Sleep plays a vital role in defining the daily activities of virtually all animals. During periods of sleep, the parasympathetic nervous system becomes active and induces a relaxed state in response to increased levels of the hormone melatonin. Yet, despite its ubiquity in the animal kingdom, the purpose of sleep and its role in our daily lives has been disputed by scientists. Two scientists discuss their theories about the purpose of sleep.

Scientist 1

During periods of sleep, animals are able to conserve energy that they would otherwise be spending on unnecessary activity. If an animal’s primary food source is most abundant during daylight, it is a waste of precious energy to be moving about at night. For example, many herbivores, such as squirrels, are diurnal (sleep during the night) because their food source is available during the day, while many insectivores, such as bats, are nocturnal (sleep during the day) because their food source is available during the night. Food sources, as an animal’s most valuable resource, dictate their sleep cycles. Many animal traits observable today evolved as a result of the supply and demand of food in their natural habitat.

Scientist 2

During waking hours, it is true that the body utilizes large amounts of energy. However, the role of sleep is to restore biological products that were utilized during periods of wakefulness, rather than simply avoid utilizing energy in the first place. Many types of biological molecules, such as hormones, are released throughout the body while an animal is active. Sleep serves as a period of inactivity during which the body can manufacture and store a supply of these molecules for future use during the next period of activity. Furthermore, sleep allows the body to repair cellular damages that has accumulated during waking hours. Experimental evidence shows that when animals are deprived of sleep, their immune system quickly weakens and death rates increase. Sleep is necessary for animals to prevent accumulation of damage and to regenerate crucial biomolecules for daily life.

Both scientists give evidence to support their theories. The evidence given by Scientist 1 can best be described as __________.

Sleep plays a vital role in defining the daily activities of virtually all animals. During periods of sleep, the parasympathetic nervous system becomes active and induces a relaxed state in response to increased levels of the hormone melatonin. Yet, despite its ubiquity in the animal kingdom, the purpose of sleep and its role in our daily lives has been disputed by scientists. Two scientists discuss their theories about the purpose of sleep.

Scientist 1

During periods of sleep, animals are able to conserve energy that they would otherwise be spending on unnecessary activity. If an animal’s primary food source is most abundant during daylight, it is a waste of precious energy to be moving about at night. For example, many herbivores, such as squirrels, are diurnal (sleep during the night) because their food source is available during the day, while many insectivores, such as bats, are nocturnal (sleep during the day) because their food source is available during the night. Food sources, as an animal’s most valuable resource, dictate their sleep cycles. Many animal traits observable today evolved as a result of the supply and demand of food in their natural habitat.

Scientist 2

During waking hours, it is true that the body utilizes large amounts of energy. However, the role of sleep is to restore biological products that were utilized during periods of wakefulness, rather than simply avoid utilizing energy in the first place. Many types of biological molecules, such as hormones, are released throughout the body while an animal is active. Sleep serves as a period of inactivity during which the body can manufacture and store a supply of these molecules for future use during the next period of activity. Furthermore, sleep allows the body to repair cellular damages that has accumulated during waking hours. Experimental evidence shows that when animals are deprived of sleep, their immune system quickly weakens and death rates increase. Sleep is necessary for animals to prevent accumulation of damage and to regenerate crucial biomolecules for daily life.

Both scientists give evidence to support their theories. The evidence given by Scientist 2 can best be described as __________.

Dominant alleles (D) produce dominant characteristics; recessive alleles (d) produce recessive characteristics.  Dominant alleles are expressed whenever present (DD, Dd) but recessive alleles are expressed only when the dominant allele is absent (dd) 

A study was done in which the visual traits of two plants and their offspring was tested.  In this study, Plant A, a Tall Purple plant, was mated with Plant B, a Tall Pink plant.  In previous generations Plant A’s parents were always tall but were sometimes pink.  Plant B’s parents were sometimes tall or short and sometimes were pink or purple.  It has been determined that the dominant trait for height is tall (H) and the dominant trait for color is purple (P). 

Breeding both plants will result in offspring that have recessive and dominant traits.  The chart below contains all the possibilities for their offspring.  

Figure 1.

Figure 2.                   HH Pp x Hh pp    Offspring

 What traits would an offspring have with hh PP alleles?  

Dominant alleles (D) produce dominant characteristics; recessive alleles (d) produce recessive characteristics.  Dominant alleles are expressed whenever present (DD, Dd) but recessive alleles are expressed only when the dominant allele is absent (dd) 

A study was done in which the visual traits of two plants and their offspring was tested.  In this study, Plant A, a Tall Purple plant, was mated with Plant B, a Tall Pink plant.  In previous generations Plant A’s parents were always tall but were sometimes pink.  Plant B’s parents were sometimes tall or short and sometimes were pink or purple.  It has been determined that the dominant trait for height is tall (H) and the dominant trait for color is purple (P). 

Breeding both plants will result in offspring that have recessive and dominant traits.  The chart below contains all the possibilities for their offspring. 

Figure 1.

Figure 2.                     HH Pp x Hh pp    Offspring

What is the probability that the offspring in Figure 2 will be tall and purple? 

Dominant alleles (D) produce dominant characteristics; recessive alleles (d) produce recessive characteristics.  Dominant alleles are expressed whenever present (DD, Dd) but recessive alleles are expressed only when the dominant allele is absent (dd) 

A study was done in which the visual traits of two plants and their offspring was tested.  In this study, Plant A, a Tall Purple plant, was mated with Plant B, a Tall Pink plant.  In previous generations Plant A’s parents were always tall but were sometimes pink.  Plant B’s parents were sometimes tall or short and sometimes were pink or purple.  It has been determined that the dominant trait for height is tall (H) and the dominant trait for color is purple (P). 

Breeding both plants will result in offspring that have recessive and dominant traits.  The chart below contains all the possibilities for their offspring. 

Figure 1.

Figure 2.                     HH Pp x Hh pp    Offspring

What is the ratio of pink plants to purple plants? 

Dominant alleles (D) produce dominant characteristics; recessive alleles (d) produce recessive characteristics.  Dominant alleles are expressed whenever present (DD, Dd) but recessive alleles are expressed only when the dominant allele is absent (dd) 

A study was done in which the visual traits of two plants and their offspring was tested.  In this study, Plant A, a Tall Purple plant, was mated with Plant B, a Tall Pink plant.  It has been determined that the dominant trait for height is tall (H) and the dominant trait for color is purple (P). 

Breeding both plants will result in offspring that have recessive and dominant traits.  The chart below contains all the possibilities for their offspring. 

Figure 1.

Figure 2.                     HH Pp x Hh pp    Offspring

Why are there no short offspring? 

A group of scientists wanted to test the effects of Nitra-Grow, a chemical additive that can be given to plants to help them grow.  3 test groups of plants were given all the same time of sunlight, the same type of soil, and the same amount of water.  Plant A was given no extra chemicals.  Plant B was given 5g of Nitra-Grow.  Plant C was given 5g of Ammonia to see if Nitra-Grow worked any better than a basic nitrogen-based household product.  The plants are then measured on 5 consecutive days to find their average height (in cm).

Suppose on day 6, here are the results of each of the 3 plants.

What could you say about the effectiveness of Nitra-Grow?

The chart above shows the height growth of three different plant species after a period of 2 weeks. Each plant species was grown in 4 different soil mediums. All the plants were grown in the same environment with equal amounts of light, water, and oxygen. 

Based on the chart above, which plant species was consistently taller than the other plant species regardless of soil medium?

The chart above shows the height growth of three different plant species after a period of 2 weeks. Each plant species was grown in 4 different soil mediums. All the plants were grown in the same environment with equal amounts of light, water, and oxygen.

Which soil medium provides the tallest plant growth? 

Use the following diagram to answer questions 8–12:

What are the optimal conditions (temperature and pH) for enzyme A?