biology homework answers free

biology homework answers free

Exploring the Wonders of Biology: A Comprehensive Guide

1. Introduction to Biology

One remarkable thing is the great variety of organisms on Earth. On land, in the water, and even in the air, there is great diversity of organisms with varying form and sizes, and in their various life process activities. Yet with all this diversity, all organisms also have the common features of life. If you study them very carefully, you will notice other things that are true for all sorts of organisms as well. When you have completed this Section, take a self-test to see what you remember and have learned about the different aspects of living things. Finally, write a brief report for your family or class on the diversity and properties of all living things.

The word biology has its origins in two Greek words, bios means “life”, and logia means “to study”, which means that the subject of biology is the “study of life”. Exploring the wonders of biology is a journey that takes you through living things, starting with the stuff from which all living organisms are made. Without it, nothing living could exist; it is one of the essential components of life. Water is another important component; in fact, its unique properties affect almost every aspect of biology. Hollow groups of molecules have special properties that are important in ensuring that your cells function properly. There are many surprises in the world of molecules and their interactions. To further understand living things today, we will discuss some of these surprises. Everything, both living and nonliving things that we can see, is made up of atoms of various chemical elements. However, the millions of different kinds of atoms are only about 100.

Section I: The World of a Cell – The Secret of Life

2. Cell Biology and Genetics

A cell is the smallest unit of life. It is this feature that differentiates living things from non-living things. Cells also have similar amenities to housekeeping apartments in large cities. For example, like apartments, cells contain organelles, energy-generating machinery, structural materials, and a central storage area. However, whereas the uniform division of amenities in an apartment building cannot be altered, cells can produce more of a particular organelle or storage product if the environment of the cell changes. Cells also have nucleic acid molecules that are capable of storing and transmitting genetic information. In this regard, cells are quite remarkable. They are able to create copies of themselves, producing offspring that share the same genetic information. All of the cells in a human, for example, have the same genetic information.

Living organisms are composed of a nearly countless number of cells. Relative to the number of cells that exist in an adult organism (many have 10 trillion cells), the number of cell types is not great. The wonderful diversity of cell types is what makes life on Earth unique. We will limit our discussion to the most important cell types, however.

3. Evolution and Biodiversity

The mechanisms of evolution can be grouped under the headings species modification and extinction, geographic distribution, patterns of relatedness, and changes in development, all topics covered in this book.

Our planet harbors remarkable biological diversity. One of biology’s principal concerns is for scientific methods to help humans understand and sustain Earth’s diverse forms of life. Evolution is remarkably broad in its reach. Very substantial evidence supports three major points: All species now living on Earth are descendants of a comparatively small number of original, primitive life forms. Humans are one species among several million species now living on Earth. An understanding of evolution is essential for correctly interpreting and understanding most biological events. These events may be large scale (such as the extinction of species or the appearance of mimicry in new groups of organisms) or quite small scale (such as the resurgence of bacteria resistant to antibiotics, or the history of a single genetic mutation that can have a specific effect on metabolism).

4. Ecology and Environmental Biology

In order to differentiate and classify the large number of species according to certain characteristics, taxonomy was created many hundreds of years ago. Carolus Linnaeus’s widely used eighteenth-century system enabled every known plant and animal species to be classified systematically. Since then, the range and amount of detail of information have increased that taxonomy can contain. In the present taxonomy system, the ‘Scientific Name’ provides precise detailed information about any recognized species and this knowledge is also cumulative. This makes it possible to find information about additional striking features, such as with what brains Nautilus pompilius has or from what the fruit flies of the family Tephritidae or the spots of Carbonel-Dalfour snail draw their attractions. The search is not simple, to obtain the most accurate possible address, several different addresses are often necessary.

Biodiversity refers to the sum of all species that inhabit an ecosystem or an entire planet. The disappearance of certain species in specific areas, such as farmland, is often necessary but leads to a gradual loss of biodiversity in the long term. The more biodiversity a biotope possesses, the better it can cope with natural and human-made changes. The benefits that biodiversity can provide are diverse. They range from the supply of plant and animal food to the control of waste products such as wood, to the production of oxygen, the storage of water, and the reduction of climatic impacts on nature and living conditions.

5. Human Biology and Health

About 3,000,000 sweat glands in the skin help regulate the body’s temperature. When the body is hot, the sweat glands produce sweat, which reduces the body’s temperature by evaporating through the sweat pores. At the same time, blood circulation and most body activities also help regulate body temperature. Heat can be lost by having the blood in the arteries near the surface of the skin give up their heat to the cooler air. Heat can also be lost to cold or cool objects or liquids when the temperature of the skin is higher than these objects or liquids. As heat is lost from the skin to keep the body cool on a hot day, the blood vessels near the skin expand and the flow of blood through them increases. This helps carry the body heat away through the skin. Small amounts of heat can be gained in warm or hot environments in the same way. The brain has a control center to help maintain a constant internal temperature. For most people, this temperature is 98.6 degrees Fahrenheit.

Located near the lower part of the human body is the human body’s largest organ – the skin. The skin serves as a cushion covering for the muscles and bones. Some of the skin’s functions are cooling the body through the process of perspiration, and protecting the body from harmful bacteria, chemicals, and other hazardous substances. The skin has various kinds of specialized cells and nerve endings. These cells and nerve endings help humans touch with sensitivity, warmth and cold sensations, and respond quickly when they step on a piece of glass or a sharp object. The skin also has cells that produce melanin, a dark pigment that protects underlying skin cells from the harmful effects of ultraviolet radiation from the sun.