Chapter Six Test Review

Scientists learn about past extinctions by studying fossils because fossils provide important evidence of past life forms and can help scientists understand the events and conditions that led to the extinction of certain species. Fossils can reveal information about the diversity of species, their habitats, and the changes that occurred in the environment over time. By analyzing fossils, scientists can reconstruct the history of life on Earth and gain insights into the causes and consequences of past extinctions.

A pesticide is a chemical used to kill insects. It is a substance that is specifically designed to control or eliminate pests, such as insects, that can cause harm to crops, plants, or humans. Pesticides are commonly used in agriculture to protect crops from pests and increase yields. They work by interfering with the pests' nervous system, reproduction, or other essential biological processes, ultimately leading to their death. Pesticides come in various forms, including sprays, powders, and granules, and they are an essential tool in pest control and agriculture.

Earthworms are beneficial to the environment as they move through the soil because their digested material enriches the soil. Earthworms consume organic matter, such as dead plant material, and break it down into nutrient-rich castings. These castings are then deposited in the soil, improving its fertility and structure. The nutrients released by earthworms through their digestion process, such as nitrogen, phosphorus, and potassium, are essential for plant growth. Therefore, earthworms play a vital role in enhancing soil quality and promoting healthy plant growth, making their presence beneficial rather than harmful.

When the last of a species dies, it means that there are no more individuals of that species left alive. This leads to the complete disappearance of the species from the Earth, making it extinct. Extinction occurs when a species fails to reproduce and replace its members, resulting in the loss of genetic diversity and the end of its existence.

Offspring inherit genes from their parents. This means that they receive genetic material from their parents, which determines their traits and characteristics. Inheritance is a fundamental process in genetics, where genetic information is passed down from one generation to the next. Through inheritance, offspring acquire a combination of genes from both their mother and father, shaping their physical and biological traits.

A hummingbird's long beak is a structural adaptation because it is a physical feature that has evolved over time to help the bird survive and thrive in its environment. The long beak allows the hummingbird to reach deep into flowers to extract nectar, which is its primary source of food. This adaptation gives the hummingbird an advantage over other birds that may not be able to access the same food sources.

Poisons in ecosystems can indeed travel through the food chain. This occurs when organisms at one trophic level consume organisms from a lower trophic level that have been exposed to or have accumulated poisons. These poisons can then bioaccumulate in the bodies of organisms at higher trophic levels, leading to potential harm or even death. This process is known as biomagnification and is a significant concern in environmental and wildlife conservation efforts.

The statement "All changes in ecosystems are fast and sudden" is incorrect. Ecosystems undergo various types of changes, some of which can occur slowly over long periods of time, while others may happen rapidly. Ecosystem changes can be influenced by natural processes, such as gradual climate change or slow geological events, as well as human activities, which can have both gradual and sudden impacts on ecosystems. Therefore, it is not true that all changes in ecosystems are fast and sudden.

A group of bees working together is a behavioral adaptation. Bees have evolved to have a complex social structure where they work collectively for the benefit of the entire colony. Each bee has a specific role, such as foraging, nursing the young, or building the hive. This behavior allows bees to efficiently gather nectar, pollen, and other resources, as well as defend their colony from predators. Working together in a coordinated manner is a behavior that has developed over time and enables bees to survive and thrive in their environment.

If a new species is introduced into a habitat where it has no predators, it will likely increase in number. Without predators, the species will not face natural limitations on its population growth, such as predation or competition for resources. This lack of predators allows the species to reproduce and thrive, leading to an increase in its population size. However, it is important to note that other factors, such as availability of resources and environmental conditions, can also influence population growth.

Introducing zebra mussels in the United States created changes in the ecosystems they joined because they have no natural predators. Without predators to keep their population in check, zebra mussels can rapidly reproduce and outcompete native species for resources. This can lead to a decline in biodiversity and disrupt the balance of the ecosystem. The absence of natural predators also allows zebra mussels to spread and colonize new areas, further impacting the ecosystems they invade.

Acid rain is caused by air pollution, specifically by the release of pollutants such as sulfur dioxide and nitrogen oxide into the atmosphere. These pollutants are primarily emitted by industrial processes, power plants, and vehicles. When they combine with water vapor in the air, they form acids that can fall to the ground as acid rain. Landfills and water pollution do not directly cause acid rain.

A mutation refers to a change in an organism's genes. Mutations can occur spontaneously or be induced by external factors such as radiation or chemicals. These changes can result in alterations to an organism's physical characteristics, behavior, or even its ability to survive and reproduce. Mutations are a fundamental source of genetic diversity and play a crucial role in evolution.

A structural adaptation refers to a physical change in the body of an organism that enables it to better survive in its environment. This can include features such as camouflage, specialized body parts, or protective coverings. Unlike behavioral adaptations, which involve changes in an organism's behavior, structural adaptations involve changes in its physical characteristics. Mutations, on the other hand, refer to changes in an organism's genetic material and can potentially lead to structural adaptations. Therefore, the correct answer is structural adaptation.

Plants and animals do not receive 1/3 of their genes from each parent and get 1/3 of their own unique genes. In reality, they inherit a combination of genes from both parents through sexual reproduction. The specific proportion of genes inherited from each parent can vary, and they also have their own unique set of genes. Therefore, the statement is false.

Adaptations to an environment can help a species live longer because they enable the species to better survive and reproduce in their specific surroundings. These adaptations can include physical characteristics, behaviors, or physiological changes that enhance the species' ability to find food, avoid predators, withstand harsh conditions, or compete for resources. By having traits that are well-suited to their environment, species are more likely to thrive and pass on their advantageous traits to future generations, increasing their chances of survival and longevity.

The bald eagle became endangered due to the widespread use of pesticides. Pesticides, such as DDT, were commonly used in the mid-20th century, which caused the bald eagle population to decline significantly. These chemicals accumulated in the eagles' prey, leading to thinning of their eggshells and reproductive issues. As a result, the bald eagle population dwindled, and it was listed as an endangered species in 1978.

The correct answer is "a snowshoe hare turns white in winter." This is an example of how the environment affects the appearance of an organism because the snowshoe hare's fur changes color to blend in with its snowy surroundings during the winter season. This adaptation helps the hare to camouflage and avoid predators, showcasing the influence of the environment on its appearance.

A behavioral adaptation is an inherited behavior that helps an organism survive. This means that certain behaviors are passed down from generation to generation because they increase the chances of survival for the organism. These behaviors can include things like hunting strategies, mating rituals, or communication methods. By exhibiting these behaviors, organisms are able to adapt to their environment and increase their chances of finding food, avoiding predators, and reproducing successfully.

A mutation is a change in an organism's genes that can be passed from parent to offspring. It is a permanent alteration in the DNA sequence, which can lead to variations in physical characteristics, behavior, or other traits. Mutations can occur spontaneously or due to environmental factors, and they play a crucial role in evolution by providing genetic diversity for natural selection to act upon. Symbiosis refers to a close and long-term interaction between different species, while behavior refers to the actions and responses exhibited by an organism.