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Biology—Semester B

Evolution, Shmoop style.

  • Credit Recovery Enabled
  • Course Length: 18 weeks
  • Course Type: Basic
  • Category:
    • Science
    • High School

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Shmoop's Biology course has been granted a-g certification, which means it has met the rigorous iNACOL Standards for Quality Online Courses and will now be honored as part of the requirements for admission into the University of California system.

This course has also been certified by Quality Matters, a trusted quality assurance organization that provides course review services to certify the quality of online and blended courses.

You know the Circle of Life? Well, it turns out that's not just a catchy tune that Disney made up. Life keeps on slippin', slippin', slippin' into the future, and with Semester B of Shmoop's Biology course, you can, too.

This course is all about understanding the processes behind life as we know it. That means we'll tackle all kinds of big ideas of life, and the living thereof.

  • This semester starts with the big "E"—evolution. How did all of the variety (which is the spice of life, dontcha know) in living things come about? Whether it's a chameleon's shooting tongue or a cat's bilateral symmetry, those traits had to come from somewhere.
  • To really dig into how species evolve, we have to look at the genetics of entire populations at a time. Get out your floatees and swim trunks, we're taking a dip in the gene pool.
  • Living things don't live in a vacuum...uh, we meant for that to be more figurative than literal, actually. The survival of every species depends on both its environment and the community of other species that they share that space with. Ecology is the study of how all these different pieces interact, and we're going to study it, too.
  • Does the thought of thousands of microscopic creepy-crawlies living on and in your body make you queasy? Well, it's more like trillions. We'll learn about our tiny fellow passengers through life, bacteria and viruses.
  • The semester will close out with a one-two punch of in-depth study of plants and animals. Yeah, we've been talking about them throughout the entire course, but now we're gonna look reaaal close at 'em.

We'll cover it all with interactive lessons, engaging readings, and active activities to keep you going with the vigor of flesh-eating bacteria.

P.S. Biology is a two-semester course. You're looking at Semester B, but you can check out Semester A here.

Required Skills

Knowledge of basic pre-algebra concepts

Unit Breakdown

7 Biology—Semester B - Evolution

This unit starts by saluting the father of evolution, Mr. Charles Darwin. From there we'll move on to the golden topic of the unit: natural selection. We'll show the multiple lines of evidence that support evolution—it's not just dusty fossils and DNA, but a whole host of consistent facts. Finally, we'll look a little closer at how entirely new species can form.

8 Biology—Semester B - Population Genetics

What do you get when you cross Mendel and Darwin? A centuries-old, and very confused, zombie? Nah, it's population genetics (and thank goodness). This unit takes the study of both fields further, looking at how populations evolve, the role of mutations in evolution, what the deal is with lethal alleles, and the Hardy-Weinberg equilibrium principle. We'll also hash out what effects humans have had on other species, and how we can undo some of the more unpleasant ones.

9 Biology—Semester B - Ecology

Now we're moving beyond the individual organisms studied in the previous units and expanding to a big-picture view. We are, unfortunately, doing so figuratively, so lower your expectations a smidge; there is no hot air balloon ride planned for this unit. Ecology explores how organisms interact with both the living and non-living parts of their environment. Starting with biodiversity, we'll learn about species interactions, population ecology, energy cycles, and how nutrients get from the outside world and into us.

10 Biology—Semester B - Microorganisms

Shmoop's got the scoop on all (living) things microscopic. You'll learn about the structures and functions of viruses, bacteria, fungi, and parasites, and then show off your newfound knowledge by creating a CDC-style brochure.

11 Biology—Semester B - Plants

We think that plants are seriously underrated. They can make their own food from light and they reproduce without even moving. That's pretty cool. In this unit, we'll get intimately familiar with plants (...not that familiar), focusing on plant evolution, physiology, and ecology.

12 Biology—Semester B - Animals

To wrap up this course, we'll learn the ins and outs (literally!) of animals, including one we're all pretty familiar with: human beings. After a foray into different classifications of animals, we'll focus on physiology, including everyone's favorite systems, the circulatory, immune, endocrine, endocrine, and reproductive systems.

Recommended prerequisites:

  • Pre-Algebra II—Semester A
  • Pre-Algebra II—Semester B
  • Pre-Algebra I—Semester A
  • Pre-Algebra I—Semester B
  • Biology—Semester A

    • Sample Lesson - Introduction

    Lesson 7.01: Evolution Introduction and Darwin

    When most people hear the term evolution, they think of a dude named Charles Darwin. It's like when you hear a large group of shrieking girls, you think some celeb must be nearby…or maybe that creepy kid with all the snakes. Anyway, the point is, Darwin is practically synonymous with evolution.



    a black and white portrait of Charles Darwin
    Darwin: the dudest of dudes.
    (Source)

    We know you're dying to find out just what Charles Darwin did that was so special (and why he looks like someone just ate his last Bagel Bite). Charles Darwin wasn't just some stodgy old Brit whose goal in life was to put milk in his tea (weird) and annoy creationists. With his theory of natural selection, he changed the way the entire world viewed and understood, well, the world. He didn't do it by digging up a bunch of t-rexes or finding fish fossils with legs either. He started small—he figured this all out by observing little birds called finches.

    Through countless hours of observation in the field, Darwin discovered that traits that help an organism successfully reproduce become passed down to offspring. And then those babies have babies, and their baby's babies have babies, and pretty soon those traits become more common in the population.

    Well, duh…when you put it like that, it sounds obvious.

    The way that traits are naturally selected is a fairly simple process, and it describes how species begin to adapt to their environments. This eventually became the basis for the theory of evolution, which says that all organisms are descended from a common ancestor, including human beings. Darwin wrote down all of this in a super famous book called On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life in 1859. Yep, that's the actual title.

    As for the grouchy look on his face, we can only guess that it's because his findings were met with much skepticism. We can't blame him, though. Wouldn't you be a little miffed if, after a five-year voyage and countless hours studying animals, people didn't believe your theories? How rude!

    Anyway…let's learn more about this Darwin guy and how he was enlightened by finches. Then we can get rid of all of our misconceptions about what evolution is or isn't and figure out exactly what the deal is.

    Sample Lesson - Reading

    Reading 7.7.01a: The Origin of Species

    In this reading, we'll get a feel for what Darwin did during those countless hours of observing finches to come up with the whole Origin of Species thing. They must have been fascinating birds…right? As you're reading, pay close attention to the pictures of these little guys. What differences do you think Darwin saw in the similar (yet different) species?

    Perhaps he noticed that one species of finch was of similar size, had the same beak size and shape, or had similar coloring, and these traits differed from other species. Being the ultra-cool dude that he was, maybe he then noticed that some of these traits overlapped with other species of finch. That gave him the idea that each species of finch must be derived from a common ancestor…and voila, the origin of the species. Easy peasy lemon squeezy.

    Remember, though, that Darwin didn't know about DNA, genotypes, or alleles. Nah, Darwin was old school, and that makes his theory of natural selection pretty darn amazing. The genetic details were hammered out after Darwin's time, but they still supported his theory. Ah, the beauty of science.

    Sample Lesson - Reading

    Reading 7.7.01b: Evolutionary Theory

    The modern theory of evolution can be simplified into three little words: descent with modifications. There. We're done. Time for your test.

    Well…not quite. Descent with modifications means that a species changes due to slight alterations in its traits over time.

    The main driving force behind evolution is natural selection, which is a fancy way of saying that some individuals are better at passing on their genes than others due to increased fitness, or because they look really cool on a motorcycle.

    So if one peacock gets all the ladies because his feathers are super blingy, all of his many chicklets will also have that bling. Shake ya tail feathers! After a period of time, the species will have changed enough that most if not all peacocks have flashy tails. And the dudes with the unflashy tails will have been bred out of the gene pool. Harsh.

    Evolution can also be caused by genetic drift, which is when a random event occurs that causes some individuals to pass on their genes more than others regardless of their fitness. You can imagine that enough random events happen over time (weather, sickness, epic facial hair being cool) that the look of a species will be different in a few thousand years' time.

    We'll go into the finer details of evolution later on in this unit, but for now we just want to understand the big picture view of how evolution works. So here's the short-short version:

    • There are 3 main factors that drive evolution: variation, natural selection, and time.
    • Variation comes about thanks to random mutations of DNA and recombination of DNA the old-fashioned way (i.e. by individuals reproducing).
    • Variation leads to individuals of any given species with a wide diversity of traits.
    • Natural selection weeds out individuals that don't have the best traits.
    • Natural selection isn't just some nebulous blob with a secret agenda deciding what those so-called "best traits" are. Natural selection is caused by real-life things, namely competition (for food, mates, etc.), predators, and changes in the environment.
    • None of this happens overnight. Heck, not even over a couple of years. We're talking thousands of years for a new species to evolve in most cases, and sometimes even millions of years.

    There we have it, evolution in six handy bullet points, and if we really want to boil evolution down to its essence, it comes down to that first bullet point: evolution is driven by variation, natural selection, and time. If you've got these three traits on your hands, then you've totally got evolution. Possibly on your hands. No, don't wipe it off.

    Sample Lesson - Activity

    Activity 7.01a: Evolution in Fast Forward

    Evolution can be hard to study, because it's not something we can sit down and watch—even if we come prepared for the long haul with a giant soda and a tub of popcorn. What we can watch, though, are videos put together by scientists who've dedicated their lives to studying evolution, and that's exactly what we're going to do.

    Specifically, we're going to watch two videos about biologists studying butterflies that are on the verge of splitting up into two different species. This is sort of a big deal, because again, evolution is usually super slow. Capturing the exact moment when a species evolves into two separate ones is like photographing a shooting star…or that moment when someone sneezes and their phlegm cloud is still floating mid-air. Priceless.

    First up, watch this video of a scientific team studying butterflies they feel are ready to split into two different species while in a controlled habitat. Make sure to take notes, and when you're all done, answer the questions below.

    1. What is speciation?

    2. What's the difference between white and yellow butterflies in Ecuador versus white and yellow butterflies in Costa Rica? What's the significance of this difference?

    3. What did researchers observe when they put the Ecuadorian butterflies into captivity?

    4. What two traits seem to be linked genetically in yellow Ecuadorian butterflies? Is this evidence for or against the hypothesis that the butterflies might speciate?

    5. How else do color patterns affect butterflies evolutionarily, beyond potential mating preference?

    6. What is the significance of discovering the mating preference in the yellow Ecuadorian butterflies?

    7. When will scientists know for sure if they really have caught evolution in the act?

    Science Short Answer Rubric - 25 Points

    OutstandingProficientDevelopingNeeds Improvement
    Work is Shown

    All work is clearly and logically shown. Steps are clearly connected and legible. Necessary diagrams or graphs are included and labeled.

    (15)

    Work is logically laid out and understandable. Diagrams and graphs should still be shown, but it might have a few leaps in logic or skipped steps.

    (13)

    Work is shown, but doesn't always relate to the question at hand. Illogical arguments, absent crucial steps, and missing or insufficient graphs or diagrams.

    (10)

    Completely illegible and/or illogical work.

    (5)
    Answer

    All parts of the question are answered correctly, including proper units and notation.

    (10)

    Answer is mostly correct, but has rounding errors, incorrect units, or is expressed improperly.

    (9)

    Answer is incorrect, but reasonable.

    (7)

    Answer is clearly incorrect or missing.

    (4)

    Sample Lesson - Activity

    1. Darwin set out on his voyage in what year?

    2. What did Darwin observe when he compared different populations of finches?

    3. How did Darwin think that the different species arose between the finches living in different locations?

    4. Which would Darwin claim is an example of evolution?

    5. Which of the following is not essential for evolution?