Biology intro

Oxygen make up what percent of the atmosphere.

21%

How many cells in our bodies?

37 trillion

What is a gene ?

A segment of DNA, instructions to encode a protein

It is the science that links the sciences of biology and astronomy, and is concerned with the study and evolution of life forms outside the planet.

Astrobiology

What is single-celled

Bacteria

The science that investigates the distribution of living organisms in the places in which they live.

Biogeography

The science that uses theories of physics and mathematics to analyze some issues related to biology.

Biophysics

All organisms are made up of one or more cells, all the life functions of an organism occur within cells, and all cells come from preexisting cells. In fact, each living thing begins life as a single cell. Some living things, such as bacteria, remain single-celled. Other living things, including fungi, plants and animals, grow and develop into many cells. Our own bodies are made up of an estimated 37 trillion cells. It is important to remember that we humans—like all other living things—began life as a single cell.

Cell theory

What do molecules do?

Encoded with instructions to tell cells what to do.

Evolution is a change in the characteristics of living organisms over time. Evolution occurs by a process called natural selection. In natural selection, some living organisms produce more offspring than others, so they pass more genes to the next generation than others do. Over many generations, this can lead to major changes in the characteristics of living organisms. Evolution explains how living organisms are changing today and how modern living organisms have descended from ancient life forms that no longer exist on Earth. As living organisms evolve, they generally become better suited for their environment. This is because they evolve adaptations. An adaptation is a characteristic that helps a living organism survive and reproduce in a given environment.

Evolution

The characteristics of living organisms are controlled by genes, which are passed from parents to their offspring. A gene is a segment of DNA that has the instructions to encode a protein. Genes are located on larger structures, called chromosomes, that are found inside every cell. Chromosomes, in turn, contain large molecules known as DNA (deoxyribonucleic acid). Molecules of DNA are encoded with instructions that tell cells what to do.

Gene theory

Homeostasis is, by definition, the tendency toward a relatively stable equilibrium (balance), between interdependent elements. In biological systems, it pertains to maintaining a stable internal environment or keeping things constant, not just as it relates to living organisms (an example of homeostasis in humans is body temperature regulation), but also to nature as a whole. Consider the concentration of oxygen in Earth's atmosphere. Oxygen makes up 21% of the atmosphere, and this concentration is fairly constant. What keeps the concentration of oxygen constant? The answer is living organisms. Most organisms need oxygen to survive, and when they breathe, they remove oxygen from the atmosphere. On the other hand, many organisms, including plants, give off oxygen when they make food. This adds oxygen to the atmosphere. The concentration of oxygen in the atmosphere is maintained mainly by the balance between these two processes.

Homeostasis

As a field of science, biology helps us understand the living world and the ways its many species (including humans) function, evolve, and interact. Advances in many areas of biology have brought improvements in the quality of life of humans and the many species we share the world with, playing a critical role in various aspects of our lives, from medical advancements and conservation efforts to understanding the impact of climate change. It helps us develop treatments for diseases, improve agriculture, protect endangered species, and make informed decisions about our planet's health.

Reasons why Biology is important

Biology imparts scientific skills such as observation, identifying, analyzing, and evaluating data. These skills may be applied to everyday life and all professions.

Skills of a Biologist

It is the science that studies the role of biology in shaping the social structure of individuals, their culture, and the relationships that link them.

Sociobiology

What keeps the concentration of oxygen constant?

The answer is living organisms.