Biology Life on Earth 9th Edition Chapter 4 Review

Chapter 1: Introduction to Biological science

1.1 Themes and Concepts of Biology

By the terminate of this department, you volition be able to:

• Identify and describe the backdrop of life
• Draw the levels of organization among living things
• List examples of dissimilar sub disciplines in biology

Watch a video near Evolution past Natural Selection.

Biology is the science that studies life. What exactly is life? This may sound like a silly question with an obvious respond, but information technology is not like shooting fish in a barrel to define life. For example, a branch of biology chosen virology studies viruses, which exhibit some of the characteristics of living entities but lack others. It turns out that although viruses tin can assail living organisms, cause diseases, and even reproduce, they practice not see the criteria that biologists use to define life.

From its earliest beginnings, biology has wrestled with four questions: What are the shared backdrop that make something "live"? How do those various living things role? When faced with the remarkable diverseness of life, how practise we organize the dissimilar kinds of organisms so that we tin better empathize them? And, finally—what biologists ultimately seek to empathize—how did this multifariousness arise and how is it continuing? As new organisms are discovered every twenty-four hour period, biologists go on to seek answers to these and other questions.

Properties of Life

All groups of living organisms share multiple central characteristics or functions: order, sensitivity or response to stimuli, reproduction, adaptation, growth and evolution, regulation, homeostasis, and free energy processing. When viewed together, these eight characteristics serve to define life.

Society

Organisms are highly organized structures that consist of one or more cells. Fifty-fifty very unproblematic, single-celled organisms are remarkably complex. Within each jail cell, atoms brand up molecules. These in plough make upwardly cell components or organelles. Multicellular organisms, which may consist of millions of individual cells, have an advantage over single-celled organisms in that their cells can be specialized to perform specific functions, and fifty-fifty sacrificed in certain situations for the proficient of the organism every bit a whole. How these specialized cells come together to course organs such as the heart, lung, or skin in organisms like the toad shown in Figure 1. 2 volition be discussed afterwards.

Figure 1.2 A toad represents a highly organized structure consisting of cells, tissues, organs, and organ systems.

Sensitivity or Response to Stimuli

Organisms reply to various stimuli. For instance, plants can bend toward a source of light or respond to touch. Even tiny bacteria tin can motility toward or away from chemicals (a process called chemotaxis) or low-cal (phototaxis). Motility toward a stimulus is considered a positive response, while movement away from a stimulus is considered a negative response.

 

Figure one.3 The leaves of this sensitive establish (Mimosa pudica) will instantly droop and fold when touched. After a few minutes, the plant returns to its normal state.

Concept in Activeness

Sentry this video to encounter how the sensitive establish responds to a touch stimulus.

Reproduction

Single-celled organisms reproduce by first duplicating their Deoxyribonucleic acid, which is the genetic fabric, and and then dividing information technology every bit as the cell prepares to divide to course two new cells. Many multicellular organisms (those fabricated up of more than one cell) produce specialized reproductive cells that volition form new individuals. When reproduction occurs, DNA containing genes is passed forth to an organism's offspring. These genes are the reason that the offspring will belong to the same species and volition accept characteristics like to the parent, such as fur colour and blood blazon.

Adaptation

All living organisms exhibit a "fit" to their environment. Biologists refer to this fit as adaptation and it is a result of development by natural selection, which operates in every lineage of reproducing organisms. Examples of adaptations are various and unique, from oestrus-resistant Archaea that live in boiling hot springs to the tongue length of a nectar-feeding moth that matches the size of the flower from which information technology feeds. All adaptations raise the reproductive potential of the individual exhibiting them, including their ability to survive to reproduce. Adaptations are non constant. As an surroundings changes, natural selection causes the characteristics of the individuals in a population to track those changes.

Growth and Evolution

Organisms grow and develop according to specific instructions coded for past their genes. These genes provide instructions that will straight cellular growth and development, ensuring that a species' young volition grow upwardly to exhibit many of the same characteristics as its parents.

Figure one.4 Although no two look alike, these kittens have inherited genes from both parents and share many of the same characteristics.

Regulation

Even the smallest organisms are complex and crave multiple regulatory mechanisms to coordinate internal functions, such equally the transport of nutrients, response to stimuli, and coping with ecology stresses. For instance, organ systems such as the digestive or circulatory systems perform specific functions like carrying oxygen throughout the body, removing wastes, delivering nutrients to every prison cell, and cooling the torso.

Homeostasis

To function properly, cells require appropriate conditions such as proper temperature, pH, and concentrations of diverse chemicals. These conditions may, however, modify from one moment to the next. Organisms are able to maintain internal atmospheric condition within a narrow range almost constantly, despite environmental changes, through a process called homeostasis or "steady state"—the ability of an organism to maintain abiding internal weather. For case, many organisms regulate their body temperature in a procedure known equally thermoregulation. Organisms that live in cold climates, such as the polar bear, have body structures that help them withstand low temperatures and conserve body oestrus. In hot climates, organisms have methods (such equally perspiration in humans or panting in dogs) that assistance them to shed excess trunk estrus.

Effigy one.5 Polar bears and other mammals living in ice-covered regions maintain their torso temperature by generating heat and reducing heat loss through thick fur and a dumbo layer of fat under their skin.

Energy Processing

All organisms (such as the California condor shown in Effigy one.six) apply a source of energy for their metabolic activities. Some organisms capture energy from the sun and convert it into chemic energy in food; others use chemical free energy from molecules they take in.

Figure 1.half-dozen A lot of energy is required for a California condor to fly. Chemic energy derived from food is used to ability flying. California condors are an endangered species; scientists have strived to place a wing tag on each bird to help them identify and locate each individual bird.

Levels of Organization of Living Things

Living things are highly organized and structured, following a bureaucracy on a scale from small to large. The atom is the smallest and most cardinal unit of matter. Information technology consists of a nucleus surrounded by electrons. Atoms course molecules. A molecule is a chemic structure consisting of at to the lowest degree two atoms held together by a chemic bond. Many molecules that are biologically important are macromolecules, big molecules that are typically formed by combining smaller units called monomers. An example of a macromolecule is deoxyribonucleic acid (DNA), which contains the instructions for the functioning of the organism that contains it.

Figure one.7 A molecule, like this large Deoxyribonucleic acid molecule, is composed of atoms.

Concept in Action

To run across an animation of this DNA molecule, click here.

Some cells contain aggregates of macromolecules surrounded by membranes; these are called organelles. Organelles are small-scale structures that exist inside cells and perform specialized functions. All living things are fabricated of cells; the cell itself is the smallest fundamental unit of construction and function in living organisms. (This requirement is why viruses are not considered living: they are not made of cells. To make new viruses, they take to invade and hijack a living prison cell; just then can they obtain the materials they need to reproduce.) Some organisms consist of a unmarried prison cell and others are multicellular. Cells are classified as prokaryotic or eukaryotic. Prokaryotes are single-celled organisms that lack organelles surrounded by a membrane and do not have nuclei surrounded by nuclear membranes; in contrast, the cells of eukaryotes practise take membrane-bound organelles and nuclei.

In nearly multicellular organisms, cells combine to make tissues, which are groups of similar cells carrying out the same function. Organs are collections of tissues grouped together based on a common function. Organs are present not only in animals merely also in plants. An organ organization is a college level of arrangement that consists of functionally related organs. For example vertebrate animals take many organ systems, such as the circulatory arrangement that transports claret throughout the body and to and from the lungs; it includes organs such equally the heart and blood vessels. Organisms are individual living entities. For case, each tree in a wood is an organism. Unmarried-celled prokaryotes and single-celled eukaryotes are besides considered organisms and are typically referred to as microorganisms.

Effigy 1.viii From an atom to the entire Globe, biological science examines all aspects of life.

Which of the post-obit statements is fake?

1. Tissues exist within organs which exist within organ systems.
2. Communities be within populations which exist within ecosystems.
3. Organelles be within cells which exist within tissues.
4. Communities exist within ecosystems which exist in the biosphere.

All the individuals of a species living within a specific area are collectively called a population. For case, a forest may include many white pine trees. All of these pino trees correspond the population of white pine trees in this forest. Different populations may live in the same specific area. For instance, the forest with the pine copse includes populations of flowering plants and likewise insects and microbial populations. A customs is the prepare of populations inhabiting a particular area. For instance, all of the trees, flowers, insects, and other populations in a woods form the forest'south customs. The forest itself is an ecosystem. An ecosystem consists of all the living things in a particular area together with the abiotic, or non-living, parts of that environs such every bit nitrogen in the soil or rainwater. At the highest level of organization, the biosphere is the drove of all ecosystems, and it represents the zones of life on Earth. Information technology includes land, water, and portions of the atmosphere.

The Variety of Life

The science of biology is very broad in scope because at that place is a tremendous diversity of life on Earth. The source of this diversity is evolution, the process of gradual alter during which new species arise from older species. Evolutionary biologists study the development of living things in everything from the microscopic world to ecosystems.

In the 18th century, a scientist named Carl Linnaeus get-go proposed organizing the known species of organisms into a hierarchical taxonomy. In this organisation, species that are most similar to each other are put together within a grouping known every bit a genus. Furthermore, similar genera (the plural of genus) are put together within a family unit. This grouping continues until all organisms are collected together into groups at the highest level. The current taxonomic organisation now has 8 levels in its hierarchy, from everyman to highest, they are: species, genus, family, order, form, phylum, kingdom, and domain. Thus species are grouped inside genera, genera are grouped within families, families are grouped inside orders, and and so on.

Figure 1.9 This diagram shows the levels of taxonomic hierarchy for a dog, from the broadest category—domain—to the virtually specific—species.

The highest level, domain, is a relatively new addition to the system since the 1990s. Scientists now recognize three domains of life, the Eukarya, the Archaea, and the Bacteria. The domain Eukarya contains organisms that accept cells with nuclei. It includes the kingdoms of fungi, plants, animals, and several kingdoms of protists. The Archaea, are single-celled organisms without nuclei and include many extremophiles that alive in harsh environments like hot springs. The Bacteria are another quite different group of unmarried-celled organisms without nuclei. Both the Archaea and the Leaner are prokaryotes, an informal name for cells without nuclei. The recognition in the 1990s that certain "leaner," now known as the Archaea, were as different genetically and biochemically from other bacterial cells as they were from eukaryotes, motivated the recommendation to divide life into iii domains. This dramatic change in our knowledge of the tree of life demonstrates that classifications are not permanent and will modify when new information becomes available.

In addition to the hierarchical taxonomic system, Linnaeus was the first to name organisms using two unique names, now chosen the binomial naming system. Before Linnaeus, the use of mutual names to refer to organisms caused defoliation because in that location were regional differences in these mutual names. Binomial names consist of the genus name (which is capitalized) and the species name (all lower-example). Both names are set in italics when they are printed. Every species is given a unique binomial which is recognized the world over, and then that a scientist in any location can know which organism is existence referred to. For case, the North American bluish jay is known uniquely as Cyanocitta cristata. Our own species is Homo sapiens.

Effigy 1.10 These images represent dissimilar domains. The scanning electron micrograph shows (a) bacterial cells vest to the domain Bacteria, while the (b) extremophiles, seen all together as colored mats in this hot bound, vest to domain Archaea. Both the (c) sunflower and (d) lion are part of domain Eukarya.

Evolution in Action

Carl Woese and the Phylogenetic Tree

The evolutionary relationships of diverse life forms on Earth tin can be summarized in a phylogenetic tree. A phylogenetic tree is a diagram showing the evolutionary relationships among biological species based on similarities and differences in genetic or physical traits or both. A phylogenetic tree is equanimous of branch points, or nodes, and branches. The internal nodes represent ancestors and are points in evolution when, based on scientific bear witness, an antecedent is idea to take diverged to form two new species. The length of each co-operative tin be considered as estimates of relative fourth dimension.

In the past, biologists grouped living organisms into five kingdoms: animals, plants, fungi, protists, and bacteria. The pioneering work of American microbiologist Carl Woese in the early 1970s has shown, however, that life on Globe has evolved along three lineages, now called domains—Leaner, Archaea, and Eukarya. Woese proposed the domain as a new taxonomic level and Archaea as a new domain, to reflect the new phylogenetic tree. Many organisms belonging to the Archaea domain alive under extreme conditions and are called extremophiles. To construct his tree, Woese used genetic relationships rather than similarities based on morphology (shape). Various genes were used in phylogenetic studies. Woese's tree was synthetic from comparative sequencing of the genes that are universally distributed, institute in some slightly altered form in every organism, conserved (meaning that these genes have remained merely slightly changed throughout development), and of an appropriate length.

Figure 1.11 This phylogenetic tree was constructed by microbiologist Carl Woese using genetic relationships. The tree shows the separation of living organisms into 3 domains: Bacteria, Archaea, and Eukarya. Bacteria and Archaea are organisms without a nucleus or other organelles surrounded by a membrane and, therefore, are prokaryotes.

Branches of Biological Written report

Watch a video about Scientific discipline and Medicine

The scope of biology is broad and therefore contains many branches and sub disciplines. Biologists may pursue i of those sub disciplines and work in a more than focused field. For instance, molecular biology studies biological processes at the molecular level, including interactions amidst molecules such equally DNA, RNA, and proteins, too every bit the way they are regulated. Microbiology is the study of the structure and part of microorganisms. It is quite a broad branch itself, and depending on the subject area of study, there are besides microbial physiologists, ecologists, and geneticists, among others.

Another field of biological study, neurobiology, studies the biology of the nervous system, and although it is considered a branch of biology, it is also recognized as an interdisciplinary field of study known as neuroscience. Because of its interdisciplinary nature, this sub discipline studies different functions of the nervous organisation using molecular, cellular, developmental, medical, and computational approaches.

Effigy 1.12 Researchers work on excavating dinosaur fossils at a site in Castellón, Spain.

Paleontology, another branch of biology, uses fossils to written report life's history. Zoology and botany are the study of animals and plants, respectively. Biologists can also specialize as biotechnologists, ecologists, or physiologists, to name just a few areas. Biotechnologists apply the knowledge of biology to create useful products. Ecologists study the interactions of organisms in their environments. Physiologists written report the workings of cells, tissues and organs. This is just a pocket-size sample of the many fields that biologists can pursue. From our ain bodies to the world we alive in, discoveries in biology can affect us in very directly and important ways. Nosotros depend on these discoveries for our health, our food sources, and the benefits provided past our ecosystem. Because of this, noesis of biological science can benefit us in making decisions in our day-to-day lives.

The development of technology in the twentieth century that continues today, particularly the technology to describe and manipulate the genetic textile, Dna, has transformed biological science. This transformation will allow biologists to go along to understand the history of life in greater detail, how the human torso works, our human origins, and how humans can survive every bit a species on this planet despite the stresses caused by our increasing numbers. Biologists keep to decipher huge mysteries about life suggesting that we take simply begun to understand life on the planet, its history, and our relationship to it. For this and other reasons, the knowledge of biology gained through this textbook and other printed and electronic media should exist a benefit in whichever field you enter.

Forensic Scientist

Forensic scientific discipline is the application of science to reply questions related to the law. Biologists as well every bit chemists and biochemists can be forensic scientists. Forensic scientists provide scientific evidence for utilize in courts, and their job involves examining trace material associated with crimes. Interest in forensic science has increased in the last few years, mayhap considering of pop television set shows that feature forensic scientists on the job. Also, the development of molecular techniques and the establishment of DNA databases take updated the types of piece of work that forensic scientists can do. Their chore activities are primarily related to crimes against people such as murder, rape, and assail. Their work involves analyzing samples such equally hair, blood, and other body fluids and also processing Deoxyribonucleic acid found in many different environments and materials. Forensic scientists also analyze other biological testify left at crime scenes, such as insect parts or pollen grains. Students who desire to pursue careers in forensic science will near likely be required to take chemistry and biology courses likewise as some intensive math courses.

Figure 1.13 This forensic scientist works in a DNA extraction room at the U.S. Army Criminal Investigation Laboratory.

Section Summary

Biological science is the science of life. All living organisms share several key properties such as gild, sensitivity or response to stimuli, reproduction, adaptation, growth and development, regulation, homeostasis, and energy processing. Living things are highly organized following a hierarchy that includes atoms, molecules, organelles, cells, tissues, organs, and organ systems. Organisms, in plow, are grouped every bit populations, communities, ecosystems, and the biosphere. Development is the source of the tremendous biological diversity on Earth today. A diagram chosen a phylogenetic tree tin can be used to bear witness evolutionary relationships among organisms. Biological science is very broad and includes many branches and sub disciplines. Examples include molecular biology, microbiology, neurobiology, zoology, and botany, among others.

atom: a bones unit of measurement of matter that cannot exist broken downwards by normal chemical reactions

biology: the study of living organisms and their interactions with one another and their environments

biosphere: a collection of all ecosystems on Earth

prison cell: the smallest fundamental unit of structure and function in living things

customs: a gear up of populations inhabiting a particular area

ecosystem: all living things in a particular area together with the abiotic, nonliving parts of that environment

eukaryote: an organism with cells that accept nuclei and membrane-bound organelles

evolution: the process of gradual change in a population that can also lead to new species arising from older species

homeostasis: the ability of an organism to maintain abiding internal conditions

macromolecule: a big molecule typically formed by the joining of smaller molecules

molecule: a chemical structure consisting of at least two atoms held together by a chemical bond

organ: a structure formed of tissues operating together to perform a common function

organ system: the higher level of organization that consists of functionally related organs

organelle: a membrane-bound compartment or sac within a cell

organism: an individual living entity

phylogenetic tree: a diagram showing the evolutionary relationships amidst biological species based on similarities and differences in genetic or physical traits or both

population: all individuals within a species living within a specific surface area

prokaryote: a unicellular organism that lacks a nucleus or any other membrane-spring organelle

tissue: a group of like cells carrying out the same office

Media Attribution

• Figure one.2 by Ivengo(RUS) © Public Domain
• Figure ane.3 by Alex Lomas © CC Past (Attribution)
• Figure 1.four by Pieter & Renée Lanser © CC BY (Attribution)
• Effigy 1.5 by David © CC Past (Attribution)
• Figure 1.6 by Pacific Southwest Region USFWS © CC BY (Attribution)
• Figure 1.seven by Brian0918 © Public Domain
• Figure 1.8
  • "molecule": modification of piece of work by Jane Whitney;
  • "organelles": modification of work by Louisa Howard;
  • "cells": modification of work by Bruce Wetzel, Harry Schaefer, National Cancer Institute;
  • "tissue": modification of work past "Kilbad" © Public Domain
  • "organs": modification of work by Mariana Ruiz Villareal, Joaquim Alves Gaspar;
  • "organisms": modification of piece of work by Peter Dutton;
  • "ecosystem": modification of work by "gigi4791″ © CC Past (Attribution)
  • "biosphere": modification of work by NASA © Public Domain
• Effigy 1.10
  • EscherichiaColi NIAID: modification of work past Rocky Mountain Laboratories, NIAID, NIH © Public Domain
  • Extremophiles modification of piece of work by Steve Jurvetson © CC BY (Attribution)
  • Sunflower modification of work by Michael Arrighi
  • Panthera leo modification of piece of work by Frank Vassen  © CC BY (Attribution)
• Figure 1.12 by Mario Modesto © Public Domain
• Effigy one.13 by U.S. Army CID Command Public Affairs

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