Question

1. what does habitat fragmentation do?

a) makes habitats larger
b) divides habitats into smaller, isolated patches
c) creates new species
d) reduces biodiversity threats

1. the zebra muscles, pictured here, is an example of-

a) a native species
b) a keystone species
c) an endangered species
d) an invasive species

1. what caused the extinction of passenger pigeons?

a) climate change
b) habitat destruction
c) overharvesting
d) pollution

1. which of the following is not a benefit of biodiversity?

a) medicine
b) increased co₂
c) pollination
d) food security

1. in a food chain, bioaccumulation affects which organisms most?

a) primary producers
b) herbivores
c) decomposers
d) top predators

1. which of the following best defines a keystone species?

a) a species with the largest population
b) a species that only lives in one area
c) a species that shapes the structure of its ecosystem
d) a species that competes for resources

1. which is an example of habitat destruction?

a) draining wetlands for agriculture
b) building roads through forests
c) planting trees in a city
d) protecting coral reefs

Explanation:

• Question 8: Habitat fragmentation divides habitats into smaller, isolated patches. This is a well - known ecological concept.
• Question 9: Zebra Mussels are an invasive species. They are not native to many of the areas they have colonized and can cause significant ecological and economic damage.
• Question 10: Passenger pigeons were overharvested. Their large flocks made them easy targets for hunters, and combined with habitat loss (to a lesser extent in the context of their extinction), overharvesting led to their demise.
• Question 11: Increased \(CO_2\) is not a benefit of biodiversity. Biodiversity provides benefits such as medicine (many drugs are derived from natural sources), pollination (by insects and other animals), and food security (a diverse range of species can contribute to a stable food supply).
• Question 12: In a food chain, bioaccumulation affects top predators most. As toxins move up the food chain, they accumulate in higher concentrations in top predators due to their position at the end of the food chain (biomagnification).
• Question 13: A keystone species is one that shapes the structure of its ecosystem. Their presence or absence has a disproportionately large impact on the ecosystem compared to their abundance.
• Question 14: Draining wetlands for agriculture is an example of habitat destruction. Wetlands are important habitats for many species, and draining them removes that habitat. Building roads through forests is more of a habitat fragmentation example. Planting trees in a city and protecting coral reefs are not habitat destruction.

Answer:

• 8. b) Divides habitats into smaller, isolated patches
• 9. d) An invasive species
• 10. c) Overharvesting
• 11. b) Increased \(CO_2\)
• 12. d) Top predators
• 13. c) A species that shapes the structure of its ecosystem
• 14. a) Draining wetlands for agriculture