بسم الله الرحمن الرحيم
(سَنُرِيهِمْ آيَاتِنَا فِي الْآفَاقِ وَفِي أَنفُسِهِمْ حَتَّى يَتَبَيَّنَ لَهُمْ أَنَّهُ الْحَقُّ) فصلت 53 صدق الله العظيم
Al-Iraqia university Prof. Dr. Samia Alshahwani
College of medicine Y1 L1 9 .12. 2015
Human Biology
Introduction to biology (Science of the life)
Biology is the scientific study of organism (from sub atomic structure in a single- cell & life origin to human & the entire ecosystem), regarding, morphology (structure & shape), physiology (function), classification (taxonomy), genetics, growth, evolution, distribution, origin & ecology. It is a base level study that leads to different scientific areas.
Biology purview extends from life origin to the fundamental nature of human beings and their relation to other life forms. Biology is the reason of medical advances in this day and age e.g. Disease cure, organ transplant, remedies, to ease arthritis pain, improves memory, mood….etc.
Biology term is derived from Greek word bio (life), logy (study of), (Biologie) named (doctrine of life).
Biology is an experimental science, get to what make a study scientific, and to what makes things alive.
Studied organism is classified, & given a scientific name which is obtained from the genus and species, it must be written, in Italic or underlined, and the first letter capital e.g.
**Scientific name of human is Homo sapiens
Homo is the genus and sapiens is the species
Science: Is the objective, logical and repeatable attempts to understand the principles and forces operating in the universe.
Science is from Latin to know, science should be viewed on a continuous testing & evaluation process.
Humans live in an interrelated biosphere, their activities threatens ecosystems, they must, decrease their impacts on the biosphere, make wise health and environmental decisions, and this requires adequate knowledge, human must understand, care for the creation to assure survival as individuals and species, biology is central to this process.
Changes and development are occurring in modern biology, some of new
biology fields, membrane science, cryobiology, bioengineering & synthetic biology, emerged recently, there are problems in health, environment food, & energy, there is a need for new biology fields to achieve solutions, It is recommended a national initiative to accelerate the growth of the new biology to achieve solutions to different life challenges.
Biology scope Biology is very broad field, it encompasses a spectrum of disciplines, & sub disciplines, look at biology divisions, we traditionally cut biology "Layer cake,” to pieces in two distinct ways, fig. 1-1 it may be divided “horizontally" to "basic “divisions, because they are concerned with fundamentals common to all life or not restricted to a particular organism, e.g. molecular biology, cell biology, genetics, ecology, physiology, morphology, evolution............ etc & may be divided "vertically" to "taxonomic “divisions which deals with, molecular biology, cell biology, genetics. etc. of a specific organism, these disciplines are grouped by organisms being studied: e.g. microbiology, zoology, botany… etc
Fig1-1The biology layer cake basic horizontal & taxonomic vertical divisions
Traditionally biology sub disciplines are recognized on the bases of the scale at which the organisms are studied and methods used to study them.
Biologists study life over wide range of scales, at levels of:
Atomic and molecular scale, molecular biology, biochemistry, and molecular genetics.
The cell, in cell biology.
At-multi cellular scale, in anatomy, physiology, & histology.
Individual organism development, developmental biology.
More than one organism, in genetics.
Entire population, in population genetics.
Interdependent populations & their habitats, in ecology
Biology goal
Test theories developed, by utilizing scientific methods.
Apply new information in a beneficial way.
Principles of modern biology
Cell theory.
Gene theory.
Evolution.
Homeostasis.
Energy.
Human biology An interdisciplinary study area that examines human through influences and interplay of many fields as genetics, physiology, nutrition, epidemiology, ecology, evolution and population genetics, It is the study of anatomy (structure) and physiology (function) of human body.
Human biology integrates topics of health, wellness and environment.
Human biology goal:
- Introduce student to human anatomy and physiology.
-Recognize the role that human play in the biosphere.
-Apply biological principles to practical human concern
-Demonstrate, proper ethic, professional, practical & general skills.
Human biology course objectives:
By the end the student should be able to:
Recognize human organization.
Define terms concerning biology
Recognize science process.
Outline human classification
Recognize life phylogenetic tree
Clarify life chemistry
Describe cells structure & correlate them to their functions.
Outline: body anatomy, system &organ physiology & their disorders
Determine human genetics, chromosomal inheritance & patterns
Explain diseases caused by microorganisms, (infectious).
Describe cancer cells and list cancer causes, prevention.
Apply knowledge to maintain health.
*Remember the greatest wealth is health
Definitions;
Biology: The study of organisms and their environment.
Human biology: Human body structure and function study
Cell: The structural and functional unit of organism.
Tissue: A group of cell with common structure and function.
Organ: A group of tissue functioning a special task.
System: Several organs working together.
Organism: Complex individual containing organ system.
Population: Organisms of same species in particular area.
Community: The interacting population in particular area.
Ecosystem: A community and the physical environment.
Biosphere: Earth crust region with water &atmosphere inhibited by the organisms.
Cell biology: The study of different cell types.
Histology: study of primary and connective tissues.
Genetics : The study of genetic effect differences on organisms
Molecular biology: Study of biology at a molecular level.
Biochemistry: The study of molecules (e.g. proteins).
Cryobiology: The study of low temperature effects on organisms.
Bioengineering: The study with emphasis on biotechnology.
Synthetic biology: Future field focus on design and construction of new biological parts, devices, &systems for beneficial use (e.g., tumor-seeking microbes for cancer treatment)
Anthropology: Study of humans, origin, physical characteristics, institutions, beliefs
CH.1 Exploring Life & Science
life characteristics
Organization.
Energy requirement.
Homeostasis.
Response to internal & external stimuli, movement.
Reproduction and heredity
Growth and development.
Evolution and adaptation.
1-Organization:
Organisms are organized, atoms join forming cell, similar cells form tissue, several tissue form organ, organ collection form system and systems form body, human group is a population, interacting population is community, community with physical environment form ecosystem, ecosystems makes up biosphere.
Fig1.2 Biological organization levels, organisms are organized. smallest unit of living organisms is the cell; the sum of living things & locations they inhabit is biosphere\
2- Energy requirement
Humans, like all organisms, cannot maintain their organization or carry on life’s activities without an outside source of materials and energy, acquired when they eat food (Fig. 1.3). Food provides nutrient molecules, which are used as building blocks for energy.
Fig 1-3. Human acquire energy, food from plant and animal sources
Some nutrient molecules are broken down to provide the necessary energy to convert other nutrient molecules into parts and products of cells. Term metabolism describes chemical reactions that occur within a cell. The ultimate source of energy for life is the sun. Plants, algae, and some bacteria are able to harvest the energy of the sun and convert it to chemical energy by photosynthesis. Photosynthesis produces organic molecules, such as sugars, that serve as the basis of the food chain.3- Homeostasis
Homeostasis: The ability of a cell or an organism to maintain an internal environment that operates under specific conditions. Many organ systems work to maintain homeostasis, e.g. human body temperature normally fluctuates slightly between 36.5 and 37.5°C (97.7 and 99.5°F) during the day. In general, the lowest temperature usually occurs between 2 a.m. and 4 a.m., and the highest usually occurs between 6 p.m. and 10 p.m. However, activity can cause the body temperature to rise, and inactivity can cause it to decline. The cardiovascular system and the nervous system work together to maintain a constant temperature. However, the body’s ability to maintain a normal temperature is somewhat dependent on the external temperature. Even though we can shiver when we are cold and perspire when we are hot, we will die if the external temperature becomes overly cold or hot. All the systems of the human body help maintain homeostasis, the digestive system takes in nutrients, and the respiratory system exchanges gases with the environment. The cardiovascular system distributes nutrients and oxygen to the cells and picks up their wastes. The metabolic waste products of cells are excreted by the urinary system. Nervous and endocrine systems work is critical because these systems coordinate the functions of the other systems.4- Response to stimuli
Homeostasis would be impossible without the ability to respond to stimuli. Response to external stimuli is apparent, because it involve movement, e,g. quickly remove a hand from a hot stove. Certain sensory receptors also detect a change in the internal environment, and then the central nervous system brings about an appropriate response. When you are startled by a loud noise, your heart beat increases, which causes your blood pressure to increase. If blood pressure rises too high, the brain directs blood vessels to dilate, helping to restore normal blood pressure. Organism responds to external stimuli, by moving toward or away from a stimulus, movement dependent on nervous and musculoskeletal system5- Reproduction
Reproduction is a fundamental characteristic of life. Cells come into being only from pre-existing cells, when organisms reproduces, a copy of them are created and the continuance of their own kind is ensured. Following egg fertilization by a sperm cell, the resulting zygote undergoes a rapid period of growth and development.
6-Growth and development: Is common in all organisms. Fig 1.4, a- illustrates acorn progresses to a seedling before it becomes an adult oak tree,
b- Following fertilization an embryo becomes a fetus by the process of growth and development.
fig1-4. Growth & development define life, acorn become tree b, an embryo becomes a fetus
7- Evolution and Adaptation
Evolution is the process by which a species changes through time. When a new variation arises that allows certain members of to capture more resources, these members tend to survive and have more offspring than the other. Therefore, each successive generation will include more members with the new variation, which represents an adaptation to the environment.Evolution, has been going on since the origin of life and will continue, explains both unity and life diversity. All organisms share same life characteristics because their ancestry can be traced to the first cell. Organisms are diverse because they are adapted to different life ways.
Characteristics of Cells
- Eukaryotic cells
- Prokaryotic cells
There are many differences between eukaryotic and prokaryotic cell
*Students should have free, ready access to Textbook (Reference):
Madder, S., S., and Windelelspecht, M., Human biology, 12th ed.Mc Graw – hill, USA, 2012.
Thanks Samia 2015