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BIOLOGY 14 BIODIVERSITY
MODULE 3
Plant Functions
1. Roots ● Function: ○ anchorage ○ water & dissolved nutrient absorption ● Root systems: ○ Taproot & fibrous: arise from radicle ○ Adventitious: arise from anything other than radicle Root cap ● 3 regions: ○ Region of cell division: youngest cells ○ Region of elongation ○ Region of di erentiation/maturation: root hairs ● Thimble shaped mass of parenchyma cells at the tip of root; protects root from injury ● Dictyosomes or golgi bodies release lubricant cells: mucigel (lasting for 1 week) ● Important in perception of gravity (geotropism or gravitropism) ● Amyloplasts or statoliths accumulate at the bottom of cells ● Solute concentration in cytoplasm of root cell > water in soil ● Water di uses by osmosis. It crosses cortex of root to enter xylem via: ○ Symplastic route: water moves from cell to cell ; water enters cytoplasm through plasmodesmata (cytoplasmic connection) ○ Apoplastic route: water moves by capillary action ; water enters endodermis through cortex cell wall; (90% of water moves using this route) ■ Casparian strip: blocks apoplastic ● Metamorphosed root ○ Pneumatophore - mangroves ○ Photosynthetic roots ○ Buttress roots ○ Symbiotic roots: legumes form root nodule ■ Mycorrhizae “fungus roots” protects plant against pathogen & increase surface area for nutrient absorption ■ plant provide food in form of sugar and amino acid 2. Metamorphosed stem ● Tendril ● Bulb - onion bulb ● Tuber ● Rhizome - produce new indiv at nodes below ground ● Stolon - produce new indiv at nodes aboveground ● Cactus stem - store water ● Thorns - provide protection
3. Leaf Leaf of monocot plant ● Often not di erentiated into palisade and spongy layers ● Cells surrounding the vascular tissue (bundle sheath) are distinctive ; often the site for carbon fixation (C4 photosynthesis) ● Bulliform cells : turgid when there’s water (leaf is exposed); collapse when lacking water (leaves curl inwards) Leaves of an aquatic plant: ● stomata in the upper epidermis only ● large intercellular spaces in the spongy mesophyll layer provide buoyancy Metamorphosed leaf: ● Onion leaves store food ● Aloe vera leaves store water ● Leaf tendrils aid in climbing ● Bracts attract pollinator ● Dark hood trick prey ● Flowerpot plant leaves collect soil
Plant Reproduction & Development
Types of Reproduction: ● Asexual - no gametes involved; o spring are clone of parents; no genetic variation in o spring ○ Tuber - potato has buds (eyes) ○ Runner ○ Plantlet ○ Rhizome ● Sexual - involve gametes (sperm & egg); o spring genetically di erent from parents In Angiosperms: Male Gametophyte production ● Stamen = filament + anther ● Inside anther , microsporocyte (microspore mother cell) undergo meiosis to produce microspores ○ Meiosis form 4 haploid daughter cells called pollen tetrads ○ Anther = male sporangium ○ Each pollen tetrad = microspore ■ Microspores because of their small size ○ As anther matures, the 4 microspores separate ○ Haploid nucleus of each microspore undergo mitosis ○ Resulting to 2 haploid nuclei , encased in thick resistant wall forming a pollen grain ■ Pollen grain: immature male gametophyte Female gametophyte production ● Pistil = stigma + style + ovary ● Ovary contains ovules. ● Inside ovule, a megasporocyte undergoes meiosis producing megaspores. ● Meiosis form 4 haploid megaspores ● Only 1 haploid spore matures; undergoes 2 rounds of mitosis ; forming embryo sac which has 8 haploid nuclei ○ Embryo sac : female gametophyte ○ Embryo sac: 3 antipodal cells, 2 polar nuclei, 2 egg synergids
○ Thalloid (ribbon-shaped) or leafy (with stem and leaflike appendages) ● Sporophyte : ○ Brownish or yellowish ○ little or no chlorophyll ○ Has capsule which bears the spores and a stalk called a seta ★ Division Hepatophyta ○ Liverworts ○ Some are leafy, thalloid ○ Sporophytes have capsule that opens by valves, a short stem and a foot embedded in gametophytic tissue ○ Riccia have sporophytes that may be enclosed within the gametophyte ○ Thalloid genera: ■ Cyathodium, Riccia, Marchantia ○ Leafy genera: ■ Plagiochila, Bazzania ★ Anthocerotophyta ○ Hornworts ○ Thalloid ○ Green photosynthetic sporophytes are cylindrical & arise from the upper surface of the gametophyte ○ Only genus:Anthoceros ★ Bryophyta ○ Mosses ○ Brownish sporophytes with complex sporangia arising from green, leafy gametophytes ○ Capsule has a peristome that disperses the spores ○ Seta is long, thin, and long lived ○ Genera : ■ Sphagnum (peat moss) ■ Pogonatum (hairy cap, split-tooth moss) ■ Andreae (granite moss) ■ Physcomitrium (urn moss) ■ Fissidens ■ Thuidium (feather moss)
2. Pteridophytes ● Spore-bearing: ○ Psilophyta, Lycophyta, Sphenophyta, Pterophyta ● Where ferns belong ○ Pterophyta ● Fern allies ○ Psilophyta, Lycophyta, Sphenophyta ★ Division Psilophyta ○ Whisk ferns ○ Vascular plants with well-developed vascular tissues, consisting of xylem and phloem ○ Gametophytes are complex, with multicellular gametangia ○ Plants are homosporous (only one type of spores) ○ Spores contained in synangium ○ Sperms are motile ○ There is no di erentiation between root and shoot ○ Genera: ■ Psilotum, Tmesipteris ★ Lycophyta
○ Club mosses, Chinese ferns and quillworts. ○ Microphyllous ○ Produce a strobilus (a cluster of sporangia with associated sporophylls) ○ Sporangia-bearing leaves ○ Heterospory - two types of spores are produced (microspore & megaspore) ○ Gametophytes are complex, with multicellular gametangia. ○ Sperms are motile ○ Genera : ■ Lycopodium - homosporous ■ Selaginella - heterosporous ■ Isoetes - heterosporous ★ Sphenophyta ○ Horsetails ○ Ribbed joint stems ○ Homosporous ○ Spores contained in a terminal strobilus ○ Each sporangium is supported by sporangiophore (shield-shaped stalk) ○ Gametophytes are complex, with multicellular gametangia ○ Sperms are motile ○ Only genera:Equisetum ★ Pterophyta ○ Ferns ○ Fronds - feathery leaves ○ Fiddlehead/crozier - coiled young frond ○ Circinate vernation - coiling ○ Mostly homosporous, few heterosporous ○ Sorus - clusters of sporangia containing spores ■ It is located at the underside of frond ○ Indusium - membranous flap of sorus ○ Prothalli - gametophytes that are complex with multicellular gametangia ○ Sperms are motile.
3. Spermatophytes ● Gymnosperms - naked seeds ○ Pinophyta, Cycadophyta, Ginkgophyta, Gnetophyta ● Angiosperms - enclosed seeds ○ Magnoliophyta ★ Division Pinophyta ○ Conifers ○ Mostly trees, some shrubs ○ Hard or leathery leaves ○ Heterosporous; seed-forming ○ Seeds - naked at the time of fertilization ○ Archegonia - multicellular antheridia - lacking ○ Sperms are immotile ; carried by the pollen tube ○ Gametophytes - reduced , held within ovule (megagametophytes) or pollen grain (microgametophytes) ★ Cycadophyta ○ Cycads ○ Palm-like, heterosporous with large, pinnate leaves and terminal cones
FUNGI
● Immotile ● Produce spores ● Have cell walls ● Not plants because: ○ Body organization di ers from plants ○ Biochemical pathways are completely di erent ● More closely related to animals than to plants General Characteristics of Fungi
1. Body plan ● unicellular (yeast), filamentous (molds), thalloid (mushrooms) ● In filamentous & thalloid: ○ Hyphae - individual filaments ○ Mycelium - several branches forming a network ● Zygomycetes ○ Hyphae have no cross walls or septa ○ multinucleate cells ○ Chitosan - cell wall ● Ascomycetes & basidiomycetes ○ Hyphae have septa ○ Chitin - cell wall ● Fungi have chitinous cell wall unlike plants which have cellulosic cell wall. 2. Nutrition ● Heterotrophic , unlike plants ○ Biotrophs - parasites obtaining nutrients from living hosts without killing them ○ Necrotrophs - parasites obtaining nutrients from living hosts, eventually killing them ○ Saprotrophs - decomposers obtaining nutrients from dead organisms ● Secrete enzymes that digest macromolecules of their nutrient source. ● Upon breakdown of macromolecules, fungi can absorb them. 3. Life cycle ● Haplontic ○ Zygote - only diploid stage ● Zygotic meiosis ○ Zygote undergoes meiosis resulting in haploid spores that develop into hyphae. ● No male or female ● Plasmogamy - fusion of protoplasts ○ resulting in heterokaryotic cell with 2 unfused haploid nuclei from either individual ● Zygomycetes ○ heterokaryotic cell does not divide prior to karyogamy (fusion of two nuclei) that results to the diploid zygote ● Ascomycetes & basidiomycetes ○ heterokaryotic cell divides without the haploid nuclei fusing ○ produces the fruiting body ( ascocarp in ascomycetes; basidiocarp in basidiomycetes) ○ Karyogamy leads to the formation of the zygote
Example ng basidiocarp:Coprinus comatus Classification 9 phyla formed based on patterns of sexual reproduction & molecular data: ● Opisthosporidia ● Chytridiomycota ● Neocallimastigomycota ● Blastocladiomycota ● Zoopagomycota ● Mucoromycota ● Glomeromycota ● Ascomycota ● Basidiomycota
1. Chytridiomycota ● Chytrids ● Flagellated motile cells ● Water molds in freshwater ● Most are unicellular ● Allomyces form a small nonseptate mycelium ● Some parasitic ● Other feed on detritus 2. Mucoromycota
● Includes some members of
the now-defunct phylum Zygomycota (zygomycetes) & common bread mold (Rhizopus) ● Saprobes, parasites or symbionts ● Hyphae are characterized by absence of septa ● Form thick-walled zygospore after karyogamy ● Zygospore becomes dormant for months before germinating Other members formerly placed in Zygomycota are now included in Zoopagomycota and Glomeromycota.
3. Glomeromycota ● Glomeromycetes ○ Formerly placed in Zygomycota ● Do not produce zygospore or any sexual structure ● Obligate symbionts of land plants. ● Arbuscular mycorrhiza - symbiotic relationship ● Mycelia lack septa 4. Ascomycota ● Ascomycetes ● 2/3 of the kingdom ● largest phylum ● Ascus - sexual structure containing spores ○ defining feature of this group ● there are representatives that do not reproduce sexually. ● Unicellular yeasts (Saccharomyces), thalloid cup fungi (Cookeina) ● In filamentous & thalloid ○ Mycelia have septal walls with pores 5. Basidiomycota ● Basidiomycetes ● 2nd largest group
● Associations with plants called mycorrhizae ○ Mycorrhizae - symbiotic associations formed between soil fungi and plant roots ○ B eneficial to growth of plants ○ Fungi aid in the release of nitrogen by decomposition ○ Fungi receive food from the plants ○ In orchids, seed germination is totally dependent on fungal association.
3. Uses for humans ● Food industry, medicine, and agriculture. ● Improved resource e ciency ● Edible fungi such as mushrooms are sold as food. ● Saccharomyces cerevisiae in making bread and alcoholic products ● Antibiotics such as penicillin derived from Penicillium. ● Other antibiotics from fungi include cephalosporin, fumagillin, fusidic acid, and helvolic acid. ● Antitumor, antiviral, hypoglycemic, and hypolipidemic uses ANIMALS Phyla: 1. Porifera - sponge 2. Cnidaria - jellyfish, coral, hydra 3. Platyhelminthes - flatworm, tapeworm 4. Nematoda - roundworm 5. Annelida - segmented worm 6. Mollusca - snail, squid, shellfish 7. Arthropoda 8. Echinodermata - sea urchin, sea star, feather star, brittle star 9. Chordata **I. General Characteristics of Animals
- Eukaryotic, multicellular, motile** ● complex multicellular organization ● Cells → Tissues → Organs → Organ Systems For protection support movement: ○ Integumentary ○ Skeletal ○ Muscular For maintenance: ○ Digestive ○ Respiratory ○ Circulatory ○ Excretory For integration & coordination: ○ Endocrine ○ Nervous & associated sense organs For perpetuation of species ○ Reproductive 2. Lack cell wall, plastid, vacuole ● Absence of cell walls increases the variety of cell shapes; but it poses problems when animal cells are exposed to fluid environments 3. Principal carbohydrate storage product in animals is glycogen ● Excess carbohydrates stored as: Starch -plants; Glycogen -animal ● Glycogen - stored in **muscles & liver
- Cell division occur by furrowing** ● The absence of a cell wall facilitates the constriction of cell during cytokinesis (cell division) 5. Ingestive mode of nutrition ● Heterotrophic; no photosynthetic pigments; cannot manufacture own food ● Process involved:
○ Ingestion – taking in of bulk food ○ Digestion – internal, enzymatic, extracellular; occurs within specialized cavities called digestive tract ○ Absorption – broken down food are absorbed by cell lining the digestive tract; then transported to internal cells
6. Diplontic life cycle ● Haploid gamete; diploid adult ● Gametic meiosis ● Sexual reproduction ○ Gonads - reproductive organ ○ Testis produce spermatozoa; Ovary produce egg ● Some are hermaphrodites - producing both male female gamete ● Oogamous fertilization 7. Embryo-forming ● Zygote → Multicellular embryo → Adult ● Morula- continued cleavage forming a multicellular mass ● Blastula- blastocoel forming inside the morula ● Gastrulation - rearranges the blastula to form three-layered embryo with a primitive gut (archenteron) ● Movement of cell masses occur during morphogenesis to produce primary germ layers (ectoderm, mesoderm, endoderm) Organogenesis ● forms the organs from the three embryonic germ layers ○ neural tube, notochord, somites Fates of germ layers ● Ectoderm ○ Hair, nail, epidermis, brain, nerves ● Mesoderm ○ Notochord in chordates, dermis, blood vessels, heart, bones, cartilage, muscle ● Endoderm ○ Internal lining of gut & respiratory pathways, liver, pancreas In frogs, stages from fertilization to hatching is known as embryogenesis. 8. Exhibit closed type development ● Once the fully developed embryo is formed, no new organ will be produced in the adult stage ● In lizards and starfishes, new organs (i.e. tails or arms respectively) are formed by regeneration of parts cast o (anatomy) **II. Animal Body Plans
- Symmetry** ● pattern of arrangement of body parts around an axis ○ Asymmetrical - irregular arrangement; uncommon
● Vertebrate – with an endoskeleton; vertebral column surrounds the spinal cord Body cavity ● Acoelomate - lack of body cavity; single cavity is gut ● Pseudocoelomate - with pseudocoel (body cavity derived from embryo’s blastocoel) ● Coelomate - form mesoderm and archenteron III. Animal Tissues ● Cells exhibiting similar characteristics and functions form the tissues ● Tissues compose all organs and systems of the body
1. Epithelial ● For protection, absorption, secretion, and excretion ● Loosely packed with little extracellular spaces ● Avascular (lack blood vessels) ○ Squamous - flat; body surfaces ○ Columnar - trachea, urethra, esophagus, stomach, intestine ○ Cuboidal - ducts, glands, renal tubule of kidney 2. Connective ● Support, transport, protection, and repair ○ Loose (blood and adipose) ○ Dense (tendons) ○ Specialized (bone) 3. Muscular ● Striated - skeletal muscles ○ long and tapered ; muscle fibers; multinucleated , nuclei at periphery; voluntary contraction ● Smooth - outer wall of tubular bodies ○ no striations ; involuntary ○ trachea, uterus, blood vessels, GIT ● Cardiac : heart ○ resembles striated muscles, with striations called intercalated discs 4. Nervous ● Nervous system ○ Neurons - indiv functional units ○ Dendrite & axon - composing of processes ○ Cell body - contains cellular structures IV. Animal Functions A. Protection, Support, Movement ● Presence of external body covering ○ Integument ● Supporting framework ○ Skeletal ○ External: give shape ○ Internal: leverage for locomotion ● Body movement & locomotion ○ External: give shape Integument ● protective outer covering of the body ● skin + structures associated with the skin ○ One-layered epidermis - porifera & cnidaria
○ One layer epidermis with cuticle - external and non-cellular secretions prevents loss of body fluids; plat, nema, annelida ○ Epidermis secretes external skeleton (exoskeleton) ■ Calcium carbonate in mollusks & crustacean ■ Chitin cuticle; chitin includes also waxy surface ○ Thin, prickly epidermis - echinoderms ○ Keratinized skin - chordata Skeleton ● Hydrostatic skeleton - fluid under pressure in a fluid-filled cavity ; surrounded by circular & longitudinal muscle ○ Worms, cnidarian ● Exoskeleton - hard material secreted; calcium carbonate or chitin ○ Arthropods and mollusks ○ Protection from injury & desiccation BUT ○ Limits size of the organism (needs ecdysis or shedding) ● Endoskeleton - internal skeleton 2 kinds of supportive tissues: ○ Cartilage - chondrocytes; laid in matrix of protein ( collagen fibers ) and polysaccharides ■ Cartilaginous^ fishes, neonatal mammals ○ Bone- osteocytes, collagen fibers, calcium phosphate ○ Does not impede growth BUT cannot be repaired Muscles ● Striated : skeletal muscles; voluntary contraction ● Smooth : exhibits no visible striations; involuntary ● Cardiac : forms the heart B. Internal Transport ● Without circulatory
- Sea anemone, Planaria ○ Use di usion through gastrovascular cavity
○ Small size, flattened shape =
high surface-volume ratio = better absorption
- Nematode (pseudocoelomates) ○ Fluid transport through body cavity ○ Circulating fluid within pseudocoelom
- Echinoderms ○ Rely on movement of coelomic fluid ● With circulatory
- Only coelomate animals C. Ingestive Nutrition ● Heterotrophic Nutrient acquisition ● Active food seeking -vertebrates ● Substrate swallowing - worms ● Filter feeding - cnid, mollusks ● Fluid feeders - some plat and nematodes Muscular movement and nervous coordination facilitate nutrient acquisition. Types of digestive system ● Incomplete - 1 opening; gastrovascular cavity; cnid & plat
● Complete - 2 opening; digestive
tract/alimentary tract/enteron/gut ○ All except pori, cnid, plat ○ Compartmentalized
