Population Ecology
Food, water, space, and disease are all examples that can impact population growth. What do we call these impacts?
What is: Limiting Factors
Which symbiotic relationship describes two organisms both benefiting from each other?
What is: Mutualism
What type of consumer is known for eating both plants and animals?
What is: Omnivores
A region receives less than 25 cm of precipitation annually. Plants have adaptations that help them conserve water, and many animals are active primarily at night. Which biome is most likely?
What is: the Desert
A population has 75 births, 25 deaths, 10 immigration, and 20 emigration. What is the net population change?
75 - 25 + 10 - 20 = 40
A 10 km2 prairie contains 240 bison. A nearby 20 km2 prairie contains 300 bison. Which prairie has the higher population density?
What is: 10 km2 or 240 has higher population density
240/10 = 24 bison/km2 & 300/20 = 15 bison/km2
Remora fish attach themselves to sharks. The fish get free transport, protection, and scraps of food, while the shark experiences no benefit. What type of symbiotic relationship is this?
What is: Commensalism
What type of organisms are known for gaining their energy primarily from the sun?
What is: Autotrophs or Producers
Consumers = Heterotrophs
Which biome experiences long, severe summer droughts and cool, rainy winters? It has annual precipitation usually ranges from 10-30 inches. It also has frequent wildfires.
What is: Chaparral
A population increases from 100 to 150 individuals. What percentage did the population increase?
What is: 50%
(150-100) / 100 = .5 x 100 = 50%
A population of bacteria increases from 500 to 1,000 to 2,000 to 4,000 over several generations. If resources remain unlimited, what type of population growth is occurring?
What is: Exponential growth
A farmer introduces a large number of cattle into a grassland. The cattle and native bison eat the same grasses. Over time, the bison population decreases. What type of competition interaction is happening?
Intraspecific (sAme) species & Prey-Predator interactions
A grassland contains 20,000 kcal of energy stored in producers. Using the 10% Rule, approximately how much energy would be available to primary consumers?
What is: 2,000 kcal
20,000 x .10 = 2,000
A fish population increases from 1,000 to 1,800 individuals in five years. The lake's carrying capactiy is estimated at 2,000. Predict: What is likely to happen as the population approaches 2,000 and why?
What is: population will demonstrate characteristics of logistic growth because once it hits carrying capacity the growth will slow/crash back down.
A deer population in a forest increases rapidly. Once the population reaches approximately 800 deer, the population fluctuates between 750-850 for several years. What does the 800 deer value represent?
What is: Carrying Capacity
Logistic growth because the deer population reached the amount that environment can support.
Logging forest in the Pacific Northwest clears/removes big trees, but the soil remains packed with nutrients. Fast-growing bushes and small alder trees grow first, followed decades later by towering evergreen conifers. What type of ecological growth is this?
What is: Secondary Succession
What is a keystone species and how can losing one impact a food chain?
What is: keystone species hold an entire ecosystem together & removal can result in the collapse of a food chain
Invasive Species: not original to ecosystem & can cause negative impact on food chains by creating a new interspecific competition.
Which biome experiences long, severe winters with short, mild summers? It is the world's largest land biome that consist of cone-bearing evergreen trees like pine, spruce, and fir.
What is: Taiga or Boreal Biomes
Tundra biome is completely treeless & experiences much harsher, longer winters
What is: Density-dependent
What are two types of limiting factors & provide one example for each.
What is: Density-Dependent (Biotic, High Pop. Density) & Density-Independent (Abiotic, Pop. Density doesn't matter)
What is known as how species survive and interact with the environment?
What is: Niche
Create a trophic pyramid for the following food chain. The producer contains 100,000 kcal of energy. Apply the Rule of 10 to each trophic level.
Grass -- Grasshopper -- Frog -- Snake -- Hawk
What is: Grass (producer) 100,000 kcal, Grasshopper (primary consumer) 10,000 kcal, Frog (secondary consumer) 1,000 kcal, Snake (tertiary consumer) 100 kcal, and Hawk (quad. consumer) 10 kcal
Salmon spend years in the ocean, however they will swim from the ocean upstream to freshwater rivers to safely lay and fertilize their eggs. Salmon must pass through which type of aquatic biome for breeding season?
What is: Estuaries
A prairie contains grass, grasshoppers, mice, snakes, hawks, and decomposers. A prolonged drought occurs. Predict TWO changes that could occur to the ecosystem.
2. Consumer populations decrease - less food resources
3. Competition increases - organisms compete more intensely for limited resources.
4. Carrying Capacity decreases - fewer resources are available to support populations
5. Food-Web Energy Flow changes - less energy enters the food web through producers.