PLANT DIVERSITY. EVOLUTION OF LAND PLANTS KINGDOM: Plantae

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1 PLANT DIVERSITY 1 EVOLUTION OF LAND PLANTS KINGDOM: Plantae Spores Leaf Ancestral green algae Flagellated sperm for reproduction Plenty of water Nutrients and CO 2 diffuse into tissues Holdfast Flagellated sperm Mosses (470mya) Non vascular plants Need moisture to reproduce Can t lose water Nutrients in soil CO 2 in air Gravity!!! Stem Roots Vascular plants Stomata Roots and stems connected by vascular system Lignin to hold plant upright Ferns (425mya) 2 1

2 THE PLANT LIFE CYCLE Plants have a life cycle called: alternation of generations Spores (n) HAPLOID ADULT (male or female) Gametophyte plant (n) Haploid (n) Diploid (2n) Sperm (n) Egg (n) DIPLOID Meiosis ADULT with sporangia DIPLOID JUVENILE Fertilization DIPLOID ZYGOTE Sporophyte plant (2n) 3 THE PLANT LIFE CYCLE The life cycle of a fern (vascular land plant) A Fern Life Cycle Gametophyte plant (n) Key Haploid (n) Diploid (2n) Spores Male gametangium Sperm Female gametangium Egg Sporangia Meiosis Mature sporophyte Fertilization New sporophyte growing from the gametophyte Zygote 4 2

3 MOSSES PHYLUM: Bryophyta Non vascular land plants (no, xylem, phloem, lignin) No true roots or leaves Form dense mats of many individuals (no lignin to stand up!) Live in moist environments Flagellated sperm 5 FERNS PHYLA: Monilophyta and Lycophyta Vascular seedless land plants (xylem, phloem, lignin) Have true roots and leaves Spores can disperse in air but fertilization must happen in water Flagellated sperm Common in tropical and temperate forests 6 3

4 THE CARBONIFEROUS PERIOD Ferns were giant and very abundant. They contributed to the increase in oxygen in Earth s atmosphere and fossil fuels that we now use for energy. 7 VASCULAR PLANTS WITH SEEDS Evolved 360mya; account for 90% of plants today ADAPTATIONS OF VASCULAR PLANTS W/SEEDS Pollen grains carry spores through the air (haploid) Pollination male pollen grain lands on female reproductive part Fertilization after pollination, sperm fertilizes egg(s) to create diploid zygote(s) A protective seed forms around the zygote(s) with food inside Seed gets carried off into the world 8 4

5 GYMNOSPERMS (Vascular seed plants) Many phyla; mostly cone bearing trees, ginko trees, cycads Sporangia found in male and female cones Pollen released in the air Fruitless; Slow growing; Long lived; Fire factoid (conifers) Female Sporangia Longitudinal section of female cone (holds ovules) Longitudinal section of male cone (holds pollen) Male Sporangia 9 GIANT SEQUOIA TREES Example of a Gymnosperm 10 5

6 ANGIOSPERMS(Vascular seed plants) Many phyla; Flowering plants, grasses and fruits Male and female sporangia all located in the flower Produce fruit (see figure 17.7) Pollen travels in air or by animal carriers Stigma Style Ovary Carpel (female parts) Petal Anther Stamen Filament (male parts) FRUIT: The ripened ovary of a flower Receptacle Ovule Sepal 11 ANGIOSPERM POLLINATION Invest energy into making structures to maximize pollination Lots of stamens for wind pollination Nectar to attract bees & stamens that rub on bees Vibrant colors or scents can attract specific animals Birds red/orange Beetles sweet scents 12 6

7 ANGIOSPERMS PRODUCE FRUIT Fruits aid in dispersal of angiosperms Dandelion seeds: air seed dispersal Cocklebur fruits: seeds dispersed by attaching to animal fur Edible fruits: seeds dispersed and given nutrients by animal poop! Germination: The growth of a seed into a diploid sporophyte plant Fruit Seed dispersal 13 ANGIOSPERM CROPS Wheat, corn, rice and spices are all dried angiosperm fruits Evolution has created a variety of human food sources Deforestation and agriculture has altered natural habitats Need ways to farm without deforestation GMOs can tolerate, insects, heat, drought Wild plants can be found that naturally tolerate heat and drought (African grains) 14 7

8 EVOLUTION OF LAND PLANTS You should know the order of evolution of mosses, ferns, gymnosperms and angiosperms and the characteristics of each. Ancestral green alga Origin of land plants (about 470 mya) 1 Liverworts Mosses Nonvascular plants (bryophytes) Land plants Hornworts 2 Origin of vascular plants (about 425 mya) 3 Origin of seed plants (about 360 mya) Lycophytes (club mosses, spike mosses, quillworts) Monilophytes (ferns, horsetails, whisk ferns) Gymnosperms Angiosperms Seedless vascular plants Seed plants Vascular plants Millions of years ago (mya) 15 FUNGAL DIVERSITY 16 8

9 FUNGI Evolved from a heterotrophic protist Fungi are more closely related to animals than they are plants! Ancestral eukaryote Protists Protists Key All unicellular Both unicellular and multicellular All multicellular Green algae Red algae Other green algae Brown algae Land plants Protists More protists Fungi Yep. Protists Animals 17 KINGDOM: FUNGI Heterotrophs that acquire their nutrients by absorption. Hyphae (feeding structures) Have cell walls made of chitin Decomposers symbionts and parasites Asexual reproduction (molds!) Sexual reproduction (heterokaryotic stage) Mycelium: a mass of hyphae Reproductive structure Spore-producing structures (tips of hyphae) 18 9

10 FUNGAL DECOMPOSERS Some fungi break recycle dead material into nutrients Important ecosystem function Can break down toxins and pollutants Reproductive structures of mushrooms on a dead log So we eat reproductive parts of fungi. Mmmm 19 FUNGAL PARASITES 30% of fungi parasitize protists, plants and animals White nose syndrome in bats Andes Mountains frog die offs Human infections Dutch elm disease in 1926 Human food crops 20 10

11 FUNGAL SYMBIONTS Lichens are associations of green algae or cyanobacteria with fungi Fungus gets food Benefit for algae? Lichens can tolerate harsh environments (temp, moisture, soil) Sensitive to air quality Some lichens are 1000s of years old! Algal cell Fungal hyphae Reindeer moss in the arctic tundra Symbiosis: a relationship between two species living closely 21 FUNGAL SYMBIONTS Fungal mycorrhizae deliver nutrients to plants in exchange for food Fungi thread into root and form hair like projections into the soil Occurs in 80% of all plants; important in agriculture May have helped ancient plants to colonize land (present in mosses, fossil evidence) 22 11

12 Ancestral eukaryote Protists Protists Green algae Red algae Other green algae Brown algae Land plants Protists More protists Fungi Key All unicellular Both unicellular and multicellular All multicellular Yep. Protists Animals 23 ANIMAL DIVERSITY 24 12

13 ANIMAL EVOLUTION The first animals likely evolved from a heterotrophic protist 1 bya Evolved from soft to hard bodied organisms First animal fossil 575 mya Cambrian explosion 25 KINGDOM: Animalia Heterotrophs that acquire their nutrients by ingestion Lack cell walls (have collagen for support) Have specialized cells Diploid organisms that reproduce sexually Characterized by body plan 26 13

14 ANIMAL BODY PLANS Groups of animals can be distinguished by their body plans Radial animals are often sedentary (sessile) or drift passively Bilateral animals are often mobile Radial Symmetry (Anemone) Posterior Bilateral Symmetry (Lobster) Dorsal Anterior Ventral 27 KINGDOM: Animalia No true tissues Ancestral colonial protist True tissues Radial symmetry Eumetazoans Bilateral symmetry Bilaterians Ecdysozoans Lophotrochozoans Deuterostomes Sponges Cnidarians Flatworms Molluscs Annelids Nematodes Arthropods Echinoderms Chordates Invertebrates 28 14