Stpm Forum

    Summary of syllabus (Biology)


    Posts : 21
    Join date : 2010-05-07

    Summary of syllabus (Biology)

    Post  shaunling on Sat May 08, 2010 8:37 am

    Chapter 1: Basic Chemistry of a Cell
    Chapter 2: Structure of Cells and Organells
    Chapter 3: Control in Cells
    3.1 Enzymes
    - Definition and properties of enzymes

    3.1.1 Catalysis and activation energy
    - Meaning of catalysis
    - Lowering of activation energy by enzymes in a reaction

    3.1.2 Mechanism of action and kinetics
    - Lock-and-key model, affinity and Michaelis-Menten constant and Lineweaver-Burk plot

    3.1.3 Cofactors: metalions activator, coenzymes and prosthetic groups
    - Definition. examples and action

    3.1.4 Inhibitors: competitive and non-competitive
    - Definition, examples and action

    3.1.5 Classification
    - Major types according to IUB system: hydrolases, lyases, transferases, isomerases, ligases/synthetases, oxydoreductases; examples of reactions

    3.1.6 Technology: enzyme immobilisation and biosensing
    - Meaning and examples of uses

    3.2 DNA and protein synthesis

    3.2.1 DNA as genetic material
    - Experiment of Avery and colleagues

    3.2.2 Gene concept, one-gene-one-polypeptide hypothesis
    - Experiment of Beadle and Tatum

    3.2.3 DNA replication
    - Experiment of Meselson and Stahl
    - Process involved

    3.2.4 Protein synthesis
    - Transcription: processes of mRNA production
    - Translation: processes of polypeptide production
    Chapter 4: Photosynthesis
    4.1 Light reaction
    - Reaction and detailed description
    - Photoactivation of photosystem I and photosystem II
    - Photolysis of water
    - Production and roles of NADPH and ATP
    - Cyclic and non-cyclic photophosphorylation

    4.2 Dark reaction/Calvin cycle in C3* and C4* plants
    - Reaction and detailed description
    - CO2* fixation to RuBP
    - Production of PGAL until the formation of carbohydrates
    - Involvement in the formation of proteins and fatty acids
    - Anatomical and physiological differences between leaves of C3* and C4* plants
    - Krantz's anatomy
    - Hatch-Slack pathway
    - Crassulacean acid metabolism (CAM)
    - Example: cactus

    4.3 Factors limiting the rate of photosynthesis
    - Wavelength and intensity of light, temperature and carbon dioxide concentration
    - Compensation point
    Chapter 5: Respiration
    5.1 Aerobiosis

    5.1.1 Glycolysis
    - Glucose phosphorylation, fructose diphosphate production
    - Splitting into phosphoglyceraldehyde and dihydroxyacetone phosphate
    - Conversion of phosphoglyceraldehyde to pyruvate and production of ATP and NADH
    - Substrate level phosphorylation

    5.1.2 Kreb's Cycle/ Tricarboxylic acid cycle/citric acid cycle
    - Formation of acetyl coenzyme A, formation of citrate, reformation of oxaloacetate from citrate via alpha-ketoglutarate and succinate, with emphasis on the formation of NADH, FADH2 and GTP, and release of carbon dioxide
    - Calculations of total ATP production

    5.1.3 Electron transport system
    - Electron flow from NADH/FADH2 via flavoprotein, coenzyme Q and cytochrome to oxygen with the production of ATP and water
    - Effects of inhibitors (cyanide and carbon monoxide)

    5.2 Anaerobiosis
    - Differences between plants and animals: ethanol production in plants and lactic acid production in animals
    - Use of fermentation in industry with examples
    Krebs's Cycle

    1. Kreb's Cycle was first worked out by Sir Hans Krebs in 1937.
    2. It is also called the Tricarboxylic Acid Cycle or Citric Cycle.
    3. Kreb's Cycle also take place in aerobic conditions.
    4. Pyruvate will give out CO2, converting NAD+ to NADH and react with Coenzyme A to form Acetyl Coenzyme A.
    5. Acetyl Coenzyme A react with Oxaloacetate to form Citrate, catalysed by citrate synthetase enzyme.
    6. Citrate rearrange itself to become isocitrate, catalysed by Aconitase enzyme.
    7. Oxidative decarboxylation of isocitric acid produces alpha-ketoglutaric acid. CO2 is released, NAD+ is converted into NADH.
    8. Oxidative decarboxylation of alpha-ketoglutaric acid will produce succinic acid. CO2 and NADH formedGTP is produced before hydrolysed into GDP, producing energy which is used for phosphorylation of ADP to ATP.
    9. Succinate oxidised to fumarate. FADH2 is formed from FAD.
    10. Fumarate is hydrated to malate.
    11. Malate is oxidised to produce oxaloacetate again. NAD+ is converted to NADH.
    12. The whole cycle began again.

    Importance of Kreb's Cycle
    1. Forms 6C compound (citrate) that can be oxidised to produce CO2, reduced coenzyme and energy.
    2. Produces NADH and FADH2.
    3. Forms GTP.
    4. Synthesise substances such as amino acids, glycerol, chlorophyll and fatty acids.
    Chapter 6: Nutrition
    6.1 Autotroph

    6.1.1 Chemosynthesis
    - Concept with examples

    6.1.2 Photosynthesis
    - Refer topic 4 (Photosynthesis)
    - Brief description of photosynthesis in bacteria

    6.2 Heterotroph
    - Concept with examples

    6.2.1 Holozoic

    6.2.2 Saprophytic

    6.2.3 Parasitic
    Chapter 7: Gaseous Exchange
    7.1 Animals

    7.1.1 Gaseous exchange in mammals
    - Processes and structures involved
    - Haemoglobin
    - Transport of oxygen and carbon dioxide
    - Partial pressure and Bohr effect
    - Oxygen dissociation curves

    7.1.2 Breathing Cycle
    - Mechanism of breathing control
    - Chemoreceptor
    - Tidal volume, vital capacity, total lung capacity, inspiratory reserve volume, expiratory reserve volume, residual volume

    7.2 Plants

    7.2.1 Stomata
    - Structure and functions
    -Mechanism of stomatal opening and closing based on the starch-sugar hypothesis and K+ ions accumulation hypothesis
    Chapter 8: Transport
    8.1 Animals

    8.1.1 Cardiac Cycle
    - Definition of systole and diastole
    - Change in pressure and volume in aorta, left atrium and left ventricle

    8.1.2 Control of heart beat
    - Sinoatrial and atrioventricular nodes
    - Sympathetic and parasympathetic nerves
    - Detailed description of heart beat

    8.1.3 Cardiovascular diseases
    - Hypertension, arteriosclerosis and myocardial infarction
    - Meaning, causes and prevention

    8.2 Plants

    8.2.1 Xylem and ascent of sap
    - Uptake of water and ions by roots
    - Root pressure and cohesion-tension theory
    - Mechanism of transport based on water potential
    - Pathways - apoplast, symplast and vacuole

    8.2.2 Phloem and translocation
    - Mass flow/pressure flow hypothesis(Münch model), electro-osmosis, cytoplasmic streaming and peristaltic waves
    - Transport of dissolved organic substances in plants
    Phloem And Translocation
    Mass Flow/Pressure Flow Hypothesis (Münch model)

    The diagram above shows the flow for a Münch model
    *Please note that such drawing method is incorrect for reports, it is only for reference*

    What happen in the model?
    1. Due to concentration gradient, sugar solution will flow from Flask A towards Flask B.
    2. This will increase turgor pressure/hydrostatics pressure in Flask B.
    3. Since the flask is closed, water is forced out of Flask B into the basin/beaker.
    4. At the same time, water at the Flask A was forced into Flask A because of osmotic pressure in Flask A.

    1. In plants, the tube connecting the flasks will be phloem, while Flask A is the Leaf Part and Flask B is the Root Part.
    2. And the tube connecting the beaker will be xylem.
    3. The Leaf will have many nutrients(food/sugar) as the result of photosynthesis.
    4. However, the concentration of sugar at the Root part will be lower but with water.

    The Hypothesis


    Cytoplasmic Streaming

    [u]Peristaltic Waves[/u]
    Chapter 9: Homeostasis
    Chapter 10: Nervous System
    Chapter 11: Hormone or Chemical Coordination
    11.1 Humans

    11.1.1 Hormonal Action

    - Mechanism of hormone action via gene activation; examples: steroid hormones

    - Mechanism of non-steroid hormone via activation of cyclic AMP system (cascade effect); examples: adrenaline

    - Comparison between the two action mechanisms

    11.1.2 Role of hormones in reproduction

    - Site of production and the role of hormones in oestrus cycle

    - Site of production and role of hormone during pregnancy

    11.2 Plants

    - Role of hormones in plant growth and development

    11.2.1 Auxin: Growth of organs

    11.2.2 Giberellin: Root and shoot induction

    11.2.3 Cytokinin

    11.2.4 Abscisic Acid (ABA): Apical and bud dominance

    11.2.5 Ethene: Seed dormancy, flowering, abscission, senescence, fruit ripening, stomatal mechanism, parthenocarpy

    - Interaction betweeb hormones; examples: apical dominance

    11.3 Phytochromes and the effect of light on flowering

    - Definition of phytochrome

    - Mechanism of phytochrome action

    - Role of phytochromes in photoperiodism and flowering
    Roles of Hormones in Plant Growth and Development

    1. Phototropism

    2. Cell Elongation

    3. Apical Dominance

    4. Parthenocarpy

    5. Flowering

    6. Delay Abscission

    7. Activates Cambium

    8. Growth of Lateral Roots


    1. Break Seed Dormancy

    2. Bolting

    3. Dwarf to Normal

    4. Growth of Lateral Roots



    Abscisic Acid (ABA)

    Chapter 12: Immunity
    12.1 Antibody, antigen, epitope, cell-mediated response, humoral immune response.
    - Definition and description

    12.2 Lymphatic System
    - Organisation of lymphatic system and formation of lymphatic fluid
    - Relationship between lymphatic system and immunity

    12.3 Development of immunity
    - Roles of macrophages, T cells and B cells
    - Mechanism of cell-mediated response (T cell) and humoral immune response (plasma cell)

    12.4 Concept of self and non-self
    - Foreign tissue/graft rejection by the body
    - Application of concept in medicine (organ transplant)

    12.5 Acquired immune deficiency syndrome (AIDS)
    - Causes, causing agent (HIV), symptoms and prevention of AIDS
    - Mechanism of HIV infection
    Symptoms of AIDS
    1. Unexplained weight loss (more than 10%)
    2. Prolonged fever
    3. Chronic and persistent diarrhoea
    4. Chronic cough
    5. Swollen lymph nodes (neck, armpits or groin)
    6. Recurrent Herpes zoster infection, viral infection of the nerves and appears as blisters on skin
    7. Candidiasis of mouth and throat, caused by fungus, easily destroyed by healthy person's defense system.
    8. Recurring herpes simplex infection, skin viral infection, often as blisters around mouth or genitals.
    9. Disease associated with collapse of the immune system such as Kaposi sarcoma (rare form of blood cancer, purple lesions of the skin) and Pneumocystis carinii pneumonia (infection of lungs by parasite)
    Chapter 13: Reproduction
    13.1 Sexual Reproduction

    13.1.1 Plants

    - Refer topic 22 (Biodiversity) for morphological characteristics

    - Structure of sexual reproductive organ

    - Life cycle with emphasis on sexual reproduction:

    i) Algae: Spirogira

    ii) Bryophyta: Marchantia

    iii) Filicinophyta: Dryopteris

    iv) Coniferophyta: Pinus

    v) Angiospermophyta: Caesalpinia

    13.1.2 Fungi: Mucor

    - Refer to topic 22 (Biodiversity) for morphological characteristics

    - Structure of sexual reproductive organ

    - Life cycle with emphasis on sexual reproduction

    13.1.3 Animals

    - Refer topic 22 (Biodiversity) for morphological characteristics

    - Diversity of sexual reproductive systems and overall comparison

    - Mechanism of fertilization (internal and external)

    - Oviparity, Ovoviviparity and Viviparity

    i) Ciliophora: Paramecium

    ii) Cnidaria: Hydra

    iii) Annelida: Pheretima

    iv) Arthropoda: Periplaneta

    v) Amphibia: Rana

    vi) Reptilia: Naja

    vii) Aves: Columba

    ix) Mammalia: Rattus

    13.2 Asexual Reproduction

    - Definition and examples only

    13.2.1 Parthenogenesis

    - Aphis and Apis

    13.2.2 Paedogenesis

    - Amphioxus

    13.2.3 Polyembriony

    - Fasciola

    13.2.4 Sporulation

    - Dryopteris and Plasmodium

    13.2.5 Budding

    - Hydra and Saccharomyces

    13.2.6 Binary fission

    - Amoeba

    13.2.7 Regeneration

    - Planaria

    13.2.8 Vegetative

    - Allium, Solanum, Yucca, Zingiber
    Chapter 14: Development
    14.1 Animals

    14.1.1 Embryology

    - Brief description of major stages

    - Beginning after fertilisation from cleavage to organogenesis (blastula and gastrula)

    - Organ formation from ectoderm, mesoderm and endoderm

    14.1.2 Human fetal development

    - Roles of placenta, chorion, amniotic fluid and allantois

    - Roles of progesterone and oestrogen

    14.1.3 Parturition process in human

    - Roles of progesterone, oestrogen, oxytocin and prolactin

    14.2 Plants

    14.2.1 Seed development

    - Development of seeds and fruits after fertilization

    - Structure of monocotyledonous and dicotyledonous seeds

    14.2.2 Seed germination

    - Mobilisation of nutrients after imbibition (role of giberrelin)
    Chapter 15: Growth
    15.1 Measurement

    - Parameters and methods of measurement (suitability and problems)

    15.2 Types of growth curve

    - Absolute growth curve

    - Absolute growth rate curve

    - Relative growth rate curve

    15.3 Growth pattern

    - Limited growth (human)

    - Unlimited growth (perennial plants/woody plants)

    - Allometric growth (human)

    - Isometric growth (fish)

    - Intermittent growth (insect)

    15.4 Ecdysis and metamorphosis

    - Definition

    - Role of hormones (neurosecretion, juvenile hormone and ecdysone)

    - Ecdysis and metamorphosis in insects

    15.5 Dormancy

    - Concept, importance and examples

    15.5.1 Animals

    - Hibernation, aestivation and diapause

    15.5.2 Plants

    - Seed dormancy

    - Factors affecting seed dormancy and methods of overcoming them
    Chapter 16: Transmission Genetics
    16.1 Mendelian Genetics
    - Definition of the terms gamete, gene, allele, dominant and recessive alleles, homozygote, heterozygote, phenotype, genotype, filial generation (P1, P2, F1, F2), type of crosses (test cross, back cross, reciprocal cross, selfing) and pure cross
    - Mendel's experiment on monohybrid and dihybrid crosses/inheritance
    - Characteristics of pea plants used by Mendel

    16.1.1 Monohybrid
    - Monohybrid cross and its results
    - Mendel's first law (Law of Seggregation) and its relation to meiosis
    - Calculations of genotypic and phenotypic ratios (Punnett square and branch/fork method)

    16.1.2 Dihybrid
    - Dihybrid cross and its results
    - Mendel's second law (law of Independant assortment) and its' relation to meiosis
    - Calculations of genotypic and phenotypic ratios until F2 generation (Punnett square and branch/fork methods)

    16.2 Modification of Mendelian Genetics
    - Crosses that result in ratios differing from the classic Mendelian 3:1 and 9:3:3:1 ratios

    16.2.1 Codominance
    - Definition
    - Examplke of inheritance: MN blood group in humans
    - Calculations of genotypic and phenotypic ratios

    16.2.2 Incomplete Doiminance
    - Definition
    - Example of inheritance : Antirrhinum (snapdragon) flower colour
    - Calculations of genotypic and phenotypic ratios

    16.2.3 Multiple Alleles
    - Definition
    - Example of inheritance: human ABO blood group
    - Calcuylations of genotypic and phenotypic ratios

    16.2.4 Lethal Genes
    - Definition
    - Example of inheritance: coat colour in mice
    - Calculations of genotypic and phenotypic ratios

    16.2.5 Polygenes
    - Definition
    - Example of inheritance: height in humans

    16.2.6 Linked Genes
    - Definition of linked genes and sex-linked genes
    - Effect of crossing over on ratio of dihybrid crosses
    - Parental and recombinant phenotypes
    - Examples: Drosophila eye colour and haemophilia in humans
    - Calculations of genotypic and phenotypic ratios
    - Pedigree analysis
    - Sex determination in humans

    16.2.7 Epistasis
    - Definition and examples only

    16.3 Genetic Mapping
    - Calculayions of distance between two loci based on percentage of cross-over
    - Examples of calculations for Drosophila
    -Determining the relative position of a gene on a chromosome based on percentage of cross-over
    Chapter 17: Mutation
    17.1 Classification
    - Spontaneous and induced
    - Examples of mutagens

    17.2 Gene Mutation
    - Mutation at DNA level

    17.2.1 Substitution
    - Definition
    - Example: sickle-cell anaemia

    17.2.2 Insertion/Addition
    - Definition
    - Frameshift mutation

    17.2.3 Deletion
    - Definition
    - Frameshift mutation
    - Example: thalassaemia major

    17.2.4 Inversion
    - Definition

    17.3 Chromosomal Mutation
    - Chromosomal aberration

    17.3.1 Change in chromosome number
    - Aneuploidy and euploidy/polyploidy
    - Definition of autosome and sex chromosome

    i) Aneuploidy
    - Definition
    - Non-disjunction during meiosis
    - Abnormalities of autosome number
    -- Monosomy: resulting in sterility and retarded growth
    -- Trisomy: Down's syndrome (trisomy 21)
    - Abnormalities of sex chromosome number
    -- Klinefelter syndrome (47, XXY)
    -- Turner syndrome (45, X)

    ii) Euploidy/polyploidy
    - Definition of euploidy/polyploidy, autopolyploidy and allopolyploidy
    - Examples in plants

    17.3.2 Change in chromosome structure
    i) Inversion - Definition
    ii) Translocation - Definition
    iii) Deletion - Definition
    iv) Duplication/Multiplication - Definition

    Chapter 18: Population Genetics
    18.1 Concept Of Gene Pool
    - Concept of gene pool, allele and genotype frequencies in a population
    - Relationship between population genetics and evolution

    18.2 Hardy-Weinberg Law
    - Genetic equilibrium and allele frequency
    - Requirements for genetic equilibrium
    -- Large-sized population
    -- Random mating
    -- No mutation
    -- No migration
    - Hardy-Weinberg equilibrium
    -- p^2 + 2 pq + q^2 = 1 and p + q = 1
    - Calculations of allele and genotype frequencies in a population
    Chapter 19: Gene Regulation and Expression
    Lactose Operon

    - Experiment of Jacob and Monod

    - Induced and constitutive enzyme production

    - Components of lactose operon and function of each component
    --> Component of regulator genes: an inducer, a promoter and an operator
    --> Components of structural genes: genes Z, Y and A

    - Effect of presence or absence of lactose on lactose operon
    1. Structural gene is a gene coding a polypeptide.
    2. A group of genes in prokaryotes that is regulated and expressed together is known as operon.
    3. Besides the structural genes, an operon also include a promoter and operator.
    4. Regulator is not included in an operon but it exists to regulate the genes.
    5. There are two kinds of operons:
    (i) inducible operons: Lactose operon
    --> it is stimulated or induced when an inducer interacts with a regulatory protein
    (ii) repressible operons: Tryptophan operon
    --> its transcription id inhibited when a repressor binds allosterically to a regulatory protein.
    Experiment of Jacob and Monod
    1. Earliest experiment about gene regulation and expression study was studied by Francois Jacob and Jacques Monod in 1940s.
    2. It's about syntheis of enzymes by Escherichia coli bacteria in a culture medium.
    3. First, they cultured Escherichia coli in a medium containing glucose as respiratory substrate. Their growth is in a fast rate.
    4. Then, the bacteria are transferred into a lactose medium, where lactose is the respiratory medium.
    5. It is found that their growth rate is slow at first. But then, the rate resumes to normal after some time.
    Chapter 20: Modern Genetics Technology
    Chapter 21: Taxonomy
    Chapter 22: Biodiversity
    Chapter 23: Variation and the Theories of Evolution
    23.1 Variation
    - Definition and importance

    23.1.1 Continuous and discontinuous variation
    - Definition, differences and examples

    23.1.2 Source
    i) Genetic
    - Sexual reproduction
    - Random assortment of homologous chromosomes during meiosis
    - Crossing-over, chromosome mutation, gene mutation, polygenes, dominant and recessive gene/alleles

    ii) Environment
    - Factors and influences

    23.2 Selection
    - Definition, description, importance and examples

    23.2.1 Natural Selection
    - Stabilising selection
    - Directional selection
    - Disruptive selection
    - Sexual selection
    - Polymorphism

    23.2.2 Artificial Selection
    - Breeding of farm animals and crop plants
    - Controlled/selective breeding (inbreeding, outbreeding)
    - Human and animal sperm banks

    23.3 Speciation
    - Definition, description, importance and examples

    23.3.1 Concept of species
    - Problems in defining species

    23.3.2 Speciation process
    - Formation of new species
    - Isolation, genetic drift, hybridisation and adaptive radiation

    23.4 Evolution
    23.4.1 Lamarck's Theory
    -Theory and examples

    23.4.2 Darwin-Wallace's Theory
    - Theory and examples

    23.4.3 Evidence supporting theory of evolution
    - Paleontology
    - Geographical distribution
    - Comparative anatomy
    - Comparative embryology
    - Biochemistry
    - DNA homology

    Chapter 24: Ecosystem
    24.1 Organisation of Life
    - Concept, hierarchy and interaction

    24.1.1 Components of life: organisms, populations and communities, ecosystems, biomes and biospheres
    - Definition and examples
    - Emphasis on dynamism of ecosystems

    24.1.2 Niche and habitat

    24.2 Biogeochemical cycles
    - Sulphur and phosphorus cycles

    24.3 Energy
    - First and second law of thermodynamics

    24.3.1 Flow
    - Definition, one example of ecosystem: pond/forest

    24.3.2 Transfer
    - Efficiency of energy transfer by producers, consumers and composers
    - One example of ecosystem: pond/forest
    Important Concepts of Ecology
    1. Ecology: study of interactions between organisms and organisms with their environments

    2. Biosphere (Ecosphere): all parts of planet Earth inhabited by living organisms. It stretches from the bottom of the ocean to the upper atmosphere = all the communities and ecosystems in planet Earth

    3. Biotic components: living components in the ecosystem, such as plants, animals, humans and microorganisms

    4. Abiotic components: non-living components of the ecosystem such as water, soil, air, rocks, snow and others.

    5. Environment: surrounding of an organism including all biotic and abiotic components. The environment of an organism usually includes water, air, soil and living things.

    6. Habitat: specific area(place) of the physical environment where an organism lives. Example: Forest as habitat of monkeys, Meadow as habitat of deers.

    7. Microhabitat: particular place in the habitat where and organism lives. Microhabitat can be an area under a rock, for ants.

    8. Community: all organisms living in the same habitat. Mangrove swamp community consists of mangrove trees, birds, crabs, monkeys, snakes, microorganisms...etc.

    9. Biome: large community unit that extends over wide biogeographical area, determined by area. Hence, biome can be said as a climatically delineated assemblage of organisms that have a characteristic appearance and is distribute over a wide geographical area. This community is usually complex and its animals and plants have certain characteristics. Example: Terrestrial biome are tropical forest, Mediterranean forest, deciduous forests, savanna, tundra, desert and prairie. Ocean is a single biome.

    10. Bion: independant individual organism living in any ecological system.
    Chapter 25: Quantitative Ecology
    25.1 Population ecology
    - Biotic potential
    - Natality
    - Mortality
    - Migration
    - Survivorship
    - r and K strategies
    - Population growth
    - Factors limiting population size and distribution
    - Liebig's law
    - Shelford's law

    25.2 Applied ecology
    - Carrying capacity
    - Management and conservation of ecosystems
    - Sustainable development; examples: forestry, agriculture and fishery

    25.3 Quantitative methods

    25.3.1 Sampling theories
    - Definition, description, importance and examples

    i) Central limit theorem
    - Practical application

    ii) Optimum sample size
    - Practical application

    25.3.2 Types of estimation
    - Examples and calculations

    --> Sampling methods
    - Quadrat
    - Line transect
    - Belt Transect
    - Capture-recapture/mark-release-recapture method

    25.3.4 Sampling parameters
    - Frequency
    - Density
    - Coverage
    Wind and Water
    1. They affects the dispersion of organism. They also affects the distribution of fruits, seeds and spores.

    2. Wind increase evapotranspiration thereby decreasing moisture. Hence, windy habitats are usually inhabited by xerophytes.

    3. Strong water currents causes erosion that would then determine the type of species that line the riverbanks.

    4. Plankton and algae species are also found in small amounts in fast flowing waters. In the beaches, waves and beach sand prevent plants from inhabiting there.

      Current date/time is Wed Jan 16, 2019 4:35 pm