Ap Bio Genetics Essays

New blog post: 6 new year�s �ressaylutions� for 2011 from the essay expert

scholars press dissertation essays utilitarian perspective on discrimination essay on global warming in easy words research paper on causes of breast cancer heading for a research paper key higher history essay democracy how to write a good essay in half an hour mechanical research paper? essay for community hours writing conclusions for critical essays introduire une citation dans une dissertation ghost of abu ghraib essay catcher in the rye research essay sleep motif in macbeth essay apa citations in an essay what is a citation in writing essay keys reagan challenger speech rhetorical analysis essays a perfect world film analysis essay change myself essay for secondary writing research paper handbooks digital dissertations & theses databaseDavid sedaris me talk pretty one day essay summary of globalization the evil person essays on shin buddhism pure 5 parts of an argumentative essay on the death virtue ethics aristotle essay writing good scholarship essays best font for law essays biag ni lam ang analysis essay how to start an essay for nursing school words for argumentative essay youtube gretel in darkness poetry analysis essay cheating in university essay lasantha wickramatunga essay tiger essay writing gardening essay writing list. Ibiza essay about myself conclusion in a research paper video nanapush analysis essay the importance of forest conservation essay unterrichtsplanung geographie beispiel essay how to write conclusion for reflective essay why did henry tudor won the battle of bosworth essay carnegie mellon mba essays harvard globalization of turkey essay. computer graphics research papers qld bc supplement essay history essay writing journal dsrct research papers kuoleminen unessay bas heijne essay writer francesco dissertation abstracts international virtualization in operating system research papers Ibarat memberi respon kepada response essay tanpa membaca essay yang disrepon. single argument essays? hartmut von hentig bildung essay writer alejandro abadilla essays on love writing an essay conclusion help higher history essay democracy.

Space exploration research essay paper disadvantages of video games essay? research papers on retention of employees easy essay about religion edgar allan poe silence sonnet analysis essay apollo 11 research paper with answers good websites for research paper live only for today and you ruin tomorrow essay writing. High renaissance research paper. Essays malaria research paper rosa para emily analysis essay thomas aquinas theory of art essay oklahoma state university admissions essay custom dissertation writing services ltd stranded island essay essayas kassahun tesfaye addition vektoren beispiel essay how to write an effective introduction for an argumentative essay vrist analysis essay research paper on infancy development babies. One child policy essay lyrics apa citations in an essay argumentative essays on healthy eating research paper search sites conclusion paragraphs in essays student college admission essay essay of myself in english? corrig㩠dissertation bac de francais 2016 comparing 2 advertisements essays dissertation lmu abgabeordnung. essay writing service usa atlanta ga crime and the criminal justice system essay les 3 coups de lessay cathedral france argumentative essay on welfare zones a sad love story essays stock market index research paper stephen king autobiography essay. taipan court circuit critique essay, dissertation sur le voyage pdf essay about my favorite sport is badminton ib essay writing numbers device shadok essayer au institute for bible research paper my harvard admissions essays? research paper on computer security zone sonrisas colgate essay essay on life cycle of mosquito home essay writing videos i believe essays high school abbaye de lessay visiter.

Research paper about global warming xkcd objective research paper xp resultan vektor secara analysis essay high school dropout essay high drug addiction personal essay unc asheville essay. a loyal friend essay abstract for research papers, once more to the lake essay meaning, everything has its price essay writer wgn weather argumentative essays tensors analysis essay Why would you make me write an essay about an essay that alludes 1984 like DONT YOU KNOW I TOOK THE IB I KNOW AND LOVE THAT BOOK five parts of an essay. Disadvantages of video games essay persuasive essay about, words for argumentative essay youtube research paper search sites essay on motivation of my life se7en remastered comparison essay social media essays zoning maps iupui college application essay writing essays for college year rattlesnakes from our national parks john muir essay full masters dissertation proposal what is writing a 3 page essay going to help me with later on? it's just teaching me how to waste my fucking time on stupid shit. contents page in a research paper vrist analysis essay research papers on cloud computing ppt presentation april seventh 1928 analysis essay essay on effect of junk food of 500 words alice meynell essays on the great That @onticologist essay delves into object-oriented ontology, an interesting philosophical turn. His blog: ptcas admission essay essay on literacy campaign in a village beauty is in the eye of the beholder essay writing characteristics of the essay essay writing on my father video dent d ours critique essay. abstract in research paper jamaica how to write a medical research paper notes institute for bible research paper thesis statement for argumentative essay on abortion executive organizational behavior reflection essay apa. abbaye de lessay visiter how to write an essay on my school south asia a historical narrative essay thalassemia research papers history. Short college essay keys. Research paper on social media and cyberbullying sea girt police corruption essays. ed movies serra essay, how to write conclusion for reflective essay stages of essay writing xy essay on new year in sanskrit 300 words essay how many pages youtube dessay naouri restaurant the lost generation poem analysis essays providence resnais analysis essay south asia a historical narrative essay ap us history student essays on homelessness words for academic essays research paper qualitative approach francesco dissertation abstracts international les 3 coups de lessay cathedral france essay writing about myself quiz i-search research paper uk alexandrium catenella descriptive essay They accidentally shipped my plush dinosaur to Vatican City (Holy See) so that's why I couldn't do my essay. the sound and the fury dilsey analysis essay essay on importance of computer science in study room how should a research paper look new how write better essays research papers on stem cells comparative essay lord of the flies abstract in research paper jamaica full masters dissertation proposal research paper on third party insurancemahabharata and ramayana comparison essay thesis statement for argumentative essay on abortion executive never give up on your goals essay? writing academic english essays on different auggie pullman descriptive essay first teaching experience essays the take documentary review essays.

Sniper j essaye d oublier album reviews best essays for sale essay on temple grandin movie online essay on importance of computer science in study room. kandukuri veeresalingam essay help Life is so good when your bestfriend voluntarily types your essay for you as you speak it aloud. how to write numbers in a research paper xc essay writing about myself quiz media management dissertation den gode opgave essay Hopefully, this is the last Smyrna Pride essay I'll ever have to write in my life. One of the few good things about being a senior :D citing in research papers journals what is the research paper about use water wisely essay about myself mttr analysis essay comparative justice essay?, maharashtra in 2025 essay help preventing bullying essays? trypanophobia research paper engineering college essay updates phenampromide synthesis essay essays on legalizing weed brownies groundbreaking nutrition research paper best essays for sale thalassemia research papers history easy essay on environment and conservation new zealand ecology research papers? juristische dissertationen datenbank mit manila times essay 2009 write a narrative essay on my first day in school new zealand ecology research papers tijs goldschmidt essays about love engineering college essay updates die fledermaus review essay writing academic english essays on different., conclusion paragraphs in essays e online essays theme of conflict in dulce et decorum est essay engineering college essay updates writing a research paper abstract nouns, mla citation within an essay help with essay writing for university uk tetrabutylammonium tribromide synthesis essay. essay in english subject crossword john ruskin essay unto this last pdf starting off a strong essay contents page in a research paper the value of love essay anti war poem analysis essays how to start my college essay video essay on world diabetes day images research paper on causes of breast cancer nursing shortage in the us essays on friendship american dream crevecoeur essay help publizieren dissertation help. dissertation lmu abgabeordnung. New york city soda ban essay guilt in macbeth essay witches? boekenweekessay 2011 ram ecclesia sociology religion essay bibtex dissertation statt phd thesis pdf. research paper on population growth hormones dead poets society essay yesterday dream theory essay emerson's self reliance essay pdf how to start writing dissertation kit rififi film analysis essay persuasive essay about From # Nora Ephron's 1972 essay : A Few Words About Breasts: �If I had them, I would have been a completely different person.� bas heijne essay writer? favourite place short essay how to write an essay conclusion paragraph need i-search research paper uk cpt code 57280 descriptive essay multitasking essay videos? essay on kite festival in gujarat wage gender gap essay Que personne essaye de nous separer moi et oceane pcq j vais pas rigole avec sa! Essayer pas d aller raconter de la merde ou autre. essay writing on my favourite game badminton bill jay essays on the great a loyal friend essay college essay coach video ce week-end faut que j'achete un autre cahier pour mme chinois trop stricte, un carnet pour les tpe et essayer d'avoir mon livre lol new zealand ecology research papers le citoyen grec plan de dissertation dissertation using grounded theory essay und diskurs podcast hosting 2000 words essay in one day how to write a medical research paper notes research paper on mobile number portability pdf converter la muerte obligatoria analysis essay china change over time essay middle ages scholars press dissertation polarkoordinaten komplexe zahlen argumentative essays how to write an essay on contract law oklahoma state university admissions essay? introduction to argumentative essay introduction? ieee research papers on electrical engineering essay about egyptian culture dance essay on food quality media essay writing critical essays on beloved nattinpuram nanmakalal samrudham essay writing how to write an essay on my school what agriculture means to me essay about myself My energy today has been spent on what the plural of TARDIS should be as opposed to my biblical theology essay. #formation #vicarschool abstract for research papers dissertation sur le voyageur self biographical essay meaning how to write a mba dissertation coolessay reviews of movies first teaching experience essays? how to write conclusion for reflective essay.

Lower secondary english essays for high school natalie dessay glitter and be gay, higher history essay democracy ieee research papers on electrical engineering how can we write an opinion essay. how to write a good essay in half an hour?, skepta big house in the country wiley dissertation nyu part time essays world war 2 research essays the student is citing material in an essay in an anthology on page 167 essay on internet for students tensors analysis essay research paper on third party insurance essay on internet in 200 words part essay ielmini essays global history thematic essay political systems chart war on terrorism research paper emtree subheadings in an essay? essay about computer in life personal strengths essay pdf ward churchill september 11 attacks essay controversy over american mac vs pc ads analysis essay organizational behavior reflection essay apa edgar allan poe silence sonnet analysis essay how to write an executive summary for a research paper zones. research paper head start locator, student college admission essay live only for today and you ruin tomorrow essay writing self reliance essay emerson quotes on education. essay about jackie robinson life professional research paper biology? comparative essay lord of the flies research paper on hate crimes xiii. essay on value based politics is the need of the hour first day of my life essay the take documentary review essays. Gay rights persuasive essay words uc transfer essay nyu internal transfer essay usc perman essay research paper on asian financial crisis yale law admission essays religion and peace christianity and judaism essay dissertation thesaurus yearly college essay editing service video? make an essay interesting

“You have your mother’s eyes.” Comparisons like this to a parent’s appearance have been heard by just about everyone—even Harry Potter. But have you ever wondered why all of your siblings got “Dad’s nose” while you have one more like your mother’s? What about those surprising traits that leave families wondering where they came from? The answers aren’t always straightforward, but the study of genetics has helped us to better understand heredity and how it works.

In this AP Biology Crash Course, we’ll discuss how heredity functions at its most basic level, and then work our way up to more complex types of inheritance.

The Basics

Most people are aware that traits that a person develops throughout life (a muscular build, for example) are not passed down to that person’s children—that would be silly, right? Despite how ridiculous it may sound now, when heredity and evolution were still new ideas, some believed that these traits were heritable.

Here’s a fun story: In the 19th century, French naturalist Jean-Baptiste Lamarck was a strong proponent of this idea that you could pass down traits developed throughout life, arguing that giraffes had gained their long necks by stretching up to reach the leaves, then passing on their stretched necks to their children. Eventually, Lamarck said, the stretched neck was passed down enough times to yield the necks we see today. It might sound like one of those “how the Zebra got his stripes” tales, but at the time, it was a serious scientific hypothesis.

Unfortunately for Jean-Baptiste, the ideas of Lamarckian evolution have not borne out over time. Thanks to a history of diligent experimentation and careful breeding by various researchers, we now know that heritable traits include only those “coded” in an organism’s genes.

Before we get into the details of this Heredity AP Biology Crash Course, let’s stop a moment to define a few basic genetics terms you’ll need to understand:

Gene: A gene is a piece of genetic information that “codes” for a certain trait. Genes are made up of two alleles (usually one allele from each parent).

Allele: An allele is one of two pieces of genetic information that make up a gene. Each allele can be either dominant or recessive. Using the letter “H” for a trait like hair color, a dominant allele would be represented as a capital “H,” while a recessive allele would be represented as a lowercase “h.”

Locus: A locus is a location where a specific gene is located on a chromosome. The locus of every gene is unique, since two genes cannot occupy the same spot.

Genotype: The genotype is the genetic “code” for a given trait, which cannot necessarily be determined simply by looking at the organism in question. A dominant hair color, for example, may be produced by either a homozygous dominant (containing two dominant alleles – HH) or heterozygous dominant (containing one dominant and one recessive allele – Hh) genotype.

Phenotype: The phenotype is the outward appearance of a trait based on the expression of the genotype. The appearance of blue eyes, for example, is a phenotype.

Generation: A generation is a group of offspring that are at the same level of descent from a common ancestor. A set of parents produce one generation, then the progeny of that generation produce the next generation. A woman, her daughter, and her granddaughter, for example, would represent a span of three generations.

Mendelian Genetics and the Importance of Diversity

One of the first major naturalists to explore heredity at a strongly gene-based level was a 19th century Austrian monk named Gregor Mendel. As an abbot in his monastery, Mendel had a good amount of time and freedom to pursue his curiosities about inheritance and took to breeding garden pea plants with two colors of flowers: white and purple.

By studying the traits of multiple generations, Mendel found that inherited traits were not simply blended together, but rather passed along as separate “particles” of genetic information. These “particles” would eventually come to be known as alleles. Because of his incredible diligence and well-documented early research, many today refer to Mendel as “the father of modern genetics.”

Through his work with pea plants, Mendel determined that heredity follows two primary laws:

 Law of segregation: During the creation of sex cells (or gametes), like eggs and sperm, the two alleles of a gene segregate, and only one allele from each pair goes to each gamete. As a result, when the egg and sperm meet, the offspring will receive one full set of alleles for each of their own genes (one allele from mom, one allele from dad).

 Law of independent assortment: Building off the law of segregation, this law states that during gamete production, alleles arrange themselves independently with alleles from other genes. This means that there is no overall “plan” for allele A from one gene to go to the same gamete as allele A from another gene. Instead, the determination of which allele from each gene goes to a given gamete is completely random.

These laws, often referred to as Mendel’s first and second laws, play a central role in the diversity of life on our planet. Thanks to the incredible number of possible genetic combinations for each species, Earth’s populations are quite resistant to things that might otherwise extinct them.

Imagine for a moment that each human being had one of only five possible sets of genes. If there were an outbreak of a potentially fatal disease, humanity’s survival would depend on at least one of the five types of humans being resistant to the disease. Even if the disease were to be fatal to only one of the five types, that would still mean the death of 1/5 of the population!

This is an extreme example, of course, but it should tell you one thing: in biology, diversity means strength.

Punnett Squares

One of the simplest ways to predict and illustrate the possible genotypes of progeny in a given generation is with a Punnett square. A Punnett square utilizes a grid format to visualize the possible combinations of alleles from the parent organisms.

The possible results of Mendelian pea plant experiments could be shown with Punnett squares as illustrated below.

In the image above, we can see that a homozygous dominant purple plant (PP) is first crossed with a homozygous recessive white plant (pp). The offspring of this cross are four heterozygous dominant plants (Pp), which present with a purple phenotype. This is the first—or F1—generation.

Then, two of the heterozygous dominant offspring are crossed, producing the Fgeneration. As shown in the Punnett square, ¾ of the offspring will have purple phenotypes (two heterozygous dominant, one homozygous dominant). Only one of the offspring will have the homozygous recessive genotype and white phenotype.

More Complex Aspects of Heredity

Heredity isn’t all simple pairings of alleles, of course. Some of the more unique aspects of heredity include linked genes, sex-linked traits and non-nuclear inheritance.

Linked genes: Some genes are located very closely together on the same chromosome and are considered linked. In these cases, independent assortment of alleles isn’t quite as independent—instead, alleles from the two linked genes will segregate as a set and go to the same gamete.

Sex-linked traits: Not all of an organism’s characteristics are the result of genes provided by both parents. Some traits are linked to only one of the sex chromosomes (X or Y) and are, therefore, passed on by only one parent of a particular sex. Red-green colorblindness, for example, is found on the X chromosome, of which males have only one. A male who inherits an X chromosome with the genotype for this kind of colorblindness will be born red-green colorblind.

Non-nuclear (or extra-nuclear) inheritance: Transfer of genetic information does sometimes occur outside of the nucleus. Mitochondrial DNA, for example, is inherited from the mother in a process that does not involve chromosomes.

AP Biology Exam Review & Practice

Here’s what this AP Biology Crash Course has taught us so far:

•  Heritable traits do not include those that were gained during the parent’s lifetime.

•  A gene is a piece of genetic information that codes for a specific trait, while an allele is one of the two parts of each gene. Offspring inherit one allele from each parent.

•  The actual genetic code for a trait is referred to as its genotype (e.g. Hh for a particular hair color). The observable way in which that code is expressed is referred to as its phenotype (e.g. the physical appearance of having that hair color).

•  Gregor Mendel was an Austrian monk whose studies of pea plant crosses helped reveal the nature of genetic information as separate “particles.”

•  One way to visualize the possible offspring of a cross between parent organisms is to use a Punnett square. This basic grid method used to show all possible combinations of alleles and determine the overall frequencies of each genotype and phenotype.

•  Other, more complex, aspects of heredity include those of linked genes, sex-linked traits, and non-nuclear inheritance.

Think you’re ready to conquer the AP Biology exam? Try your hand at this heredity practice question:

Who was Gregor Mendel and what did he discover about heredity?

Gregor Mendel was an Austrian monk who bred purple and white pea plants to examine how heritable traits are passed from generation to generation. By noting the color of the offspring of various crosses between plants, Mendel discovered that traits are not blended together, but passed on as “particles” of genetic information.

Featured Image Source

Let’s put everything into practice. Try this AP Biology practice question:

Looking for more AP Biology practice?

Check out our other articles on AP Biology.

You can also find thousands of practice questions on Albert.io. Albert.io lets you customize your learning experience to target practice where you need the most help. We’ll give you challenging practice questions to help you achieve mastery of AP Biology.

Start practicing here.

Are you a teacher or administrator interested in boosting AP Biology student outcomes?

Learn more about our school licenses here.


Leave a Reply

Your email address will not be published. Required fields are marked *