Bio Semester 2 Review

The number of different species in the biosphere is called

• biodiversity
• ecological diversity
• genetic diversity
• species diversity

A population of organisms grows

• with no natural restrictions except the availability of food
• when birth rate is higher than the death rate
• only in the absence of predators or natural diseases
• all of these

Rabbits introduced into Australia over 100 years ago have become serious pests to farmers. Rabbit populations increased so much that they caused many native species of plant eaters to relocate. What is the most logical explanation for their increased numbers?

• Rabbits have a high death rate
• There are few effective predators
• Additional rabbit species have been introduced
• There is an increase in rabbit competitors

Which are two ways a population can decrease in size?

• increased immigration and decreased emigration
• increased death rate and increased immigration
• decreased birth rate and increased emigration
• decreased emigration and increased birth rate

Sea stars are strong predators for marine organisms such as clams and mussels. An ecologist studying an ocean ecosystem performed an experiment in which the sea stars were removed from the ecosystem. After the removal of the sea stars

• The ecosystem became more diverse
• Food webs in the ecosystem became more complex
• The size of the ecosystem was reduced
• The number of species in the ecosystem was reduced

Which of the following choices describes the population changes shown on the graph during time 1990 to 2000?

• Increased birthrate
• Constant death rate
• Decreased birthrate
• Constant birthrate

Rainforests have been cut down to open ground for farming in some tropical areas of the world.  After a period of farming, the soil is too poor to grow food and the area becomes desert like.  How does the change in habitat from rainforest to desert affect biodiversity in the area?

• biodiversity remains the same
• biodiversity increases
• biodiversity decreases
• it is impossible to tell

The movement of organisms into a given area from another area is called

• Immigration
• Emigration
• Population shift
• Carrying capacity

Which of the following threaten biodiversity?

• Introducing foreign species
• Pollution
• Climate changes
• All of these

Which of the following is NOT a hypothesis that helps to explain: Greater biodiversity occurs at tropical latitudes (near the equator) than at latitudes farther from the equator?

• Plants can photosynthesize all year creating more energy reserves
• There is less competition for resources among species in the tropics
• Tropical habitats have stable climates, so species have diversified more in these areas
• Tropical habitats are warmer and more living things prefer warm climates