8.1 Responses to the Environment

Place the times in the correct order to represent the hierarchy for the level of ecology, from the simplest to the most complex.

• Community

• Population

• Biome

• Individual (Organism)

• Ecosystem

Place the times in the correct order to represent the hierarchy for the level of ecology, from the simplest to the most complex.

• biotic and abiotic factors interacting

• groups of different species interacting

• group of the same species

• only one

Which statement about response to environmental stimuli is true?

• Short-day plants flower when there is a long photoperiod

• Plants experiencing phototropism move toward sunlight

• Navigating birds lack and internal compass, so they rely on stars.

• A circadian clock operates during daylight hours

Which statement about communication is false?

• Brightly colored flowers communicate a source of nectar to pollinators.

• Rattlesnakes use auditory communication when threatened.

• Animals mark their territories using chemical communication.

• Plants are unable to use chemical communication.

Which statement is true about innate or learned (adaptive) behaviors?

• Innate behaviors are performed better over time

• Imprinting on a parent is an example of innate behavior

• Imitation is an example of a learned behavior

• Courtship displays in birds are commonly learned behaviors

Which statement about social behavior is false?

• The fitness costs of social living outweigh the fitness benefits

• Benefits include the ability of predators to capture and subdue large prey

• Costs include having to share food with other members of the same species

• Some species are highly social, living in groups that number in the thousands.

Tags

NGSS.HS-LS2-8

Students conduct an experiment with a population of bacteria named Alcaligenes faecalis. These bacteria move by using a tail-like structure called a flagellum. The students place two groups of bacteria into two beakers containing the same medium. The students place a capillary tube containing water into the first beaker, and they place a capillary tube filled with glucose dissolved water into the second tube. Both the water and glucose can diffuse out of the capillary tubes and into the medium into the beakers. The students observe the movements of the bacteria in both beakers. After a period of time, the students record the location of the bacteria in the beakers, which are represented by the dots in the figure.

Identify the independent variable in the experiment.

• The presence of glucose

• The presence of Alcaligenes faecalis

• The presence of the water-containing capillary tube

• The presence of the medium into which Alcaligenes faecalis are placed.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

Students conduct an experiment with a population of bacteria named Alcaligenes faecalis. These bacteria move by using a tail-like structure called a flagellum. The students place two groups of bacteria into two beakers containing the same medium. The students place a capillary tube containing water into the first beaker, and they place a capillary tube filled with glucose dissolved water into the second tube. Both the water and glucose can diffuse out of the capillary tubes and into the medium into the beakers. The students observe the movements of the bacteria in both beakers. After a period of time, the students record the location of the bacteria in the beakers, which are represented by the dots in the figure.

Which best described the movement of the bacteria in the beaker with no glucose?

• Kinesis

• Taxis

• Navigation

• Directed movement

Tags

NGSS.MS-LS2-1

Rattlesnakes rattle their tails to ward off potential predators. The rattling sound communicates to other animals that the rattlesnake is poisonous and will retaliate if attacked. In recent decades, ecologist in the western United States have observed an increase in the percentage of the rattlesnake population that is unable to make any rattling sound. Researchers also observed an increase in humans finding and killing rattlesnakes in the same region during the same time of day. Which best explains why the rattlesnake population is increasingly unable to make a rattling sound?

• Rattlesnakes that rattle their tails have an increased fitness because they are less likely to be found by animals that are hunting them.

• Rattlesnakes that do not rattle their tails have a decreased fitness because they are less likely to be found by humans that are hunting them.

• Rattlesnakes that do not rattle their tails have an increased fitness because they are less likely to be found by humans that are hunting them.

• Rattlesnakes that rattle their tails have an increased fitness because they scare off humans that are hunting them.

Tags

NGSS.MS-LS4-4

A group of scientist conducted an experiment to study how a type of fish called the stickleback fish behave in response to seeing brine shrimp, which are a food source for the fish. The scientist placed 35 shrimp in a clear glass tube then put the tube into the middle of an aquarium containing one stickleback fish. The glass tube prevented the shrimp from being eaten by the fish. The data presented in the figure were collected from observing how many times, over a period of 10 minutes, the fish bit at the glass tube attempting to eat the shrimp. The number of attempts each fish made were averaged and plotted on the graph. Error bars are calculated at +/-1 standard error on either side of the mean.

Identify the type of behavior, including whether the behavior is innate or learned that the fish displayed over the 10 minutes of the experiment. Justify your answer.

Answer explanation

The stickleback fish displayed habituation, which is an innate behavior that can be modified through experience. Habituation occurs when an organism decreases or stops responding to a stimulus after repeated exposure when the stimulus has no positive or negative consequence.

Justification 1: The graph shows that at the beginning of the experiment (0–2 minutes), the fish made many attempts to bite the glass tube, averaging more than 3 attempts. Over time, the number of attempts steadily decreased to around 1.5 attempts, even though the shrimp were still present. This decrease in response supports habituation because the fish gradually stopped responding to a stimulus (shrimp behind glass) that had no reward.

Justification 2: The behavior is innate because the fish’s initial biting at the shrimp is instinctive—it did not need to learn to recognize food as prey. However, the reduction in attempts over the 10-minute period shows learning through experience (modification of the innate behavior). The fish recognized that biting at the glass tube did not lead to food.

Justification 3: The presence of error bars shows that the trend was consistent across multiple trials with different fish. This indicates that habituation is not random but a common adaptive response, helping the fish conserve energy instead of wasting it on unrewarding stimuli.

Tags

NGSS.MS-LS2-1