Principles of life
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1. Principles of Life. Chapter 1 Principles of Life. Key Concepts 1.1 Living Organisms Share Common Aspects of Structure, Function, and Energy Flow 1.2 Genetic Systems Control the Flow, Exchange, Storage, and Use of Information 1.3 Organisms Interact with and Affect Their Environments.

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Principles of life

1

Principles of Life


Chapter 1 principles of life

Chapter 1 Principles of Life

  • Key Concepts

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

  • 1.2 Genetic Systems Control the Flow, Exchange, Storage, and Use of Information

  • 1.3 Organisms Interact with and Affect Their Environments


Chapter 1 principles of life1

Chapter 1 Principles of Life

1.4 Evolution Explains Both the Unity and Diversity of Life

1.5 Science Is Based on Quantifiable Observations and Experiments


Concept 1 1 living organisms share common aspects of structure function and energy flow

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

  • Biology—the scientific study of living things

  • “Living things”—All the diverse organisms descended from a single-celled ancestor (a single common ancestor)


Concept 1 1 living organisms share common aspects of structure function and energy flow1

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 chemical components and similar structures

• Contain genetic information that uses a nearly universal code

• Convert molecules obtained from their environment into new biological molecules

• Extract energy from the environment and use it to do biological work


Concept 1 1 living organisms share common aspects of structure function and energy flow2

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

Regulate their internal environment

• Replicate their genetic information in the same manner when reproducing

• Share sequence similarities among a fundamental set of genes

• Evolve through gradual changes in genetic information


Concept 1 1 living organisms share common aspects of structure function and energy flow3

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

Earth formed between 4.6 and 4.5 billion years ago.

It was some 600 million years or more before the earliest life evolved.


Figure 1 1 life s calendar

Figure 1.1 Life’s Calendar


Concept 1 1 living organisms share common aspects of structure function and energy flow4

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

Complex biological molecules possibly arose from random associations 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 nucleic acids


Concept 1 1 living organisms share common aspects of structure function and energy flow5

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

Biological molecules were enclosed in membranes, to form the first cells.

Fatty acids were important in forming membranes.


Concept 1 1 living organisms share common aspects of structure function and energy flow6

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

For 2 billion years, organisms were unicellular prokaryotes.

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

There was little or no O2 in the atmosphere, and hence no protective ozone (O3) layer.


Figure 1 2 the basic unit of life is the cell

Figure 1.2 The Basic Unit of Life is the Cell


Concept 1 1 living organisms share common aspects of structure function and energy flow7

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

Photosynthesis evolved about 2.7 billion years ago.

The energy of sunlight is transformed into the energy of biological molecules.

Earliest photosynthetic cells were probably similar to cyanobacteria.

O2 was a byproduct of photosynthesis, and it began to accumulate in the atmosphere.


Figure 1 3 photosynthetic organisms changed earth s atmosphere part 1

Figure 1.3 Photosynthetic Organisms Changed Earth’s Atmosphere (Part 1)


Figure 1 3 photosynthetic organisms changed earth s atmosphere part 2

Figure 1.3 Photosynthetic Organisms Changed Earth’s Atmosphere (Part 2)


Concept 1 1 living organisms share common aspects of structure function and energy flow8

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

O2 was poisonous to many early prokaryotes.

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

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


Concept 1 1 living organisms share common aspects of structure function and energy flow9

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

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

This layer absorbs UV light, and its formation allowed organisms to move from the ocean to land.


Concept 1 1 living organisms share common aspects of structure function and energy flow10

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

Some cells evolved membrane-enclosed compartments called organelles.

Example: The nucleus contains the genetic information.

These cells are eukaryotes.

Prokaryotes lack nuclei and other internal compartments.


Concept 1 1 living organisms share common aspects of structure function and energy flow11

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

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

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

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


Concept 1 1 living organisms share common aspects of structure function and energy flow12

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

Multicellular organisms arose about 1 billion years ago.

Cellular specialization—cells became specialized to perform certain functions.


Concept 1 1 living organisms share common aspects of structure function and energy flow13

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

Evolution of species:

Mutations are introduced when a genome is replicated.

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


Concept 1 1 living organisms share common aspects of structure function and energy flow14

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

Each species has a distinct scientific name, a binomial:

• Genus name

• Species name

Example: Homo sapiens


Concept 1 1 living organisms share common aspects of structure function and energy flow15

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

Evolutionary relationships of species can be determined by comparing genomes.

A phylogenetic tree documents and diagrams evolutionary relationships.


Figure 1 4 the tree of life

Figure 1.4 The Tree of Life


Concept 1 1 living organisms share common aspects of structure function and energy flow16

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

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

Three domains of life:

• Bacteria (prokaryotes)

• Archaea (prokaryotes)

• Eukarya (eukaryotes)


Concept 1 1 living organisms share common aspects of structure function and energy flow17

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

Because all life is related, discoveries made using one type of organism can be extended to other types.

Biologists use model systems for research, such as the green alga Chlorella to study photosynthesis.


Concept 1 2 genetic systems control the flow exchange storage and use of information

Concept 1.2 Genetic Systems Control the Flow, Exchange, Storage, and Use of Information

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

DNA consists of repeating subunits called nucleotides.

Gene—a specific segment of DNA that contains information for making a protein

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


Figure 1 5 dna is life s blueprint

Figure 1.5 DNA Is Life’s Blueprint


Concept 1 2 genetic systems control the flow exchange storage and use of information1

Concept 1.2 Genetic Systems Control the Flow, Exchange, Storage, and Use of Information

Mutations alter nucleotide sequences of a gene, and the protein is often altered as well.

Mutations may occur during replication, or be caused by chemicals and radiation.

Most are harmful or have no effect, but some may improve the functioning of the organism.

Mutations are the raw material of evolution.


Concept 1 2 genetic systems control the flow exchange storage and use of information2

Concept 1.2 Genetic Systems Control the Flow, Exchange, Storage, and Use of Information

Complete genome sequences have been determined for many organisms.

Genome sequences are used to study the genetic basis of everything from physical structure to inherited diseases, and evolutionary relationships.


Concept 1 3 organisms interact with and affect their environments

Concept 1.3 Organisms Interact with and Affect Their Environments

Biological systems are organized in a hierarchy.

Traditionally, biologists concentrated on one level of the hierarchy, but today much biology involves integrating investigations across many levels.


Figure 1 6 biology is studied at many levels of organization part 1

Figure 1.6 Biology Is Studied at Many Levels of Organization (Part 1)


Figure 1 6 biology is studied at many levels of organization part 2

Figure 1.6 Biology Is Studied at Many Levels of Organization (Part 2)


Concept 1 3 organisms interact with and affect their environments1

Concept 1.3 Organisms Interact with and Affect Their Environments

Living organisms acquire nutrients from their environments.

Nutrients supply energy and materials for biochemical reactions.

Some reactions break nutrient molecules into smaller units, releasing energy for work.


Concept 1 3 organisms interact with and affect their environments2

Concept 1.3 Organisms Interact with and Affect Their Environments

Examples of cellular work:

Synthesis—building new complex molecules from smaller chemical units

Movement of molecules, or the whole organism

Electrical work of information processing in nervous systems


Concept 1 3 organisms interact with and affect their environments3

Concept 1.3 Organisms Interact with and Affect Their Environments

Metabolism 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.


Concept 1 3 organisms interact with and affect their environments4

Concept 1.3 Organisms Interact with and Affect Their Environments

In multicellular organisms, cells are specialized, or differentiated.

Differentiated cells are organized into tissues.

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


Concept 1 3 organisms interact with and affect their environments5

Concept 1.3 Organisms Interact with and Affect Their Environments

Multicellular organisms have an internal environmentthat is acellular—an extracellular environment of fluids.

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

Regulatory systems maintain homeostasis in both multicellular organisms and in individual cells.


Concept 1 3 organisms interact with and affect their environments6

Concept 1.3 Organisms Interact with and Affect Their Environments

Organisms interact:

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

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

Communities plus their abiotic environment constitute an ecosystem.


Concept 1 3 organisms interact with and affect their environments7

Concept 1.3 Organisms Interact with and Affect Their Environments

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

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


Concept 1 3 organisms interact with and affect their environments8

Concept 1.3 Organisms Interact with and Affect Their Environments

Interactions of plants and animals are major evolutionary forces that produce specialized adaptations.

Species interaction with one another and with their environment is the subject of ecology.


Concept 1 4 evolution explains both the unity and diversity of life

Concept 1.4 Evolution Explains Both the Unity and Diversity of Life

Evolution 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 ancestor by the mechanism of natural selection.


Concept 1 4 evolution explains both the unity and diversity of life1

Concept 1.4 Evolution Explains Both the Unity and Diversity of Life

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


Figure 1 7 adaptations to the environment part 1

Figure 1.7 Adaptations to the Environment (Part 1)


Figure 1 7 adaptations to the environment part 2

Figure 1.7 Adaptations to the Environment (Part 2)


Figure 1 7 adaptations to the environment part 3

Figure 1.7 Adaptations to the Environment (Part 3)


Figure 1 7 adaptations to the environment part 4

Figure 1.7 Adaptations to the Environment (Part 4)


Concept 1 4 evolution explains both the unity and diversity of life2

Concept 1.4 Evolution Explains Both the Unity and Diversity of Life

In science, a theory 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 facts

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


Concept 1 4 evolution explains both the unity and diversity of life3

Concept 1.4 Evolution Explains Both the Unity and Diversity of Life

Evolution can be observed and measured by:

Changes in genetic composition of populations over short time frames

The fossil record—population changes over very long time frames


Concept 1 5 science is based on quantifiable observations and experiments

Concept 1.5 Science Is Based on Quantifiable Observations and Experiments

Scientific investigations are based on observation and experimentation.

Understanding the natural history of organisms—how they get food, reproduce, behave, regulate internal environments, and interact with other organisms—facilitates observation and leads to questions.


Concept 1 5 science is based on quantifiable observations and experiments1

Concept 1.5 Science Is Based on Quantifiable Observations and Experiments

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

Observations must be quantified by measurement and mathematical and statistical calculations.


Concept 1 5 science is based on quantifiable observations and experiments2

Concept 1.5 Science Is Based on Quantifiable Observations and Experiments

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

  • Observations

  • Questions

  • Hypotheses

  • Predictions

  • Testing


Figure 1 8 scientific methodology

Figure 1.8 Scientific Methodology


Concept 1 5 science is based on quantifiable observations and experiments3

Concept 1.5 Science Is Based on Quantifiable Observations and Experiments

Inductive logic leads to tentative explanations called hypotheses.

Deductive logic is used to make predictions.

Experiments are designed to test these predictions.


Concept 1 5 science is based on quantifiable observations and experiments4

Concept 1.5 Science Is Based on Quantifiable Observations and Experiments

Controlled experiments manipulate the variable that is predicted to cause differences between groups.

Independent variable—the variable being manipulated

Dependent variable—the response that is measured


Figure 1 9 controlled experiments manipulate a variable part 1

Figure 1.9 Controlled Experiments Manipulate a Variable (Part 1)


Figure 1 9 controlled experiments manipulate a variable part 2

Figure 1.9 Controlled Experiments Manipulate a Variable (Part 2)


Concept 1 5 science is based on quantifiable observations and experiments5

Concept 1.5 Science Is Based on Quantifiable Observations and Experiments

Comparative experiments look for differences between samples or groups.

The variables cannot be controlled; data are gathered from different sample groups and compared.


Figure 1 10 comparative experiments look for differences among groups part 1

Figure 1.10 Comparative Experiments Look for Differences among Groups (Part 1)


Figure 1 10 comparative experiments look for differences among groups part 2

Figure 1.10 Comparative Experiments Look for Differences among Groups (Part 2)


Concept 1 5 science is based on quantifiable observations and experiments6

Concept 1.5 Science Is Based on Quantifiable Observations and Experiments

Statistical methods help scientists determine if differences between groups are significant.

Statistical tests start with a null hypothesis—that no differences exists.

Statistical methods eliminate the possibility that results are due to random variation.


Concept 1 5 science is based on quantifiable observations and experiments7

Concept 1.5 Science Is Based on Quantifiable Observations and Experiments

Not all forms of inquiry into nature are scientific.

Scientific hypotheses must be testable, and have the potential of being rejected.

Science depends on evidence that comes from reproducible and quantifiable observations.


Concept 1 5 science is based on quantifiable observations and experiments8

Concept 1.5 Science Is Based on Quantifiable Observations and Experiments

Religious or spiritual explanations of natural phenomena are not testable and therefore are not science.

Science and religion are nonoverlapping approaches to inquiry.


Concept 1 5 science is based on quantifiable observations and experiments9

Concept 1.5 Science Is Based on Quantifiable Observations and Experiments

Scientific advances that may contribute to human welfare may also raise ethical questions.

Science describes how the world works; it is silent on the question of how the world “ought to be.”

Contributions from other forms of human inquiry may help us come to grips with such questions.


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