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Biology is a methodological study of life and living things. It is the branch of science that primarily deals with the structure, function, growth, evolution, and distribution of organisms.
Definition
Definition
Biology is a wide-ranging field that encompasses various other fields such as chemistry, physics, mathematics, and medicine. Biochemistry, for instance, is biology and chemistry combined. It deals primarily with the diverse biomolecules (e.g. nucleic acids, proteins, carbohydrates, and lipids), studying biomolecular structures and functions. Biophysics is another interdisciplinary field that applies approaches in physics to understand biological phenomena. Mathematics and biology can be combined in order to come up with theoretical models of biological processes, using mathematical techniques and tools. Medical biology or biomedicine is another major integration where medicine uses biological principles in clinical settings.
In contrast to the inanimate objects, a living matter is one that demonstrates life. A living entity is comprised of a cell or a group of cells, and each of these cells can carry out processes, e.g. anabolic and catabolic reactions, in order to sustain life. These reactions require energy. They are also regulated through homeostatic mechanisms. A biological entity that is alive is capable of reacting to stimuli, adapt to its environment, reproduce, and grow. The major groups of living things are animals, plants, fungi, protists, bacteria, and archaea. Biology studies their structure, function, distribution, evolution, and taxonomy.
The fundamental principles or building blocks of biology include cell theory, gene theory, evolutionary theory, homeostasis, and energy.
Cell theory
Cell theory
Cell theory studies the fundamental building blocks of life: cells.
All living things are made up of one or more cells,
the cell is the structural and functional unit,
cells come from a pre-existing process of division,
all cells have the same chemical composition, and
energy flow occurs within the cell.
Gene theory
Gene theory
The gene is the fundamental unit of heredity. In this chart (called Punnett Square), it shows how a particular phenotype of an offspring depends on the inherited alleles from the parents. In this example, the dominant trait (yellow color) is expressed on offspring inheriting the Y allele. In contrast, the offspring lacking the dominant allele and inherits yy will express the recessive trait (green color).
The gene is considered as the fundamental, physical, and functional unit of heredity. It is located on the chromosome and contains DNA. The gene stores the genetic code, i.e. a sequence of nucleotides that determines the structure of a protein or RNA. A gene is a unit of heredity because it is transmitted across generations. The phenotypic traits of an organism are based on these genes.
In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases. The Human Genome Project estimated that humans have between 20,000 and 25,000 genes. Every person has two copies of each gene, one inherited from each parent.
Gregor Johann Mendel was one of the main pioneers who established the science of genetics. He was able to determine the occurrence of unit factors (now referred to as genes) that were passed down from one generation to the next. He described these unit factors as occurring in pairs. One of the pairs will be dominant over the other (recessive). He formulated the Mendelian laws to elucidate how heredity occurs. These laws include Law of Segregation, Law of Independent Assortment, and Law of Dominance. The inheritance pattern that follows these laws is referred to as Mendelian inheritance. Conversely, an inheritance pattern that does not conform to these laws is described as Non-Mendelian.
Theory of Evolution
Theory of Evolution
This diagram shows how mutation and selection work as key factors in evolution.
Evolution describes the genetic changes in a population over successive generations driven by natural selection, mutation, hybridization, or inbreeding.
Charles Darwin created the theory of evolution. He is known for his work Origin of Species by Natural Selection (1859) after his Beagle voyage. Based on his analysis, he postulated that living things have an inherent tendency to produce offspring of the same kind. Plus, the survival of the species becomes dependent on the available food and space. As a result, organisms compete as the carrying capacity of the habitat is not able to sustain a massive population. Survival or struggle for existence becomes the force for selection that determines the future of the species.
Homeostasis
Homeostasis
Homeostasis is the tendency of an organism to maintain optimal internal conditions. It entails a system of feedback controls in order to stabilize the normal homeostatic range despite changing external conditions. For instance, the organism employs homeostatic mechanisms to regulate temperature, pH, and blood pressure.
The homeostatic system is comprised of three main components: a receptor, a control center, and an effector. The receptor of the homeostatic system includes the various sensory receptors that can detect external and internal changes. The information is sent to the control center to process it and to produce a signal to incite an appropriate response from the effector.
The concept of homeostasis is credited to Claude Bernard in 1865.
Energy and Metabolism
Energy and Metabolism
"Metabolism" refers to the set of life-sustaining chemical reactions in organisms.
Energy is essential to drive various biological processes, especially anabolic reactions. Adenosine triphosphate (ATP) is the main energy-carrier of the cell. It is released from carbohydrates through glycolysis, fermentation, and oxidative phosphorylation. Lipids are another group of biomolecules that store energy.
Branches of Biology
Branches of Biology
Biology has various sub-disciplines or branches. Here is a list:
Anatomy – the study of the animal form, particularly the human body
Astrobiology – the branch of biology concerned with the effects of outer space on living organisms and the search for extraterrestrial life
Biochemistry – the study of the structure and function of cellular components, such as proteins, carbohydrates, lipids, nucleic acids, and other biomolecules, and of their functions and transformations during life processes
Bioclimatology – a science concerned with the influence of climates on organisms, for instance, the effects of climate on the development and distribution of plants, animals, and humans
Bioengineering – or biological engineering, a broad-based engineering discipline that deals with bio-molecular and molecular processes, product design, sustainability and analysis of biological systems
Biogeography – a science that attempts to describe the changing distributions and geographic patterns of living and fossil species of plants and animals
Bioinformatics – information technology as applied to the life sciences, especially the technology used for the collection, storage, and retrieval of genomic data
Biomathematics – mathematical biology or biomathematics, an interdisciplinary field of academic study which aims at modeling natural, biological processes using mathematical techniques and tools. It has both practical and theoretical applications in biological research
Biophysics – or biological physics, interdisciplinary science that applies the theories and methods of physical sciences to questions of biology
Biotechnology – applied science concerned with biological systems, living organisms, or derivatives thereof, to make or modify products or processes for specific use
Botany – the scientific study of plants
Cell biology – the study of cells at the microscopic or at the molecular level. It includes studying the cells’ physiological properties, structures, organelles, interactions with their environment, life cycle, cell division, and apoptosis
Chronobiology – a science that studies time-related phenomena in living organisms
Conservation Biology – concerned with the studies and schemes of habitat preservation and species protection for the purpose of alleviating extinction crisis and conserving biodiversity
Cryobiology – the study of the effects of low temperatures on living organisms
Developmental Biology – the study of the processes by which an organism develops from a zygote to its full structure
Ecology – the scientific study of the relationships between plants, animals, and their environment
Ethnobiology – a study of the past and present human interactions with the environment, for instance, the use of diverse flora and fauna by indigenous societies
Evolutionary Biology – a subfield concerned with the origin and descent of species, as well as their change over time, i.e. their evolution
Freshwater Biology – a science concerned with the life and ecosystems of freshwater habitats
Genetics – a science that deals with heredity, especially the mechanisms of hereditary transmission and the variation of inherited characteristics among similar or related organisms
Geobiology – a science that combines geology and biology to study the interactions of organisms with their environment
Immunobiology – a study of the structure and function of the immune system, innate and acquired immunity, the bodily distinction of self from non-self, and laboratory techniques involving the interaction of antigens with specific antibodies
Marine Biology – the study of ocean plants and animals and their ecological relationships
Medicine – the science which relates to the prevention, cure, or alleviation of disease
Microbiology – the branch of biology that deals with microorganisms and their effects on other living organisms
Molecular Biology – the branch of biology that deals with the formation, structure, and function of macromolecules essential to life, such as nucleic acids and proteins, and especially with their role in cell replication and the transmission of genetic information
Mycology – the study of fungi
Neurobiology – the branch of biology that deals with the anatomy, physiology, and pathology of the nervous system
Paleobiology – the study of the forms of life existing in prehistoric or geologic times, as represented by the fossils of plants, animals, and other organisms
Parasitology – the study of parasites and parasitism
Pathology – the study of the nature of the disease and its causes, processes, development, and consequences
Pharmacology – the study of preparation and use of drugs and synthetic medicines
Physiology – the biological study of the functions of living organisms and their parts
Protistology – the study of protists
Psychobiology – the study of mental functioning and behavior in relation to other biological processes
Toxicology – the study of how natural or man-made poisons cause undesirable effects in living organisms
Virology – the study of viruses
Zoology – The branch of biology that deals with animals and animal life, including the study of the structure, physiology, development, and classification of animals
Ethology – the study of animal behavior
Entomology – the scientific study of insects
Ichthyology – the study of fishes
Herpetology – the science of reptiles and amphibians
Ornithology – the science of birds
Mammalogy – the study of mammals
Primatology – the science that deals with primates
Weblinks:
Weblinks:
Stanford Encyclopedia: Philosophy of Biology
Biology online - Database for terms and topics. Very extensive.
Biology Basics - Thoughtco. Nice breakdown with small lessons and videos.
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