BIO final

What defines something as alive?

1. The ability to assimilate and use energy
2. The ability to respond to their environment
3. The ability to maintain a relatively constant internal environment    (homeostasis)
4. Having evolved from other living things
5. The ability to reproduce
6. Being composed of one or more cells with information encoded by DNA
7. Being highly organized when compared to inanimate objects
8. The ability to grow and develop

Non-living objects are not self-sustaining I:Inanimate

Steps of the scientific method: [ Observation = What’s happening?  Questions = What do we want to know?  Formulate Hypothesis = Our proposed explanation for the unknown phenomena.  Must be testable  Must be falsifiable (have the potential to be proven false)  Methods/ Experimentation = Testing our hypothesis  Results = What did we discover?  Conclusion = Does it support or refute our hypothesis?]()

Atoms are made up of three subatomic particles:

Protons: component of the atom’s nucleus with a positive electrical charge. Elements are defined by number of protons.

Neutrons: component of the atom’s nucleus with no electrical charge.

Isotopes are defined by number of neutrons.

Electrons: located some distance from atomic nucleus and has a negative electrical charge.

Atoms bond together to stabilize outer (valence) shell electrons.

Types of Chemical Bonding Hydrogen bonding: a special type of covalent bond between positively charged hydrogen atoms and negatively charged atoms in separate molecules

Bound by attraction of electrical charges

Hydrogen bonds between water molecules give water many of its unique properties

Bond between electronegative oxygen and electropositive hydrogen atoms in separate water molecules.

Properties of Water The Universal Solvent

Water can dissolve more substances than any other liquid (the hydrogen bonds between water molecules pull other compounds apart)

Solute: substance being dissolved to form a solution; typically a solid.

Solvent: substance that a solute is dissolved in to form a solution; typically a liquid. Solution: a homogeneous (equal) mixture of two or more substances.

Properties of Water Water is a polar molecule Partial

 Polarity works to pull apart ions negative charge Partial positive charge

Liquid form is denser than solid form  Ice floats on water!

Properties of Water Cohesion: the tendency for like molecules to cling together due to attractive forces (like hydrogen bonds)

Surface tension: water molecules are not attracted to air and pack more tightly at interface between air and water.

Specific heat: amount of energy required to raise temp 1˚C  Water has a high specific heat compared to other molecules  Water acts as buffer to temperature changes

High heat of vaporization

 Vaporization: transformation from liquid to gas  Fastest moving water molecules transform to a gaseous state.

Macromolecules: large organic molecule, usually comprising smaller molecules (monomers) joined together to form a polymer

 Monomers: a smaller molecule that can be combined with other similar or identical molecules to create a polymer

 Polymers: a larger molecule made up of many similar or identical subunits Four major macromolecules

 Carbohydrates  Lipids  Proteins  Nucleic Acids

Monomers and Polymers Examples from common macromolecules

Carbohydrates  Essential to energy production  Simple carbohydrates (monomers)  Monosaccharides and Disaccharides  Glucose and sucrose  Complex carbohydrates (polymers)  Polysaccharides  Cellulose (indigestible plant fiber), starch, glycogen

Lipids Fatty acid: long hydrocarbon found in many lipids Triglyceride: lipid molecule formed by three fatty acids bonded to a glycerol  Most common lipid molecule found in foods

• 3H2O   Glycerol + 3 fatty acids = triglyceride + water

Nucleic acids are large molecules made up of nucleotides  Nucleotides: Organic molecules that serve as the building blocks (monomers) of nucleic acids, and are made up of a phosphate group, a sugar, and a nitrogenous base  DNA and RNA  Instructions for making proteins  ATP  Energy transfer

 Proteins: a long, folded polypeptide  Polypeptide = a chain of amino acids  Amino acid = compounds consisting of an amino and carboxyl functional group, which act as the building blocks (monomers) of proteins.

The Small Intestine  6m long!  Smaller diameter than large intestine  80% of nutrients absorbed  Receives secretions from digestive glands  Liver  Pancreas  Gallbladder

Domains of Life  Bacteria  Unicellular prokaryotes  Archaea

 Extremophiles  Eukarya  Unicellular and multicellular eukaryotes  Protists  Fungi  Plants  Animals

Prokaryotic and Eukaryotic Cells Eukaryotic cell Prokaryotic cell

Domain: Bacteria  Prokaryotic cells  No membrane bound nucleus or organelles  Circular DNA  Have a plasma membrane and a cell wall  Single-celled organisms.  Asexual reproduction.

Prokaryotic Cells Pili: attachment structures on the surface of some prokaryotes.

Nucleoid region: location of cell’s DNA (not enclosed in a nucleus).

Ribosomes: site of protein synthesis.

Cell wall: rigid structure outside of Bacterial cell membrane. chromosome (DNA)

Glycocalyx: sticky outer coating on many A typical A thin section through the rod-shaped prokaryotes. bacterium Bacillus coagulans bacterium

Flagella: locomotion organelles in some bacteria.

Domain: Eukarya  Eukaryotic cells  Larger in size  Have nucleus and other membrane bound organelles  Linear DNA  All have plasma membranes, but only plant cells have cell walls  Unicellular and multicellular organisms.  Sexual and asexual reproduction.

Cell Theory  All living organisms are composed of cells.  Cells come from pre-existing cells

Plant and Animal Cells

Protein Production Summary

Protein Production: Step 1 Transcription: process in which a section of DNA is copied onto messenger RNA (mRNA) in the nucleus. RNA polymerase mRNA DNA Direction of transcription

Protein Production: Step 2 Translation: process by which a polypeptide is produced in a ribosome from information encoded within a messenger RNA (mRNA)

Movement of Molecules Diffusion: passive movement of molecules from a region of high concentration to a region of low concentration; requires no energy input.

Movement Through the Plasma Membrane

Movement Through the Plasma Membrane Passive transport: movement of ions or molecules across the plasma membrane without the use of energy  Simple diffusion: movement of ions or molecules directly through the cell membrane without the use of a protein channel (transport protein)  Facilitated diffusion: movement of ions or molecules across the plasma membrane through a specialized protein channel (transport protein). Active transport: movement of ions or molecules across the plasma membrane against the concentration gradient with the use of energy (ATP)

Membrane Permeability

Functions of Membrane Proteins

Functions of Membrane Proteins Communication proteins: Membrane proteins that bind with signaling molecules on exterior of cell and initiate a response in the cell interior.  Binding sites specific to certain signaling molecules.  Adrenaline and beta blockers

Cellular Respiration Three-part process that converts a single glucose molecule into energy/ATP.

1. Glycolysis     2 ATP (actually 4, but 2 are used)
2. Krebs cycle     2 ATP    3. Electron transport chain     32 ATP

Glycolysis  Breakdown of 1 glucose molecule into 2 pyruvate molecules.  ONLY step of cellular respiration to occur in cytoplasm/cytosol outside of mitochondria  Two stages:  Energy investment stage: requires 2 ATP.  Energy harvesting stage (from glucose’s electrons): produces 4 ATP and 2 NADH. 38

Anaerobic Pathway Fermentation: metabolic pathway that regenerates NAD+ from NADH and allows for glycolysis to continue making ATP in the absence of oxygen.  Alcohol fermentation:  Yeast in anaerobic environment.  Lactic acid fermentation:  Occurs in muscles when ATP use exceeds oxygen intak

Alcohol Fermentation  Ethanol (drinking alcohol) is produced when acetaldehyde (pyruvate derivative) accepts electrons from NADH following glycolysis.  The resulting NAD+ then goes back to restart glycolysis

Thermoregulation and Thermodynamics Thermoregulation: Process by which animals maintain their body temperature within a normal range  Endothermic: body temperature maintained by metabolic heat  Birds, mammals, and some insects  Ectothermic: body temperature controlled by external sources  Most reptile, fish, and invertebrates  First Law of Thermodynamics: energy cannot be created or destroyed, only transferred 41

Heat Exchange with Environment  Conduction - direct transfer of heat  Convection - transfer of heat by the movement of air or water across a surface  Radiation - emission of electromagnetic waves  Evaporation - loss of heat from changing a liquid into a gas 42

Adaptations for Thermoregulation - Energy Conservation  Torpor: physiological state of decreased activity and metabolism.  Hibernation: long term torpor and a decreased body temperature in response to winter cold and food scarcity  Estivation: short or long term torpor in response to summer heat and water scarcity

Cellular Respiration and Photosynthesis Cellular Respiration: aerobic harvesting of energy  Aerobic = requires oxygen Photosynthesis: conversion of solar energy to chemical energy Photosynthesis Light energy 6H2 + 6CO2 C6H12O6 + 6O2 Carbon Glucose Oxygen O dioxide Water Cellular Respiration C6H12O6 6O2 6H2 6CO2 36AT Heat

• \
  • \
  • +       Glucose Oxygen Carbon       O P       dioxide       Water

Site of Photosynthesis Stomata: pores on leaf where gas exchange occurs Chloroplasts: organelles in plants and algae where photosynthesis occurs Thylakoids: membranes within the chloroplasts  Location of photosynthetic pigments and light reactions of photosynthesis Stroma: liquid, gel-like substance inside chloroplasts that thylakoids are suspended in  Location of dark reactions of photosynthesis (Calvin cycle)

Two Stages of Photosynthesis

1. Light Reactions: electrons from    water are excited by solar energy    and used to power the formation    of ATP and NADPH (electron    carrier)     Takes place in thylakoid membrane     Oxygen byproduct
2. Calvin Cycle: energy from light    reactions (ATP and NADPH) used    to convert CO2 to carbohydrates    by stripping carbon from CO2     Takes place in stroma

Photosynthetic Pigments Pigments: molecules that absorb and reflect certain wavelengths of light.  Primary photosynthetic pigments: responsible for majority of photosynthesis in plants  Chlorophylls a and b absorb red-orange and blue- violet wavelengths.  Secondary photosynthetic pigments: fill in the gaps where/when primary pigments cannot photosynthesize  Carotenoids absorb blue-violet and green wavelengths.  Which wavelengths do they reflect?

Stomata Stomata open Stomata closed

Evolutionary History of Plants Phylogenetic tree: diagram showing evolutionary relationships among organisms  Groups organized by their Flowers shared characteristics  Common ancestor Seeds Vascular tissue

Nonvascular Seedless Plants  Mosses, Liverworts, Hornworts  Lack vascular tissue  Transport by diffusion  Limited vertical growth  Rhizoids Mosses  Precursors to true roots; very short Liverworts  Reproduce asexually via spores (a packet of plant cells capable of growing into a new plant ONLY in a moist environment)  Reproduce sexually via gametes (sperm and eggs) Hornworts  Flagellated sperm require wet environments to be able to swim to and fertilize an egg.

Evolution of Seeds Seed: a plant embryo and its food supply inside a protective layer (seed coat); much more successful than spores.  Seed coat offers seed a longer lifespan  Allows for dormancy until environmental conditions are perfect  Cotyledons: seed leaves; first leaves to emerge and begin photosynthesis  Endosperm: energy rich tissue that nourishes developing embryo; food supply (starch).

Asexual Reproduction in Vascular Seed Plants  Vegetative propagation: a method of asexual reproduction in plants, where a root, stem, or leaf is used to grow a new plant.  Resulting plants are clones of original plant (no new genetic information is introduced)

Adaptations to Reduce Transpiration  Small, thick leaves  Hairy/light-colored leaves (reflect sunlight)  Thick, waxy cuticle (non-polar leaf coating repels water)  Sheltered/hairy stomata  Drop their leaves in a drought Ocotillo, a Sonoran  C4 and CAM photosynthesis Desert staple, has nearly all of these adaptations.

Meiosis vs. Mitosis Mitosis Meiosis  Produces 2 identical  Produces 4 non-identical daughter cells daughter cells  Daughter cells 2n (diploid)  Daughter cells n (haploid)  One cell division  Two cell divisions (Meiosis I and  Occurs in somatic cells for II) growth/development, and to  Occurs in production of egg and replace damaged or dead sperm cells (gametes) cells  Increases genetic diversity via  Does not increase genetic crossing over and independent diversity assortment

Sources of Genetic Variation Crossing over = process in which homologous chromosomes exchange reciprocal portions of themselves during Prophase I of meiosis

Comparison of Chromosome Number Haploid: cells with a single copy of each chromosome  Gametes: sex cells  Egg and sperm  Produced via meiosis Diploid: cells with two copies of each chromosome, one maternal and one paternal  Somatic cells: cells forming the body of the organism  Produced via mitosis

Males and Females Individuals have two copies of sex chromosomes in every cell.  Females = Two X chromosomes.  Males = One X and one Y chromosome. Each egg gets Half the sperm cells get an X chromosome, and one X half get a Y chromosome. chromosome.

Differences between DNA and RNA RNA is single stranded and DNA is double stranded (double contains uracil instead of helix) and contains thymine instead thymine of uracil

DNA Replication Helicase: enzyme that unwinds DNA separating it into two complementary strands. DNA Polymerase: enzyme that creates the complementary strand by adding new DNA nucleotides to the template strand.

Cancerous Tumors Malignant Benign Malignant tumor cells divide and spread to Normal adjacent tissues and to distant tissues through cells lymphatic vessels and blood vessels Lymph vessel Blood vessel Benign tumor cells may continue to divide, but are not New tumor that has invasive (they do not formed in distant spread from tumor). tissue by metastasis

Protein Synthesis: Transcription and Translation Transcription: process by which a gene’s Translation: process by which mRNA base sequence is converted to mRNA (same directs the production of a protein language but different media). (conversion to a different language).

Check your Understanding DNA Replication DNA sequence TACAATGCGACGTGC Complementary DNA A T G T T A C G C T G C A C G sequence

Check your Understanding Transcription and Translation DNA sequence TACAATGCGACGTGC AUGUUACGCUGCAC mRNA sequence G Met Leu Arg Cys Thr Amino acid sequence

Review of RNA Types

Types of Mutations Normal gene Point mutation: occurs when one base pair in mRNA the DNA is substituted Protein Met Lys Phe Gly Ala for another Base substitution Frame shift mutation: Met Lys Phe Ser Ala a mutation in which one base pair is inserted or Base deletion Missing deleted, shifting the entire sequence Met Lys Leu Ala His

Bioengineering Bioengineering or genetic engineering: deliberate modification of the characteristics of an organism by manipulating its genetic material using special technology or controlled sexual reproduction; typically done as a means of meeting societal needs, like food and medicine.  Genetically modified organism (GMO): an organism whose genome has incorporated one or more genes from another species.

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Genetically Modified Organisms (GMOs) Artificial selection: intentional reproduction of individuals in a population with a desired trait.  ONLY individuals with desired trait are allowed to reproduce.  Domesticated animals (dogs, cats, horses, etc.) and crops are results of artificial selection.  These organisms are not considered GMOs even though they have been bioengineered.  All DNA is from the same species.

Why the pea? Model organisms: organisms that are easy to care of, study, and use for comparisons to many other similar species. Peas as model organisms:  Small and easy to take care of  Inexpensive to obtain  Easily observable traits  Only 2 variants per trait  Produce large numbers of offspring in short amount of time  Can be manipulated experimentally

Genetics Terminology Genetics: branch of biology that focuses on the inheritance of traits Heredity: transmission of traits from parent to offspring; inheritance Trait: characteristic of an individual Gene: a sequence of DNA that codes for a specific protein Allele: different versions of a gene

Genotype vs. Phenotype Phenotype: observable features of an individual  Ex. Yellow seeds, white flowers Genotype: the alleles found within a particular individual Codes for  One allele from mother and one from father  Only one allele expressed as the Genotype Phenotype phenotype  Denoted as letters  Ex: YY or Yy for yellow seeds

Characterizing the Genotype - Homozygous & Heterozygous  Dominant allele: allele that determines the phenotype of a heterozygous individual; masks the recessive allele.  Denoted with a capital letter (Y or R).  Recessive allele: allele whose phenotype is only expressed in homozygous recessive individuals; masked by dominant allele.  Denoted with a lowercase letter (y or r).  Homozygous: having the same two alleles of a certain gene.  Ex:YY or yy.  Heterozygous: having two different alleles of a certain gene YY Yy yy  Ex: Yy or Rr.

Mendel’s Findings 1.Peas have two versions, or alleles, of each gene.  This is also true for many other organisms. 2.Alleles do not blend together.  Maintain their integrity from generation to generation whether they are expressed or not. 3.Males and females contribute equally to the genotype of the offspring because each gamete contains only one allele of each gene (haploid).  When gametes fuse together during fertilization, the offspring gets one allele from each parent per gene. 4.Some alleles are dominant to other alleles.  When dominant and recessive alleles are found together, the phenotype that is expressed will be that of the dominant allele.

Check Your Understanding Provide the genotypic ratio and phenotypic ratio for a cross between a man with blonde hair, and a woman with black hair who is heterozygous for the hair color gene. Blonde hair is a recessive trait. Genotypic ratio: Phenotypic ratio:

X-Linked Inheritance  X-linked disorders: genetic disorders caused by genes found on the X chromosome; can result from dominant or recessive alleles.  Ex: color blindness.  Recessive disorder: genetic disorder that does not exist in the presence of a functioning dominant allele; only expressed in homozygous recessive individuals.  Autosomal recessive disorder: caused by recessive genes found on non sex chromosomes (autosomes)  X-linked recessive disorder: caused by recessive genes found on the X chromosome  Males only need one X chromosome with a recessive gene  Not “homozygous” but still recessive

Autosomal Recessive Disorder Carrier: a person who does not suffer rom the recessive genetic disorder but who carries an allele for it that can be passed along to their offspring  Ex. Person heterozygous for albinism

Autosomal Recessive Disorders  Sickle-cell anemia: defective hemoglobin protein causes sickle cell shape.  Both mother and father must have at least one allele for sickle cell anemia; they must be carriers or express the disorder. Sickle-cell anemia  25% chance that offspring will get the disorder if both parents are carriers.

Autosomal Dominant Disorder Huntington's disease: a late-life disorder that results in the deterioration of nerve cells in the brain, leading to eventual loss of functions. is sick

Check Your Understanding X-linked recessive disorder Ex. Hemophilia Male genotype In this situation, the female does X Y not suffer from hemophilia, but her father had hemophilia. The male does not suffer from hemophilia. X Predict the chances of having a male child with hemophilia. X

Linked vs. Sex Linked  Linked traits: genes that are located on the same chromosome.  Sex linked or X-linked traits: genes that are located on the X chromosome.

Linked Traits  Almost always inherited together during meiosis.  Unaffected by crossing over because they are located so closely to each other.  Linked traits violate Mendel’s law of independent assortment.

Polyploidy  Polyploidy: a condition in which one or more sets of chromosomes have been added to the genome of a diploid organism, creating a triploid (often sterile) or tetraploid (often viable/fertile) organism; result of total nondisjunction.  Most often seen in plants that self-fertilize; can lead to “seedless” varie reduced fertility (grapes, watermelons, etc.)  Not common in animals, except fish and amphibians.

History of Evolutionary Thought Pre-1800s thoughts on the Earth and living things: • Earth and every living and non-living thing on it were created at one time. • Earth and living organisms have not changed since their creation. • The number and types of organisms that existed at dawn of creation have not changed since then.

Evidence for Evolution  Fossil record  Evidence for extinction  Evidence for diversifica

Evidence for Evolution Transitional forms: Intermediate states between ancestral form and its decedents  Archaeopteryx  Teeth of reptile  Feathers of bird  Tail with vertebrae like reptile  Claws of reptile

Radiometric Dating Radiometric dating: a technique used to determine the exact age of an object by measuring the amount of decay of radioactive elements within the object  Carbon dating  C12 and C14  Half life of C14 = 5730 years  Uranium dating  Uranium-238 to Lead-206  Half life = 4.5 billion years

Evidence for Evolution Homologous structures: structures that are physically similar (but functionally different) among closely-related groups of organisms due to a common ancestor.

Evidence for Evolution  Analogous structures: structures from different species with similar functions but not due to common ancestry.  Convergent Evolution: the independent evolution of similar features in species of different lineages.  Typically due to species evolving in similar environments

Evidence for Evolution Embryology: study of development from Fish fertilization to fetus stage Salamander  Similar structures during embryonic development among vertebrate groups Tortoise due to common ancestry  Pharyngeal gill slits Bird  Post anal tail Pharyngeal pouches Human Post-anal tail

Types of Evolutionary Change  Microevolution: evolutionary change resulting from a change of the allele frequencies of a population  Macroevolution: large-scale change occurring over long periods of time that results in the formation of new species (speciation) 2 species 1 species Time

How does microevolution occur? Population: Individuals of the same species that live in the same area at the same time and have the potential to interbreed Four mechanisms of evolutionary change within a population

1. Mutation
2. Gene flow
3. Genetic drift
4. Natural selection

Mutation Mutation: a permanent change in an organism’s DNA  Random  Organisms cannot will a change.  Primary way new alleles are created.  Only mutations that affect sex cells can be inherited.  Can be positive (beneficial) or negative (harmful) towards fitness.  Negative mutations are eliminated from populations over generations through purifying selection.

Gene Flow Gene flow: the movement of alleles from one population to another via migration.  Random with respect to fitnes  Occurs through breeding of individuals from different populations.  Can reduce genetic difference between populations.  But typically increases genetic variation in receiving population.

Genetic drift Genetic drift: a random shift in the allele frequencies of a population due to death and/or reproduction.  Random with respect to fitness  Most pronounced in small populations Reproduction results in increase in homozygous recessive individuals  Can lead to the loss or fixation of alleles  Fixation: when an allele’s frequency becomes 100% in a population.

Genetic Drift in Small Populations Genetic bottleneck: a sudden reduction in the alleles of a population, which typically results from a sudden reduction of the population. Ex. Elephant seals, ch

Natural Selection Biological fitness: ability of an individual to produce offspring, relative to other individuals of the same species in the same environment.  “Survival of the fittest” = survival to reproductive age Adaptation: heritable trait that increases the reproductive success of an individual relative to individuals lacking that trait in the same environment.  Adaptations do not occur because of random chance.

Natural Selection  Natural selection: the process by which individuals with certain heritable traits tend to produce more surviving offspring than do individuals without those traits.  Natural selection is a non-random adaptive process.  “selects” for traits that increase chances of survival in a certain environment.

Natural Selection: Peppered Moth Peppered moth:  Two morphs  Gray with black spots  Black  Limiting factor: predation In 1848, gray morph ≈ 98% of population; by 1900, black morph ≈ 95% of population  Industrial revolution:  Coal factories covered forests in soot  Increased environmental standards since then have led to an increase in gray morph again.

Evolution After Geographic Isolation Allopatric speciation: speciation that results from the geographic isolation of populations by a barrier that prevents interbreeding between populations

Speciation Without Isolation Sympatric speciation: speciation without geographic separation; mix of natural and sexual selection.  Ecological niche: the role of a species within its ecosystem (e.g. diet, diurnal/nocturnal, etc.).  If multiple niches are available in an area, a population does not need to be separated for reproductive isolation to occur.  Cichlids in Lakes Victoria, Malawi, and Tanganyika

Sympatric Speciation - Polyploidy • Polyploidy: when an organism contains more than one set of paired chromosomes; a result of nondisjunction; can lead to speciation. • Most common in plants (self-fertilization). • Can happen naturally in the wild or artificially by humans. • Typically results in infertile (seedless) varieties with larger fruits.

Adaptive Radiation Adaptive radiation: process in which organisms rapidly speciate, especially when exposed to a new environment with different challenges, new resources, and available niches.  After mass extinction events  Cambrian explosion (~500 mya)  Archipelagos  Galapagos finches  Hawaiian honeycreepers

Different Levels of Study in Ecology Ecology: Study of the interactions that living things have with each other and with their environment Individuals: study of individual organisms within an environment Population: all the members of a single species living in the same geographic area at the same time Community: populations of all species that interact with one another in the same geographic area Ecosystem: community of living organisms and the non- living physical environment with which they interact  Biotic and abiotic factors

Community Ecology Affect on Affect on Interactions among different species fitness for fitness for species 1 species 2 Competition: occurs when individuals use the Negative Negative same resources Predation and parasitism: occurs when one organism eats or absorbs nutrients from Positive Negative another Mutualism: occurs when two species interact Positive Positive in a way that confers fitness benefits to both Commensalism: occurs when one species Positive Unaffected benefits but the other species is unaffected

Life History: r-Selected and K-selected Species r-selected K-selected  Unstable environment.  Stable environment.  Fluctuating carrying capacity  Stable carrying capacity  Small organism size.  Large organism size.  Little energy used to produce  Large amount of energy used to each offspring. produce each offspring.  Many offspring produced.  Few offspring produced.  Not many survive. Why?  Majority survive  Short gestation period and early  Long gestation period and late maturity. maturity (long parental care).  Short life expectancy.  Long life expectancy.  Single reproduction in lifetime.  Multiple reproductions in lifetime.

Types of Population Growth Exponential growth: when a population’s size increases at a rate proportional to its current size (i.e. as the size increases, so does the growth rate).  Each individual produces 2 or more offspring so population keeps doubling.  Forms J-shaped curve on a graph.  What kind of environment is required for this to occur? Logistic growth: the density-dependent decrease in growth rate as population size reaches the carrying capacity (K).  As population size increases, growth rate decreases.  Forms S-shaped curve on a graph.  Birth rate decreases and death rate increases as population approaches carrying capacity.

Interaction Through Competition Ecological niche: an organism’s place or role within a community.  Space it requires, food it consumes, reproductive requirements, whether it is food for other organisms Competitive exclusion principle: two species cannot occupy the same ecological niche in the same area indefinitely, because one species will always outcompete the other.  G.F. Gause - It is not possible for two species to occupy the same ecological niche in the same

Resource Partitioning Resource partitioning: The dividing up of scarce resources among species with similar requirements.  Can lead to eventual niche differentiation  Each species focuses on its specific niche space  One niche now becomes two

Fundamental vs. Realized Niche Fundamental niche: the full range of environmental conditions and resources an organism can possibly occupy and use in the absence of competitors. Realized niche: the part of the fundamental niche that an organism occupies as a result of competitors in the habitat.

Ecosystem Diversity  Ecosystem services: all the processes through which natural ecosystems benefit humans. Examples?  Provide water, food, and building materials.  Energy production.  Medicinal benefits derived from plants.  Pollinators.  Flood and erosion control.  Water filtration.  Recycling of organic materials.  Nutrient cycling.  Recreation and cultural services.

Factors that Create the Ecosystems on Earth Distribution of solar energy:  Solar energy is greatest at the equator, making it hot.  Due to curvature of Earth, sunlight is spread out over larger areas near the poles, making these areas colder.

Factors that Create the Ecosystems on Earth

1. Solar heat causes air to    warm and rise.     Warm air holds more moisture    than cold air.
2. Rising air cools and    condenses the farther it gets    from the Earth’s surface.
3. Cooling air loses moisture    causing rainfall.     Gaseous water molecules lose    speed as they cool down and    become liquid again.

Factors that Cause the Ecosystems on Earth Hadley cell: large scale atmospheric pattern where warm, wet air rises at the equator and cools at it moves poleward, with dry air descending at about 30° N and S latitude.  Creates subtropical (30°) and polar (90°) deserts and tropical (0°) and temperate (60°) rainforests

History of Mass Extinction Events  Five mass extinction events on Earth.  Humans are currently causing the sixth mass extinction event.

Human Impacts on Biodiversity Habitat loss: the conversion or transformation of a natural area into a wholly human-occupied area of little or no use to wild species.  Typical conversion method - deforestation.  Mostly caused by expansion of agricultural land.  Palm oil plantations expansion = loss of habitat for orangutans and others.  Greatest threat to biodiversity.  Also leads to more erosion, less water retention, less oxygen production, and more carbon dioxide production.

Preservation of Species Protection of species Captive breeding Seed banks and frozen and their habitats programs zoos - DNA storage

Preservation of Species - Biodiversity Hotspots Requirements:  At least 1500 endemic plant species.  Endemic: species found only in a distinct geographic area.  70% loss of original habitat.

Preservation of Species Protected Areas  Protection of critical habitat (like biodiversity hotspots)  National parks/preserves  Marine protected areas  Wildlife corridors  Restoration of habitats !! Chaparral Restoration video

Preservation of Species - Carbon Sequestration  Carbon sink: anything that absorbs more carbon dioxide than it releases.  Ex. Forests (conservation and reforestation)  National parks and preserves  CA has nine national parks (most of any state in US)  Reforestation of degraded forests  Planting more trees can slow down global warming AND create more habitat for a variety of species (win-win).

Respiratory and Circulatory Systems

Functions of the Circulatory System  Circulatory/cardiovascular system: organ system that circulates blood through a network of vessels, transporting nutrients, gases, and hormones to cells throughout the body.  Transport: transports oxygen, nutrients, waste products, immune system cells, and hormones throughout the body.  Temperature regulation: helps maintain a body temperature that is optimum for metabolic function.  Vasoconstriction in response to cold.  Vasodilation in response to heat.  Protection: immune system cells transported throughout the body aid in fighting foreign invaders.  Platelets and white blood cells.

What’s in the Blood?  Red blood cells (erythrocytes): oxygen transport.  Contain hemoglobin. Leukocyte  Lack nucleus and most organelles. s Why?  95% of all blood cells in the body.  1/3 of all cells in the body! Platelets  White blood cells (leukocytes): immune response to disease and foreign invaders (pathogens). Pathogen s  Platelets (thrombocytes): cell Fibrin threads fragments that aid in blood clotting.

Hemoglobin  Hemoglobin: an oxygen-carrying protein made up of four polypeptide chains.  Each hemoglobin can transport four oxygen molecules bound to seats of iron molecules. What would happen if you had an iron deficiency?

The Circuits of the Circulatory System  Heart: hollow muscular organ that pumps blood through circulatory system by a series of rhythmic contractions.  Atria: chambers that receive blood entering heart.  Ventricles: chambers that pump blood out of the heart; more muscular than atria because they have to send blood out of the heart and through the body.  Pulmonary circuit: circuit of blood flow between the heart and the lungs.  Systemic circuit: circuit of blood flow between the heart and the rest of body.

Exchange at Capillaries  Capillaries are so small that erythrocytes pass through single-file.  Gases, nutrients, and waste move via diffusion.

Heart Valves  Semilunar valve: valve between ventricles and aorta or pulmonary artery.  Atrioventricular valve: valve between atria and ventricles; tricuspid and bic What is the purpose of these valves?

Cardiovascular (Heart) Disease Kills more than 750,000 people in U.S annually (leading cause of death).  Hypertension: high blood pressure; wears out your heart and arteries over time.  Atherosclerosis: hardening of arteries by accumulation of plaque (low density lipoproteins - bad cholesterol); can lead to heart attack or stroke.  Heart attack: damage or death of cardiac muscle due to blockage of coronary arteries, which supply blood to the heart muscles.  Stroke: death of nervous tissue in the brain du f carotid arteries, which supply blood to the brain. Plaque What is the best way to prevent heart disease?

The Nervous System - Communication  Nervous system: network of complex neural pathways (nerves) with a central processor (brain) that produces electrical signals to relay messages throughout the body using neurons.  Signals are interpreted and responses are elicited instantaneously  Involved in all bodily activities  Key in maintaining homeostasis  Ex. Shivering when cold

The Nervous System Central nervous system (CNS): portion of nervous system consisting of the brain and spinal cord.  Involved in interpretation of signals and initiation of response. Peripheral nervous system (PNS): portion of nervous system outside of the brain and spinal cord, which includes the sensory organs (skin, eyes, ears, mouth, etc).  Involved in reception and transduction of environmental stimuli (external and internal).

Types of Neurons Sensory neurons: nerve cells that receive signals from sensory receptors inside and on the surface of the body, then send that information to the CNS for interpretation. Interneurons: nerve cells that connect other neurons and relay information between them; only found in CNS (mainly in the spinal cord). Motor neurons: nerve cells that transmit signals from the CNS to muscles and glands involved in a response to a stimulus; elicit an action.

Reflexes Reflex: automatic involuntary response independent of interpretation by the brain. Faster than a reaction (voluntary response that involves the brain, like dodging a ball). Used to test the health of the nervous system. Reflex pathway: Sensory neuron, Spinal cord interneuron Motor neuron Automatic muscle movement

Sensory Receptors Mechanoreceptors: receptors that respond to pressure.

Senses: Touch, hearing, balance.

Thermoreceptors: receptors that respond to changes in temperature.

Senses: Touch, pit vipers’ hunting sense, spicy food (capsaicin receptor).

Chemoreceptors: receptors that respond to different chemical stimuli in the environment.

Senses: Taste, smell, solute concentration (osmoreceptors in our blood detect glucose, oxygen, and carbon dioxide levels).

Photoreceptors: receptors that respond to different wavelengths of light. Sense: Sight (rods and cones).

Touch - Mechanoreceptors, thermoreceptors, and pain receptors Touch receptors in the skin:

Pressure (tactile mechanoreceptors) Pain receptors Activated along with other receptors and elicit a rapid response for protection.

Temperature change receptors (thermoreceptors)