Human biology 15th edition pdf free download

What are the basic characteristics that define life? What evidence would you look for on Europa or Titan that would tell you that life may have existed on these moons in the past? What does it tell us if we discover life on Europa or Titan and it has similar characteristics to life on Earth?

What if it is very different? Explain the basic characteristics that are common to all living things. Describe the levels of organization of life. Summarize how the terms homeostasis, metabolism, development, and adaptation all relate to living organisms. Recognize the special relationship between life and evolution.

The science of biology is the study of living organisms and their environments. All living things Fig. Living things 1 are organized, 2 acquire materials and energy, 3 reproduce, 4 grow and develop, 5 are homeostatic, 6 respond to stimuli, and 7 have an evolutionary history. Living Things Are Organized Figure 1. A cell is the small- medicinal leech mushrooms est structural and functional unit of an organism. Some organisms are single cells. Humans are multicellular because they are composed of many different types of cells.

A nerve cell is one of the types of cells in the human body. It has a structure suitable to conducting a nerve impulse. A tissue is a group of similar cells that perform a particular function. Nervous tissue is composed of millions of nerve cells that transmit signals to all parts of the body.

Several types of tissues make up an organ, and each organ belongs to an organ system. The organs of an organ system work together to accomplish a common purpose. The brain works with the spinal cord to send commands to body parts by way of nerves. Organisms, such as trees and humans, are a collection of organ systems. The levels of biological organization extend beyond the individual. All the members of one species group of interbreeding organisms in a particular area belong to a population.

A tropical grassland may have a population of zebras, acacia trees, and humans, for example. The interacting populations of the grasslands make up a community. The community of populations interacts with the physical environment to form an ecosystem.

From the simplest one-celled organisms to complex plants and animals, all life shares seven basic characteristics. Living organisms are organized. The smallest unit of living organisms is the cell.

The sum of all living things—and the locations that they inhabit—is called the biosphere. Humans and other animals acquire materials and energy when they eat food Fig. Food provides nutrient molecules, which are used as building blocks or for energy. It takes energy work to main- Connections and Misconceptions How many cells are in your body?

The number of cells in a human body varies depending on the size of the person and whether cells have been damaged or lost. However, most estimates suggest that there are well over trillion cells in a human body. Some nutrient molecules are broken down completely to provide the necessary energy to convert other nutrient molecules into the parts and products of cells. The term metabolism describes all of the chemical reactions that occur within a cell. The ultimate source of energy for the majority of life on Earth is the sun.

Plants, algae, and some bacteria are able to harvest the energy of the sun and convert it to chemical energy by a process called photosynthesis. Photosynthesis produces organic molecules, such as sugars, that serve as the basis of the food chain for many other organisms, including humans and all other animals. Life Is Homeostatic b. For the metabolic pathways within a cell to function correctly, the environmental conditions of the cell must be kept within strict operating limits. The ability of a cell or an organism to maintain an internal environment that operates under specific conditions is called homeostasis.

In humans, many of our organ systems work to maintain homeostasis. For example, human body temperature normally fluctuates slightly between In general, the lowest temperature usually occurs between 2 a. 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. 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. This text emphasizes how 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. The work of the nervous and endocrine systems is critical because these systems coordinate the functions of the other systems.

Throughout the text, the Connecting the Concepts sections will provide you with links to more information on homeostasis. Figure 1. Humans eat plants and animals they raise for food. A red-tailed hawk captures prey to feed its young. Some animals feed only on plants, such as these grazing sheep. 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 heartbeat 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. Living things respond to external stimuli, often by moving toward or away from a stimulus, such as the sight of food.

Living things use a variety of mechanisms to move, but movement in humans and other animals is dependent upon their nervous and musculoskeletal systems. The leaves of plants track the passage of the sun during the day; when a houseplant is placed near a window, its stems bend to face the sun. The movement of an animal, whether self-directed or in response to a stimulus, constitutes a large part of its behavior. Some behaviors help us acquire food and reproduce.

Living Things Reproduce and Develop Reproduction is a fundamental characteristic of life. Cells come into being only from pre-existing cells, and all living things have parents. When living things reproduce, they create a copy of themselves and ensure the continuance of their own kind. Following the fertilization of the egg by a sperm cell, the resulting zygote undergoes a rapid period of growth and development. This is common in almost all living organisms.

In humans, growth occurs as the 5 fertilized egg develops into a fetus Fig. Growth, recognized by an increase in size and often the number of cells, is a part of development.

In humans, development includes all the changes that occur from the time the egg is fertilized until death; therefore, it includes all the changes that occur during childhood, adolescence, and adulthood. Development also includes the repair that takes place following an injury. The purpose of reproduction is to pass on a copy of the genetic information to the offspring. DNA contains the hereditary information that directs not only the structure of each cell but also its function.

The information in the DNA is contained within genes, short sequences of hereditary material that specify the instructions for a specific trait. Before reproduction occurs, DNA is replicated so that an exact copy of each gene may be passed on to the offspring. When humans reproduce, a sperm carries genes contributed by a male into the egg, which contains genes contributed by a female. The genes direct both growth and development so that the organism will eventually resemble the parents.

Sometimes, minor variations in these genes, called mutations, may result in an organism making it better suited for its environment. These mutations are the basis of evolutionary change. Living Things Adapt and Evolve Evolution is the process by which a species changes through time. When a new variation arises that allows certain members of the species to capture more resources, these members tend to survive and have more offspring than the other, unchanged members.

Therefore, each successive generation will include b. A small acorn becomes a tree, and b following fertilization, an embryo becomes a fetus by the process of growth and development. Consider, for example, a redtailed hawk, which catches and eats rabbits.

A hawk can fly, in part, because it has hollow bones to reduce its weight and flight muscles to depress and elevate its wings. When a hawk dives, its strong feet take the first shock of the landing and its long, sharp claws reach out and hold onto the prey. Evolution, which has been going on since the origin of life and which will continue as long as life exists, explains both the unity and the diversity of life. All organisms share the same characteristics of life because their ancestry can be traced to the first cell or cells.

Organisms are diverse because they are adapted to different ways of life. Check Your Progress 1. Summarize how each characteristic of life contributes to homeostasis. Explain why living things are organized.

Summarize the place of humans in the overall classification of living organisms. Describe the relationship between humans and the biosphere, and the role of culture in shaping that relationship. Both homeostasis and evolution are central themes in the study of biology. For more examples of homeostasis and evolution, refer to the following discussions. Section 9. Biologists classify living things as belonging to one of three domains. The evolutionary relationships of these domains are presented in Figure 1.

Two of these domains, domain Bacteria and domain Archaea, contain prokaryotes, Figure 1. Living organisms are classified into three domains: Bacteria, Archaea, and Eukarya. A geologic time scale is provided on the bottom for reference. This figure provides some of the characteristics of the organisms of each of the major domains and kingdoms of life. Humans belong to the domain Eukarya and kingdom Animalia.

Organisms in the third domain, Eukarya, are classified as being members of one of four kingdoms Fig. Most organisms in kingdom Animalia are invertebrates, such as the earthworm, insects, and mollusks.

Vertebrates are animals that have a nerve cord protected by a vertebral column, which gives them their name. Fish, reptiles, amphibians, and birds are all vertebrates. Vertebrates with hair or fur and mammary glands are classified as mammals. Humans, raccoons, seals, and meerkats are examples of mammals. Human beings are most closely related to apes.

We are distinguished from apes by our 1 highly developed brains, 2 completely upright stance, 3 creative language, and 4 ability to use a wide variety of tools. Humans did not evolve from apes; apes and humans share a common, apelike ancestor.

Our relationship to apes is analogous to you and your first cousin being descended from your grandparents. We could not have evolved from our cousins because we are contemporaries— living on Earth at the same time. Humans Have a Cultural Heritage Human beings have a cultural heritage in addition to a biological heritage.

Culture encompasses human activities and products passed on from one generation to the next outside of direct biological inheritance. Among animals, only humans have a language that allows us to communicate information and experiences symbolically.

We are born without knowledge of an accepted way to behave, but we gradually acquire this knowledge by adult instruction and imitation of role models. Many of the skills involve tool use, which can vary from how to hunt in the wild to how to use a computer.

Human skills have also produced a rich heritage in the arts and sciences. However, a society highly dependent on science and technology has its drawbacks as well.

Unfortunately, this cultural development may mislead us into believing that humans are somehow not part of the natural world surrounding us.

Humans Are Members of the Biosphere All living things on Earth are part of the biosphere, a living network that spans the surface of the Earth into the atmosphere and down into the soil and seas. Although humans can raise animals and crops for food, we depend on the environment for many services.

Some species of bacteria can clean up pollutants like heavy metals and pesticides. Freshwater ecosystems, such as rivers and lakes, provide fish to eat, drinking water, and water to irrigate crops. The water-holding capacity of forests prevents flooding, and the ability of forests and other ecosystems to retain soil prevents soil erosion. Many of our crops and prescription drugs were originally derived from plants that grew naturally in an ecosystem.

Some human populations around the globe still depend on wild animals as a food source. And we must not forget that almost everyone prefers to vacation in the natural beauty of an ecosystem.

Humans Threaten the Biosphere The human population tends to modify existing ecosystems for its own purposes Fig. Humans clear forests and grasslands to grow crops. Later, houses are built on what was once farmland. Clusters of houses become small towns that often grow into cities.

The overuse of water supplies by large human populations can result in desertification, or the expansion of desert regions Fig. Human activities have altered almost all ecosystems and reduced biodiversity the number of different species present. The present biodiversity of our planet has been estimated to be as high as 15 million species.

So far, under 2 million have been identified and named. It is estimated that we are now losing as many as species per day due to human activities. Many biologists are alarmed about the present rate of extinction death of a species. The dinosaurs became extinct during the last mass extinction 65 million years ago. One of the major bioethical issues of our time is preservation of the biosphere and biodiversity.

If we adopt a conservation ethic that preserves the biosphere and biodiversity, we will ensure the continued existence of our species. Connections and Misconceptions How many humans are there?

As of the end of , it was estimated that there were over 6. Each of those humans needs food, shelter, clean water and air, and materials to maintain a healthy lifestyle. We add an additional 75 million people per year—that is like adding ten New York Cities per year! This makes human population growth one of the greatest threats to the biosphere. Connecting the Concepts To learn more about the preceding material, refer to the following discussions. Chapter 22 examines recent developments in the study of human evoution.

Chapter 23 provides a more detailed look at ecosystems. Chapter 24 details some of the emerging threats that humans pose to the biosphere. Humans negatively influence many ecosystems.

When humans build cities, diversity is lost. An overuse of water resources can lead to desertification. Explain why it is important to know the evolutionary relationships between organisms. Summarize how the increase in the human population affects our biosphere. Describe the general process of the scientific method. Distinguish between a control group and an experimental group in a scientific test. Recognize the importance of scientific journals in the reporting of scientific information.

Science is a way of knowing about the natural world. When scientists study the natural world, they aim to be objective, rather than subjective.

Objective observations are supported by factual information, whereas subjective observations involve personal judgment. For example, the fat content of a particular food would be an objective observation of a nutritional study. Reporting about the good or bad taste of the food would be a subjective observation.

It is difficult to make objective observations and conclusions because we are often influenced by our prejudices. Scientists must keep in mind that scientific conclusions can change because of new findings. New findings are often made because of recent advances in techniques or equipment. This term is the preferred terminology for theories generally accepted as valid by an overwhelming number of scientists. The Scientific Method Has Steps Unlike other types of information available to us, scientific information is acquired by a process known as the scientific method.

The approach of individual scientists to their work is as varied as the scientists. For the sake of discussion, it is possible to speak of the scientific method as consisting of certain steps Fig.

After making initial observations, a scientist will, most likely, study any previous data, results and conclusions reported by previous research. Imagination and creative thinking also help a scientist formulate a hypothesis. The new data help a scientist come Observation New observations are made, and previous data are studied.

Importance of Scientific Theories in Biology Science is not just a pile of facts. The ultimate goal of science is to understand the natural world in terms of scientific theories.

Scientific theories are concepts that tell us about the order and the patterns within the natural world—in other words, how the natural world is organized. For example, following are some of the basic theories of biology. Theory Concept Cell All organisms are composed of cells, and new cells only come from pre-existing cells. Homeostasis The internal environment of an organism stays relatively constant.

Genes Organisms contain coded information that dictates their form, function, and behavior. Ecosystem Populations of organisms interact with each other and the physical environment. Evolution All organisms have a common ancestor, but each is adapted to a particular way of life. Evolution is the unifying concept of biology because it makes sense of what we know about living things. For example, the theory of evolution enables scientists to understand the variety of living things and their relationships.

It explains common structural features, physiology, patterns of development, and behaviors. The results are analyzed, and the hypothesis is supported or rejected. Scientific Theory Many experiments and observations support a theory. The return arrow indicates that a scientist often chooses to retest the same hypothesis or to test a related hypothesis.

Genres: Anatomy. Humans are a naturally inquisitive species. As children, we become fascinated with life at a very early age. We want to know how our bodies work, why there are differences, and similarities, between ourselves and the other children around us. In other words, at a very early age, children are acting like biologists. Whether this is their last science class or the first in a long career in allied health, the study of human biology is pertinent to everyone.

There are also challenges that are unique to the modern classroom. Introduction to Biotechnology Book PDF Introduction to Biotechnology is the first biotechnology paperback geared specifically for the diverse academic backgrounds of undergraduate students. With its Human Biology Mader 15th Edition Pdf Human Biology 15th Edition Free Pdf is a comprehensive introductory biology textbook that covers biology in a traditional order, from However finding Instead of being a collection Advances in Her hair was growing back, not the other way around.

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This site was designed for students of anatomy and physiology. Answers For. Biology Lab Manual.