Introduction to Biology

Study Notes

Biology is the study of living organisms (bios - life, logos - study of).
Defining "life" is difficult and scientists haven't developed an universally accepted definition.
The complexities of life and living organisms cannot be fully explained by the laws of chemistry and physics.
Biology is a large and complex subject, divided for easier study into three main branches:
- Zoology (study of animals)
- Botany (study of plants)
- Microbiology (study of microorganisms)
Within these branches, there are further areas of study, such as:
- Cell Biology (cells)
- Histology (tissues)
- Anatomy (gross body structure)
- Physiology (body functions)
- Biochemistry (biological molecules)
- Genetics (inheritance)
- Ecology (environment)

Earth has a vast array of life with a wide range of diversity.
The number of species is thought to be between 10 million and over 100 million.
Life on Earth shows dynamic relationships between living and non-living entities.
Key aspects of Earth's biodiversity include various species, genes, ecosystems (deserts, rainforests etc.).
Understanding the human body involves knowing the structure and function of its organs.
Natural resources are essential, but their use and management are critical to prevent depletion and environmental problems.
Environmental pollution, biodiversity loss, and desertification are concerns due to overexploitation of resources.
Managing natural resources and the environment is important for sustainability and avoiding crises.

Sustainable food production aims to provide sufficient food while using environmentally responsible methods.
The current human population is large and growing rapidly, necessitating the need for sustainable methods.
Methods for maintaining sustainable food production include high-yielding, disease-resistant varieties of plants and animals as well as improved post-harvest technologies.

Plants are crucial to life on Earth.
Understanding plants is important in supporting the needs of growing human populations.
Plants are the ultimate producers and support the food chain.

Health requires knowledge of diseases and their causes for effective prevention.
Communicable and non-communicable diseases are significant concerns, along with cancers, heart diseases, and chronic diseases such as kidney disease.
Scientists are working to understand these diseases.

Biological knowledge is applied in legal contexts, such as DNA fingerprinting for parentage testing, criminal investigations, and immigration disputes.

Living organisms exhibit wide variations in size, shape, form, and habitats (terrestrial, aquatic, aerial, etc.).
The basic characteristics of living beings include ordering and organization, metabolism (chemical reactions), growth and development, irritability and coordination, adaptation, reproduction and heredity.
Living organisms are organized from the molecular level through increasingly complex units up to the levels of populations, ecosystems and the biosphere.