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Biology EOCT Review


Biology EOCT Review All wish to possess knowledge, but few, comparatively speaking, are willing to pay the price. – PowerPoint PPT presentation

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Title: Biology EOCT Review

Biology EOCT Review
  • All wish to possess knowledge, but few,
    comparatively speaking, are willing to pay the

  • The study of interactions between organisms and
    their physical environment
  • Ecosystem natural unit that includes all living
    things within an area, their interactions with
    each other and all of the non-living features in
    the area
  • Biotic factors all living things
  • Abiotic factors non-living, water, air,
    temperature, soil, rainfall, sunlight, etc

Ecology cont.
  • Levels of organization within ecosystems
  • From smallest to largest
  • Organism gt Population (1 species) -gt Community
    (different species) -gtHabitat -gt Ecosystem -gt
    Biome -gt Biosphere

Ecology cont.
  • Major Land Biomes
  • Tundra
  • Permafrost, cold, lichens, mosses, grasses
  • Taiga
  • Coniferous forest (pines, spruce), long cold
    winters, soil thaws in spring and summer
  • Temperate Deciduous Forest
  • We live here, moderate rain, cold winters, warm
    summers, deciduous trees (drop leaves)
  • Tropical Rainforest
  • Great biodiversity of species, heavy rain, always
    warm, infertile soil
  • Grasslands
  • Prairies, windy, rainfall and temperature vary
    throughout year
  • Desert
  • Little rain, hot temps in the day, cold temps at
    night, drought resistant plants

Biology cont.
  • Populations
  • Population density - of individuals living in a
    given area
  • Exponential growth J-shaped curve, rapid growth
  • Logistical growth S-shaped curve usually
    present in natural populations top of S
    represents the population reaching its carrying
  • Carrying capacity maximum of individuals a
    specific environment can support

Ecology cont.
  • Energy Flow Through an Ecosystem
  • Ultimate source of energy is the SUN
  • Producers make their own food (autotrophs) then
    transfer the energy to consumers
  • Consumers heterotrophs, eat producers
  • Primary herbivores
  • Secondary carnivores
  • Omnivores eat plants and animals
  • Decomposers / Saprophytes break down dead
    organic matter

Ecology cont.
  • Energy Flow through Ecosystem
  • Food chain shows transfer of energy from one
    organism to another
  • Each step is a trophic level
  • Always starts with a producer (plant) and ends
    with a decomposer
  • Food web all the food chains in a community
    connected together
  • A food chain is one part of a food web

Ecology cont
  • Cycles
  • Energy flows through a community in 1 way, from
    the sun to the top of the food chain. Only 10
    of energy is passed on to the next trophic level.
  • Matter is recycled in an ecosystem. Decomposers
    convert matter back into a usable form for other
    living things.

  • Carbon-Dioxide-Oxygen Cycle
  • Plants take carbon dioxide out of atmosphere and
    put oxygen into atmosphere through photosynthesis
  • Heterotrophs take oxygen out of atmosphere and
    put carbon dioxide into the atmosphere through
  • Water cycle evaporation, condensation,
    precipitation, transpiration
  • Nitrogen cycle nitrogen fixing bacteria convert
    nitrogen gas into nitrates to be used by plants

  • Succession in an Ecosystem gradual steps taking
    place until an ecosystem reaches a mature and
    stable community
  • Pioneer species first to inhabit an area
    makes soil for other vegetation to inhabit
  • Climax community mature community
  • Types
  • Primary occurs in area that was previously
    unihabited (rock, lava flows)
  • Secondary a disrupted area that still has some
    soil and vegetation

  • Humans and the Environment
  • Non-renewable resources cannot be replaced in a
    short amount of time (oil, coal, natural gas,
  • Renewable resources can be replaced naturally
    in a relatively short amount of time
    (hydroelectric, solar, wind, wood)
  • Greenhouse effect trapping of heat being
    released by the earth by the atmosphere (keeps us
    warm at night)
  • Effect is increased by mans burning of fossil
    fuels puts more carbon dioxide in the air
    causes global warming

DNA and Genetics
  • Genetics study of heredity and variation of
    traits in organisms
  • Trait specific characteristic of an organism
    that is inherited
  • Gene segment of DNA on a chromosome that
    determines the characteristics of a particular

DNA and Genetics
  • DNA deoxyribonucleic acid
  • Found in every cell of an organism
  • Located with the chromosomes in the nucleus
  • Double helix shape
  • Nucleic acid made of long strands of nucleotides
  • Nucleotides nitrogen base, sugar, and phosphate
  • Adenine pairs with thymine
  • Guanine pairs with cytosine

DNA and Genetics
  • The genetic code (sequences of nucleotides)
    determines with amino acids are coded for and
    hence which proteins
  • DNA replication self-duplicating process
  • Double helix unwinds and unzips
  • Each single strand serves as a template for a new
    complimentary strand
  • Enzyme binds nucleotides to the template to form
    the new strand

DNA and Genetics
  • RNA - Ribonucleic Acid
  • Nucleic acid
  • 3 differences from DNA
  • Sugar is ribose instead of deoxyribose
  • Nitrogen bases adenine, uracil,
  • guanine, and cytosine
  • Single stranded
  • 3 types of RNA
  • Messenger RNA carries DNA nucleotide sequence
    out of the nucleus to the ribosomes
  • Transfer RNA transports amino acids to the
    ribosomes for protein assembly
  • Ribosomal RNA makes up the structure of the

DNA and Genetics
  • DNA Transcription mRNA molecule is synthesized
    from the DNA molecule in the nucleus
  • DNA unwinds and unzips
  • Complementary RNA nucleotides pair with one of
    the DNA template strands
  • mRNA strand detaches from the DNA and goes out to
    the ribosomes in the cytoplasm to carry out
    protein synthesis

DNA and Genetics
  • DNA Translation takes place in the ribosomes
  • Translates the genetic code into a protein by
    assembling a chain of specific amino acid
  • 3 nitrogen bases a triplet codon a specific
    amino acid
  • Order of codons determines order of amino acids
    which determine the protein that is synthesized
  • tRNA brings in anti-codons to attach to the
    complementary codon
  • When anti-codons pair with codons, amino acids
    are attached together in a chain
  • Assembly ends when a stop codon is reached and
    the protein is released to the cell for use

Genetics and Gregor Mendel
  • Mendel studied inheritance in pea plants
  • Mendel father of genetics
  • Hybrid offspring of cross between a homozygous
    dominant parent and a homozygous recessive parent
  • Concluded that offspring have two genes form each
    trait, one from each parent
  • Alleles different forms of the same gene

Mendelian Genetics
  • Law of Dominance- when 2 different alleles are
    inherited, one is expressed (dominant) and one is
    hidden (recessive)
  • Law of Segregation the two different forms of
    an allele randomly separate during meiosis
    during fertilization new combos of the alleles
    come together
  • Laws of Independent Assortment genes for
    different traits sort out separately from one
    another during meiosis

Incomplete Dominance
Mendelian Genetics
  • Genome genes present in an organism
  • Human genome project mapping out locations of
    genes (and the traits they code for) in the 23
    pairs of chromosomes
  • Phenotype physical appearance of a trait (tall
  • Genotype allele combonation in an organism (TT,
  • Homozygous alleles are the same
  • Heterozygous alleles are different (hybrid)

Mendelian Genetics
  • Probability likelihood that an event will occur
  • Punnet Square chart that shows all the possible
    combinations of gametes and their probabilities
    when two organisms are crossed
  • Monohybid cross two alleles for one trait
  • Dihybrid cross two pairs of different traits at
    one time

  • Sexual reproduction male and female sex cells
    (gametes) fuse during fertilization
  • Gametes are haploid (1 set of chromosomes) n
  • Zygotes are diploid (2 sets) 2n

Meiosis And fertilization
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