Learning Curve Chapter 1

Scientists estimate that life arose on Earth approximately _______ years ago.

4 billion

Which is an example of a positive feedback system?

A puppy suckling on its mother causes an increase in levels of a hormone in the mother's body that activates milk production.

Which statement supports the idea that biological systems are dynamic, not static?

A small percentage of the atoms present in a human infant are present in the human at age 80.

Which statement about scientific methods is true?

After forming a hypothesis, scientists apply logical reasoning to make predictions from the hypothesis.

Scientists have found organisms from each of the three domains that express a protein called cytochrome c. According to this phylogenetic tree, which organism would be expected to have a cytochrome c gene most similar in DNA sequence to the cytochrome c gene from a human?

An organism classified as a fungus

Which is a key point in Darwin's explanation of evolution?

Any trait that confers an increase in the probability of survival and reproduction will spread through the population.

Groups of 50 house flies were kept in three chambers under the same conditions except for temperature. After 4 hours, the number of surviving flies was counted in each chamber and expressed as a percentage of the total. The results raised new questions that the data cannot be used to answer. Which is a new question prompted by the data shown?

Are house flies that are sensitive to heat also sensitive to cold, or are the two governed by separate mechanisms?

Imagine that NASA sends a probe to one of Jupiter's moons. The probe takes a sample from one of the methane lakes and returns to Earth. Pictures of the sample, taken through a microscope, reveal a cell-like structure remarkably similar to a simple prokaryotic organism. The structure is placed in a dish containing a liquid bacterial growth medium and observed over several days. Which observation best supports the hypothesis that this is a living organism?

Atoms in compounds in the medium are later traced to the structure's membrane.

A key biological principle is that evolution explains the diversity as well as the unity of life. Which example illustrates this principle with respect to the unity of life?

Bacteria and human cells have a core set of proteins in common, and genes for these proteins bear similarities in nucleotide sequence.

A biological system composed of Components A, B, and C is shown in the figure. Five experimental trials were run, and the results were summarized in the table. Which conclusion can be drawn from these results?

C regulates the system through negative feedback.

Which research problem would be best approached using bioinformatics?

Comparing healthy and affected members in a population to see whether a disorder has a genetic basis

What term refers to a set of mathematical equations that describe a biological system?

Computational model

_______ is required to maintain organization in living systems.

Energy

Which statement explains the concept of feedback as it applies to biological systems?

Feedback is a process in which the amount of one component of a system affects the rate at which the system operates.

The information needed to produce proteins is contained in

Genes

Which is an example of an organ system?

Heart, arteries, capillaries, and veins

Darwin referred to the differing survival and reproduction among individuals of a population as

Natural selection

A biologist hypothesizes that increasing carbon dioxide levels in the atmosphere causes an increase in plant growth. A controlled experiment using one species of plant was conducted using different groups of plants over a two-week growing period. Each group contained 20 plants randomly split into control and experimental groups. The plants received identical treatment, except CÓ exposure. The table summarizes results as average height increases along with a plus/minus value indicating the range of individual plant height measured. Can the data be used to support the biologist's hypothesis? Why or why not

No, because the variability in the data for each group is so large that statistical analysis would be needed to discern any differences.

Which shows the correct order of important first events in the history of life?

Nucleic acid evolution, first archaea, first cyanobacteria, first nucleus, first chloroplasts

Which statement correctly explains why the development of photosynthesis changed the course of evolutionary history?

Photosynthesis provided a mechanism for the production of food that supported non-photosynthetic organisms.

Which design for an experiment would best test the hypothesis that blue flowers are more attractive to bees than pink or white flowers?

Plant an equal mix of pink, white, and blue flowering plants of species D inside a greenhouse. Release bees of the same species and count each visit to each flower color.

Data on bird populations can be collected using special nets to capture birds in their habitat. Imagine the species and sex of each captured bird are determined from its physical characteristics; the bird's age is assessed by examining whether juvenile or adult feathers are present; and wing length, beak length, and the bird's weight are determined before the bird is released. Which of these observations are qualitative, and which are quantitative?

Qualitative: species, sex, age; quantitative: weight, wing length, beak length

In science, a theory is a body of scientific work that has undergone rigorous _______ to establish facts and principles used to make predictions about the natural world.

Testing

A biologist claims to have discovered a single-celled organism that is evolutionarily unrelated to any organisms known to inhabit Earth. Which observation made during an extensive study of the organism most solidly supports the biologist's claim?

The chemical identities of the amino acids making up the organism's proteins differ from those found in bacteria.

Which statement refers to part of the scientific basis for the conclusion that evolution is a fact?

The process of evolution has been observed and measured in the lab.

A group of spiders of the same species lives in a wetland region, feeding on numerous species of winged insects that become ensnared in their webs. Several species of birds, as well as a number of small mammal species, feed on the spiders. Which statement correctly characterizes this scenario?

The wetland is a landscape composed of several communities, one of which includes the population of spider species, the populations of bird species that prey on the spiders, and the populations of insect species preyed on by spiders.

When do atoms making up cells in a tree become fixed in those cells for the duration of the cell's existence?

When the tree dies

The process of evolution can be inferred from the fact that

flu vaccines must be updated annually to keep up with changing viruses.

The various types of cells in a multicellular organism

have functions determined by protein expression

In terms of increasing complexity, the order of parts of a multicellular animal is

molecule, cell, tissue, organ, organ system.

Scientists postulate that the critical step for the emergence of life on Earth was the appearance of

nucleic acids.

An example of an organismal-level system is one that

provides delivery of oxygen to cells in a human.

Milk snakes are a species of non-poisonous snakes that inhabit a wide geographical range throughout North America. They can be gray, tan, red, orange, or black with or without bands of yellow, black, or white. Biologists have proposed that brightly colored milk snakes are adapted to regions where similarly colored poisonous snakes live because the color wards off potential predators. This is a(n) _______ explanation.

proximate

A biologist who is developing a mathematical model to describe a set of changes in a cell is conducting a(n)

systems analysis.

A group of differentiated cells that work together to carry out a similar function is known as a(n)

tissue.

If the living things we observe today had originated from multiple origins instead of a single origin, they would be more likely to

use a variety of genetic codes.