APES Biodiversity

Name En-Yu Liu Date 12/5/24 Period 3o

Do You Understand the Big Ideas? 

Living World: Biodiversity


Use your textbook, notes, labs, and other resources from the class to thoroughly answer these questions. Remember that these answers will be one of your main study materials for the AP test in May, so the more complete your answers are, the more helpful they will be to you months from now. If information on the question is available in your textbook, the page numbers are in parenthesis after the question. 


After answering all of the questions in this Big Idea review sheet, use the tools provided in your textbook to make sure that you understand how all of the topics are interconnected.  Use the visual representation, key terms, practice multiple choice, and practice free response questions at the end of the module in the textbook to make sure that you have a thorough understanding of the topics.


  1. What are the four components of natural selection and how do they lead to evolution? (from activities in class  and textbook pages 138-141)

Genes and Genetic Variation: Genetic makeup determines the characteristics of species and those positive mutations can be passed along to the next generation allowing for evolution to occur.


Evolution by Artificial Selection: Artificial selection is when humans specifically pick and breed a species to their liking which causes that species to change and evolve to human preference. 


Evolution by Natural Selection: Natural selection is when the environment and its factors determine what traits and characteristics are most preferable and prevail. This means organisms that are able to adapt evolve to have those traits.


Evolution by Random Processes: Processes like mutations and gene flow can often have unpredictable changes in a species that get passed onto the next generation and contribute to evolution.


  1. Define adaptations. (from textbook page 138)

Natural or artificial processes that create a new trait in a species that improves its fitness.


  1. Explain how new species evolve. Use geographical isolation and reproductive isolation in your answer. (from textbook pages 140-144)

Geographical and reproductive isolation establishes environmental barriers that separate certain species and force them to adapt to and evolve under certain conditions. 


  1. Define extinction. What is the background extinction rate, and how does it compare to a mass extinction? (from textbook pages 125-126)

Extinction is when a species has been completely wiped out and has no living organisms left. Background extinction rate is the expected and natural rate of extinction. On the other hand, mass extinction is when a large and unnatural number of species go extinct over a short period of time.


  1. How do island size and isolation impact the number of species and change of extinction on islands? (from class activity and textbook pages 113-118)

The bigger the island the more species and less rate of extinction. More isolated islands have less species and a higher extinction rate.



  1. Describe the three types of biodiversity. (from class activity and textbook pages 97-99).

Genetic Diversity: A measure in the variation of genetics in a population. Usually the higher the population the higher the diversity and the lower the population the lower the diversity


Species Diversity: The number of species in a region or a particular ecosystem. 

Ecosystem Diversity: The variety of different ecosystems in a region, such as the river ecosystems, temperate forests and oceans in a region. 


  1. The main factors that lead to a decrease in biodiversity are included in the acronym HIPPCO. What does each stand for? (from class activity)

H - Habitat Loss + Degradation

I - Invasive Species

P - Population Growth (humans)

P - Pollution

C - Climate Change

O - Overharvesting


  1. What are the two criteria for an area to be categorized as a biodiversity hotspot? (from class activity and textbook pages 164-165)

The number of endemic species. Endemic species are organisms that live exclusively in one habitat and usually there are many other endemic species living there as well making the area biodiversity hotspots.


The total number of species in an area. Some scientists think that endemic species numbers are not enough and want to consider the total number of species and threatened species as well. Because of this some areas with high biodiversity do not have high numbers of endemic species.


  1. Species diversity is made up of two components. Name and describe both. (from textbook page 102)

Biodiversity can be quantified based on species richness and evenness. Richness is how biodiverse an ecosystem is and evenness is how much of each species there is in each area. 


  1. What happens to species diversity as you move from the equator to the poles? (from class activity)

Species diversity decreases due to the fact that tropical zones have more suitable conditions for different species, while the cold temperatures closer to the poles can only support a much fewer number of species.


  1. Explain each of the following: (from textbook pages 122, 98, 26-27, 155-157, )

    1. Ecological niche

The abiotic factors that allow a certain species to survive and reproduce.


  1. Habitat

The natural home or ecosystem where a certain species lives.


  1. Generalist species

Species that are able to adapt and survive in various habitats and ecosystems.


  1. Specialist species

Species that can only survive and live in their natural habitat.


  1. Native species

Species that have lived in the same habitat for a long historical range


  1. Nonnative species

Species that have expanded to habitats they did not previously live in. Invasive species are nonnative species that expand in population rapidly due to having few predators, fast reproduction, immunity to diseases etc.



  1. Indicator species

Species that can show different characteristics of an ecosystem.


  1. Keystone species

Species that do not have a large population but still have a huge impact on an ecosystem.

  1. How do primary ecological succession and secondary ecological succession differ? (from textbook pages 150-151)

Primary succession: When terrestrial ecosystems begin from pioneer species such as algae, lichen and moss (organisms that need little to no soil to survive). Those pioneer species erode the rocks they live on and the combination of eroded rocks and that organic matter creates soil. That soil eventually becomes suitable for plants and growing ecosystems.


Secondary succession: When new ecosystems are born from disturbed areas that have not lost their soil. Secondary succession happens after a natural event such as a fire, or hurricane that removes vegetation but leaves soil behind. Plants that are able to disperse rapidly then take over the area and give rise to a new ecosystem. 


  1. It is useful to distinguish between two aspects of stability in ecosystems. Describe each: (from textbook pages 130)


  1. Resistance (also called inertia)

How well an ecosystem can handle a disturbance in the flow of energy and matter. The less effect the higher the resistance


  1. Resilience

How fast an ecosystem can return to its original state after a disruption. The higher the resilience, the quicker it returns to its original state. 


  1. How and why do we measure biodiversity? (from class activity)

Scientists use the Shannon-Weiner Diversity Index which involves the formula H = -ΣPi * lnPi to mathematically calculate biodiversity based on the amount of each species in the ecosystem. 


  1. How does habitat destruction impact biodiversity? (from class activity)

Habitat destruction leads to less biodiversity due to the fact that less species can be supported with fewer resources and room to live.


  1. Describe clear-cutting timber and selective harvesting. What are the ecological impacts of each? (from class activity)

Clear cutting timber is when all the trees in an area are removed at the same time in order to reduce costs for lumber companies. This can cause environmental impacts such as disruption of the water cycle, reduced air quality, and reduced habitat for native species.


Selective harvesting is the removal of only specific trees in an area that meet a certain criteria for a lumber company's needs. Selective harvesting sometimes does have a positive effect in clearing up space and promoting growth of other plant species, but can also lead to removal of habitat for species that require the trees being harvested as a habitat. 


  1. How can forests be protected? What are the benefits of protecting forests? (from class activity)

Forests can be conserved and protected in a few different ways. Laws and regulations can be established to prevent excessive deforestation and protect areas at risk, new trees can be planted to restore damaged forests, and enforcing already existing laws.


  1. Populations can grow exponentially and logistically. Differentiate between these. (from textbook page 181-183 and class activity)

Exponential growth: Exponential growth models the growth of an organism disregarding limiting factors and where the population can increase to its biotic potential. This results in a model that starts off relatively small before growing and spiking as the population and reproduction rate increases. 


Logistical Growth: Logistic growth models the growth of a species when it is limited by limiting factors and carrying capacity. This means that it resembles the J like curve of an exponential growth at first before eventually flattening out into an S shape at the top as it approaches the carrying capacity.


  1. How can species be distributed? What is the most common form of distribution? Because of the way species are distributed, what should we keep in mind when we are developing land for human use such as housing? (from class activities)

There are three ways that species can be distributed that are the most common. Firstly, they can be dispersed uniformly, where the amount of a species in each area is relatively equal. Next, they can be distributed in clumps, where species are distributed in clumps, where in some areas there are large groupings and in others there are none. Finally, there is random distribution, where the distribution is erratic with no visible pattern. 


  1. Every species has their ecological tolerances for all conditions in the environment. How do the combination of these tolerances make up their fundamental and realized niche? (from textbook pages 122-123 and class activity)

Range of ecological tolerance represents the types of conditions under which species can survive, grow, and reproduce. How well species can tolerate factors like temperature, humidity, food supply etc. determines where those organisms fit into an ecosystem and their ecological niche. 


  1. How is fire good for ecosystems? How have humans made fires more intense? (from class notes)

Controlled and natural fires can get rid of dead vegetation, encourage new growth by increasing the nitrogen and water solubility in the soil, and improving habitats for some wildlife. Humans have made fires worse by contributing to starting fires and also climate change. Climate change has caused higher temperatures and drier vegetation, both conditions that encourage wildfires.


  1. What are ecosystem services? Give examples of each. (from class notes and textbook pages 105-108)

Ecosystem services are the processes that naturally produce life sustaining resources such as water, timer, fisheries, and agricultural crops. They benefit people directly by providing food and water and indirectly by making the ecosystems healthier for us humans to live in. 


  1. Define invasive species. What are some traits that invasive species tend to have? What problems can invasive species cause in an ecosystem? (from class activity)

An invasive species is a nonnative species that has been introduced into an ecosystem and causes damage or harm, largely due to their uncontrollable numbers. Invasive species often possess traits like having few predators, fast reproduction, immunity to diseases, and the ability to eat many things for sustenance.