Keystone Biology Review

Central York High School

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Topics

Cells and Cell Processes

Continuity and Unity of Life

• Explain the characteristics common to all organisms◦ Describe the characteristics of life shared by all prokaryotic

and eukaryotic organisms

• Describe relationships between structure and function at biological levels of organization◦ Compare cellular structures and their functions in

prokaryotic and eukaryotic cells

◦ Describe and interpret relationships between structure and

function at various levels of biological organization

Basic Biological Principles

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Prokaryotes: Unicellular organisms with no nucleus or membrane-bound organelles◦ Bacteria

Eukaryotes: Unicellular or multicellular organisms with a nucleus and membrane-bound organelles◦ Plants, Animals, Fungi and Protists

Basic Biological PrinciplesDescribe the characteristics of life shared by all prokaryotic and eukaryotic organisms

All living organisms:

DNA – universal genetic code

Growth and Development

Cells – basic unit of life

Metabolism – Chemical reactions in the body

(ex: photosynthesis and respiration)

Reproduce

Response

Evolve – as a species, change over time

Dr Green Can Make Really Rotten Eggs

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Basic Biological PrinciplesCompare cellular structures and their functions in prokaryotic and eukaryotic cells

Prokaryotes Eukaryotes

Size Small Animals – largePlants – Very large

Examples Bacteria (E. coli) Plants, Animals, Fungi, and Protists

DNA Yes – circular strand of DNA Yes – folded into chromosomes

Ribosomes Yes Yes

Cell Membrane ALWAYS! ALWAYS!

Cell Wall Usually(made of peptidoglycan)

Animals – NOPlants – Yes (cellulose)

Membrane – Bound Organelles None

Golgi apparatus, mitochondria, chloroplasts, Endoplasmic Reticulum,

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Basic Biological PrinciplesCompare cellular structures and their functions in prokaryotic and eukaryotic cells

Organelle FunctionNucleus Contains DNA, Controls CellRibosomes Makes first version of proteinsEndoplasmic Reticulum

Rough – Protein assemblySmooth – Lipid synthesis

Golgi apparatus Modifies, sorts and packages proteinsLysosomes Contain enzymes that break down materialsVacuoles Material storageMitochondria Site of cellular respirationChloroplasts Site of photosynthesis – plants only!Cytoskeleton Maintain cell shapeCytoplasm “Cell liquid” – everything in the cell except the nucleus

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Basic Biological PrinciplesCompare cellular structures and their functions in prokaryotic and eukaryotic cells

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Cell specialization:

Stem cells divide to

become specialized

cells, where some

genes are “turned off”

*This allows a single

celled zygote to

divide and become

every other cell type

Basic Biological PrinciplesDescribe and interpret relationships between structure and function at various levels of biological organization

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• Describe how the unique properties of water support life on Earth

◦ Describe the unique properties of water and how these properties support

life on Earth

• Describe and interpret relationships between structure and functions

at various levels of biochemical organization (i.e., atoms, molecules,

and macromolecules)

◦ Explain how carbon is uniquely suited to form biological macromolecules

◦ Compare the structure and function of carbohydrates, lipids, proteins, and

nucleic acids in organisms

◦ Describe how biological macromolecules form from monomers

• Explain how enzymes regulate biochemical reactions within a cell

◦ Describe the role of an enzyme as a catalyst in regulating a specific

biochemical reaction

◦ Explain how factors such as pH, temperature, and concentration levels can

affect enzyme function

The Chemical Basis for Life

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The Chemical Basis for Life

Charact-eristic

Explanation How it supports life on Earth

Polarity Electrons pull more toward oxygen than hydrogen, so there is an overall negative charge near oxygen and positive near hydrogen

Polarity leads to cohesion, adhesion, and water’s property as a universal solvent

Cohesion Water molecules stick together Cause capillary action

Adhesion Water molecules attract to other molecules Cause capillary action

Capillary action Water molecules move up small vessels Ex: Trees use cap. act. to get water to tops

Density Solid water (ice) is less dense than liquid water Ex: Polar bears! And lakes don’t freeze solid

High specific heat

It takes a lot of heat to increase the temp. of water; good at resisting temperature change

Ex: Oceans and lakes regulate Earth temps; sweating removes heat

Universal Solvent

Water is polar and can dissolve other polar substances Water is the main solvent for most chemical reactions in living organisms

Describe the unique properties of water and how these properties support life on Earth (e.g., freezing point, high specific heat, cohesion)

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The Chemical Basis for Life

• Carbon has four valence electrons

• Carbon can:◦ Bond with itself

◦ Bond with other molecules

◦ Form up to four covalent bonds

◦ Form single, double, or triple

bonds

• Carbon is the basis for living organisms due to this ability

Explain how carbon is uniquely suited to form biological macromolecules

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The Chemical Basis for LifeCompare the structure and function of carbohydrates, lipids, proteins, and nucleic acids in organisms

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Fats, Oils, Waxes

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The Chemical Basis for Life

• Carbohydrates – ◦ Carbon, hydrogen and oxygen in 1:2:1 ratio◦ Quick energy for the cell

• Lipids – ◦ Mostly carbon and hydrogen with some oxygen◦ Insoluble in water◦ Fats, oils, waxes and steroids

• Proteins – ◦ CHON(s) : Carbon, hydrogen, oxygen, nitrogen, sometimes sulfur◦ Structure, hormones, enzymes, transport

• Nucleic Acids – ◦ Nucleotides: 5 carbon sugar, phosphate (PO4) and nitrogen bases◦ Genetic information

Compare the structure and function of carbohydrates, lipids, proteins, and nucleic acids in organisms

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The Chemical Basis for Life

• Condensation:

◦ AKA “dehydration synthesis”

◦ Bond monomers together to

form polymers

◦ Removal of water

• Hydrolysis

◦ “water breaking”

◦ Addition of water molecule to

separate polymers into

smaller units

Describe how biological macromolecules form from monomers

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The Chemical Basis for Life

• Enzymes are biological catalysts which reduce the activation energy, or energy necessary to start a reaction.

• This allows chemical reactions to happen in the body that would otherwise not be possible.

Describe the role of an enzyme as a catalyst in regulating a specific biochemical reaction

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The Chemical Basis for Life

• Every enzymes operates best under optimal pH and temperature◦ If conditions are outside of optimal, then overall function will decrease◦ Each enzyme has a different optimal pH and temp; enzymes in the

stomach work best with acidic pH whereas enzymes in bacteria that live in hot springs would have optimal pH in higher temperatures

• Enzymes are proteins – when proteins are too hot or the pH is too acidic or basic, they can become denatured.

• Once a protein is denatured, it willnot work again

• Enzymes end in -ase

Explain how factors such as pH, temperature, and concentration levels can affect enzyme function

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• Identify and describe the cell structures involved in processing energy.◦ Describe the fundamental roles of plastids (e.g.,

chloroplasts) and mitochondria in energy transformation

• Identify and describe how organisms obtain and transform energy for their life processes◦ Compare the basic transformation of energy during

photosynthesis and cellular respiration

◦ Describe the role of ATP in biochemical reactions

Bioenergetics

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Bioenergetics

Chloroplasts

• Only in plants and photosynthetic algae

• Photosynthesis

Describe the fundamental roles of plastids (e.g., chloroplasts) and mitochondria in energy transformation

Mitochondria

• In all eukaryotes

• Cellular respiration

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Bioenergetics

Photosynthesis• Light dependent reactions

◦ Light is used to break water◦ Light energy transferred to

chemical energy in ATP and NADPH

◦ Oxygen released as waste

• Light Independent reactions◦ “Carbon fixation”◦ ATP and NADH are used to

create covalent bonds between carbons (from CO2)

◦ Sugars are produced as long term storage for energy

Compare the basic transformation of energy during photosynthesis and cellular respiration

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Bioenergetics

Cellular Respiration

• Glycolysis◦ Breaks glucose into 2 pyruvate

• Krebs Cycle◦ Breaks pyruvates fully into CO2, which

is released as waste

◦ Releases energy as NADH and FADH2

• Electron Transport Chain◦ Passes electrons from NADH and

FADH2 onto oxygen (“final electron acceptor”)

◦ ATP Synthase makes 32 ATP

◦ Water released as waste

Compare the basic transformation of energy during photosynthesis and cellular respiration

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Bioenergetics

PHOTOSYNTHESIS

CO2 + H2O C6H12O6 + O2

RESPIRATION

C6H12O6 + O2 CO2 + H2O

Look! They’re opposites!

Compare the basic transformation of energy during photosynthesis and cellular respiration

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Bioenergetics

• ATP = Adenosine TRI Phosphate

3

Describe the role of ATP in biochemical reactions

• Cell “Battery”

• ATP = fully charged

• ADP (adenosine di phosphate) = empty battery

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• Identify and describe the cell structures involved in transport of materials into, out of, and throughout a cell◦ Describe how the structure of the plasma membrane allows

it to function as a regulatory structure and/or protective

barrier of a cell

◦ Compare the mechanisms that transport materials across

the plasma membrane

◦ Describe how membrane-bound cellular organelles facilitate

the transport of materials within a cell

• Explain mechanisms that permit organisms to maintain biological balance between their internal and external environments◦ Explain how organisms maintain homeostasis

Homeostasis and Transport

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Homeostasis and Transport

Small, non-polar molecules can move

through membrane

Molecules which are large and in charge

cannot go through the membrane

Describe how the structure of the plasma membrane allows it to function as a regulatory structure and/or protective barrier of a cell

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Homeostasis and TransportCompare the mechanisms that transport materials across the plasma

membrane (i.e., passive transport – diffusion, osmosis, facilitated diffusion; and active transport – pumps, endocytosis, exocytosis)

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Homeostasis and TransportCompare the mechanisms that transport materials across the plasma

membrane (i.e., passive transport – diffusion, osmosis, facilitated diffusion; and active transport – pumps, endocytosis, exocytosis)

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Homeostasis and Transport

• Endoplasmic Reticulum◦ Rough: Has ribosomes on it; primarily for synthesizing polypeptides – strings of amino acids

which will be folded into proteins

◦ Smooth: No ribosomes; synthesizes lipids and can store materials

• Golgi Apparatus◦ Closely associated with the

rER; folds and assembles

polypeptides into active

proteins and packages

them into vesicles

• Vesicles◦ Can take materials from

the Golgi throughout the cell

◦ Can fuse with the cell

membrane to send materials out

of the cell, such as

neurotransmitters, hormones,

or other chemicals

Describe how membrane-bound cellular organelles (e.g. endoplasmic reticulum, Golgi apparatus) facilitate the transport of materials within a cell

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Homeostasis and Transport

• Thermoregulation (maintaining constant temperature)

◦ Too cold? Shiver, vasoconstriction – keeping blood in the core by making

blood vessels throughout the body smaller

◦ Too hot? Sweat, vasodilate – move blood to the extremities to release heat

• Water regulation (osmotic balance!) – cells must be bathed in isotonic

solutions or else they may swell or shrink

◦ Too much water? PEE!

◦ Too little water? Retain water, increase thirst

• Oxygen Regulation – O2 is necessary for cellular respiration. CO2

levels also influence pH of the blood which has an affect on enzyme

activity.

◦ Low oxygen levels / acidic pH / too much CO2? Breathe more!

Explain how organisms maintain homeostasis (e.g., thermoregulation, water regulation, oxygen regulation)

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• Describe the three stages of the cell cycle: interphase, nuclear division, cytokinesis◦ Describe the events that occur during the cell cycle:

interphase, nuclear division (i.e., mitosis or meiosis),

cytokinesis

◦ Compare the processes and outcomes of mitotic and

meiotic nuclear divisions

• Explain how genetic information is inherited◦ Describe how the process of DNA replication results in the

transmission and/or conservation of genetic information

◦ Explain the functional relationships between DNA, genes,

alleles, and chromosomes and their roles in inheritance

Cell Growth and Reproduction

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Cell Growth and Reproduction

• Interphase◦ G1: Growth◦ S: DNA replication◦ G2: Continued growth;

preparation for mitosis

• M- phase – Cell division◦ M-phase : Nuclear division

(mitosis or meiosis)● Prophase

● Metaphase

● Anaphase

● Telophase

◦ Cytokinesis: Cytoplasmic division

Describe the events that occur during the cell cycle: interphase, nuclear division (i.e. mitosis or meiosis), cytokinesis

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Cell Growth and ReproductionCompare the processes and outcomes of mitotic and meiotic nuclear

divisions

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Cell Growth and ReproductionCompare the processes and outcomes of mitotic and meiotic nuclear

divisions

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Cell Growth and Reproduction

• Helicase – unzips DNA

• DNA Polymerase – adds nucleotides to the exposed template strands

• A can only bond with T

• C can only bond with G

• The result is that

each strand is

identical to the

previous strand

Describe how the process of DNA replication results in the transmission and/or conservation of genetic information

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Cell Growth and Reproduction

• Nucleus contains DNA

• DNA is arranged into two sets of 23 different chromosomes – one set is inherited from each parent

• Each chromosome is composed of different genes◦ Each gene codes for a protein

• Homologous chromosomes

may contain the same

genes (such as eye color)

but with different versions

(blue vs. brown) –

each version is called an

allele

Explain the functional relationship between DNA, genes, alleles, and chromosomes and their roles in inheritance

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• Compare Mendelian and non-Mendelian patterns of inheritance◦ Describe and/or predict observed patterns of inheritance◦ Describe processes that can alter composition or number of

chromosomes

• Explain the process of protein synthesis (i.e., transcription, translation, and protein modification)◦ Describe how the processes of transcription and translation are similar

in all organisms◦ Describe the role of ribosomes, endoplasmic reticulum, Golgi

apparatus, and the nucleus in the production of specific types of proteins

• Explain how genetic information is expressed◦ Describe how genetic mutations alter the DNA sequence and may or

may not affect phenotype

• Apply scientific thinking, processes, tools, and technologies to the study of genetics◦ Explain how genetic engineering has impacted the fields of medicine,

forensics, and agriculture

Genetics

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Genetics

• Mendelian Genetics = Dominant / Recessive◦ Presence of one or two copies of dominant allele leads to

dominant phenotype (physical expression of gene)

◦ Must have two recessive alleles to have recessive phenotype

Describe and/or predict observed patterns of inheritance (i.e., dominant, recessive, co-dominance, incomplete dominance, sex-linked, polygenic, and multiple alleles)

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Genetics

• Co-dominance◦ Allele is expressed when

present◦ Ex: A and B blood types in

humans; “peppered chicken”

Describe and/or predict observed patterns of inheritance (i.e., dominant, recessive, co-dominance, incomplete dominance, sex-linked, polygenic, and multiple alleles)

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• Incomplete dominance◦ Heterozygous individuals

are a mix between either homozygous phenotype

◦ Ex: Red and white flower makes pink flower

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Genetics

• Sex linked◦ Gene is on X or Y chromosome◦ Females receive two Xs, males

get one X and one Y; more likely to get trait

◦ Ex: Color blindness, Haemophilia

Describe and/or predict observed patterns of inheritance (i.e., dominant, recessive, co-dominance, incomplete dominance, sex-linked, polygenic, and multiple alleles)

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• Polygenic◦ When multiple genes

control one trait

◦ Skin color

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GeneticsDescribe the processes that can alter composition or number of chromosomes (i.e., crossing-over, nondisjunction, duplication, translocation, deletion, insertion, and inversion)

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• Nondisjunction

• Causes monosomies and trisomies (Down Syndrome, Turner Syndrome)

• Crossing Over

• Mixes parent

DNA

• Other

chromosomal

mutations

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GeneticsDescribe how the processes of transcription and translation are similar in all organisms

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Genetics

RNA

• mRNA (messenger)◦ transcribed from DNA template and

carries code from nucleus to

cytoplasm;

◦ read in groups of three = codons

• rRNA (ribosomal)◦ Makes up the ribosome

• tRNA (transfer)◦ Carries amino acids to the

ribosomes to make proteins

Describe the role of ribosomes, endoplasmic reticulum, Golgi apparatus, and the nucleus in the production of specific types of proteins

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Genetics

Protein Synthesis

1. Transcription ◦ DNA acts as a template for mRNA

◦ RNA polymerase links nucleotides

together

◦ Pre-mRNA contains introns and exons;

exons are expressed, while introns interrupt, and are cut out

2. Translation◦ On ribosomes

◦ Anticodon on tRNA links to mRNA codon to bring the correct amino acid to the growing polypeptide chain

3. Modification◦ Polypeptide chains are folded into proteins by the ER and golgi into a protein’s

secondary and tertiary structures◦ Several proteins can be put together to make protein’s quaternary structure

Describe the role of ribosomes, endoplasmic reticulum, Golgi apparatus, and the nucleus in the production of specific types of proteins

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Genetics

• Mutation: Any change in DNA• Point mutation: one nucleotide is substituted, inserted or deleted◦ Silent: (has no effect on phenotype)

● Nucleotide substitution that occurs in noncoding region

● OR codon changes but codes for the same amino acid

◦ Missense:● Nucleotide substitution resulting in different amino acid

● Ex: achondroplasia dwarfism

◦ Nonsense:● Substitution causes a premature stop codon; shortened protein

● Ex: Muscular dystrophy

◦ Frameshift: ● Addition or loss of one nucleotide, causing the reading frame to shift;

all subsequent codons are read incorrectly● Ex: Cystic fibrosis, Crohn’s disease

Describe how genetic mutations alter the DNA sequence and may or may not affect phenotype (e.g., silent, nonsense, frame-shift)

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Genetics

Selective breeding:

• Allowing only those with desired characteristics to reproduce

• Most domestic animals and crop plants◦ Hybridization: crossing dissimilar individuals to get the best

traits from both

◦ Inbreeding: breeding of individuals with similar

characteristics

Explain how genetic engineering has impacted the fields of medicine, forensics, and agriculture (e.g., selective breeding, gene splicing, cloning, genetically modified organisms, gene therapy)

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Genetics

Gene Splicing:

• Combining DNA from different sources

Genetically Modified Organisms:

• Organisms with genes from other species

• Bacteria: used to produce human proteins as medications

• Animals: Make human proteins or are able to grow extra large for extra meat

• Plants: Crops have insecticide genes and grow super large

Explain how genetic engineering has impacted the fields of medicine, forensics, and agriculture (e.g., selective breeding, gene splicing, cloning, genetically modified organisms, gene therapy)

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Genetics

Cloning:

• Producing genetically identical organisms or tissue• Goal: make copies of transgenic organisms; clone tissues to allow gene therapy

Gene therapy:• Correcting a faulty or missing gene with a correctly working gene

Explain how genetic engineering has impacted the fields of medicine, forensics, and agriculture (e.g., selective breeding, gene splicing, cloning, genetically modified organisms, gene therapy)

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• Explain the mechanisms of evolution◦ Explain how natural selection can impact allele frequencies

in a population

◦ Describe the factors that can contribute to the development

of new species

◦ Explain how genetic mutations may result in genotypic and

phenotypic variations within a population

• Analyze the sources of evidence for biological evolution◦ Interpret evidence supporting the theory of evolution

• Apply scientific thinking, processes, tools, and technologies in the study of the theory of evolution◦ Distinguish between scientific terms: hypothesis, inference,

law, theory, principle, fact, and observation

The Theory of Evolution

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The Theory of Evolution

Natural Selection: Survival of the Fittest!

Explain how natural selection can impact allele frequencies in a population

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(and reproduction) Fittest: Those with the best adaptations (phenotype!) to an environment can pass their genes to offspring

Evolution = Change in allele frequency•Due to:

•Small populations•Non-random mating•Immigration / Emigration•Natural Selection•Mutations

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The Theory of Evolution

Speciation: Development of two or more daughter species from one original species

Describe the factors that can contribute to the development of new species (e.g., isolating mechanisms, genetic drift, founder effect, migration)

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• Caused by reproductive isolation: Populations of one species continue evolving without interbreeding until they are no longer able to reproduce

• Physical barriers• Reproductive barriers

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The Theory of Evolution

Genetic mutations: ◦ If beneficial: will cause allow individual to survive

◦ If harmful: will cause individual to die or have lower

reproductive success

◦ … not really sure what else to say here.

Explain how genetic mutations may result in genotypic and phenotypic variations within a population

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The Theory of Evolution

Evidence of Evolution

Interpret evidence supporting the theory of evolution (i.e., fossil, anatomical, physiological, embryological, biochemical, and universal genetic code)

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Show that species change over time

Comparative anatomy and embryology: similarities in structure and development indicate a common ancestor

Geographic distribution: Organisms that live closer together evolved from each other more recently and therefore look more similar

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The Theory of Evolution

Hypothesis: Proposed, scientifically testable explanation for an observed phenomenon

◦ Scientists test their hypotheses

Inference: assumption based on prior experience◦ Scientists make inferences based on what is already known to deduce a possible

hypothesis

Law: A generalized statement which connects may theories but does not seek to explain them

◦ Ex: Law of gravitational force; does not explain why gravity exists, simply that it does

Theory: An explanation of natural phenomena which links together many hypotheses

◦ Ex: Theory of evolution describes why fossil records are the way they are and why species distribution looks as it does

Principle: Concept based on scientific laws and axioms

Fact: An absolute truth

Observation: Direct method of gathering information

Distinguish between scientific terms: hypothesis, inference, law, theory, principle, fact, and observation

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• Describe ecological levels of organization in the biosphere◦ Describe the levels of ecological organization

◦ Describe characteristic biotic and abiotic components of aquatic and terrestrial ecosystems

• Describe interactions and relationships in an ecosystem◦ Describe how energy flows through an ecosystem

◦ Describe biotic interactions in an ecosystem

◦ Describe how matter recycles through an ecosystem

◦ Describe how ecosystems change in response to natural and human disturbances

◦ Describe the effects of limiting factors on population dynamics and potential species extinction

Ecology

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EcologyDescribe the levels of ecological organization (i.e., organism, population, community, ecosystem, biome, and biosphere)

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Ecology

• Biotic = living

• Abiotic = non-living

Describe characteristic biotic and abiotic components of aquatic and terrestrial ecosystems

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Ecology

• Producers: ◦ convert solar energy into chemical

energy◦ Use photosynthesis (usually)

◦ Basis of all food webs and food chains

• Consumers: Eat others◦ Primary consumers: Eat producers

(plants) i.e. herbivores◦ Secondary consumers: Eat primary

consumers; i.e. carnivores◦ Tertiary consumers etc: Eat

higher-level consumers

Note: Arrows point in the direction of energy flow, i.e. FROM producers TO consumers!

Describe how energy flows through an ecosystem (e.g., food chains, food webs, energy pyramids)

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Ecology

Biotic interactions: Living organisms’ interactions with one another◦ Competition: Organisms competing for similar resources

● Niche: Each species has its own niche based on what it eats,

what eats it and what nutrients and habitats it needs

◦ Predation: One organism eating another

◦ Symbiosis: Two organisms which interact with one another

● Mutualism: Both organisms benefit (ex: dog and human)

● Commensalism: One organism benefits, one is unaffected (ex:

clownfish and sea anenome)

● Parasitism: One organism benefits, one is harmed (ex:

tapeworm in human gut)

Describe biotic interactions in an ecosystem (e.g., competition, predation, symbiosis)

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EcologyDescribe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle)

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EcologyDescribe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle)

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EcologyDescribe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle)

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EcologyDescribe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle)

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Ecology

Climate change:

◦ Increased emissions of greenhouse gases; global temps rise

Nonnative species:

◦ Introducing species to a new habitat, which may outcompete native

species or grow uncontrollably due to lack of natural predator

Pollution:

◦ Biomagnification: Toxins move up trophic levels and become more

concentrated

◦ Acid rain

◦ Eutrophication: Nitrogen and phosphorus-rich compounds flow into

waterways and algae bloom, using up all oxygen and other organisms

suffocate

Describe how ecosystems change in response to natural and human disturbances (e.g., climate changes, introduction of nonnative species, pollution, fires)

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Ecology

Limiting factor: Something which prohibits the growth of a population◦ Density independent: Relies on current population size;

large populations will be limited in size

● Usually biotic factors, such as predation, disease, competition

◦ Density independent: Does not rely on population size; any

population size may be affected

● Usually abiotic factors, such as drought, hurricane, extreme

fluctuations in weather

Describe the effect of limiting factors on population dynamics and potential species extinction

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