Bio 102 General Biology 2 PDF

GENERAL BIOLOGY II BIO 102 GENERALIZE SURVEY OF PLANTS AND ANIMAL KINGDOM Classifications of Living Organisms Aristotle (384-322 BC) a Greek philosopher, was the first to make an attempt to classify living organisms. The present method of classifying and naming living organisms is...

GENERAL BIOLOGY II BIO 102 GENERALIZE SURVEY OF PLANTS AND ANIMAL KINGDOM Classifications of Living Organisms Aristotle (384-322 BC) a Greek philosopher, was the first to make an attempt to classify living organisms. The present method of classifying and naming living organisms is based on the work of Linnaeus (1707-1778), a Swedish naturalist. The study of the general principle of classification is known as taxonomy or systematic.  Hierarchy of Living Organisms Kingdom has the largest group of organisms. Each kingdom is split into smaller groups, and these groups into even smaller groups and so on. The arrangement of living organisms in this hierarchy from the highest to the lowest is as follows: Kingdom Phylum or Division (Plants) Class Order Genus Species  As we go down the variety of organisms decreases. The kingdom has the largest variety of organisms. They have certain important features in common but show many differences. The species is the smallest unit of Classification. They are identical in general appearance. They can mate with one another and produce fertile offspring. Organisms within a species are very closely related  Binomial Nomenclature This is the use of a standard system to name living organisms, though we are familiar with common names of living organisms such as Mango, Goat, Pawpaw, Lion etc. In Binomial Nomenclature, each kind of organisms is given two names: the first name is the genus to which the organism belongs and the second been the species to which it belongs. On the genius name begins with an initial capital letter, Hence the scientific name of Pawpaw is Carica Papaya, Lizard – Agama agama. The names are written in italics or underlined separately.  Kingdoms All living organism were placed into two kingdoms by Linnaeus. The Kingdom was plants and animals. This is known as two – kingdom classification. In this classification, many one-celled organisms could not fit in properly; it failed to establish clear-cut distinction between plants and animals. It also could not indicate correct relations among organisms.  So, in 1969, Whittaker proposed the five- kingdom classification which is generally used at present. The classifications are: Moneras Protists Fungi Plantae and Animalia  The Kingdom Monera contains the prokaryotes – Which are the very simple –celled organisms that has no true nuclei. The eukaryotes- which cells are highly organized with definite or true nuclei are classified into the four remaining kingdom: protist, Kingdom Monera (Prokaryotes) Single- Celled organisms, motile or non- motile, microscopic. Simple – Celled Structure with no definite nucleus. Examples includes Bacteria, Blue-green algae, actinomycetes  Kingdom Protista (Eukaryotes) Single –Celled, motile or non-motile. Organisms are much larger than the monerans. Complex Cell Structure with a definite nucleus. Examples includes: Chlamydomonas, Amoeba  Kingdom Fungi (Eukaryotes) Non-motile organisms usually of thread-like structure or hyphae. Plant- like but cannot carry out photosynthesis due to absence of chlorophyll, obtain food through surface from living or non living organism source by absorption, reproduction could be by asexual or sexual or sexual spores. Examples includes: moulds, Mushrooms, shine moulds, yeasts.  Kingdom Plantae Many-celled, non-motile, contain Chlorophyll that enables them make their own food by Photosynthesis. Plants have indeterminate growth. Examples includes: Mosses, Ferns, Pines, Seed Plants (yam, bean, and plants).  Kingdom Plantae Plants can readily be understood in the context of their autotrophic mode of nutrition. They simply transform light energy into chemical energy by anchoring firmly in one place with a maximum surface area to capture sunlight. Plants use the cheapest material around, water and carbohydrate to generate size. Because plants are immobile, they are extremely responsive to environmental cues and have their life cycle in perfect synchrony with the seasons.  Plants have a unique mode of development. This involves giving by meristems at their tips. They also have remarkable power of regeneration. Any single plant cell can regenerate an entire plant with its cell types. The cells have cellulose cell wall.  The plant kingdom is mainly classified into: Thallophytes (Alga) Bryophytes Pteridophytes Gymnosperms Angiosperms  Tracheophytes (Pteridophytes, Gymnosperm and Angiosperm) The tracheophytes are known as vascular plants. This is because they have vessels or vascular tissues for conducting water and food. They are the largest group of plants which includes the seed plants (flowering plants) as well as some spore-bearing, non flowering plants like ferns.  Pteridophytes, A pteridophyte is a vascular plant (with xylem and phloem) that reproduces by means of spores. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as "cryptogams ", meaning that their means of reproduction is hidden E.g fern in forest  Gymnosperm The gymnosperms 'revealed seeds') are a group of seed-producing plants that includes conifers, cycads, Ginkgo, and gnetophytes, forming the clade Gymnospermae. The term gymnosperm comes from the composite word in Greek: 'naked' and seed'), literally meaning 'naked seeds'. The name is based on the unenclosed condition of their seeds (called ovules in their unfertilized state). E.g conifers, cycade, ginkgo biloba, pine tree Gymnosperm  Angiosperm Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae commonly called angiosperms. They include all forbs (flowering plants without a woody stem), grasses and grass-like plants, a vast majority of broad-leaved trees, shrubs and vines, and most aquatic plants. The term "angiosperm" is derived from the Greek words ('container, vessel') and8 ('seed'), meaning that the seeds are enclosed within a fruit. They are by far the most diverse group of land plants with 64 orders, 416 families, approximately 13,000 known genera and 300,000 known species. Angiosperms were formerly called Magnoliophyta (/mæɡˌnoʊliˈɒfətə, -əˈfaɪtə/). Flowering plants  Evaluation 1. Differentiate between Bryophytes and Tracheophytes 2. Why are invertebrates grouped under the kingdom Animalia  Evaluation 2 Give an example(s) of the following alga types: 1. Green Algae 2. Brown Algae 3. Golden – Brown Algae 4. Yellow-green Algae  Monocotyledonous Root The anatomy of the monocot root is similar to the dicot root in many respects. It has epidermis, cortex, endodermis, pericycle, vascular bundles and pith. As compared to the dicot root which have fewer xylem bundles, there are usually more than six (polyarch) xylem bundles in the monocot root. Pith is large and well developed. Monocotyledonous roots do not undergo any secondary growth.  Dicotyledonous Stem The transverse section of a typical young dicotyledonous stem shows that the epidermis is the outermost protective layer of the stem Covered with a thin layer of cuticle, it may bear trichomes and a few stomata.  Algae or Thallophyta Objectives Algal Morphology Characteristic Forms of Algae Classification of Algae Spirogyra Structure of a spirogyra Ecological Adaptation  Introduction In this unit we shall be looking at the first classification of the plant kingdom, which is the Algae. Algae show great diversity in size and structure. They are unicellular, Colonical, filamentous and thalloid in form. Some are microscopic, while others are very big in size. They do not form complex organs or tissues. The study of their ultra structure under electron microscope shows that blue-green algae have prokaryotic type of cell like that of bacteria while all other algae are eukaryotes  Algal Morphology Morphologically, algae can be distinguished as unicellular, colonial, filamentous, heterotrichus, thalloid and polysiphoid forms. Examples of each of these types of algae are given below.  Various Forms of Algae 1. Unicellular Algae: Example Anacystis, Microcystis 2. Colonial Algae Microcystic, Volvox 3. Filamentions Algae Nostoc} blue-green algae; Ulothrix, Oedogonium 4. Heterotrichous Algae Draparnaldiopsis, Coleochaete, Ectocarpus 5. Thalloid Ulva, Fucus} Brown algae 6. Polysiphonoid Polysiphonia (Red algae)  Characteristics of Algae They are simple plants without roots, stems and leaves. They have Chlorophyll. Some have blue, yellow, brown and red pigments with the chlorophyll. Majority are uni-cellular while few are multicellular. Some, such as sea weeds are large. They are mainly aquatic, with a few on damp soils and shady places examples are spirogyra, anabaena and Sargassum The cell wall of algae is composed of a true celloulose. Reserve carbohydrates are usually starch and not glycogen as in fungi.  Classification of algae 1. Cyanophyta (prokaryotic algae) or blue-green algae eg. Including Nostoc, An abaena, Oscillatoria. 2. Chlorophyta (algae) eg. Chlamydomonas, Spirogyra, Chlorella 3. Phaeophyta (brown algae) eg. Fucus, Sargassum, laminaria. 4. Xantophyta (yellow –green algae) eg. Vaucheria, Botrydium 5. Chrysophyta (Golden-Brown algae) eg. Synura, Mallomonas, Chromalina. 6. Euglenophyta (Euglenoids) eg. Euglena, Trachelommas. 7. Dinophyta (Dinoflagellates) e.g. Ceratium, Peridinum. 8. Crytophyta(Crytomanads) e.g. Crytomones, Chroomonas. 9. Bucillariophyta (Diatoms) eg. Diatoma, fragilaria.  Spirogyra Spirogyra a green algae belongs to the family Chlorophyceae and the order conjulaes or Zygnematales. It is a cosmopolitan plant which forms a tangled mass of filaments floratiny on stagnant fresh water, especially in ponds, ditches, springs and streams. Some species grow in running water. Such species produce a short unicellular organ of attachment, called hapteron, for anchorage on Sea weeds.  Spirogyra is commonly found as bright green masses of thread-like or filamentous structures on the surfaces of waters, and is often referred to as a “Pond Scum”.  Structure of a Spirogyra Mature filament is unbranched and consists of single row of identical cylindrical cells joined end to end. Cell wall is made of Cellulose and pectin External cell wall is covered by mucilage, making it shinny. Cyloplasm is a thin layer with spiral bands of chloroplast. Nucleus is suspended at the centre by strands of Cytoplasm. Chloroplast contains small nodular protoplasmic bodies called the pyrenoids. Starch grains are deposited around each pyrenoid.  Algae range from Unicellar (microscopic) to large (macroscopic) thalloid forms growing in variety of habitats almost all over the surface of earth. Wherever there is water, a little moisture or water vapours, and light, however feeble, Algae are sure to appear as green, yellow or brown patch. When several types of algae grow together under similar natural conditions we call them communities. The composition of a community is determines by the physical and chemical nature of the habitat. In many cases, the algal community indicates to us about the nature of the habitat, whether, it is rich or poor in nutrients or polluted etc., in other words it serves as an ecological indicator.  Aquatic Algae Most of the algae grow in water; however, there are also sub-aerial algae. Depending on the concentration of salts there are various kinds of water bodies, such as fresh water brackish water, sea water, brine-salt lakes and salt pans. There habitats nowadays may contain many types of pollutants, like excessive organic metal, heavy metals, pesticides, industrial effluents which are produced and dumped into them by man. This greatly affects algae and other organisms present in the water.  Fresh Water Habitats Fresh water habitats comprise of rivers, mountains streams, lakes and temporary rainwater puddles. Examples of Algae find here include green algae like oedogonium, diatoms, desmids, etc. In slow flowing rivers with rocky shores, one may find many filamentous algae like spirogyra, oedogonium. The surface of submerged rocks also shows epiphytic algae like desmids and Cyanobacteria.  Marine Habitats Sea inhabits largest number of algae collectively known as seaweed. Seacoast is periodically flooded and exposed to sun because of the feeds. The area between the high tide and low tide level is known as intertidal zone. The seaweed that grows in the intertidal zone face alternate drying and wetting. They are also firmily attached to the underlying rocks by means of hold fasts. At times they may get detached and found flowing in the open sea as in the case of Sargasso sea. Example of seaweed include Sargassum wightii (brown algae), Turbinaria, gracilaria edulis  Special Attributes Algae are also found in special habitats where environmental conditions are in extreme such as Brines and salt lakes where cyano bacteria (Anabaeria) and Unicellulal green alga Dunaliella can be found; Thermal Regions (not water) thermal springs with temperatures ranging from 40º to 70 ºc) inhabit alga like oscillareria, Mastigocladus and Cyanobacteria; Polar Regions (extremely cold climate conditions) where Nostoc, oscillatoria, can be found.  Soil and Subaerial Algae Surface layers of soils provide a favourable substratum when wet for the growth of several types of algas. Terrestrial algae such anabaena, play a major role as primary colonizers on newly exposed areas. Subaerial algae obtain their water from the moisture in air and grow if moisture is available. They are capable of enduring drought like the soil algae. One can see dark brown patches, sometimes with a velvelty carpet like cushions covering extensively the exposed surfaces of buildings, walls, finances, asbestos, roofs, rock surfaces and also tree trunks.  Evaluation Give an example(s) of the following alga types: 1. Green Algae 2. Brown Algae 3. Golden – Brown Algae 4. Yellow-green Algae  Evaluation Outline the general characteristic features of named Algae 2. Describe the structure of filamentous Algae  BRYOPHYTES During the course of evolution, a change from aquatic habitat to terrestrial habitat occurred and the only primitive land plants evolved. These are known as bryophytes. Although bryophytes colonize terrestrial habitats but they are still dependent on water for completion of their life cycle. They produce motile male gametes which require a thin film of water for their motility to reach the non-motile female gamete to accomplish fertilization.  General Characteristics of Bryophytes Bryophytes lack roots and do not have vascular system. Some mosses have a primitive system of tubes that conduct water and food – conducting tubes are called leptoids. A single plant is very small, hardly a few cm in size. It seldom grows large because of lack of supporting tissues. Bryophytes show two distinct and well defined phases of life cycle, sexual and asexual which follow each other. T he gametophyte is haploid and produces gametes. The Sporophytes is diploid and produces spore. The haploid generation alternates with diploid genetic known as Alternation of generation. The gametophyte may be thalloid or has an axis differential into stem-like and leaf-like structures which have xylem and phloem. The gametophyte is green, photosynthetic and nutritionally independent, and anchors to the soil by unicellular or multicellular filaments called rhizoids.  Rhizoids appear like roots but they lack vascular tissues  Morphology of Bryophytes Bryophyte is mostly divided into liverworts and mosses.  Liverworts Gametophytes usually are close to the ground. There are 2 forms of liverworts namely; thalloid liverworts (gametophyte) and is dorsi-ventral, with upper and lower surfaces. Leafy liverworts (differentiated into leaf-like and stem-like structures). Leaves of liverworts are without midribs. Grows on moist ground or rocks that are also wet. (can be found in muddy areas. Examples include Marchantia and Riccia  Mosses This is the largest class of Bryophytes. They are divided into three subclasses: Sphagnidae (Reat mosses) Andreaide rock mosses) and Bryidae (true mosses). Example includes funaria  BRYOPHYTE summary 1. Bryophytes are simple non-vascular land plants and it is believe that they evolved from green algae because of several common characteristics. 2. Bryophytes shows two distinct and well defined phase of life cycle ie. The gametophyte phase and the sporophyte phase. The gametophyte produces the gamete while the sporophyte produces the spore. 3. The challenges of land environment for a plant are fixation to the ground conduction of water and dispersal of sperms and spores. Bryophytes take care of there by developing land adaptations such as epidermis, cuticles, stomata, air spores, rhizoids, etc. 4. Liverworts (Marchantia) and Mosses (Funaria) are example of Bryophytes.  Pteridophyte General Characteristics of Pteridophytes i. Pteridophytes have two distinct phases in the life cycle. These are Gametophyte and Sporophytes which follow each other in regular succession. The two generations look different.  Xtics of Pteridophytes cont’d ii. The sporophyte is the dominant generation, independent of the gametophyte; it possesses a vascular system and it is in a different habitat. iii. Pteridophytes exhibit a great variation in form, size and structure. iv. Most are herbaceous except a few woody tree ferns. v. They may be dorsi-ventral or radial in symmetry. vi. They have dichotomously or laterally branched stems that bear megaphyllous leaves. vii. Roots are generally adventitious, the primary embryonic root being short-lived. viii. Spores are produced in special structures called the sporangia that are invariably subtended by life-like appendages known as sporophylls. ix. In most cases, the sporangia are compacted to form distinct spore producing regions called the strobile. The sporangia in some cases, may be produced within specialized structures called the sporocarp. x. The leaves of a fern plant is called frond. xi. Pteridophytes, in general, are homophonous i.e. they produce only one-type of spores. However, a few species produce two types of spores (micro- spores and megaspores). xii. They form green, dorsiventrally differential, thallose gametophytes with sex organs restricted to the ventral surface. xiii. The female reproductive structure is archegonium and the male reproductive structure is antheridium.  Relationship of Pteridophytes with Other Groups Pteridophytes and Bryophytes: Similarities 1. Liverworts and Pteridophytes show similarity in vegetative structure of gametophytes. 2. Their female and male reproductive structures are archegonium and antheridium, respectively. 3. The opening of the mature sexual reproductive organs and the subsequent fertilizations are condition by the presence of water in liquid salt. ie both require water for fertilization. 4. They usually show a distinct and clearly defined heteromorphic alternative of generations and the two generations follow each other in regular succession. 5. The spores arise in the same manner in both groups. 6. Development of embryo occurs in the archegonium. 7. The young sporophyte or embryo is partially parasitic upon the gametophyte.  Difference 1. In Pteridophytes, the sporophyte is independent at maturity and is the dominant phase of life cycle instead of gametophyte as in bryophytes. 2. The Sporophyte has true roots, stems, and leaves and well developed conducting tissues-xylem and phloem, which are absent in bryophytes. 3. Some of the Pteridophyte is heterosporous but all the bryophytes are homosporous. Pteridophytes and Flowering Plants In Pteridophytes, plant body is not divided into root and shoots system, in flowering plants, plant body differentiated into distinct root and shoot system. Vascular bundles are less developed in Pteridophytes, (tracheids) Flowering plants has well developed vascular bundles (xylem and phloem). There is no pollen grain, pollen tube; in Pteridophytes following plant has pollen grain. Pteridophytes have no seeds (but sori) while flowering plants produce seeds with cotyledons or endosperms.  Morphology of a Pteridophyte– Pteris vittata Pteris is a widely distributed genus with about 250 species. It grows abundantly in cool, damp and shady places in tropical and subtropical regions of the world. Pteris Vittata is a low level fern which brings out new leaves throughout the year. It is very common along mountain walls and grows up to 1200 metres above sea level.  All the species of pteris are terrestrial, perennial herbs with either creeping or semi erect rhizome covered by scales. Roots arise either from the lower surface or all over the surface of rhizome. Leaves are compound in most species, but a few have simple leaves eg. Pteris cretica. The stalk of leaf continues as rachis and bears leaflets called pinnae. In Pteris vittata, the pinnae present near the base are tips are smaller than those in the middle.  Condition for Adaptation Sporophyte shows greater degree of complexity in structural organization. It is organized into stem, root and leaves. The Vascular tissues (xylem and Phloem) are developed only in the sporophyte. The aerial parts are covered with a layer of cuticle. On the Epidermis, there are stomata for the exchange of gases. These anatomical complexities of the sporophyte of Pteridophytes helped in inhabiting a much wider range of environmental condition than the gametophyte could do.  Alternation of Generation Heteromorphy ---alternation of distinct generation Haploid gametophyte –1n set of chromosome Diploid sporophyte– 2n set of chromosome Gametophyte produce sperm and egg Sporophyte produce spores  Evaluation Outline the relationship between Pteridophytes and Bryophytes in respect to their similarities and Differences.  SEED PLANTS (GYMNOSPERM AND ANGIOSPERM) Seed plants are seed producing vascular plants. They are also called Spermatophyte. They have well developed roots, stems and leaves. The seeds containing the embryo develops from a fertilize egg of a very small gametophyte which is completely dependent on the sporophytes, the plant form we see around us. The efficient seed dispersal of seed plants account for their continued existence and widespread occurrence. The fertilization of the egg is by the male gamete which is brought by pollination, followed by the growth of the pollen tube which carries the male gamete to the egg. Water is not needed in this process, hence the seed plants are true land plants. In this unit, we shall be looking at the seed plants: Gymnosperm and Angiosperms.  OBJECTIVES By the end of this unit, you should be able to: list out general characteristics of seed plants outline the specific characteristics features of gymnosperms and angiosperms highlight morphological characteristic of a named gymnosperm and angiosperm classify gymnosperms and angiosperm highlight the terrestrial (ecological) of seed plants.  General Characteristics of Seed Plants They are terrestrially adapted i.e they are land plants. The gametophytes of seed plants become more reduced and dependent on the sporophytes. They produce two types of spores (Megaspores and Microspores) ie. they are heterospores. They undergo pollination which replaces swimming as the mechanism for delivering sperm to egg. They produce seed.  Gymnosperms Classification Gymnosperms are generally classified into four divisions. These are - Coniferophyta - the conifers - Cycadeophyta - Cycads - Ginkophyta - ginko - Gnetophyta - gnetae.  Conifers Among the gymnospems, the conifers are the most important. They have the following characteristics: They are cone bearing plants with vascular tissue. All are woody plants; the great majority been trees with just a few shrubs. Species can be found growing naturally in almost all parts of the world. They are frequently dominating plants in their habitats. They are of immense value, primarily for timber and paper production. The wood of conifers is known as softwood. Examples are: Cedars, Cypresses, Pines, Redwoods etc. External Morphology of Conifers All are wood plants, and most are trees. Majority has a monopocal growth (ie. a single, straight trunk with side branches) with optical dominance. Size varies from less than a metre, to over 100 meters. They are the world largest, tallest and oldest living things. Ecological Adaptation of Conifer The have distinctly scented pesin, which is secreted to protect the tree against insect infestation and fungal infection of woods. They maintain high rates of photosynthesis at relatively low temperature. Their needles (leaves) have thick warty coatings and sunken stomatas which prevent excessive loss. The sapwood column is large and acts as a short-term reservoir that supplies water to foliage during drought periods.  Angiosperms The angiosperms are also known as flowering plants. They occupy every habitat on earth except extreme environments. They live as epiphytes (i.e living on other plants); as floating and rooted aquatics in both fresh water and Marine habitats, and as terrestrial plants that vary tremendously in size, longevity and overall form. They can be small herbs, parasitic plants, shrubs, vines or giant trees. They are also sources for other important resources such as medicine and timber.  Classification Angiosperm are generally classified into two (2). These are: Monocotyledons (Monocots) Dicotyledons (Dicots). General features of Angiosperms They could be photoautotroph, Saprobes or parasitic. Mostly pollinated by insects, birds, and other animals, while some are by wind They have vessels (xylem and phloem). The monocots include lilies, grasses, corn, wheat, palms, while the dicots include roses, maples, oaks, peas, and beans. Angiosperms posses certain external features that remarkably distinguish them from other seed plants. This feature includes: 1. Flowers They have modified leaves Has sepals – usually green Petals –brightly colored and insect pollinated Petals –drab – wind pollinated Has carpels – female reproductive organ. Has stamen- male reproductive organ.  2. Fruits It protects documents seeds. They have mature ovary. Simple fruit has single ovary flower (e.g. Pea pod, apple) Aggregate fruit – produce from separate flowers (e.g pineapple) Modifications for dispersal includes: attractive food, dispersal by wind, burns.  Terrestrial Adaptation of Vascular Plant (Seed Plants) Possession of cuticle They do not need immediate aquatic habitat. Roots have no cuticle. They are woody materials made of Cellulose and lignin. Possession of vascular tissues (Xylem and Phloem).  Evaluation 1. Outline how conifers are terrestrially adapted. 2. What are the distinguishing features of a flowering plant?