Studying Life: What does it mean to be alive?
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Transcript of Studying Life: What does it mean to be alive?
Studying Life: What does it mean to be alive?
Objectives: 1. Describe some
characteristics of living things
2. Explain how life can be studied at different levels
Question:1. What does it mean to be
alive?2. What do all living things
have in common?3. Are there any non-living
objects that have living characteristics? Is this fire alive???
1. Cells All living things are made
up of cells Cells are the smallest units
of an organism that can be considered alive
Cells can grow, respond, and reproduce
Despite their small size, they are complex and highly organized
Unicellular organisms = 1 cell
Multicellular = many cells
Stem Cells
2. Reproduction All living things produce
other living things There are 2 types of
reproduction
=Sexual: cells from 2 different parents unite to form first cell
=Asexual: New organism as a single parent
3. Based on a Genetic Code
Offspring resemble their parents
Asexual reproduction results in offspring with identical traits
Sexual reproduction creates variety with similar features
DNA: carries directions for inheritance
4. Growth and Development
All living things grow at some point in their lives
For many single-celled organisms growth is simply an increase in size
For multi-cellular organisms they develop from one cell into many through cell division
As the cells develop they take on different rolls
Nerve Cell Skin Cells
Blood Cells
5. Materials and Energy Organisms need materials
and energy to stay alive Metabolism: process of
breaking down materials for energy that is needed to make other vital materials
Autotrophs: use sunlight as their source of energy
Heterotrophs: consume other organisms for energy
Autotroph or Heterotroph?
6. Response to Environment Organisms detect and
respond to stimuli in the environment
7. Maintain Internal Balance Homeostasis: process of
maintaining a stable internal environment (Temperature)
8. Evolution Change of a species over
time
Individuals do not evolve Groups of organisms can
change