Study Island- Biogeology

Certain species of birds roost in large numbers in caves formed by limestone. As the birds exhale, the moisture in the cave reacts with the exhaled carbon dioxide to form carbonic acid. Over time, the resulting carbonic acid can create pockets in the cave walls that change the shape and volume of the cave.Which of the following statements is best supported by the information above?

Actions taken by organisms can cause changes to geologic features.

Which of the following statements about Earth's atmosphere are true?

Animal life has significantly changed the atmosphere. Before cyanobacteria existed, the atmosphere had very little oxygen.

Which of the following best describes the coevolution of the Earth's systems with life on Earth?

Changes in life forms alter landforms, causing further evolution of life forms.

Earth's current atmosphere contains mostly nitrogen. Other gases such as oxygen and carbon dioxide are also present and are used by living organisms. What was Earth's atmosphere like a long time ago, when life first appeared?

Earth's atmosphere was very different than it is today.

Plant life could not exist on land until there was nutrient-rich soil in which the plants could grow. Scientists hypothesize that microbes were instrumental in the formation of soil. Which of the following pieces of evidence best supports scientists' theory that soil formed after microbes inhabited land?

Fossil remains indicate that microbes appeared on land about 750 million years before plants.

The magnetosphere—a magnetic field surrounding the Earth—is generated by electric currents in the Earth's outer core. How does the magnetosphere help to make Earth habitable?

It protects Earth from solar wind.

Earth's current atmosphere is approximately 21 percent oxygen. On early Earth, however, virtually no free oxygen existed in the atmosphere. Where did the free oxygen in Earth's atmosphere come from?

It was released during photosynthesis performed by ocean-dwelling bacteria.

Which of the following is a way in which the evolution of land plants affected the Earth system?

Land plants changed patterns of weathering and erosion.

Cyanobacteria form stromatolites by binding particles of sediment into layers that harden into sedimentary rock over thousands of years. The image below shows stromatolite fossils located in Western Australia.Based on the information about stromatolites, which statement best describes the relationship between the geologic landscape and life on Earth?

Living organisms can form structures that gradually fossilize into geological formations.

Scientists now believe life on Earth evolved in the oceans long before living things appeared on land. Why is this likely?

Ocean water offered protection against harmful radiation until an atmosphere could form.

Which statement best illustrates the concept that, historically, changes in the biosphere affected the Earth's other systems?

Organic material from decomposed microbial mats combined with minerals from eroding rocks to enrich soil.

Photosynthetic autotrophs are organisms that use light energy and carbon dioxide to make sugar and oxygen. Aerobic heterotrophs, on the other hand, are organisms that use oxygen and organic carbon for energy, and release carbon dioxide as a waste product. Earth's early atmosphere contained very little free oxygen.Based on the information above, which of the following is most likely true?

Photosynthetic autotrophs evolved before aerobic heterotophs.

Unlike today's atmosphere, Earth's early atmosphere contained very little free oxygen (O2). Evidence in the rock record shows that the atmosphere began to gain large amounts of free oxygen around two billion years ago.Based on what is known about the oxygen cycle and today's atmosphere, which of the following explains the buildup of free oxygen two billion years ago?

Photosynthetic organisms became more common on Earth.

Early in Earth's history, organisms did not live on the land. How does this relate to the history of Earth's soils?

Soils became richer in organic material after land organisms evolved.

Since the formation of the Earth, both its surface and the living things on it have undergone many changes. Which of the following best describes the relationship between the development of the Earth's surface and the development of life on Earth?

The changing surface of the Earth determined what kinds of organisms could exist.

Animal life could not exist on Earth until there was a large amount of oxygen (O2) in the atmosphere. The majority of scientists believe that most of this oxygen was produced by cyanobacteria, which are a type of photosynthetic bacteria. Which of the following pieces of evidence best supports scientists' theory that cyanobacteria produced oxygen that led to animal life on Earth?

The oldest fossils that have been found are of cyanobacteria.

Coral is a soft-bodied marine organism that lives in colonies within a calcium carbonate skeletal framework called a reef. As coral dies, fragments of the skeletal framework sink to the ocean floor.Limestone is a sedimentary rock that is made of calcium carbonate. Which of the following most likely describes how the formation of limestone is related to the presence of coral colonies in a marine habitat?

The pressure of ocean water compacts the skeletal remains of coral colonies into limestone.

Coral thrives in clear, warm salt water and depends on photosynthetic algae to provide oxygen necessary for survival.There is scientific evidence that approximately 250 million years ago, there was a significant decrease in the Earth's coral population. Which change to the Earth's systems most likely caused the decrease in the coral population?

a decrease in oxygen available in the ocean

How does Earth's atmosphere support life?

by regulating temperature by reflecting harmful rays from the Sun by providing breathable air

Over the course of the Earth's history, many types of organisms have caused changes to the Earth's surface. The appearance of which of the following types of organisms most directly affected the shapes of the coastlines of continents?

coral

Around 2 billion years ago, oxygen gas began to bubble up from Earth's oceans and mix with the gases in the atmosphere. The oxygen had originally been excreted as metabolic waste from which of the following organisms?

cyanobacteria

Scientists theorize that it would have been impossible for early life forms to survive in the presence of oxygen, and yet, it would be impossible for modern life forms to survive without it. For example, experiments have shown that amino acids cannot form in the presence of atmospheric oxygen, and yet, ozone cannot form without it.Which of the following organisms contributed the most to the shift between an oxygen-free atmosphere to an oxygenated atmosphere?

cyanobacteria

Cyanobacteria, or blue-green algae, possess thick cell walls and are larger than most bacteria. As colonies of cyanobacteria grow in aquatic environments, they can secrete calcium carbonate, trap sediment, and cement the sediment together to form stromatolites, such as the ones shown below.Scientists have determined that cyanobacteria have been in existence for approximately 3.5 billion years. What evidence do they have to support their theory?

fossil records found in the stromatolites

The Earth's earliest atmosphere formed

from gases that came from the Earth's interior.

When continents first formed on the Earth, they consisted of solid rock. As a result, it was not possible for land plants to exist. Which of the following processes contributed the most to the Earth's ability to support land plants?

microbes living on land

Which of the following were components of Earth's earliest atmosphere?

nitrogen carbon dioxide water vapor

Cyanobacteria are a type of bacteria that uses photosynthesis to produce food. Through photosynthesis, cyanobacteria take in carbon dioxide and release oxygen.Cyanobacteria first appeared about 3.5 billion years ago. Based on their use of photosynthesis, cyanobacteria caused more _______ to begin accumulating in the Earth's atmosphere 3.5 billion years ago.

oxygen

During Earth's early history, little or no free oxygen existed in the atmosphere. After unicellular life evolved on earth, the atmosphere became oxygenated through a biological process. Which of the following biological processes is responsible for introducing free oxygen to Earth's atmosphere?

photosynthesis

Which of the following is hypothesized to be the early source of free oxygen in Earth's atmosphere?

photosynthesis by cyanobacteria

Lichens are formed when fungi exist in a symbiotic relationship with either algae or cyanobacteria. Given that lichens can accelerate the weathering of the rocks that they live on, which of the following is the most likely result of the evolution of lichens?

soil formation