Score More. Spend Less. Bundle 3+ College Prep products for 20% off.

AP® Biology Unit 8 Review and Practice Test: Ecology

Confused about where to begin your AP® Biology Unit 8 review? Here is your one-stop solution! UWorld brings you a comprehensive coverage of Ecology, where AP specialists provide step-by-step explanations of topics like Population, Ecology, Community Ecology, Biodiversity, and more. In addition, our exam-level AP Bio Unit 8 MCQs strengthens your understanding of concepts and brings you closer to scoring a 5.

AP Biology prep course suite by UWorld

Boost Your Confidence and Score High with Our AP Biology Unit 8 Review

Ready to kickstart your Unit 8 AP® Bio prep? Our study materials make even the toughest topics easy to understand. Together, our study guide, question bank, video lessons, and study tools provide students an all-in-one learning experience, helping them study smarter, not harder.

Watch

Engaging Video Lessons

Say no to boring, text-heavy explanations! UWorld offers short, focused, and image-rich AP Biology Unit 8 video lessons to simplify complex concepts, helping you learn faster, understand better, and retain longer.

Preview Video Lesson
Buy Now
UWorld’s AP Bio Video Lessons and Online Study Guide
UWorld’s AP Biology Study Guide Prep book
Read

Interactive Study Guides

Our study guide is aligned with the College Board® CED, so you study the most relevant content. Each topic comes with thorough explanations, well-labelled diagrams, and check-points to fully prepare you for the exam.

Preview Book
Buy Now
Practice

Try These AP Biology Unit 8 Practice Test Questions

And the next step? Lots and lots of Practice! Our AP Bio Unit 8 MCQs match the difficulty level of the actual exam, so nothing catches you by surprise on the test day. Each question includes detailed explanations and rationales, helping you understand the “why” behind every answer choice.
Try these sample practice questions with detailed answer explanations:
Ecology Practice Tests

Question

Bats are flying mammals that can locate quiet flying prey (eg, moths) in the dark by producing sound waves at certain frequencies that reflect off the prey back to the bat. Bats' ears are specialized to detect the reflected sound frequencies.

Some species of tiger moths (genus Cisthene) carry toxins from plants they feed on. These toxins make the tiger moths distasteful to bats. Bats learn to avoid eating such toxin-carrying moths because the tiger moths produce sounds at specific frequencies that the bats can detect. Other moth species (genus Yponomeuta) produce sounds at the same frequency as those produced by tiger moths.

Which of the following claims is most consistent with this information?

A. Yponomeuta moths that produce less sound are less likely to be eaten by bats.
B. Bats cannot detect sounds at the frequency produced by Yponomeuta moths.
C. Yponomeuta moths that sound like tiger moths to bats produce more surviving offspring.
D. Tiger moths and Yponomeuta moths obtain the same toxins by eating the same plants.

Explanation

Signaling behaviors can affect organisms from the same or different species and increase organisms' reproductive success (ie, evolutionary fitness) in various ways (eg, improving self-defense, increasing the ability to obtain food and find mates).

According to the question, certain toxin-carrying tiger moths are distasteful to bats and produce sounds at frequencies detected by bats. Therefore, bats learn to avoid eating these tiger moths.

However, some moths of the genus Yponomeuta produce sounds at the same frequency as the tiger moths that are distasteful to bats. Because bats tend to avoid eating the distasteful tiger moths, bats would also avoid eating Yponomeuta moths that produce the same frequencies, making it more likely that such moths would survive to reproduce.

Therefore, a claim that is consistent with the presented information is that Yponomeuta moths that sound like tiger moths to bats produce more surviving offspring.

(Choice A) Yponomeuta moths that produce less sound are more likely (not less likely) to be eaten by bats. The bats would not receive as strong a signal to avoid Yponomeuta moths, and the bats can still target these moths using reflected sound.

(Choice B) Tiger moths produce sound frequencies that bats can hear, and Yponomeuta moths produce sounds at the same frequencies; therefore, bats can detect sounds at the frequency produced by Yponomeuta moths.

(Choice D) No information is given in the question indicating that tiger moths and Yponomeuta moths eat the same plants.

Things to remember:
Organisms produce signals that affect the behavior of other organisms. Signal production can benefit organisms in various ways that increase their reproductive success.

Question

The yellow mealworm beetle (Tenebrio molitor) is an ectothermic insect found in many different areas of the world and is often considered a pest because its larvae feed on grains stored for human consumption. Studies have shown that yellow mealworm beetle larvae can respond to cold temperatures by producing specialized proteins called thermal hysteresis proteins (THPs), which inhibit the formation of ice crystals in larval body fluids. In a 4-week experiment to test the effect of cold temperatures on THP production, one group of larvae was incubated at 22 °C for the duration of the experiment whereas other groups were exposed to a cold temperature (5 °C) for varying amounts of time. The concentrations of THP isolated from the body fluids of each group at the end of the experiment are shown in the above graph. Which of the following conclusions is best supported by the data in the graph?

A. THP is expressed only in yellow mealworm beetle larvae that have been exposed to cold temperatures for at least 1 week.
B. Yellow mealworm beetle larvae are constantly regulating their body temperatures through homeostatic mechanisms that generate internal body heat to promote adaptation to cold temperatures.
C. Yellow mealworm beetle larvae are unable to perform cellular respiration at low temperatures, so THP levels must increase with lower temperatures to increase the chances of larvae survival.
D. Yellow mealworm beetle larvae require more THP when exposed to low environmental temperatures to prevent freezing as their body temperatures drop.

Explanation

Organisms regulate their internal body temperatures to maintain homeostasis and are classified as follows:

  • Endotherms can generate heat via internal metabolic processes (eg, the electron transport chain in cellular respiration), maintaining stable body temperatures regardless of environmental temperatures.

  • Ectotherms cannot regulate metabolic heat production, so their body temperatures vary depending on environmental temperatures. However, ectotherms may regulate their body temperatures through behaviors (eg, moving from shady to sunny areas).

Some ectotherms have also evolved adaptations that allow them to inhabit colder environments. For example, ectothermic mealworm beetle larvae have thermal hysteresis proteins (THPs) in their body fluids that inhibit internal ice crystal formation when temperatures are low.

The graph shows that relative THP concentration was highest in larvae exposed to cold temperatures for prolonged periods of time. Because they are ectotherms, mealworm beetle larvae likely require more THP when exposed to low environmental temperatures to prevent freezing as their body temperatures drop.

(Choice A) Because the graph shows that larvae still express a small amount of THP at 22 °C, THPs do not require cold temperatures to be expressed.

(Choice B) Because mealworm beetles are ectotherms, they would not be able to regulate their body temperature internally via homeostatic mechanisms.

(Choice C) All organisms, including mealworm beetles, must perform some form of cellular respiration to generate cellular energy (ie, ATP).

Things to remember:
In contrast to endotherms, ectotherms cannot metabolically regulate their body temperatures and must use behaviors or adaptations to adjust for environmental temperature fluctuations.

Question

Grasshoppers living in a Wisconsin field community consume vegetation as a source of energy. A researcher observed that the number of grasshoppers in this community decreased when predators were present and increased when predators were absent. The researcher proposed that the abundance of wolf spiders, a main predator of grasshoppers in this community, was the limiting factor for the grasshopper population. Which of the following forms of data, in addition to assessing the number of grasshoppers, would be most suitable for the researcher to collect each day on a test portion of the field?

A. Grasshopper feeding activity (minutes/day)
B. Amount of wolf spider eggs produced (g/spider)
C. Density of adult wolf spiders in the area (number of spiders/m2)
D. Amount of vegetation (number of plants/m2)

Explanation

Communities consist of populations of organisms that interact with one another in various ways (eg, feeding relationships between trophic levels), which may cause communities to change over time.

In this question, the number of grasshoppers living in a field community decreased when predators were present and increased when predators were absent. The researcher proposed that the abundance of wolf spiders, a main predator of grasshoppers, was the limiting factor for the grasshopper population. The limiting factor in a population has the most impactful role in restricting population size.

Accordingly, the most suitable form of data for the researcher to collect in order to test this proposal would be the count of adult wolf spiders in the area (number of spiders/m2). For example, high numbers of wolf spiders would cause increased grasshopper consumption, thereby decreasing the grasshopper population size.

(Choice A) Examining grasshopper feeding activity would help only to determine the amount of vegetation consumed by grasshoppers per day and would not provide information about how the abundance of wolf spiders impacts grasshopper populations.

(Choice B) Examining only the amount of wolf spider eggs (not hatched into adults) would not provide information about how the number of predatory adult wolf spiders may affect grasshopper populations.

(Choice D) Because grasshoppers consume vegetation, determining the amount of vegetation in the area would provide information about food availability for grasshoppers, not about how the abundance of wolf spiders may impact grasshopper populations.

Things to remember:
Within biological communities, interactions between populations of organisms may cause changes (eg, changes in population size or access to resources) to the community's structure as time passes.

Buy Now
UWorld Dark Blue logo

Study Anywhere, Anytime

Tackle practice questions on the ride home from a game, review topic videos between classes, or dive into a study guide while waiting for friends at the coffee shop. Everything you need for AP Biology Unit 8 review is always at your fingertips with the UWorld app.

App Store
Google Play

Stand Out
with a Top Score in AP Biology

Finish your Unit 8 AP Biology review and continue mastering all units with UWorld. Boost your performance and set yourself apart as a strong candidate for competitive colleges, majors, and scholarships by earning a top score.

Choose Your Subscription
Dream Score Plan
360-Day
$169
Deep Learning Plan
180-Day
$149
Score Booster Plan
90-Day (No print book, only digital)
$129
Introductory Plan
30-Day (No print book, only digital)
$99
Buy Now!

Get our all-in-one course today!

  • Focused AP Bio Videos
  • Print & Digital Study Guide
  • 500+ Exam-style Practice Questions
  • Customizable Quiz Generator
  • Adjustable Study Planner
  • Realistic Timed Test Simulation
  • Colorful Visual Explanations
  • Progress Dashboard
  • Smart Flashcards & Digital Notebook
Explore our free trial and frequently asked questions.
7-Day Free Trial Subscription FAQs

Hear From Our AP Students

UWorld’s service is pretty good and helps provide a lot of explanations on subjects I haven’t been confident on before.

— AP Student

The questions here are the most realistic to the AP tests I've seen so far! I appreciate the ability to customize tests as well.

— AP Student

The best part is that all options are well-explained, telling clearly why they are not the right option.

— AP Student
Read More Reviews

Frequently Asked Questions (FAQs)

Following are the topics covered in AP Bio Unit 8: Ecology:

  1. Responses to the Environment
  2. Energy Flow Through Ecosystems
  3. Population Ecology
  4. Effect of Density on Populations
  5. Community Ecology
  6. Biodiversity
  7. Disruptions in Ecosystems
You should ideally start your AP Bio prep at least 2-3 months before the exam. Create a study timetable that works well for you and stick to it. Next, for a thorough AP Bio Unit 8 review, use a quality prep course like UWorld’s, which comes with an extensive question bank, a comprehensive study guide, engaging video lessons, interactive study tools, and a performance dashboard, to get a complete content coverage and achieve your desired score.

You should ideally start your AP Bio prep at least 2-3 months before the exam. Create a study timetable that works well for you and stick to it. Next, for a thorough AP Bio Unit 8 review, use a quality prep course like UWorld’s, which comes with an extensive question bank, a comprehensive study guide, engaging video lessons, interactive study tools, and a performance dashboard, to get a complete content coverage and achieve your desired score.

Yes, you can use Khan Academy for a basic understanding of concepts or use UWorld’s free trial to get an idea about our prep book, practice questions, and teaching methodology. Once you’re happy with the free trial, buy the full subscription to unlock the complete set of questions and study tools.

AP Bio Unit 8: Ecology consists of two types of questions, each accounting for 50% of the total score:

  1. Multiple-Choice (MCQs)
  2. Free-Response (FRQs) 

The MCQ section requires you to have a good grasp of key biology concepts whereas the FRQ section requires you to apply your knowledge to real-world and scientific situations.

Practice is key. You can use College Board’s past year FRQs to understand the difficulty level of the questions. This winter, UWorld is launching AP Biology Ecology FRQs with an AI-powered scoring system to help you understand what graders expect from your essays and learn how to write high-scoring answers.

AP Biology Ecology unit accounts for 10-15% of the total exam weight and requires approximately 19-21 class periods to complete the course contents.

Most students trust UWorld’s AP Biology Unit 8 study guide for its detailed explanation of concepts, colorful visuals, and Check-for-Understanding questions. You can buy our prep book directly from UWorld’s website or through Amazon.

Yes, UWorld lets you generate customized practice tests specifically for Unit 8. This topic-wise targeted practice helps you go over concepts as many times as you want, until you are confident about taking the exam.

Greenhouse effect refers to when certain gases in Earth’s atmosphere such as carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons trap heat to keep the planet warm enough to support life. In ecology, it is a crucial discussion because excessive greenhouse gases can lead to climate change and affect ecosystems and biodiversity.

Scroll to Top

Frequently Asked Questions

New Purchase: All new subscriptions go into effect from the time they are activated and not at the time of setup/purchase. A subscription can be activated immediately or any time thereafter. If your initial purchase consists of multiple courses (Qbank, Self-Assessment exam, CCS, etc.), each can be activated individually and independently via your account on our website. This process of activating a subscription after purchase allows you the flexibility to start a subscription when you are truly ready to use it.

We recommend that all subscriptions be activated within 180 days of setup/purchase. Once a subscription is activated, it cannot be paused or suspended for any reason and will run continuously for the duration of the course material.

Renewal: A renewal is an extension of time to continue access to a current activated subscription. Because a renewal is an extension to an already active subscription, it is effective from the existing expiration date, not from the day of purchase and cannot be deferred to start at a later date/time.

Note: All of our subscriptions are based on the Eastern Time Zone (GMT/UTC -5 hours or New York Time), which may be different than your local time zone.

Any of our product offerings can be purchased from our website with payment due in full at time of purchase via a credit or debit card with American Express/Discover/MasterCard or Visa logo.

You will need to register for an account in order to purchase any of our products. Once you have registered for an account or if you already have an account:

  • Log in to your UWorld account
  • Click on the Cart icon at the top of the page and then select your desired product to see a list of available packages and their prices
  • Select the package you wish to purchase
  • Verify your profile information, address, and educational status, then click the Update button
  • Enter your Billing address and credit/debit card information, then click Review Order
  • Verify that the correct product is in your cart and click Place Order
  • A purchase receipt will automatically be sent to your registered email address

If you complete your purchase but do not receive a receipt, please contact the Customer Care Team at [email protected]

You can subscribe to any of our online courses/services using a credit or debit card with a Visa, MasterCard, Discover or American Express logo. After a successful payment, your subscription will immediately be available for activation via your account on our website or available complementary mobile applications.

You can also subscribe via personal check, money order, or demand drafts taken in U.S. dollars. These types of payments should be mailed to us and should include the name of the subscription and the duration, along with the details asked for in the registration form. We will set up your account as soon as we receive your payment and notify you via email of your access credentials. All direct-mail payments must be in U.S. dollars and made payable to:

UWorld, LLC
9111 Cypress Waters Blvd
Suite 300
Dallas, TX 75019

We do not accept cash via mail, currencies other than U.S. dollars or payments via fax.

Individuals purchasing our CPA Review product may finance their purchase using Affirm during checkout process. Your eligibility depends on your credit score and other criteria, as per Affirm’s policies (outlined here). A soft credit check, a credit check that does not affect your credit score, will be performed by Affirm to determine your loan eligibility. You will need a US based bank account to qualify.

All refunds are evaluated on a case-by-case basis for products purchased directly from UWorld. One case has no bearing on another. Refund amounts determined by UWorld are final.

In-App Purchases: We are unable to process any refunds for purchases made via mobile application (in-app). Please contact Apple for all refund/credit requests for Apple in-app purchases.

USMLE Step 2 CS, Step 3 CCS, Subject Reviews & Self-Assessment Exams: These subscriptions are non-refundable, non-transferable, and cannot be converted into another subscription.

CPA Review: Students may request to cancel their CPA review product only within 10-days of activation of any of the materials. To qualify for a refund, no more than 10% of the course (lectures, Qbank, or a combination there-of) may have been used per exam section. All CPA Review refunds are subject to a cancellation fee of $75 (for single section purchases) or $250 (for package
purchases), plus any applicable shipping charges. No return of merchandise is necessary.

All other Qbanks: Refunds are considered for subscriptions of more than 30 days. Refund amounts are based on the number of days elapsed since the subscription start date or the number of questions used, whichever amounts to a higher deductible.

Example scenarion: An individual purchases a 180-day Qbank subscription and generates a few test blocks equal to 20% of the questions in the Qbank. After 45 days, he/she requests a refund. Because the elapsed duration is greater than the percentage of questions used, the refund amount will be based on a subscription converted to the closest duration (60 days) by deducting the applicable 60-day subscription fee from the refund. In the same scenario, if the individual had used 85% of the questions, the refund would be 15% of the subscription fee paid.

Note 1: A processing fee of 10% (minimum of $10 and maximum of $25) will be applied to all refund amounts.

Note 2: All refunds, pro-rated or otherwise, must be requested within 360 days of original purchase. Refunds for purchases made more than 360 days ago will be issued as non-refundable, non-transferable store credit.

Note 3: Subscribers must notify UWorld of their intent to obtain a refund before activating their subscription (or) during the active duration. If the reset option is used or all of the questions are used, no refund will be allowed (see “I want to reset/delete my Qbank test history (or) start all over again, is this possible?” below for further details). No refunds will be offered for expired subscriptions.

Note 4: For combination package purchases, individual subscription fees will be applied when calculating the refund. If any self-assessment Exam(s) is utilized from a package, the entire purchase is rendered non-refundable.

Note 5: Although access to Qbanks via certain mobile devices is provided as an additional feature, it is not intended to be a replacement for computer access, and no refunds or cancellations will be honored due to user inability to install and/or use the provided software on any mobile device (regardless of whether the device meets the minimum system requirements).

Please use the following steps to purchase a renewal for your subscription:

  • Log in to your account on our website
  • Click on the User Icon in the top right corner of the screen
  • Click on the Renew button corresponding to your subscription
  • Select the Renewal duration you wish to purchase
  • Verify your profile information, address, and educational status, then click the Update button
  • Enter your Billing address and credit/debit card information, then click Review Order
  • Verify that the correct package is in your cart and click Place Order

Upon a successful transaction, you will be sent a confirmation email receipt.

A renewal is an extension of time to continue accessing an active subscription, and it will not start the subscription over, provide a reset, or grant access to additional questions that were not previously accessible. Because a renewal is an extension to an already active subscription, it is effective from the existing expiration date, not from the date of purchase, and cannot be deferred in any way to start at a later date/time.

Please note that to qualify for renewal pricing, you will need to renew the course before it expires. Renewals are not offered to expired subscriptions. If you fail to secure a renewal before the expiration date, you will need to purchase a new subscription at the regular price directly from our website to regain access to the material.

Note: All times and dates displayed for subscription expiration correspond with the Eastern Time Zone (GMT/UTC -5 hours or New York Time), which may be different than your local time zone.

Note: If your initial purchase was a combination package, you will need to renew each active subscription individually. You do not need to renew a course that has not been activated.

You may request to upgrade or downgrade your subscription purchase as long as it has not been activated. If you purchase a combination package, all included subscriptions must be unused. Please be advised that current subscription pricing will apply.

If your subscription has been activated, unfortunately, we cannot upgrade it retroactively. If seeking to downgrade, please refer to our refund policy for available options.

We do not offer custom duration(s) or combination packages other than those outlined on the website. Please refer to our purchase page for currently available subscriptions (including discounted combination packages for some products).

Self-Assessment exam subscriptions are for 14 days each. Subscribers whose active subscription(s) have not expired can purchase renewals from 7 days or more at any time before their active subscription expires. Please refer to the respective course description page for renewal options.

We offer a demo on each of our product pages that contains a sample of the product interface and a few sample questions. We do not offer guest/trial accounts to test our software and view materials.

It is possible to purchase a subscription as a gift for someone else. However, the intended recipient will need to register an account on our website (or have an account registered for them, with their profile information entered accurately). If the user is present at the time of purchase, the purchase can be made from their account on our website using any credit or debit card with a Visa, MasterCard, American Express, or Discover logo.

If the user is not present, or you wish for the gift to be a surprise, please contact Support directly using the contact form to arrange payment for the gift subscription. You will need to provide the user’s registered email address so the account can be located.