About This Chapter
Populations and Biological Communities - Chapter Summary
The video lessons in this chapter offer an engaging way to review important concepts related to populations and biological communities. You'll study population density and survivorship as well as the impact of invasive species on environments. Our instructors discuss concepts like island biogeography, interspecific competition and metapopulations.
The video lessons also delve into kinds of symbiotic relationships, such as mutualism and parasitism, as well as types of predator-prey interactions. By the time you make it through the chapter, you should be able to:
- Define population density
- Discuss possible outcomes of interspecific competition
- Identify strategies used by predators and prey
- List and describe types of symbiotic relationships
- Explain factors that affect a population's carrying capacity
- Understand dispersal mechanisms
- Recognize the significance of metapopulation theory in conservation
- Describe the process of ecological succession
- Explain the impact of introduced and invasive species on ecological balance
Developed by professional instructors, our lessons are entertaining and concise. The videos are typically a few minutes long and include real-world examples and graphics. Use the included tags to jump around the videos so you can easily review excerpts. Transcripts-- many of which include links to other related text lessons--accompany each lesson, as well. You can see how well you understand the chapter's terms and concepts by taking the multiple-choice lesson quizzes.
1. Populations: Density, Survivorship and Life Histories
Have you ever wondered how biologists determine the populations of animals in a particular geographic area? Watch this video lesson to find out, and discover how scientists look at the survivorship and life histories of many different species.
2. Interspecific Competition, Competitive Exclusion & Niche Differentiation
What happens when two similar species that consume the same resources occupy the same space? Interspecific competition, that's what! Watch our video lesson to learn about the outcomes of this ecological battle.
3. Predator/Prey Interactions, Camouflage, Mimicry & Warning Coloration
You probably know that skunks can be quite stinky, bees sting and monarch butterflies are pretty, but do you know why? This lesson will introduce you to the reasons why some animals look or act the way they do and how these things relate to the predator/prey relationship.
4. Symbiotic Relationships: Mutualism, Commensalism & Parasitism
If your cat or dog has ever had fleas, you've witnessed symbiosis in action. In this lesson, learn the many types of symbiosis in biology, and how these relationships can have a positive, negative, or neutral effect on the individual species.
5. Carrying Capacity, Migration & Dispersion
Have you ever wondered why some types of birds fly south in the winter or why some animals form territories? Watch this video to learn about a species' maximum growth capabilities, the way its members group themselves and why they might migrate to new locations every year.
6. Dispersal, Colonization, and Island Biogeography
Have you ever gone in your backyard and discovered a wild raspberry bush that has never been there before? How did it get there? Why is there only one bush year after year? In this lesson, you'll study how plant and animal species colonize in new areas through dispersal and immigration and how some species thrive in a new area while others fail.
7. Conservation Biology, Habitat Fragmentation, and Metapopulations
It's becoming harder to conserve large, unbroken tracts of wilderness. Is there another way for conservation biologists to ensure the survival of a species? In this lesson, you'll learn about habitat fragmentation and metapopulations.
8. Ecological Succession: From Pioneer to Climax Communities
Just as people grow and change so, too, do ecosystems. Watch this lesson to learn about ecological succession from the beginning stages of development to a community's ultimate destination, or climax.
9. How Introduced and Invasive Species Alter Ecological Balance
What happens to your block when a new neighbor moves in? Something changes, right? Now think about that on an ecological scale: what happens to an environment when a new SPECIES moves in?
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