What is biology?

• The scientific study of life poses questions about the living world and seeks answers through scientific inquiry and central activities of biology

  • A biosphere consists of all life on Earth and all the places where life exists

  • An ecosystem consists of all the living things in a particular area along with the non-living components

  • A biological community is the array of organisms inhabiting a particular ecosystem

  • A population consists of all the individuals of a species living within the bounds of a specified area

  • Individual living things are called organisms

The two types of cells

• A eukaryotic cell contains membrane-enclosed organelles. Some organelles, such as the DNA-contained nucleus, are found in the cells of all eukaryotes; other organelles are specific to particular cell types

• Prokaryotic cells lack a nuclear or other membrane-enclosed organelles(generally smaller than eukaryotic cells)

Evolution

• Evolution is the scientific explanation for the unity and diversity of organisms

The Three Domains of Life

• Prokaryotic organisms - these are single-celled organisms

  • Bacteria

  • Archae

• Eukarya - all the eukaryotes are grouped into this domain

  • This domain contains three kingdoms of multicellular eukaryotes

    • Plantae

    • Fungi

    • Animalia

Charles Darwin and the Theory of Natural Selection

• Species accumulate differences from their ancestors as they adapt to different environments over time.

• “Natural selection” is a primary cause of the descent with modification

  • Natural selection is when the natural environment consistently “selects” certain traits among naturally occurring variant traits in the population

Scientists and the study of nature

• An inquiry is the search for information and explanations of natural phenomena

• Data is recorded observations

• A hypothesis is an explanation, based on observations and assumptions, that leads to testable predictions

• An experiment is a scientific test, often carried out under controlled conditions