rhizaria Unikonts Opisthokonts Amoebozoans meiosis Figure 27.9 Life Cycle of the Malarial Parasite (A) Like many parasi6c species, the apicomplexan Plasmodium falciparum has a complex life cycle, part of which is spent in mosquitoes of the genus Anopheles and part in humans. The sexual phase (gamete fusion) of this life cycle takes place in the insect, and the zygote is the only diploid stage. (B) Encysted Plasmodium zygotes (ar6ﬁcially colored blue) cover the stomach wall of a mosquito. Invasive sporozoites will hatch from the cysts and be transmiCed to a human, in whom the parasite causes malaria. • Zygote (in mosquito) ‐ very brief diploid stage • Sporozoites ‐ haploid • Gametocytes (in human), get transferred to the mosquito and develop into gametes, undergo fusion to form the zygote Fungi Chromalveolates Plantae Excavates Rhizaria Unikonts Opisthokonts Amoebozoans Lae5porus see LIFE 9th ed. Fig. 27.1 Fungi ‘ • Like animals and chaonoﬂagellates, fungi are opisthokonts (“behind”+”pole”[ﬂagellum]) – These 3 groups descended from a common ancestor that probably had a ﬂagellum • Fungi have these characteris6cs that are shared (and inherited from the very ﬁrst ancestral fungus*) – Absorp6ve heterotrophy – Cell wall (dis6nct from bacterial, plant cell walls) • Cell wall has chi6n (dis6nct from chi6n of arthropod animals) – long polymerized carbohydrate molecule that provides structural rigidity (*phylogenetic term = synapomorphies ->
discussed later in the course) Fungal anatomy • Four of the ﬁve recognized groups of fungi have both unicellular and mul6cellular forms – No unicellular forms known in the glomeromycetes – Unicellular species are called yeasts • In mul6cellular species – Body (vegeta6vely growing mass) is called the mycelium – Individual ﬁlaments are called hyphae (sing. hypha) – Some hyphae are separated by septa (sing. septum), which are incomplete walls, others are coenocy(c (mul6ple nuclei) Saccharomyces The fungal lifestyle • In6mate contact with substrate for absorp6on of nutrients • Many species can tolerate temperature extremes and high concentra6ons of nutrients (hypertonic environments) • But, most fungi need moist environments • Mycelia of many fungi are unseen • Mycelia can grow quickly and a single individual can become massive in size...
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- Spring '08