Chapter 1 Principles of Life



Chapter 1 Principles of Life

Concept 1.1 Living Organisms Share Common Aspects of Structure, Function, and Energy Flow

Characteristics shared by all living organisms:

Composed of a common set of _______________________________________.

• Contain genetic information that uses a nearly __________________________.

• Convert molecules obtained from ____________________________________.

• Extract energy from the environment and _____________________________.

Regulate their ________________________________.

• Replicate their genetic information in the same manner __________________.

• Share sequence similarities among a __________________.

• Evolve through gradual changes __________________.

Earth formed between __________________.

It was some __________________or more before the earliest life evolved.

Complex biological molecules possibly arose from __________________ __________________ of chemicals in the early environment.

Experiments that simulate conditions on early Earth show that this was possible.

Critical step for evolution of life—formation of __________________

For 2 billion years, organisms were unicellular __________________.

Early prokaryotes were confined to oceans, where they were protected from __________________.

There was little or no O2 in the atmosphere, and hence no protective __________________layer.

__________________ evolved about 2.7 billion years ago.

The energy of__________________is transformed into the energy of biological molecules.

Earliest photosynthetic cells were probably similar to __________________.

__________________ was a byproduct of photosynthesis, and it began to accumulate in the atmosphere.

O2 was poisonous to many early __________________.

Organisms that could tolerate O2 evolved __________________metabolism (energy production using O2), which is more efficient than __________________ metabolism.

Organisms were able to grow larger. Aerobic metabolism is used by most living organisms today.

O2 also produced a layer of ozone (O3) in the upper atmosphere.

This layer absorbs __________________, and its formation allowed organisms to move from the ocean to __________________.

Some cells evolved membrane-enclosed compartments called __________________.

Example: The __________________contains the genetic information.

These cells are __________________.

__________________ lack nuclei and other internal compartments.

Some organelles may have originated by __________________, when larger cells engulfed smaller ones.

__________________ (site of energy generation) probably evolved from engulfed prokaryotic organisms.

__________________ (site of photosynthesis) probably evolved from photosynthetic prokaryotes.

Multicellular organisms arose about 1 billion years ago.

Cellular __________________—cells became specialized to perform certain functions.

Evolution of species:

__________________ are introduced when a genome is replicated.

Some mutations give rise to structural and functional changes in organisms, and new __________________ arise.

Each species has a distinct scientific name, a __________________:

• Genus name

• Species name

Example: Homo sapiens

Relationships in the tree of life are determined by fossil evidence, structures, metabolic processes, behavior, and molecular analyses of genomes.

Three domains of life:

• __________________ (prokaryotes)

• __________________ (prokaryotes)

• __________________ (eukaryotes)

Concept 1.2 Genetic Systems Control the Flow, Exchange,

Storage, and Use of Information

__________________—the sum total of all the information encoded by an organism’s genes

__________________ consists of repeating subunits called nucleotides.

__________________—a specific segment of DNA that contains information for making a __________________.

Proteins govern chemical reactions in cells and form much of an organism’s structure.

Concept 1.3 Organisms Interact with and Affect Their Environments

Examples of cellular work:

__________________—building new complex molecules from smaller chemical units

Movement of molecules, or the whole organism

Electrical work of information processing in __________________ systems

__________________ is the sum total of all chemical transformations and other work done in all cells of an organism.

The reactions are integrally linked—the products of one are the raw materials of the next.

In multicellular organisms, cells are specialized, or __________________.

Differentiated cells are organized into __________________.

Tissue types are organized into __________________, and __________________ are groups of organs with interrelated functions.

Multicellular organisms have an internal environment that is __________________—an extracellular environment of fluids.

__________________—maintenance of a narrow range of conditions in this internal environment

Regulatory systems maintain homeostasis in both multicellular organisms and in __________________cells.

__________________—group of individuals of the same species that interact with one another

A __________________—populations of all the species that live in the same area and interact

Communities plus their __________________environment constitute an __________________.

Individuals may compete with each other for resources, or they may __________________ (e.g., in a termite colony).

Plants also compete for light and water, and many form complex __________________with fungi, bacteria, and animals.

Concept 1.4 Evolution Explains Both the Unity and Diversity of Life

__________________is a change in genetic makeup of biological populations through time—a major unifying principle of biology.

Charles Darwin proposed that all living organisms are descended from a common __________________by the mechanism of __________________selection.

Natural selection leads to __________________—structural, physiological, or behavioral traits that enhance an organism’s chances of survival and reproduction

In science, a __________________is a body of scientific work in which rigorously tested and well-established facts and principles are used to make predictions about the natural world.

Evolutionary theory is:

(1) a body of knowledge supported by __________________

(2) the resulting understanding of mechanisms by which populations have changed and diversified over time, and continue to __________________

Evolution can be observed and measured by:

Changes in _________________composition of populations over short time frames

The _________________record—population changes over very long time frame

Concept 1.5 Science Is Based on Quantifiable Observations and Experiments

_________________is enhanced by technology: microscopes, imaging, genome sequencing, and satellites.

Observations must be _________________by measurement and mathematical and statistical calculations.

The _________________ (hypothesis–prediction (H–P) method):

Inductive logic leads to tentative explanations called _________________.

Experiments are designed to test these _________________.

_________________manipulate the _________________that is predicted to cause differences between groups.

_________________variable—the variable being manipulated

_________________variable—the response that is measured

Statistical methods help scientists determine if _________________between groups are significant.

Statistical tests start with a _________________hypothesis—that no differences exist.

Statistical methods eliminate the possibility that results are due to _________________variation.

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