OVERVIEW:

pp. 5-

What is biology?

The study of life….we ask and answer questions about the natural world….how things work, interact with the environment, and change over time.

Examples of things biology cover:

Air pollution

Technological tools

Predict future food supply

Curing diseases

Which foods are healthy

DO ACTIVITY!

Are these things alive?

1. Leaf

2. Water

4. Fire

Things that are living or were once living?

Eight characteristics of life:

1)  And 2) organization and presence of one or more cells

  1. cell is the smallest unit that can perform all life’s processes
  2. made up of one cell is unicellular (i.e. bacteria)
  3. made up of multiple cells is multicellular (i.e. humans)

-refer to pages 6 and 7: levels of organization in the owl

non-living rock: has shape but usually irregular (not organized like an owl: think about owls of the same species…are all rocks the same?)

3)  response to a stimulus

  1. a physical or chemical change in the internal or external environment (i.e. if I shined a flashlight in your eye, your pupil would dialate)

4)  homeostasis

  1. stable internal conditions despite environmental changes (i.e. we sweat to maintain reasonable body temperature; an owl can fluff up its feathers in cold weather to trap a layer of insulating air)

5)  metabolism

  1. sum of all the chemical reactions that take in and transform energy and materials from the environment (i.e. plants use photosynthesis to create sugar molecules)
  2. think: we need energy to live, repair, move, grow

6)  growth and development

  1. growth: division and enlargement of cells (cell division – form new cells from an existing cell..unicellular organisms generally just get larger, whereas multicellular organisms develop)
  2. development = process organism goes through to become mature adult (cells specialized for function, for instance carrying oxygen in the blood)

non-living icicle: grows with more water being added and freezing…not the water that started out literally growing more and forming an icicle

7)  reproduction

  1. nonessential for survival of the individual, but essential for the continuation of a species (hereditary info passed on through DNA, with short segments called genes)
  2. sexual (individuals like us..combination of hereditary info of 2 organisms in the same species) vs. asexual (bacterium splits into 2 identical cells)

8)  change through time or “evolve”

  1. change through time is important for survival in a changing world

How can we understand so many different organisms??

Themes in biology!

Diversity of life is amazing…..single-celled organisms that thrive inside thick Antarctic ice that never thaws, whales containing 1,000 trillion cells that migrate from Alaska to Mexico, plants that can capture and eat insects

Biologists have identified more than 1.5 million species on Earth

Unity in life: features that living things have in common

-genetic code (how cells use the hereditary information in DNA)

-create lineages (see p. 10); more distant branches = more distantly related organisms (“tree of life” with more similar organisms on closer branches)

The “tree” has three main branches…called domains (three main subdivisions of all organisms). In that there is a six kingdom classification system

1)  Bacteria

I.  Bacteria

2)  Archaea

I.  Archaea

3)  Eukarya (larger and more familiar organisms…animals, plants, fungi)

I.  Animalia

II.  Plantae

III.  Fungi

IV.  Protista

Ecology – studies organisms interacting with each other and with the environment

è  ecologists study species as well as ecosystems = communities of living species and their physical environments (organisms depend on each other as well as on nutrients, water, gases, heat, etc. in their physical surroundings…panther eats bird which eats nuts from trees, tree needs carbon dioxide and water, carbon dioxide is a main byproduct of all animals)

Evolution of Life:

Although individuals change during their lifetime, their basic genetic charcteristics do not change

-populations of living organisms do change through time, or evolve

Evolution = (aka descent with modification) is the process in which the inherited chracteristics within populations change over generations, such that genetically distinct populations can develop

->natural selection – organisms have certain favorable traits that are better able to survive and reproduce successfully than organisms that lack these traits

-> adaptations –traits that improve an individual’s ability to survive and reproduce (rabbits with white fur and short ears in a snowy place may avoid predators and frostbitten ears more often than those with dark fur and long ears…so more white rabbits make it and reproduce leaves us with a next generation of rabbits with a higher percentage of animals carrying genes for white fur and short ears)

We can think of the tree of life as somewhat mapping out where organisms came from