WorksheetsBiodiversity + Its Threats
Total questions: 58
Worksheet time: 51mins
How can the decline of a single species affect an entire ecosystem?
It can trigger profound, cascading effects because species play interconnected roles that support system balance and functionality.
It has no meaningful impact because most species are independent of one another.
It only affects top predators while leaving other trophic levels unchanged.
It causes only short-term disturbances that quickly disappear without wider consequences.
What is a food web?
A model representing many interconnected food chains and pathways through which energy and matter flow in a group of organisms
A diagram showing a single predator–prey relationship for one species
A chart of population sizes for plants and animals over time
A map of migration routes that animals follow each year
In the illustrated food web, which organism is a producer?
Corn
Wolf
Eagle
Python
What is background extinction?
The gradual process of species becoming extinct over time
The sudden loss of most species in a short period
The disappearance of only large mammals due to hunting
The permanent loss of habitat without species loss
Which factors can change a stable ecosystem? Select all that apply.
Activity of other organisms
Climate changes
Natural disasters
Random chance with no environmental or biological cause
Why are scientists concerned about current extinction patterns?
The present extinction rate is about 1000 times higher than the normal background rate
Extinction rates are steadily decreasing worldwide
Only plants are currently going extinct at unusual rates
Extinctions now occur solely due to volcanic eruptions
Match each extinct species with a primary cause described.
Dodo bird
Human hunting and invasive species such as rats, pigs and dogs
Passenger pigeon
Commercial hunting that killed hundreds to thousands at a time
Woolly mammoth
Rapid climate change combined with human hunting
Pinta giant tortoise
Hunted for food and competition from introduced goats
What is a mass extinction?
An event in which a large percentage of all living species become extinct in a relatively short period of time
The gradual loss of a few species over millions of years
The extinction of one predator that causes a trophic cascade
A local population decline that later recovers
What fraction of plant and animal species may become extinct during the second half of this century?
Between one-third and two-thirds
Less than one-tenth
Almost all species
Exactly three-quarters
Mass extinctions infographic with five panels lists Ordovician, Devonian, Permian, Triassic, and K–T events with death rates and times. Which event is shown with the highest death rate on this chart?
Ordovician (85% death rate)
Devonian (70% death rate)
Permian (95% death rate)
Triassic (76% death rate)
According to the mass extinctions infographic, which result is listed for the K–T event that occurred about 65 million years ago?
Widespread fires
Oxygen removed from oceans
Desertification of land
Coastal areas destroyed
Match each mass extinction on the infographic to the approximate time it occurred.
Ordovician
445 million years ago
Devonian
340 million years ago
Permian
250 million years ago
Triassic
200 million years ago
The graph titled “Big Five Mass Extinctions in Earth’s History” marks End Permian (about 250 Mya). What percentage of species is indicated as extinct for this event?
96%
80%
75%
76%
On the same graph, a mass extinction is defined by the loss of at least what percentage of species within a short geological period (around 2 million years)?
50%
60%
75%
90%
Which of the following are listed as anthropogenic changes? Select all that apply.
Habitat loss
Pollution
Overexploitation
Plate tectonics
What effect do anthropogenic changes have on ecosystems?
They can disrupt an ecosystem and threaten the survival of some species.
They increase the carrying capacity for all species.
They ensure stability regardless of environmental changes.
They always lead to the formation of new species.
Which of the following anthropogenic changes are depicted? Select all that apply.
Pollution from waste dumping
Deforestation and logging
Industrial emissions from power plants
Glacial advance due to natural cooling
Which specific ocean region is identified as a major convergence zone for floating debris where garbage patches form?
North Pacific Subtropical Convergence Zone
South Atlantic Gyre
Indian Ocean Monsoon Trough
Arctic Circle
The images of turtles, dolphins, and seals amid floating bags, fishing nets, and plastic rings depict which primary threat to marine organisms?
Oil spill toxicity
Thermal pollution from power plants
Entanglement and ingestion caused by marine plastic debris
Ocean acidification from increased CO2
Humans are altering conditions on Earth at a pace that outstrips what processes in some species?
Seasonal migration
Evolution of new traits that allow coping with new conditions
Daily circadian rhythms
Cell division during growth
Which items are identified as natural resources found in the biosphere? Select all that apply.
Clean water
Smartphone batteries
Solar energy
Plastic packaging
Evolving species might lack what, threatening their survival?
Suitable weather forecasts
The natural resources they need
Access to domestic animals
Protection from all predators
What is overexploitation?
Releasing captive-bred animals to restore populations
Excessive use of species that have economic value
Protecting habitat by limiting harvest quotas
Replacing native species with nonnative ornamentals
Which action is given as an example of habitat destruction with a direct impact on global biodiversity?
Selective thinning in an urban park
Clearing tropical rainforests
Planting shelterbelts on farms
Controlled burns in fire-adapted prairies
What ecosystem outcome is noted as a consequence of habitat disruption such as overfishing?
Immediate species recovery
A chain reaction that affects an entire ecosystem
Complete immunity to invasive species
Stabilization of population sizes
Which option best describes the human activities illustrated?
Sustainable forestry with selective cutting and low bycatch
Industrial overfishing and large-scale logging for economic gain
Habitat restoration through replanting and stock enhancement
Creation of wildlife corridors to reduce fragmentation
What environmental impact do these scenes exemplify?
Volcanic eruption damage
Urban air pollution from vehicles
Loss of habitat due to deforestation
Coral reef bleaching
When harbor seal and sea lion populations declined during the 1970s, what change occurred in killer whale feeding behavior?
They ate more sea otters.
They ate more fish instead of marine mammals.
They migrated away and ate less overall.
They switched to eating kelp.
How did a decline in sea otters affect kelp?
Sea urchin populations increased, which reduced kelp.
Sea urchin populations decreased, which increased kelp.
Kelp was unaffected because sea urchins changed diet.
Kelp increased due to less predation by otters.
Which species’ decline directly led to an increase in sea urchins?
Sea otters
Whales
Fish
Killer whales
What is habitat fragmentation?
The separation of an ecosystem into small pieces of land.
An increase in biodiversity within a single large habitat.
Seasonal animal migration across an intact ecosystem.
The deposition of pollutants at the edge of a habitat.
What are edge effects?
Different environmental conditions that occur along the boundaries of an ecosystem.
Erosion that occurs where roads cut across forests.
Movement patterns of animals that follow habitat edges.
Human construction of roads through interior habitats.
Which outcomes are likely results of habitat fragmentation? Select all that apply.
Patches may lack any core area.
The size of habitat available to species can be reduced.
Populations of species with more specialized requirements may reduce.
Edge species are unable to live in the unique conditions along habitat boundaries.
What happens when temperatures increase beyond what species have evolved to tolerate?
Species that cannot adapt die, threatening survival and dependent species.
All species quickly adapt, increasing biodiversity.
Species migrate and overall ecosystem stability increases.
Temperatures eventually decrease back to previous levels.
Scientists predict that climate change will threaten approximately what percentage of all land species by 2050?
10%
25%
50%
75%
Match each organism with the climate-related impact
Polar bears
Losing land to hunt
Emperor penguins
Chicks may drown if their fur does not become waterproof as seasons warm
Coral reefs
Bleaching due to an increase in carbon dioxide
What is the stated effect of increased carbon dioxide on coral reefs?
Bleaching of reef structures
Rapid coral growth
Stronger shells and skeletons
No significant change
What does biological magnification describe?
An increasing concentration of toxic substances in organisms at higher trophic levels
A decrease in toxin levels as energy flows through a food chain
The dilution of pollutants in air and water over time
The breakdown of toxins by soil microbes at each trophic level
Pollution is described as changing the composition of which environmental components?
Air, soil, and water
Only air and water
Only soil
Only air
Which group is most likely to have the highest mercury levels and thus be eaten only a few times per month?
Large predatory fish such as shark
Mid‑level fish such as trout
Small organisms such as krill
Shellfish such as oyster
The mercury food‑chain diagram shows a toxic substance increasing in concentration at higher trophic levels. What process does this illustrate?
Biological magnification
Bioremediation
Eutrophication
Nitrogen fixation
Which reaction leads to the formation of the acids responsible for acid rain?
Sulfur and nitrogen compounds reacting with water to form sulfuric and nitric acids
Carbon compounds reacting with oxygen to form carbonic acid
Sodium and chlorine reacting with water to form hydrochloric acid
Calcium reacting with carbonate to form limestone
What is a direct effect of acid precipitation on soils as stated in the slide?
Removal of calcium, potassium, and other nutrients from the soil
Increased nitrogen fixation by soil bacteria
Rapid increase in soil pH, making it more basic
Formation of new minerals that enhance fertility
Which scenario most likely triggers extensive algae growth and destroys underwater habitats?
Runoff carrying fertilizers, animal waste, sewage, or other substances rich in nitrogen and phosphorus
Increased wave action that mixes oxygen into surface waters
Reduced sunlight reaching the water due to cloud cover
Introduction of herbivorous fish that graze on algae
Which acid forms when water combines with carbon dioxide in soil and bedrock
Carbonic acid ( H2CO3 )
Sulfuric acid ( H2SO4 )
Nitric acid ( HNO3 )
Hydrochloric acid ( HCl )
The forest image adjacent to the acid‑rain diagram shows widespread tree mortality. Which mechanism best explains this outcome?
Leaching of essential nutrients from soils, depriving plants of calcium and potassium
Rapid tree growth causing resource depletion
Increased photosynthesis due to extra water in rainfall
Improved soil fertility following deposition of sulfates and nitrates
Which habitat has the greatest impact resulting from edge effects?
A
A and B equally
B
neither A nor B
Which habitat naturally supports the greater amount of biodiversity?
A
A and B equally
B
neither A nor B
Select the three types of biodiversity.
*Be sure to select all three correct answers!
Species
Technological
Industrial
Genetic
Ecosystem
In our classroom, we have a high amount of __________?
Species Diversity
Genetic Diversity
Ecosystem Diversity
Industrial Diversity
Tigers living in warm climates have thinner coats of fur than those in cool climates. This is an example of:
Genetic diversity
Species diversity
Ecosystem diversity
Genera diversity
A region that includes tigers, eagles, lizards, fish, rabbits, and many other types of organisms would be best described as having a high level of
taxonomic diversity
genetic diversity
ecosystem diversity
species diversity
High levels of biodiversity tend to
have little or no effect on ecosystems
decrease an ecosystem's resistance to change
increase the stability of an ecosystem
make an ecosystem less resilient
The 3 different types of biodiversity are;
Genes, Population, Habitats
Genes, Species, Ecosystems
Species, Habitats, Communities
Biosphere, Genes, Habitats
The variety of life in the world or in a particular habitat or ecosystem
Biodiversity
Demography
Carrying capacity
Poaching
Food Web B is an example of...
Low biodiversity and low sustainability. If the producer dies then all the food web will suffer.
High biodiversity and high sustainability. If an organism is removed the food web will continue with no effect.
Which ecosystem has a higher diversity?
Community A
Community B
They are the same
