Bio Exam 4 Content

Evolution

-A change in the allele frequency of a population over time -happens over generations -biologically, you as individuals cannot evolve -evolution? thinking about groups, their genes + how things change from generation to generation, often over very large periods of time -tells us why certain characteristics are prevalent in a population

Race in Humans

-A famous study in 1972 by Dr. Richard Lewonton compared DNA of 9 socially-defined races, including Caucasian, South Asian, African and Aboriginal Australian Results: -85% of genetic variation was between individuals within the same population (between two Africans from the same local population, between two South Asians from the same local population, etc.) -8.3% of genetic variation was between different populations from the same "race" (between two Africans from different local populations of Africans, between two South Asians from different local populations of South Asians, etc.) -6.3% of genetic variation was between individuals from different "races"

Population

-A group of individuals of the same species that live in the same geographic area

Innate immunity

-A non-specific response -Rapid response to general, non-self cues -Innate: doesn't really change in terms of how it respond to invaders -Body isn't recognizing particular bacteria or virus getting in, body just knows there is a potential invaders, try to kill antigen getting in -Something we are born with, doesn't really change throughout life, doesn't change in response to specific type of invaders -Innate cells don't care what they're looking at (bacteria, virus, etc) do not act in response to specific pathogen, don't know "who" is causing the problem, just knows potentially being invaded

Bacteria can be "'good"

-A part of natural flora, help protect us against other types of harmful bacteria -Helpful In digestion, used in food production (yogurt, cheese), environment (decomposers, chemical cycles> help clean environment, create medically useful substances -Normal inhabitants of the body that keep harmful organisms in check and produce vitamin k -Human intestines have approx 500-1000 species of bacteria. -Their cells outnumber all other cells in the body by more than 10X -Mental health can be related to gut bacteria

Viruses (2)

-Difficult to Destroy -Hard to kill a virus inside a host cell without killing the host cell itself -Antiviral drugs often block a step of viral replication/reproduction, don't kill virus, just prevent its reproduction -Best way to prevent viral infections is through vaccination, get very good at fighting virus or preventing to even get it in the first place -hard to create drugs that only target the virus and not the host cell

Some things studying evolution cannot do

-Doesn't tell us about things earlier than the first living organisms -Explain the purpose of life -Explain how our planet came to be, although there are areas of science that deal with this -Explain the role of an omnipotent power -Evolution + faith answer 2 diff questions, science tries to document factual character of the natural world and religion operates in the realm of human purposes, meanings and values

Pathway of forming memory cells from B cells

-Each B cell has receptors for a different antigen on its surface. The antigen binds to the B cell with appropriate receptors The selected B cell divides, producing a clone of cells all bearing receptors specific for that particular antigen. Plasma cells produce antibodies specific for this particular antigen. Memory cells remain to bring about a quick response to that antigen in the future.

Anaphylactic shock

-Extreme allergic reaction that can be fatal -Cause cause pooling of blood in capillaries which makes breathing difficult, or can cause swelling, muscles in airway to contract + close shut -Common triggers> more severe allergens, not pollen or dust mites, could be insect stings, especially from bees, wasps, yellow jackets and hornets -Medications including penicillin -Foods such as shellfish, peanuts

1. Threat (Adaptive immunity)

-Foreign organism or molecule (an antigen) enters the body

Adaptive Immunity

-Future protection -Memory cells created to protect the body from a future threat by the same pathogen -If that pathogen tries to invade again, the body's response is rapid and powerful -More antibodies + stronger immune response, we take advantage of this through the create of vaccines

Neuraminidase

Affects the release of viral particles, bind to receptors to help it get out

B cell and antigen

Antigen binds directly to B cell which initiates massive response by body.

When does B cell clone itself?

B clones itself when message it received from helper T cell that is has also found the antigen. -Some of the clones become plasma B cells, some will become memory cells if infected again by same pathogen, then call memory cells.

Hemagglutinin

Protein that will bind to your cell receptors that will let virus in

simple way to think of evolution

Response to change in the environment

HIV and AIDS

Human Immunodeficiency Virus/Acquired Immune deficiency Syndrome -Infection of the immune system .virus attacks Helper T cells -If Helper T isn't functioning, prevents an immune response, unable to fight infection, unable to eliminate cancer -not necessarily HIV infecting T cells that can be deadly, its that is makes person get different infection that can end up being deadly -Opportunistic infection: May be deadly for those with compromised immune systems -HIV is the virus, AIDS is the syndrome that can result from the virus

Antigenic drift

Minor changes (mutations) in these proteins that allow the virus to evade the immune system, virus is still H3N2, but a slightly different version -Viruses with mutations more likely to survive and reproduce

pathogens

disease-causing organisms -can be bacteria, viruses, fungi, protists

selective pressure

environmental conditions that select for certain characteristics of individuals and select against other characteristics, when the environment pushes an individual or population to adapt or evolve, an evolutionary force that causes a particular phenotype to be more favorable in certain environmental condition

tonsils (immune system)

help protect you against things trying to get into your body, can trap and kill things like bacteria or other pathogens going into body through respiratory tract

Some things we know now about evolution and the world in general

-Life on earth spans over 4 billion years -Evolution on earth is constant, there are always populations changing or responding to their environment, all organisms are always changing, biodiversity always changing but not always at the same rates -Evolution is not directional, we do not go from less to more complex (or not becoming, "better") -Evolution evolves over time, so it's not right to say that we are "More evolved" because every single organism on this planet is evolving

2. Detection (Adaptive immunity)

-Macrophage detects foreign organism or molecule and engulfs it and digests the invader, the macrophage places a piece of the invader (antigen) on its surface with the self (MHC) marker -Macrophages can initiate this response by alerting B + T cells. Macrophage encounters + engulfs bacteria + breaks it down, macrophage has MHC markers that will bind to antigen, once MHC has bound to antigen, they go out to surface of cell and macrophage basically waves it around to alert Helper T cell which initiates rest of immune response

3. Alert (Adaptive immunity)

-Macrophages present antigens to helper T cells and secretes a chemical that helps activate the helper T cell -Macrophages are antigen-presenting cells -Helper T cells are the main switch for the adaptive immune response

Job of plasma B cells

-Make antibodies -Job is to shed receptors, once receptors leave surface of cell, they are now antibodies. So antibodies are really shed B cell receptors. -Antibodies can find other antigens throughout body + bind to them, can neutralize it, kill it or call over a macrophage

Gene Flow

-Migration -Movement of individuals into or out of a population -Could end up resulting with a change in allele frequency because they take their alleles with them -Difference with this and founder effect is in gene flow we are moving between two established populations -Gene flow causes evolution if individuals move from one population to another, causing a change in allele frequencies in either population -After initial movement, population has not evolved

Why are vaccines controversial

-Misinformation is a powerful, deadly tool -Anecdotal evidence and flawed logic -"This child wasn't vaccinated and hasn't gotten sick, so vaccines aren't necessary"

Major histocompatibility complex (MHC) markers

-Molecules found on our own cells that label cells as "self: -Used by the immune system to distinguish cells of your own body from foreign invaders -Body is able to bind with them, they are basically receptors -If something doesn't have right MHC markers on surface, body is able to go into attack

Influenza A susceptibility in birds

-Most (all?) of the major influenza A subtypes occur in birds -Only a few circulate in humans, and then it's generally one or two at a time -bird influenzas couldn't infect humans because their receptors are different than ours, which determine susceptibility to flu

What are some different ways that allele frequency of a particular population could change?

-Mutation can become more frequent in future generations if beneficial, natural selection and mutation happening together, leading to evolution of population -If mutation shows up + persists> evolved due to mutation -If mutation shows up + becomes more frequent because it is beneficial, example of mutation + natural selection that acted on that mutation

Natural selection can lead to adaptation

-Natural Selection can result in a population that is well adapted to its current environment -if a trait is beneficial then able to or expect to see that trait become more + more frequent in the population or individuals have different versions of a trait that is also helpful because its how previous generation was able to survive/pass on those genes -population can adapt, individuals cannot evolve or adapt

Condition 1: Variation for a trait

-Natural selection doesn't happen when people have the same alleles for a trait cause they can only pass on those alleles to the next generation and next generation won't have a different frequency of the alleles, it'll be the exact same as previous generation cause of only one version to look at -have to have variation of the particular trait, more variation occurs beyond what we can see

Antigen

-Nonself substance or organism that triggers an immune response -Usually large molecules, such as proteins, polysaccharides or nucleic acids -Often found on surface of invaders

Autoimmune disorders

-Occur when the immune system fails to distinguish between self + nonself + attacks tissues -Classification can be Organ specific or Non-organ specific -Organ specific> usually caused by problematic T cells, examples: Hashimoto's thyroiditis, Type 1 diabetes -Non-organ specific> Usually caused by problematic B cells, examples: Systemic lupus erythematous, rheumatoid arthritis

Natural Selection

-One way evolution can happen -Not to be used synonymously with evolution -some individuals are better suited to their current environment, these individuals are more likely to survive and reproduce in the environment -better at getting food or finding mates or evading predators, etc. -biological fitness: how likely an individual is to survive and pass on their genes to the next generation based --"Survival of the fittest", not physical fitness --Based on alleles (evolution=change in the alleles over time) -Results in a population that is well adapted to that environment, offspring passes on these inherited traits -if the environment changes, the fitness of traits may change as well, why evolution doesn't result in perfection -not proactive, it is responsive

Adaptation

-Over time, organisms come to have traits that suit them to the conditions in a particular environment -if the environment changes, these traits may no longer be adaptive -Traits may no longer be helpful in the future so individuals that were well adapted no longer are, can't just change their genes -Adaptation is result of a change in genes, either adapted to current environment or not -If whole population doesn't have any versions of a trait that would be helpful in this new environment, population can not adapt to change and go so they go extinct

Allergies

-Overreaction by the immune system to a harmless antigen (an allergen) -No possible invasion, no serious destruction to the body -Immune system responding to something it doesn't need to be responding to, not likely to infect you or cause serious damage to the body -examples: pollen grains or dust mites

Influenza A in pigs

-Pigs are very susceptible to the flu -have receptors for bird subtypes and human subtypes > "mixing pot" -This is a problem for humans because of our very close relationship to pigs, they are very important livestock all over world, pigs can catch it from us, we can get sick from them, don't wanna lose livestock to infection either

Example of founder effect

-Polydactyly in Amish -Amish population have a higher population of polydactyl allele versus large U.S. population, they left and established a new population for religious reasons, they did not establish population because of this, just by chance -By chance, there was a higher proportion of polydactyl alleles in founders

spleen (immune system)

-Produces important cells needed in immune system, also filters out some of blood, includes things trying to infect you

Bacteria can be "bad"

-Release toxins that damage tissue and can make you sick, sometimes the they are constantly releasing toxins, other times they are in their cell wall so they aren't released until they die which can impact when or how sick you feel during the progression of infection -^can feel sick when they start dying a lot -Cause about half of all human infectious diseases

Allergies> Why does our body do this to us?

-Research from Europe 1. Observations> Children that grow up on rural farms tend to report fewer allergies and asthma than children that do not grow up on farms 2. Hypothesis: Exposure to germs in childhood is important for the development of the immune system because it increases tolerance of environmental particles or microbes. Teaches immune system what to respond to. 3. Test: Compare the bacterial population in the mattresses of children that live on farms and those that do not live on farms

With this population of survivors (bacteria with low permeability), what will the next generation of bacteria look like (assuming the trait is heritable)?

-Shift in distribution of alleles> offspring all have Low permeability to a given antibiotic and therefore high resistance

Bacteria

-Single-celled organisms that rapidly reproduce asexually -prokaryotes -Unless a mutation arises, all offspring that are genetically identical to parent + each other -larger than viruses -have cell wall which can determine permeability to antibiotics, gives lots of protection to bacteria to prevent things from damaging their membrane, singled cell organisms needed an added layer of protection -whether or not antibiotic is able to kill bacteria depends if antibiotic is able to penetrate the cell wall -three diff shapes: spherical called cocci, rod-shaped called bacilli, spiral-shaped called spirilla

Human skin color

-Skin color determined by genes -Skin color associated with "race" -race implies distinction; biologically unique groups -Skin color is heritable; determined by our genes

Population Bottleneck

-Special case of genetic drift -A large portion of the population is lost, resulting in a drastic reduction of variation of alleles -Drastic portion of population lost that we have almost no variation in alleles as a result -Humans cause rather than experience this

Founder effect

-Special case of genetic drift -A portion of the population leaves and establishes a new population -The allele frequency of the new population may vary from the "source", SP allele frequency may look different cause alleles the group took with them after they left -alleles that are changing don't have anything to do with WHY new population was started, it is by chance

Heat (sign of inflammation)

-Temperature rises as a result of increased blood flow -Speeds healing and activities of defensive cells -Can help when trying to repair injury, help heal wound + help immune cells fighting potential invaders

Adaptive immunity

-The body "adapts" to specific pathogens over time -Remembers those pathogens in case of a future reinvasion attempt -Changes in response to specific pathogens -Will involve B and T cells, types of white blood cells capable to responding to specific antigens

Genetic drift

-A random change in allele frequency, unrelated to any allele's influence on reproductive success -Alleles In the next generation has different alleles to work with -Alleles in question have nothing to do with fitness -Biological fitness> how likely an individual is to survive and pass on their genes to the next generation -Natural disasters (like a flood)are a common example, wrong place at wrong time, when they die so do their alleles -Can lead to fixation: all individuals of a population have the same allele for a given trait which is not usually a good thing because variation is helpful

selective pressure w viruses

-Ability to get in and out of host cell, some forms more successful in certain environments than others, depends on which proteins and mutations you have, proteins are genetic, change with mutation

Allele frequency

-Alleles are alternative forms of genes -frequency is referencing what proportion of the population has one allele compared to another

Fever (innate immunity)

-An abnormally high body temperature -Caused by chemicals that reset the brain's thermostat to a higher temperature -A mild or moderate fever and helps fight some bacterial infections because it increased white blood cell count, metabolism and tissue repair, makes immune system more efficient so it can kill invaders -A very high fever (over 105 F or 40.6 C) is dangerous because proteins can denature which are the building blocks of everything

Mutations

-An alteration of the base-pair sequence in the DNA of an individual's gamete-producing cells that changes an allele's frequency -Source of all new variations in species, usually harmful, sometimes benign or beneficial, how new alleles are created -DNA in the gametes is inherited -Mutations are random, we can't make predictions about them, can estimate how many mutations will show up in a population, but don't know which genes will be mutated or the effects (beneficial, benign or harmful) of the mutation -Nearly all of them reduce an organisms' fitness, less likely to survive and reproduce

An evolutionary arms race: the red queen hypothesis

-Antibiotic resistance can be explained by the Red Queen Hypothesis -Organisms are in an arms race with each other -We change in response to each other -Predator-prey, disease-host -Developing new ways to overcome each others weapons, protections versus ways of infecting

5. Building specific defenses (adaptive immunity)

-B cells form plasma cells that secrete antibodies (specific to antigen) into the bloodstream, which binds to antigens -T cells form cytotoxic T cells that attack -Process by which immune cells increase in number is termed clonal selection

Which B cells to activate?

-B cells, when they're made, are like snowflakes -No two are identical -The receptors on their surfaces are all slightly different -These are what become antibodies -Helper T activates B cells that have also detected the same antigen, their antibodies are specific to the antigen -In order to have immune response, right helper t capable of binding to antigen has to be activated, also have to have B cells with right receptors that can bind to antigen, both helper T and B will have had to detected the antigen

When does HIV become AIDS?

-Based on T- cell count (CD4) -Below 200 per microliter of blood is AIDS, not able to fight infection

Pain (sign of inflammation)

-Can be caused by excess fluid, bacterial toxins (bacteria can release painful toxins), chemicals released at sight of infection

Antibiotics

-Chemicals that inhibit the growth of bacteria, disrupt processes in bacteria but not in human cells -inhibiting potential for bacteria to grow + reproduce, targeted at part of bacteria human cells don't have, often cell walls, have to get through cell wall, able to attack bacterial cells without attacking human cells

Vaccines

-Contain an antigen, putting a part of the pathogen in your body, but not enough that is could actually infect you -Part of the pathogen (protein or nucleic acid) OR weakened or killed pathogen -Elicits an immune response without actually "getting" the infection -Body will "remember" the antigen for later -Memory T and B cells produced -If exposed to the pathogen, the body swiftly eliminated it before it becomes a problem -Might feel sick from vaccine, it is just immune cells ramping up -Safe and effective for those with healthy immune systems

Example of skin color in family

-Couple had twin girls, one with dark skin and one with light skin -What we see in this family that is VERY closely related, people can have different skin color -So, skin color is not a good indicator of biological difference, they share many same genes (the twins)

Inflammation (innate immunity)

-Destroys + cleans out invaders and helps repair and restore damaged tissue -Body recognizes there's a problem and a potential invasion -Response from body when damaging is happening, doesn't know specific invader but knows there are things trying to get in at site of this damage or things that are in that are causing damage -Four signs 1. Redness 2. Heat 3. Swelling 4. Pain

Viruses - Antigens- Vaccines

-Genes for the antigens mutate -Antigen for flu is H + N proteins which regularly change so vaccines for flu one year won't work for next year -usually subtle differences, but enough that we don't "recognize" them as well' -need new vaccines every year -Scientists study changes (evolution) in common strains during "flu season", analyze the flu all year around + make predictions -February: WHO consortium makes predictions about flu next season, develop vaccine based on these predictions -Vaccines contain antigens for multiple types of viruses and subtypes, even if it doesn't work well with one type of flu, still lot of protection against other types of flu exposed to

Genetic drift (2)

-Genetic drift typically reduces the variation in a population, could lose all of our variation -The impact of genetic drift is much greater in a small population, more likely to drift to fixation -Species all shows one trait over time -Populations that are smaller will be more susceptible to genetic drift -for ex. flood takes out larger portion of smaller population, more likely to take away different alleles, less likely to lose entire variation of an allele in a larger population, not reduce variation or diversity as much

Influenza A

-Genetic material is single stranded RNA, 8 segments of RNA,1 gene each, males 8 proteins -Has an outer membrane (envelope) -proteins stick out of the envelope -2 types> Hemagglutinin (H) Neuraminidase (N) -proteins are the little spikes on the outside of viruses

Hemagglutinin and Neuraminidase

-H important in the virus, entering the cell -N important in the virus, exiting the cell -These two proteins are the major influenza antigens, body capable of recognizing as "non-self" to stimulate immune response -The genes for these proteins can change, somewhat frequently -High mutation rate, because we're talking about antigens, mutations can be helpful to viruses' ability to reproduce -Because viruses are so simple, mutations are typically not as harmful -Next generations > different from the previous -Because body can learn to recognize antigens, virus can benefit by change happening on the regular, so host Bodies can't recognize antigen anymore , virus is capable of evolving -by seeing genetic change over generations in viruses, evolution is demonstrated

Some things evolution can do

-Help us understand how organisms fit in with each other and their environment -Helps us understand how organisms have changed over time -Help us predict how organisms will respond to change in the future, this is very critical in discussion of pathogen, how they've changed and how they are likely to change in the future, helps create things like antibiotics, also important in agriculture + general human life

4. Alarm (Adaptive immunity)

-Helper T cells activate appropriate B cells and T cells to destroy the specific antigen, no B or T cells are exactly the same, not activated at same time -When activated, these cells divide to form clones (identical copies) of cells designed to eliminate the specific antigen from the body -T cells look for cells which are infected or harmed by pathogen -Helper T cells also look a little different from each other, like B cells, differ in receptors

Result of test (comparing bacterial population in the mattresses of children that live on farms and those that do not live on farm)

-Highest prevalence, highest number of hay fever symptoms are associated with very low bacterial load in mattresses (endotoxin load) saying children that are reporting hay fever + most symptoms are ones with pretty low bacterial load in mattresses, children with a lot of bacteria in mattresses don't have nearly as much hay fever or as bad of symptoms, consistent with global patterns -1980s- 10% of western populations suffer from allergies -2012: 30% of western population suffer from allergies ^ consistent with lifestyle changes, more suburban + urban living, tend to sanitize environments, think cleaning products

Swelling (sign of inflammation)

-Histamine causes capillaries to become leaky, and fluid seeps into tissues -Fluid brings clotting factors, oxygen and nutrients -Histamine makes blood vessels leaky so fluid + cells can leak out, so can get closer to surface where wound is, which causes swelling, fluid not just circulating through body, it's staying in one place -Swelling itself is body defending and repairing

Redness (sign of inflammation)

-Histamines released, which causes blood vessels to dilate , become leaky, let fluid leak out of blood vessels -Blood flow to the area increases, delivering defensive cells and removing dead cells and toxins -Bringing blood + the cells that are in blood + fluid to site of injury, with that blood comes redness, blood brings helpful cells, only dead cells or toxic cells can be carried away

Protecting the body (immune system)

-Ideally, your body would block pathogens before they invade the body -The first line of defense: physical and chemical barriers including skin saliva, ear wax, mucus, bacteria (micro flora) -Anything that gets past your barriers will have to be attacked and potentially remembered (second and third line defense)

How viruses get into cells

-In order for virus to get into cells, has to bind to a receptor and get "invited in" by cell once virus is in, replicates, to get out to infect other cells, it has to bind to receptor and get "escorted out"

Immune disorders

-Increases in allergies and autoimmune disorders is probably multi-faceted -exposure to non-infectious microbes -exposure to parasites -changing environments, climate change -Gut microbiome changes -Antibiotic use -Etc.

Autoimmune Disorders and Infectious Disease

-Infectious disease goes down, autoimmune disorders go up -The "Old Friends" hypothesis> Human immune system evolved while exposed to many pathogens and parasites -the immune system needs exercise, just like our other systems, start to make errors and have problems, referencing autoimmune disorders

Disparities seen in society in socially constructed racial groups

-The disparities we see in society are products of social constructs and not of genetics -Skin color doesn't give very meaningful differences between individuals or differences between groups -When we see biological issues that affect groups differently, those are gonna be result of social disparities not result of genetics -Examples: COVID-19 mortality rate in AI/AN people in 2020 was almost 4x higher than in white people -primarily due to social vulnerability, not biology -maternal mortality is more than 3x higher for black women than white women -primarily due to standard of care and treatment by health professionals, not biology -due to access to resources, social vulnerability

immune system's role

-There are microbes attempting to invade your body everyday, constantly under attack, try to use your body's resources, potentially damaging and harming you -Your body needs to block, attack and remember those invaders -Immune system will also attack problematic cells (of your own body), cancer cells or anything that it doesn't recognize

Condition 3: Differential Reproductive Success

-There are more organisms born than can survive and reproduce + pass on genes to the next generation, not everyone passes on genes to the next generation -Organisms are continually struggling for existence -Some organisms are more likely to win this struggle and survive and reproduce -Survival of the "Good enough", those that are able to out compete others, does not result in perfection

Race in Humans (2)

-There is more variation found within groups than across groups -External phenotypes influences by approx. .01% of our total DNA -Populations of humans have a high degree of genetic similarity -Skin color is the result of expression of multiple genes as is not indicative of relatedness -limited # of genes under strong selective pressure depending on the environment -In humans, race is a social construct and its not biologically meaningful -Skin color is only made up small # of genes which don't seem to have anything to do with relatedness -can't distinguish humans based on racial groups

viruses and cancer

-Viruses cause about 5% of cancers in the United States -Viruses may have oncogenes among which enter the host cell and start producing proteins from those genes -Viral DNA may be inserted into host DNA at a site that disrupts the functioning of a gene that regulates cell division in host, cells may have problems replicating efficiently or doing it when they shouldn't be -Viruses may interfere with immune system, make us more likely to develop cancer in part because takes the immune systems ability to fight off cancers

Adaptive immunity (2)

-When B and T cells are activated by helper T, some will become plasma B (shed antibodies) and cytotoxic T to fight the invader high now, travel through body to shed antibodies to go find problem and kill it -Some become memory B cells and memory T cells, and will wait in case the pathogen attempts reentry at another time, next time the immune system is able to eliminate it very quickly, you don't get sick

Antibiotic resistance

-When bacteria become resistant (not person), antibiotics are no longer effective -Made worse by overuse and misuse of antibiotics, ex: methicillin-resistant Staphylococcus aureus -created a selective pressure for bacteria, change in response to that pressure, bad for humans -when we look at bacterial population within human body or anywhere, they have variability in how susceptible to antibiotics -for a given mechanism of antibiotic resistance a bacterial population has variation

Viruses

-When viruses get into cells they are replicating viruses for it, new virus being made is released or shed from the host cell -Release of new viruses from the host cell causes problems -Rapid release can cell death, slow release leads to persistent infections, can cause cell damage if releases slowly which makes it harder to fight -Some viruses remain dormant in the host cell for long periods and cause latent infections, without replicating or moving to different parts of body -At any time, the virus can begin replicating and cause cell death upon release of new viruses -When become active again, can cause infection later on for ex. chicken pox as a kid, reemerges + affects nerves it was dormant in, now person could get shingles which looks different than when they initially got the virus

Phagocytes (innate immunity)

-White blood cells -Basic recognition of non-self cues -Engulfs and destroys anything that isn't recognizable as belonging to the body (antigen) -Example: Macrophages -At any given time, there are approx 34 billion phagocytes circulating the body -eat + break down + poop out antigen

Natural Killer (NK) Cells (Innate Immunity)

-White blood cells -Search out abnormal cells and kill them -Cancerous cells, cells with viruses -Release chemicals that break down cell membrane of problematic cell, punch holes of membrane, cell sort of bleeds out

Organisms do not "adapt to survive"

-You either have the traits to be successful (mate and survive) in your environment or you don't, if environment changes + your traits are no longer adaptive, probably not able to survive and reproduce -When the environment changes, what's beneficial may also change -Those with the traits best suited to the environment at the time are most likely to survive and reproduce, passing their genes on to the next generation -No direction, traits don't just arise because you "need" them to -Evolution does not result in "perfection" -Can't change and develop traits you want or need, you either have it or you do not and if not there, population goes extinct

The Immune system

-an organ system -includes spleen, thymus, lymph vessels and lymph nodes and various immune cells

why is the flu vaccine different ever year?

-antigenic drift & antigenic shift

selective pressure + antibiotics

-apply a selective pressure+ antibiotics -most susceptible die quickly -With additional treatment, more die > symptoms improve, over time, those with moderate permeability die off -shift in allele frequency in population losing lots of alleles or genes that make bacteria susceptible to antibiotics

time, in consideration of evolution

-evolution happens over time -time: generations, because we are talking about a change in genes, individuals can't evolve (can not change your genes) -The next generation could have a different allele frequency than the previous generation

lymph (immune systen)

-fluid similar to blood, except no red blood cells and vessels it travels through are different than blood vessels, move cells to where they need to go so immune cells needing to go to different parts of the body can travel through the lymph, it also drains debris, infectious agents you killed to help get it out of body - have different lymph nodes all along and can get swollen when you have infections, lymph is moving cells and helping get rid of infection, those lymph nodes will house some important cells

H1N1-A Current Seasonal Strain

-in 2009, H1N1 drifted (shifted?) dramatically, no immunity, no vaccine for it -had been around for long time, but exposure we had wasn't doing anything, immune systems were not primed, vaccines that had been developing did not work for it -6 of the 8 genes have been analyzed and their origins traced -Hemagglutinin- swine origin, midway between N. American and Eurasian swine genes -Neuraminidase and matrix protein (M)- from Eurasian swine- new to N. America -PA and PB2-Avian origins -PB1- from human seasonal H3N2 influenza (major influenza circulating since 1970s, those genes have different origins, within H1N1 genes from pigs, birds, human flus show how important bird, human and pig connection is in flu)

permeability to antibiotics

-lot of variation in this trait of permeability to antibiotics, it is a genetic, heritable trait -permeability> can antibiotics get into bacteria, can they cross the cell wall get into bacteria to disrupt it + die -bacteria w high permeability- very susceptible to antibiotics, very low fitness -bacteria with low permeability- antibiotics not as likely to penetrate cell wall, bacteria more likely to survive with antibiotics -

antigenic shift

-more occasional -switch from one major subtype to another H2N1> H2N2

Condition 2: traits are heritable

-must be true since traits will be determined by genes

Influenza A Subtypes

-name and described based on H + proteins -18 different types of H described H1- H18 -11 different types of N described N1-N11 -Most are found in birds, birds very susceptible to flu, let any H in, let any N out -H1-H3 and N1-N2 have previously been described in humans, humans more selective -Can have various combinations H1N1, H1N2, H2N2, etc.

issue with not finishing antibiotic treatment

-people often stop taking antibiotics early when they start feeling better, symptoms go down, but still have some bacteria, ones with the lowest permeability in body, those need most treatment to kill, those left and are not killed off so they survive and reproduce -eventually, left with only the individuals most resistant to a given antibiotic -this infection can return and potentially worsen as the population evolves and resistance is prevalent in next generation

Antibiotic resistance (2)

-slowing spread of antibiotic resistance -Use antibiotics responsibly -Do not insist on antibiotics against doctor's advice -Take antibiotic exactly as prescribed -Reduce risk of infection by washing hands frequently, rinsing fruits and vegetables and cooking meat thoroughly

Species

-the ability to breed and produce viable offspring that survive until adulthood and can go on to have their own offspring -if two individuals could breed and have offspring but that offspring is sterile, those two individuals would not be considered the same species -may be made up of many populations in different geographic areas

Before Darwin and Wallace

-up until 1700+1800s, people generally believed biodiversity is fixed (unchanging), the earth is young (approx. 6000 years old), humans are superior or, "Perfect." -Observations started to challenge these ideas, people organized their thoughts + ideas together to share these observations -Fossils are evidence that the world looked different than it does now (at the time) -Darwin was the first to publish his ideas on how species have changed over time with influence from Alfred Wallace, and was not the only one to come up with these ideas he just had resources to publish his ideas -before, people thought world is the same now as it's always been -there was resistance to Darwin's ideas at first but at the same time, many researchers were headed toward this explanation

Migration (gene flow) 3 steps

1. Before migration> Two populations of the same species exist in separate locations. In one example, they are separated by a mountain range 2. Migration> A group of individuals from population 1 migrates over the mountain range 3. After migration> The migrating individuals are able to survive and reproduce in the new population

Immune defenses of the body

1. First line of defense: physical and chemical barriers 2. Second line of defense: innate immunity 3. Third line of defense: adaptive immunity

The point of adaptive immunity

1. Produce antibodies, which come from B cells and bind to antigen to neutralize, kill or call over phagocytes (one way phagocytes know what antigen to engulf is through seeing a bunch of antibodies around of cell), this is known as "Antibody-mediated response" 2. Produce cytotoxic T cells which are like NK cells but respond to specific problematic cells, so they kill problematic cells (cancerous, infected with a virus), this is known as "Cell-mediated response) 3. Create memory cells for the next time, involves B and T cells

3 Conditions for Natural Selection

1. There must be variation for the trait within the population 2. The variation must be heritable 3. Individuals with one version of the trait must survive + produce more offspring than those with a different version of the trait

Steps of Adaptive Immunity

1. Threat 2. Detection 3. Alert 4. Alarm 5. Building Specific Defenses

Steps of Adaptive Immunity

1. Threat, 2. Detection, 3. Alert, 4. Alarm, 5. Building Specific Defenses

Helper T cell and macrophage

Helper T cell is presented by macrophage

Mechanisms of evolution or change

There are 4 ways or reasons why future generations may have a different allele frequency than previous generations -the four don't happen in a vacuum 1. Natural Selection 2.Genetic Drift (Founder Effect & Population Bottleneck) 3. Gene Flow 4. Mutation -Population can experience multiple at a time or interact with each other as noted with natural selection and mutation