Basics of Biology - Alison

Four Basic Principles of Biology

Gene Theory

• Traits are inherited through gene transmission.

• Genes are located on Chromosomes and contain DNA

• DNA is believed to have all of the information necessary to keep an organism alive.

Cell Theory

• The Cell is the basic unit of life

• All organisms are made up of cells. They can be either single-celled (like bacteria) or multi-celled (like animals and plants)

• Cells contain a nucleus that has other organelles, chromosomes and DNA

Evolution

• Any genetic change in which populations change over time/several generations

• Changes may be big or small

• Changes may be noticeable or not so noticeable

• The theory of evolution by natural selection has given the best explanation as to why there are so many diverse species on Earth.

Homeostasis

• Ability to maintain a consistent internal environment in response to environmental changes

• Homeostasis is the act of holding a relatively stable internal environment within an organism’s cells.

Major Branches of Biology

Botany

• Study of different aspects of plants

• Theophrastus is known as the father of Botany

Zoology

• Study of various aspects relating to animals

• Aristotle is known as the father of Zoology

Microbiology

• Deals with the task of different elements of microorganism

• Leeuwenhoek is the father of Microbiology

Main Branches of Biology

Taxonomy

• Practice of identifying different organisms, classifying them and giving them unique scientific names

• Derived from the Greek taxis which means “arrangement” and nomos meaning “law”

• Methodology_^* and principles of systematic_^* botany and zoology

• Sets up arrangements of hierarchy in plants and animals in superior and subordinate groups

Morphology

• Study of external forms, color, size, shape, structure and relative position_^* of various living organs of living beings

• Focuses on both internal and external structures and their form

Anatomy

• Scientific study of structure of organisms

• Encompasses both internal and external parts and how they are organized, i.e. the heart or reproductive organs in angiosperms_^*

• Can be applied to various organisms, including humans, animals, plants and microorganisms.

Subfields of Anatomy

• Gross - study of large structures visible to the naked eye

• Microscopic - study of tissues and cells

• Comparative - structural similarities and difference in organisms

Histology

• Study of tissue organization and structure as observed through a light microscope_^*

• Samples are sectioned, stained and then examined under a light microscope

• Microscopic counterpart to gross anatomy

• Can be used to diagnose and treat conditions like cancer, Chron’s disease, colitis, uterine fibroids and infections

• Can be used to identify pathogens like bacteria, parasites and fungi

• Can indicate levels of heavy metals and other toxins

Cytology

• Study of form and structure of cells, including the nucleus and organelle’s behaviors

• Generally involves looking at a single cell type at a time, while Histology looks at an entire block of tissue at a time

• Cells are collected from bodily fluids by scraping, brushing or from aspiration

• Samples are then stained and examined under a microscope by a cytotechnologist

• Cytology in medicine typically looks for malignant or abnormal cells

Cell Biology

• Study of morphological, physiochemical organization, biochemical, physiological, genetic, developmental, pathological and evolutionary aspects of a cell and its components.

• Study of Cells, their structure, function and life cycle

  • Structure: physical makeup of cells including size, shape and composition

  • Function: tasks cells perform such as growth, energy production, and reproduction

  • Communication: how cells respond to substances outside the cell

  • Cycle: the stages cells go through including replication_^*, transcription*, translation*

  • Metabolism: chemical reactions that occur in cells such as cellular respiration

Molecular Biology

• Study of nature, physiochemical organization, synthesis working and interaction of bio-molecules that bring about and control various activities of the protoplasm_^*

• How molecules are synthesized, modified and interact

• How molecules regulate gene expression_^*

• How molecules define cell structure and function

• How molecules interact with each other, such as DNA, RNA and proteins

• Studies the molecular basis of biological activity

Physiology

• Studies functioning of living organisms, animals, plants, and their constituent_^* tissues or cells

• Asks questions about internal workings of organisms and how they interact with the world around them

• Tests how organs and systems within the body work, communicate and how they combine efforts to make conditions favorable for survival

• Often separated into several sub-categories

Embryology

• The study of fertilization, growth, division and differentiation of the zygote into embryos or early development of living beings before attaining the structure and size of the offspring

  • Comparative Embryology*

  • Experimental Embryology*

  • Chemical Embryology*

  • Vertebrate Embryology*

  • Tetralogy_^*

Ecology

• The study of living organisms’ relationships to other organisms and their environment

Genetics

• The study of inheritance of characteristics or heredity and variations

• Expression and transmission of traits from parents to offspring

• Genes may influence characteristics such as eye color, height and susceptibility to certain illnesses

Eugenics

• Science that deals with factors relating to improvement or impairment of race, especially in human beings

Evolution

• Study of origin of life and new types of organisms from the previous ones by modifications involving genetic changes and adaptations

Paleontology

• Study of fossils or remains and impressions of past organisms present in rocks from different ages

Exobiology

• Scientific Inquiry dealing with possibility of life in outer space

Virology

• Study of viruses including structure, function and how they cause disease

• Subfield of Microbiology

• Includes soil type, rivers, mountains, environment, etc.

Microbiology

• Study of Microorganisms or microbes

• Includes bacteria, archaea, algae, fungi, protozoa and viruses

• 17th century discovery of organisms invisible to the naked eye

• Has been believed that “invisible” entities cause sickness and decay since the 13th century

Characteristics of Living Organisms

Seven Characteristics of Living Organisms

• Order

• Sensitivity or response to the environment

• Reproduction

• Growth and Development

• Regulation

• Homeostasis

• Energy Processing

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