SAT II Biology E : Ecology

Study concepts, example questions & explanations for SAT II Biology E

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Example Questions

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Example Question #1 : Ecology

Which of the following is an example of primary consumers?

Possible Answers:

Fungi that gain energy from detritus

Foxes eating squirrels 

Algae

Grass

Deer eating grass

Correct answer:

Deer eating grass

Explanation:

A primary consumer is any animal that consumes primary producers (autotrophs). Autotrophs consist of any creatures that create their own energy (in the form of sugars) from sunlight. Grass and algae would be considered autotrophs. Deer are the only animals shown here that consume autotrophs and are, therefore, primary consumers.

Example Question #1 : Ecology

Which of the following is not a primary producer?

Possible Answers:

Mosses

Kelp

Grasses

Ferns

Mushrooms

Correct answer:

Mushrooms

Explanation:

A mushroom is a decomposer and not a producer. All of the other options are photosynthetic producers.

Example Question #2 : Ecology

Which of the following would be considered a primary consumer?

Possible Answers:

Grass

Fungus

Snake

Rabbit

Hawk

Correct answer:

Rabbit

Explanation:

A primary consumer is a herbivore that consumes only producers or autotrophs. For this question, rabbits only eat plants and so they would be considered the primary consumers. Grass and other organisms that can manufacture their own food are classified as primary producers. Snakes and hawks hunt other animals (such as rabbits) for food, so they must be at least secondary consumers. Fungi break down dead organisms for nutrition and are thus classified as decomposers.

Example Question #81 : Sat Subject Test In Biology

Which of the following are reasons why invasive species are often successful?

I. Lack of competition

II. Lack of predators

III. Specialized diet

Possible Answers:

I only

I and III only

II and III only

II only

I and II only

Correct answer:

I and II only

Explanation:

Lack of competition and predators allow invasive species to thrive and increase in population number. While diet may affect a population's success in inhabiting a new environment, it is not necessarily a reason for increased success in invasive species.

Example Question #3 : Ecology

Remoras are fish that use their sucker-like mouths to attach onto the skin of other animals. They often attach to sharks and consume dead skin cells, any food discarded from the shark, and other organisms that may feed on the shark itself. The relationship between the shark and the remora is an example of which of the following?

Possible Answers:

Predation

Decomposition

Commensalism

Parasitism

Competition

Correct answer:

Commensalism

Explanation:

This is an example of commensalism as one species benefits (the remora) and the other species is not affected (the shark). The remora gains food and has to use little energy to obtain that food whereas the shark does not notice the small remora riding on its skin. The remora does not prey on the shark, the two are not in competition with each other because the remora consumes discarded food, and the remora does not harm the shark, so it is not a parasite. 

Example Question #4 : Ecology

Which of the following is true about competition?

Possible Answers:

The term only refers to animals and not plants.

Competition is only temporary and does not result in a loss of fitness.

Competition can occur within a species and between species.

One species will eventually out compete the other and thus one species will go extinct.

Competition refers to two individuals directly interacting in a way that prevents one individual from accessing a resource.

Correct answer:

Competition can occur within a species and between species.

Explanation:

The term refers to all living organisms and can directly or indirectly lower the fitness of the other individual. A competitor may or may not go extinct. It is also possible that one species or community will exploit a slightly different niche over time to avoid competition or lessen its effects or the affect of competition may be enough to reduce population numbers but not cause the species to go extinct entirely.

Example Question #1 : Types Of Interspecies Relationships

Which of the following exemplifies a mutualistic relationship?

Possible Answers:

Barnacles and whales

Ospreys and fish

Bees and flowers

Dogs and fleas

Algae and sunlight

Correct answer:

Bees and flowers

Explanation:

A mutualistic relationship is a type of interspecies interaction in which both of the participating organisms gain some sort of benefit. In this case, the bee benefits by receiving food from the flower in the form of nectar. The flower, in turn, is provided with a means of pollination when the bees transport pollen from flower to flower as they gather nectar. Barnacles and whales is an example of commensalism, since the barnacles benefit without either helping nor harming the whales. Dogs and fleas is and example of parasitism, since the dog is harmed while the fleas benefit. Ospreys and fish is an example of a predator-prey relationship, as the osprey hunts the fish for food. Algae and sunlight is not a viable choice for a mutualistic relationship as the sun is not an organism.

Example Question #1 : Species Relationships

Which of the following describes a symbiotic relationship between two organisms in which one organism benefits and the other is harmed?

Possible Answers:

Mutualism

Parasitism

Competition

Divergent evolution

Commensalism

Correct answer:

Parasitism

Explanation:

Mutualism, parasitism, and commensalism are all symbiotic relationships (close, long-term interactions between two species). Parasitism correctly describes a symbiotic relationship in which one organism benefits and another is harmed (for example, giardia is a parasite found in contaminated water that can live in human intestines and cause gastrointestinal distress). Mutualism describes a relationship in which both species benefit from the interaction. Competition describes an interspecies (or intraspecies) relationship in which two species (or two members of the same species) occupying the same habitat compete for resources and the fitness of one species is harmful to the other (for example, two male deer competing to establish a dominance hierarchy or an invasive plant species taking nutrients from a native species). Commensalism describes a relationship in which one organism benefits and another organism neither benefits nor is harmed (for example, a cattle egret eating insects as it follows grazing cattle). Divergent evolution is not an interspecies relationship but an evolutionary concept by which the accumulation of differences between groups can lead to the formation of new species, often due to species diffusion to different, isolated environments.

Example Question #1 : Biodiversity

Mammals that lay eggs, such as the platypus or echidna, are called which of the following?

Possible Answers:

Prokaryotes

Placentals

Marsupials

Monotremes

Autotrophs

Correct answer:

Monotremes

Explanation:

Egg-laying mammals are rare, and are called monotremes (order monotremata). Marsupials are mammals that bear live young who continue to develop in a pouch. Most mammals are placental (such as humans), with live births and a placenta that facilitates nutrient and waste exchange between the mother and the fetus. Prokaryotes are microscopic single celled organisms lacking distinct nuclei and organelles. Autotrophs are organisms who make their own food (organic raw material) from inorganic energy sources. 

Example Question #81 : Sat Subject Test In Biology

Which biome is characterized by hot, dry weather with mild, rainy winters, some vegetation, and occasional fires?

Possible Answers:

Temperate grassland

Temperate forest

Desert 

Savanna

Chaparral 

Correct answer:

Chaparral 

Explanation:

The chaparral biome is known for being rather dry and for having these characteristics. They are different than deserts, as deserts do not have a rainy season. While savannas are often warm, they have a longer 6-8 month rainy season.

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