BIOL 1543 1st Edition Lecture 16 Outline of Last Lecture I The Origin of Species II What is a species III Species Definitions IV Maintaining Species V MECHANISMS OF SPECIATION VI The tempo of speciation can appear steady or jumpy VII Complex structures VIII History of the Universe IX But how do we know how old things are X Radiometric dating XI Continental Drift XII Earth s Geographical History XIII Consequences of plate tectonics XIV Mass extinctions are followed by diversification XV Phylogeny and Systematics XVI Arranging Life into Kingdoms is a work in progress Outline of Current Lecture I PROKARYOTES II PROTISTS the early Eukaryotes III Plants have adaptations for life on land IV Seedless plants dominated vast coal forests V Seed Plants VI Fruits are the ripened ovary of a flower VII Angiosperms VIII Kingdom FUNGI IX Fungi X What is an animal XI Kingdom Animalia XII Phylum PORIFERA XIII Phylum CNIDARIA XIV Phyla PLATYHELMINTHES and NEMATODA XV Phylum MOLLUSCA XVI Phylum ANNELIDA XVII Phylum ARTHROPODA XVIII Phylum ECHINODERMATA Current Lecture I PROKARYOTES a Prokaryotes appeared on Earth billions of years ago b They are the oldest life forms and remain the most numerous and widespread organisms c The prokaryote domains Archaea and Bacteria are distinguished mainly by genetic differences II PROTISTS the early Eukaryotes a The eukaryotic cell probably originated as a community of prokaryotes i Eukaryotic cells evolved from prokaryotic cells more than 2 billion years ago ii The nucleus and endomembrane system probably evolved from infoldings of the plasma membrane iii Mitochondria and chloroplasts probably evolved from aerobic and photosynthetic endosymbionts respectively III Plants have adaptations for life on land a Plants are multicellular photosynthetic eukaryotes with specific adaptations that are not found in algae i know the definition and the definition of each word in the definition b Supporting the Plant Body i The cell walls of some plant tissues are thickened and strengthened by lignin the chemical that causes thickening of cell plant body c Maintaining Moisture i A waxy cuticle covers the stems and leaves of plants and helps retain water ii Stomata are tiny pores in leaves that allow for gas exchange d Obtaining resources from two sources i Plants have vascular tissue to distribute nutrients throughout the organism xylem microscopic tubes that carry water and minerals up from the roots and phloem tubes that disperse sugar throughout the organism 1 resources from air and soil e Reproducing on Land i Many living plants produce gametes that are encased in protective structures 1 Spores found in nonflowering plants a small usually single cell reproductive body highly resistant to desiccation that can grow into a new organism 2 Seeds found in flowering plants the embryo with food in a protective covering f divided into the nonvascular plants and vascular plant don t need to know the timeline i vascular plants are divided into seedless and seed plants 1 club mosses and ferns spores 2 seed plants Gymnosperms and Angiosperms ii Liver warts horn wart and mosses bryophytes are nonvascular plants IV Seedless plants dominated vast coal forests a Ferns and other seedless plants once dominated ancient forests 360 300 mya Their remains formed coal and other fossil fuels Burning these returns CO2 to the atmosphere b carboniferous coal forests c cycads plants that lived during the dinosaurs V Seed Plants a Seed plants have pollen grains that transport sperm Their embryos are protected in seeds i Gymnosperms produce seeds in cones 1 used for lumber and paper ii The seeds of angiosperms protective ovaries fruits develop within VI Fruits are the ripened ovary of a flower a The key development of angiosperms is the flower the reproductive organ Fertilized eggs within ovaries in the flowers develop into fruits b Fruits are structures adapted for seed dispersal i three types 1 fruit acts to attract animals who eat the fruit go somewhere else and poop out the seeds 2 seed acts to harness natural forces 3 based on the adhesive nature of the seed VII Angiosperms a Agriculture is based almost entirely on angiosperms i Angiosperms provide most of our food and other important commercial products drinks as well 1 about 25 of angiosperms our medications come from ii Through artificial selection and genetic engineering we have influenced the evolution of these plants b Interactions with animals have profoundly influenced angiosperm evolution c produces nectar attracts animals VIII Kingdom FUNGI a Fungi absorb food after digesting it outside their bodies i Fungi are heterotrophic cannot make its own food eukaryotes that digest their food externally and absorb the nutrients ii Most of a fungus is underground 1 a massive feeding network mycelium cells called hyphae long branching filament cells of fungi 2 apothecium the cup shaped reproductive structure seen in fungi IX Fungi a Fungi have enormous ecological benefits and practical uses i They are essential decomposers and provide antibiotics and food X What is an animal a Animals are eukaryotic multicellular heterotrophs that ingest their food b Of the 1 5 million species of organisms known to science over two thirds are animals c Humans have a long history of studying animal diversity but classifying an animal isn t always easy d Biologists often encounter classification problems when organisms evolve similar characteristics e Animals can be characterized by basic features of their body plan i Animal body plans may vary in symmetry body cavity or embryonic development ii radial divided into segments Bilateral right half is a mirror image of the left half and asymmetric symmetry XI Kingdom Animalia a A phylogenetic tree based on morphological comparisons i Protostomes the first embryonic opening they develop is the mouth ii Deuterostomes the first embryonic opening is the anus iii Sponges most underdeveloped organism don t show any specialized body parts or functions XII Phylum PORIFERA a Sponges have a relatively simple porous body i Sponges are the simplest animals they have no true tissues There is also no symmetry in their body plans ii are sessile organisms meaning they stay in the same place b Special cells filter food from the water passing through the porous body i Sponges are known as suspension feeders AKA filter feeders XIII Phylum CNIDARIA a Cnidarians have true tissues and radial symmetry b Their two body forms are attached polyps