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Results The response rate among the patients who received high-dose therapy was 81 percent (including complete responses in 22 percent and very good partial responses in 16 percent), whereas it was 57 percent (complete responses in 5 percent and very good partial responses in 9 percent) in the group treated with conventional chemotherapy (P. Criteria for Enrollment Patients less than 65 years of age who had Durie–Salmon stage II or III myeloma were eligible for the study.

The criteria for exclusion were prior treatment for myeloma, another type of cancer, abnormal cardiac function (systolic ejection fraction 2.0 mg per deciliter [>35 μmol per liter]; or serum aminotransferase values more than four times the normal value), and psychiatric disease. Between October 1990 and May 1993, 204 patients from 32 French centers and 1 Belgian center were enrolled. Four patients were excluded, two each because of age over 65 years and violations of the study protocol (the use of allogeneic transplantation to improve a first response).

Two hundred patients in all were evaluated. The study was approved by the institutional ethics committees, and the patients gave informed consent. Conventional-Dose Chemotherapy The protocol consisted of alternating cycles of combinations of chemotherapeutic agents, known as VMCP and BVAP. The VMCP regimen included vincristine (1 mg intravenously on day 1), melphalan (5 mg per square meter of body-surface area orally on days 1 to 4), cyclophosphamide (110 mg per square meter orally on days 1 to 4), and prednisone (60 mg per square meter orally on days 1 to 4).

The BVAP regimen included vincristine (1 mg intravenously on day 1), carmustine (30 mg per square meter intravenously on day 1), doxorubicin (30 mg per square meter intravenously on day 1), and prednisone (60 mg per square meter orally on days 1 to 4). These alternating cycles of VMCP and BVAP were administered at 3-week intervals for 12 months, for a total of 18 cycles. Recombinant interferon alfa was administered three times a week in a dose of 3 million U per square meter from cycle 9 until the occurrence of any relapse. Criteria for a Response A complete remission was defined as the absence of a paraprotein on electrophoresis of serum and urine and 5 percent or fewer plasma cells with normal morphologic features in a bone marrow aspirate (the absence of paraprotein was not confirmed in all cases by immunofixation). A return of normal immunoglobulins was not included in the definition. Statistical Analysis The proportions of patients with a given characteristic were compared by the chi-square test or by Fisher's exact test.

Differences in the means of continuous measurements were tested by Student's t-test and checked by the Mann–Whitney U test. All tests were two-tailed. The duration of event-free survival was calculated for all patients from the date of randomization until the time of progression of disease, relapse, death, or the date the patient was last known to be in remission. Curves for event-free survival and overall survival were plotted according to the method of Kaplan and Meier and were compared by the log-rank test.

Prognostic factors for overall survival and event-free survival were determined by the Cox proportional-hazards model in the analysis of covariates. The following variables were included in the univariate analysis: age, Durie–Salmon stage, the isotype of the monoclonal (M) component, beta 2-microglobulin level, bone marrow plasmacytosis, and treatment group.

The objective was to compare the two treatment groups with respect to survival. The random assignment of at least 100 patients to each treatment group was needed to ensure a 5 percent level of significance and a power of 80 percent if the true probabilities of survival five years after diagnosis were 10 percent in the conventional-dose group and 50 percent in the high-dose (and transplantation) group.

The study was completed after 200 patients were enrolled. All randomized patients were studied in their assigned treatment groups on an intention-to-treat basis. Completion of Assigned Therapy The patients enrolled in the conventional-dose group received a median of 18 cycles (range, 2 to 18) of VMCP and BVAP. Seventy-four patients enrolled in the high-dose group underwent transplantation.

The median time from diagnosis to transplantation was 5.5 months (range, 4 to 11). Among the 26 patients who did not undergo transplantation, 5 died prematurely, 6 had poor performance status, 5 had abnormal renal function, and 10 had insufficient amounts of bone marrow in the sample collected. These exclusions were related to the age of the patients, since 12 of 67 patients 60 years of age or less (18 percent) did not undergo transplantation, as compared with 14 of 33 patients over 60 years of age (42 percent, P = 0.01). One hundred forty-three patients received interferon alfa (73 in the conventional-dose group and 70 in the high-dose group). Interferon alfa was introduced sooner after diagnosis in the conventional-dose group than in the high-dose group (mean [±SD] number of months before treatment, 8±2.8 vs.

10±3.2; P = 0.01). Eighty-six patients (43 in each group) had to discontinue this treatment (9 because of thrombocytopenia and 77 because of relapse).

Interferon alfa was administered for a median of 12 months in the conventional-dose group and 11 months in the high-dose group. Response Rate Before transplantation (i.e., after four cycles of chemotherapy), the response rate was similar in the two treatment groups.

As compared with conventional chemotherapy, high-dose therapy with transplantation improved the response rate (P. Event-Free and Overall Survival In the conventional-dose group, treated with chemotherapy only, the median follow-up of the surviving patients was 37 months (range, 26 to 60; standard deviation, 8) from the time of randomization. The median event-free survival was 18 months, and the median overall survival 37.4 months. The probabilities of event-free survival and overall survival for five years after the diagnosis were 10 percent and 12 percent, respectively ( Figure 1 Event-free Survival According to Treatment Group. The numbers shown below the time points are probabilities of event-free survival (the percentages of patients surviving event-free) and 95 percent confidence intervals. And Figure 2 Overall Survival According to Treatment Group.

The numbers shown below the time points are probabilities of overall survival (the percentages of patients surviving) and 95 percent confidence intervals. Fifty-two patients died, 47 because of the progression of disease and 5 because of the toxic effects of treatment. In the high-dose group, treated with four cycles of chemotherapy and transplantation, the median follow-up of the surviving patients was 41 months (range, 22 to 60; standard deviation, 11) from the time of randomization. The median event-free survival was 27 months, and the median survival has not been reached as of this writing. The probabilities of event-free survival and overall survival for five years after the diagnosis were 28 percent and 52 percent, respectively ( and ). Edius After Effects Filter Plug In Bridge Download Free here. The high-dose group had significantly longer event-free (P =0.01) and overall (P = 0.03) survival than the conventional-dose group ( and ).

Thirty-seven patients in the high-dose group died, 30 because of the progression of disease and 7 because of the toxic effects of treatment (including 2 transplantation-related deaths). Prognostic Factors for Event-Free and Overall Survival In the multivariate analysis of all 200 patients, event-free survival was significantly related to the level of beta 2-microglobulin in serum (P. The High-Dose Group Seventy-four patients in the high-dose group underwent transplantation. The median proportion of plasma cells in the bone marrow graft was 9 percent (range, 0 to 50 percent; standard deviation, 14). The median duration of neutropenia (. Salvage Therapy In the conventional-dose group, 50 patients relapsed.

Five patients received no salvage therapy, 36 received either the VAD regimen (a continuous intravenous infusion of 0.4 mg of vincristine per square meter and 9 mg of doxorubicin per square meter over a 24-hour period for four days, with 40 mg of oral dexamethasone per day on days 1 through 4) or another regimen of conventional chemotherapy, and 9 received high-dose therapy (140 mg of melphalan per square meter, with or without total-body irradiation) supported by autologous hematopoietic stem cells. With a median follow-up among the surviving patients of 11 months from the time of relapse, the probability of survival for two years after relapse was 25 percent in the conventional-dose group (95 percent confidence interval, 12 to 44 percent). In the high-dose group, 46 patients relapsed. Five patients received no salvage therapy, 33 received the VAD regimen or another form of conventional chemotherapy, and 8 received high-dose melphalan (140 mg per square meter) supported by autologous hematopoietic stem cells. With a median follow-up among the surviving patients of 15 months from the time of relapse, the probability of survival for two years after relapse was 35 percent in the high-dose group (95 percent confidence interval, 18 to 57 percent), a proportion not significantly different from that in the conventional-dose group.

Discussion Alkylating agents and prednisone have been the standard therapy for myeloma for the past three decades. The rates of response to this treatment range from 40 to 60 percent, but the median duration of survival does not exceed three years.

The combination of alkylating agents with vincristine and doxorubicin has not had better results than therapy with melphalan and prednisone. The value of maintenance treatment with interferon alfa in prolonging the response and survival has been assessed in randomized trials, which found that the effect of interferon alfa on survival, if any, is marginal. In our trial, there was a response rate of 57 percent and a median survival of three years in the conventional-therapy group despite the combined use of VMCP, BVAP, and interferon alfa. High-dose therapy has been reported to improve survival in myeloma when given to patients with newly diagnosed disease.

These results are difficult to assess because the recruitment of patients for transplantation is subject to a selection bias with regard to age, performance status, and renal function. Our trial, which was designed to avoid these sources of bias, demonstrates that high-dose therapy improves both event-free and overall survival. The probability of event-free survival for five years after the diagnosis was 12 percent in the conventional-dose group and 28 percent in the group treated with high-dose therapy and transplantation (P = 0.01). Survival in these two groups was 12 percent and 52 percent, respectively (P =0.03). A study by the Southwest Oncology Group comparing high-dose therapy with conventional chemotherapy confirms our results. The data in that study justify the further development of high-dose therapy programs.

The optimal timing of these treatments remains to be determined. In our trial, transplantation was performed as part of the initial therapy. Whether delayed transplantation, given at the time of a progression of disease, would have similar results will be clarified in ongoing trials. An objective of our trial was to evaluate the feasibility and toxic effects of transplantation.

Twenty-six percent of patients assigned to this treatment could not receive it. The most common reasons were poor performance status and insufficient bone marrow collection, due to the poor response rate observed after the initial regimen of VMCP and BVAP. Initial chemotherapy with a regimen such as VAD, which can induce responses in 70 to 80 percent of patients after two to three cycles, could lower the exclusion rate. The risk of life-threatening toxic effects in the high-dose group was a major concern, but transplant-related deaths occurred in only 2 of the 74 patients. The rate of death from toxic effects was similar in both groups. Hematopoietic growth factors, reported to improve the recovery of neutrophils after transplantation, were not administered in our trial.

The duration of severe marrow aplasia may be shorter in patients given peripheral-blood stem cells than in those supported with autologous marrow. We are evaluating this possibility. In our trial the probability of event-free survival for five years after the diagnosis was only 28 percent among the patients in the high-dose group. Strategies to improve these results are warranted. Our results demonstrate that a complete response is the most important prognostic factor for survival.

It is plausible that a high rate of complete response may be attained with more aggressive therapy. The absence of a plateau in the curve for event-free survival among our patients justifies the development of new strategies to control any residual disease after transplantation. Interleukin-2, interleukin-4, retinoids, B-cell–directed immunotoxins, and vaccination with idiotypes are being investigated. References • 1 Sporn JR, McIntyre OR. Chemotherapy of previously untreated multiple myeloma patients: an analysis of recent treatment results. Semin Oncol 1986;13:318-325 • 2 Bergsagel DE.

Is aggressive chemotherapy more effective in the treatment of plasma cell myeloma? Eur J Cancer Clin Oncol 1989;25:159-161 • 3 McElwain TJ, Powles RL. High-dose intravenous melphalan for plasma-cell leukaemia and myeloma. Lancet 1983;2:822-824 • 4 Selby PJ, McElwain TJ, Nandi AC, et al. Multiple myeloma treated with high dose intravenous melphalan. Br J Haematol 1987;66:55-62 • 5 Barlogie B, Alexanian R, Dicke KA, et al. High-dose chemoradiotherapy and autologous bone marrow transplantation for resistant multiple myeloma.

Blood 1987;70:869-872 • 6 Barlogie B, Hall R, Zander A, Dicke K, Alexanian R. High-dose melphalan with autologous bone marrow transplantation for multiple myeloma. Blood 19-1301 • 7 Barlogie B, Gahrton G. Bone marrow transplantation in multiple myeloma. Bone Marrow Transplant 1991;7:71-79 • 8 Gore ME, Selby PJ, Viner C, et al. Intensive treatment of multiple myeloma and criteria for complete remission. Lancet 1989;2:879-882 • 9 Jagannath S, Barlogie B, Dicke K, et al.

Autologous bone marrow transplantation in multiple myeloma: identification of prognostic factors. Blood 19-1866 • 10 Attal M, Huguet F, Schlaifer D, et al. Intensive combined therapy for previously untreated aggressive myeloma. Blood 19-1136 • 11 Harousseau JL, Milpied N, Laporte JP, et al.

Double-intensive therapy in high-risk multiple myeloma. Blood 19-2833 • 12 Lokhorst HM, Meuwissen OJ, Verdonck LF, Dekker AW. High-risk multiple myeloma treated with high-dose melphalan. J Clin Oncol 1992;10:47-51 • 13 Anderson KC, Barut BA, Ritz J, et al. Monoclonal antibody-purged autologous bone marrow transplantation therapy for multiple myeloma. Blood 1991;77:712-720 • 14 Reece DE, Barnett MJ, Connors JM, et al.

Treatment of multiple myeloma with intensive chemotherapy followed by autologous BMT using marrow purged with 4-hydroperoxycyclophosphamide. Bone Marrow Transplant 1993;11:139-146 • 15 Fermand JP, Chevret S, Ravaud P, et al. High-dose chemoradiotherapy and autologous blood stem cell transplantation in multiple myeloma: results of a phase II trial involving 63 patients. Blood 19-2009 • 16 Reiffers J, Marit G, Boiron JM. Autologous blood stem cell transplantation in high-risk multiple myeloma.

Br J Haematol 1989;72:296-297 • 17 Gianni AM, Tarella C, Bregni M, et al. High-dose sequential chemoradiotherapy, a widely applicable regimen, confers survival benefit to patients with high-risk multiple myeloma. J Clin Oncol 1994;12:503-509 • 18 Cunningham D, Paz-Ares L, Gore ME, et al. High-dose melphalan for multiple myeloma: long-term follow-up data.

J Clin Oncol 1994;12:764-768 • 19 Cunningham D, Paz-Ares L, Milan S, et al. High-dose melphalan and autologous bone marrow transplantation as consolidation in previously untreated myeloma.

J Clin Oncol 1994;12:759-763 • 20 Vesole DH, Barlogie B, Jagannath S, et al. High-dose therapy for refractory multiple myeloma: improved prognosis with better supportive care and double transplants. Blood 1994;84:950-956 • 21 Bjorkstrand B, Ljungman P, Bird JM.

For other uses, see. Biology deals with the study of the many living. • top: bacteria and • bottom: and Biology is the that involves the study of and living, including their physical and,, and. Modern biology is a vast field, composed of many. Despite the broad scope and the complexity of the science, there are certain unifying concepts that consolidate it into a single, coherent field. In general, biology recognizes the as the basic unit of life, as the basic unit of, and as the engine that propels the creation of new. It is also understood that all organisms survive by consuming and transforming and by their internal environment.

Sub-disciplines of biology are defined by the scale at which life is studied, the kinds of organisms studied, and the methods used to study them: examines the rudimentary chemistry of life; studies the complex interactions among biological; examines the basic building-block of all life, the; examines the physical and chemical functions of,, and; examines how organisms interact in their; and examines the processes that produced the diversity of life. Main article: Cell theory states that the is the fundamental unit of, that all living things are composed of one or more cells, and that all cells arise from other cells through. In, every cell in the organism's body derives ultimately from a single cell in a fertilized. The cell is also considered to be the basic unit in many pathological processes. In addition, the phenomenon of occurs in cells in processes that are part of the function known as. Finally, cells contain hereditary information (), which is passed from cell to cell during cell division. Research into the origin of life,, amounts to an attempt to discover the origin of the first cells.

Main article: A central organizing concept in biology is that life changes and develops through evolution, and that all life-forms known have a. The theory of evolution postulates that all on the, both living and extinct, have descended from a common ancestor or an ancestral. This is believed to have appeared about. Biologists regard the ubiquity of the as definitive evidence in favor of the theory of universal common descent for all,, and (see: ). The term 'evolution' was introduced into the scientific lexicon by in 1809, and fifty years later posited a scientific model of natural selection as evolution's driving force.

( is recognized as the co-discoverer of this concept as he helped research and experiment with the concept of evolution.) Evolution is now used to explain the great variations of life found on Earth. Darwin theorized that species flourish or die when subjected to the processes of. Was embraced as an additional mechanism of evolutionary development in the of the theory. The evolutionary history of the —which describes the characteristics of the various species from which it descended—together with its genealogical relationship to every other species is known as its. Widely varied approaches to biology generate information about phylogeny.

These include the comparisons of, a product of (more particularly ), and comparisons of or other records of ancient organisms, a product of. Biologists organize and analyze evolutionary relationships through various methods, including,, and. (For a summary of major events in the evolution of life as currently understood by biologists, see.) Evolution is relevant to the understanding of the natural history of life forms and to the understanding of the organization of current life forms. But, those organizations can only be understood in the light of how they came to be by way of the process of evolution. Consequently, evolution is central to all fields of biology.

Main article: are the primary units of inheritance in all organisms. A gene is a unit of and corresponds to a region of that influences the form or function of an organism in specific ways. All organisms, from bacteria to animals, share the same basic machinery that copies and translates DNA into. Cells a DNA gene into an version of the gene, and a then the RNA into a sequence of known as a protein. The from RNA codon to amino acid is the same for most organisms.

For example, a sequence of DNA that codes for in humans also codes for insulin when inserted into other organisms, such as plants. DNA is found as linear in, and circular chromosomes in. A chromosome is an organized structure consisting of and. The set of chromosomes in a cell and any other hereditary information found in the,, or other locations is collectively known as a cell's.

Download Vidio Drag Rx King. In eukaryotes, genomic DNA is localized in the, or with small amounts in and. In prokaryotes, the DNA is held within an irregularly shaped body in the cytoplasm called the.

The genetic information in a genome is held within genes, and the complete assemblage of this information in an organism is called its. The secretes, which directs the to secrete. In turn, ACTH directs the adrenal cortex to secrete, such as. The GCs then reduce the rate of secretion by the hypothalamus and the pituitary gland once a sufficient amount of GCs has been released. Homeostasis is the ability of an to regulate its internal environment to maintain stable conditions by means of multiple adjustments that are controlled by interrelated regulation mechanisms.

All living, whether or, exhibit homeostasis. To maintain dynamic equilibrium and effectively carry out certain functions, a system must detect and respond to perturbations. After the detection of a perturbation, a biological system normally responds through that stabilize conditions by reducing or increasing the activity of an organ or system. One example is the release of when sugar levels are too low.

Basic overview of. Energy The survival of a living organism depends on the continuous input of. Chemical reactions that are responsible for its structure and function are tuned to extract from substances that act as its food and transform them to help form new cells and sustain them. In this process, of that constitute play two roles; first, they contain energy that can be transformed and reused in that organism's biological,; second, food can be transformed into new molecular structures (biomolecules) that are of use to that organism.

The organisms responsible for the introduction of energy into an ecosystem are known as producers. Nearly all such organisms originally draw their energy from the sun. Plants and other use solar energy via a process known as to convert raw materials into organic molecules, such as, whose bonds can be broken to release energy. A few, however, depend entirely on energy extracted by from,, or other non- energy sources.

Some of the energy thus captured produces and energy that is available for growth and development of other forms. The majority of the rest of this biomass and energy are lost as waste molecules and heat. The most important processes for converting the energy trapped in chemical substances into energy useful to sustain life are and. Study and research Structural. Schematic of typical animal depicting the various and structures. Is the study of biology at the molecular level. This field overlaps with other areas of biology, particularly those of and.

Molecular biology is a study of the interactions of the various systems within a cell, including the interrelationships of DNA, RNA, and protein synthesis and how those interactions are regulated. The next larger scale,, studies the structural and properties of, including their internal, interactions with other cells, and with their. This is done on both the and levels, for unicellular organisms such as, as well as the specialized cells of multicellular organisms such as. Understanding the structure and function of cells is fundamental to all of the biological sciences. The similarities and differences between cell types are particularly relevant to molecular biology.

Is a treatment of the macroscopic forms of such structures and organ systems. Is the science of,, and the variation of. Genes encode the information needed by cells for the synthesis of proteins, which in turn play a central role in influencing the final of the organism. Genetics provides research tools used in the investigation of the function of a particular gene, or the analysis of. Within organisms, genetic information is physically represented as, within which it is represented by a particular of amino acids in particular. Studies the process by which organisms grow and develop. Developmental biology, originated from, studies the genetic control of,, and 'cellular,' which is the process that progressively gives rise to,, and.

For developmental biology include the round worm, the fruit fly, the zebrafish, the mouse, and the weed. (A model organism is a that is extensively studied to understand particular biological, with the expectation that discoveries made in that organism provide insight into the workings of other organisms.) Physiological. Main article: Physiology is the study of the mechanical, physical, and biochemical processes of living organisms function as a whole. The theme of 'structure to function' is central to biology.

Physiological studies have traditionally been divided into and, but some principles of physiology are universal, no matter what particular is being studied. For example, what is learned about the physiology of cells can also apply to human cells. The field of animal physiology extends the tools and methods of to non-human species. Plant physiology borrows techniques from both research fields.

Physiology is the study the interaction of how, for example, the,,,, and systems, function and interact. The study of these systems is shared with such oriented disciplines as and. Evolutionary is concerned with the origin and descent of, and their change over time. It employs scientists from many taxonomically oriented disciplines, for example, those with special training in particular such as,,, or, but are of use in answering more general questions about evolution. Evolutionary biology is partly based on, which uses the record to answer questions about the mode and tempo of evolution, and partly on the developments in areas such as. In the 1980s, re-entered evolutionary biology after its initial exclusion from the through the study of.,, and are related fields often considered part of evolutionary biology.

Main article: Multiple events create a tree structured system of relationships between species. The role of is to study these relationships and thus the differences and similarities between species and groups of species. However, systematics was an active field of research long before evolutionary thinking was common. Traditionally, living things have been divided into five kingdoms:;;;;.

However, many scientists now consider this five-kingdom system outdated. Modern alternative classification systems generally begin with the: (originally Archaebacteria); (originally Eubacteria) and (including,,, and ) These domains reflect whether the cells have nuclei or not, as well as differences in the chemical composition of key biomolecules such as. Further, each kingdom is broken down recursively until each species is separately classified.

The order is:;;;;;;;. Outside of these categories, there are obligate intracellular that are 'on the edge of life' in terms of activity, meaning that many scientists do not actually classify such structures as alive, due to their lack of at least one or more of the fundamental functions or characteristics that define life. They are classified as,,,. The scientific name of an organism is generated from its genus and species. For example, humans are listed as.

Homo is the genus, and sapiens the species. When writing the scientific name of an organism, it is proper to capitalize the first letter in the genus and put all of the species in lowercase. Additionally, the entire term may be italicized or underlined. The dominant classification system is called the.

It includes ranks and. How organisms are named is governed by international agreements such as the (ICN), the (ICZN), and the (ICNB). The classification of,,, and all other sub-viral agents that demonstrate biological characteristics is conducted by the (ICTV) and is known as the International Code of Viral Classification and Nomenclature (ICVCN). However, several other viral classification systems do exist. A merging draft,, was published in 1997 in an attempt to standardize nomenclature in these three areas, but has yet to be formally adopted. The BioCode draft has received little attention since 1997; its originally planned implementation date of January 1, 2000, has passed unnoticed. A revised BioCode that, instead of replacing the existing codes, would provide a unified context for them, was proposed in 2011.

However, the of 2011 declined to consider the BioCode proposal. The remains outside the BioCode, which does not include viral classification. Main articles:,,, and is the study of the distribution and abundance of, the interaction between them and their. An organism shares an environment that includes other organisms and as well as local (non-living) such as and.

One reason that biological systems can be difficult to study is that so many different interactions with other organisms and the environment are possible, even on small scales. A microscopic responding to a local sugar gradient is responding to its environment as much as a lion searching for food in the African. For any species, can be,,,. Matters become more complex when two or more species interact in an.

Ecological systems are studied at several different levels, from the scale of the ecology of individual organisms, to those of, to the and finally the. The term is often used interchangeably with, although population biology is more frequently used in the case of,, and, while the term population ecology is more commonly applied to the study of plants and animals. Ecology draws on many subdisciplines. Is the study of animal (particularly that of social animals such as and ), and is sometimes considered a branch of zoology. Ethologists have been particularly concerned with the of behavior and the understanding of behavior in terms of the theory of. In one sense, the first modern ethologist was, whose book,, influenced many ethologists to come.

Studies the spatial distribution of organisms on the, focusing on such topics as,, and, and. Basic unresolved problems in biology. Main article: Despite the profound advances made over recent decades in our understanding of life's fundamental processes, some basic problems have remained unresolved. One of the major unresolved problems in biology is the primary adaptive function of sex, and particularly its key processes in eukaryotes of meiosis and homologous recombination. One view is that sex evolved primarily as an adaptation that promoted increased genetic diversity (see references e.g. An alternative view is that sex is an adaptation for promoting accurate DNA repair in germ-line DNA, and that increased genetic diversity is primarily a byproduct that may be useful in the long run.

Another basic unresolved problem in biology is the biologic basis of aging. At present, there is no consensus view on the underlying cause of aging. Various competing theories are outlined in. Branches These are the main branches of biology: For a more detailed list, see. • Alberts, Bruce; Johnson, A; Lewis, J; Raff, M; Roberts, K; Walter, P (2002). Molecular Biology of the Cell (4th ed.).

• Begon, Michael; Townsend, CR; Harper, JL (2005). Blackwell Publishing Limited... Biology (7th ed.). Benjamin-Cummings Publishing Company...

Why Big Fierce Animals are Rare: An Ecologist's Perspective (reissue ed.). Princeton University Press... • Mayr, Ernst (1982).. Harvard University Press.. • Hoagland, Mahlon (2001). The Way Life Works (reprint ed.).

Jones and Bartlett Publishers inc... • Janovy, John Jr. On Becoming a Biologist (2nd ed.). Bison Books...

Biology, Visualizing Life. Holt, Rinehart, and Winston... • Tobin, Allan; Dusheck, Jennie (2005). Asking About Life (3rd ed.). Belmont, CA: Wadsworth.. External links Wikibooks has more on the topic of: Wikisource has original works on the topic: Look up in Wiktionary, the free dictionary.

Wikiversity has learning resources about. • at Curlie (based on ) • • • •.

• – Idaho National Laboratory •: A multi-authored, distributed Internet project containing information about phylogeny and biodiversity. • • Journal links • A peer-reviewed, open-access journal published by the • General journal publishing from all areas of biology • A journal publishing Biology papers of general interest • Internationally Renowned Science Publication – See Sections of the Life Sciences • A biological journal publishing significant peer-reviewed scientific papers • An journal publishing of broad relevance •.