Ch. 1 Biology: The Science of Life  There is an estimated 40 million species of organisms that exist on Earth. Only about 2 million of those have been named.  What does this tell you?  What is Biology?  The study of life

 Living organisms were recorded about 3.5 to 3.8 billion years ago.  According to fossil evidence.  The Earth is thought to be 5 billion years old.

7 Themes of Biology  1. Evolution  2. Reproduction & Inheritance  3. Development  4. Structure & Function  5. Energy Relationships  6. Ecology  7. Science & Society

Evolution  Evolution is the theory that species change over time.  Natural Selection – is the theory that if organisms have better inherited traits they are able to survive better and thus pass those traits on (reproduce). “Survival of the fittest”. Ex. Living – Extinct - Molecular  Receiving better traits is called adaptations. Those organisms that don’t adapt, don’t survive to pass on their traits.  Video Video Clip

 Better traits get pass on because of adaptations. Pg. 8  By studying fossils of an organism we can determine whether an organism evolved or adapted over time.  Every thing changes  Computers, electronics, machines, cars, etc.

Reproduction & Inheritance  Reproduction involves the transfer of genetic information from parent to offspring.  Genetic information is stored in DNA. Each parent passes on a gamete containing DNA.  Genes are short segments of DNA that contain chemical messages for certain traits.  Ex. Brown eyes, blonde hair  Chromosomes  DNA  Traits  Genes

 There are 2 types of reproduction  1. Sexual  egg gamete & sperm gamete  2. Asexual  where genetic information from different organisms is not combined  Ex. Organism divides into 2 separate organisms  The receiving of traits from the parents is called?  Inheritance

Development  What are all organisms composed of?  Cells  An organism with many cells is called?  Multicellular  An organism with only one cell is called?  Unicellular  By what process do cells divide?  Mitosis

Structure & Function  Morphology describes the structure and form of an organism.  Ex. The morphology of a frog’s leg. (function & form)  The anatomy of an organism deals with the internal make up of an organism.  Ex. Frog’s heart

Energy Relationship  Where do all organism essentially get their energy from?  Sun  mainly by photosynthesis  What are organisms called that acquire energy by making their own food?  Autotrophs – Examples???  What are organisms called that acquire energy by eating other organisms?  Heterotrophs – Examples???

Ecology  What is ecology?  The study of the interactions among organisms and their environment in which they live.  By studying an organisms environment & its interactions with other organisms scientists are able to produce a safe & healthy environment for organisms to live in.

Science & Society  What is ethics?  Study of what is right or wrong from our moral choices.  What is bioethics?  The use of ethics in biological concerns.  Issues of concern  Cloning -- discuss ; Euthanasia – discuss  Abortion – discuss ; Aids – discuss  Stem cell – discuss ; cryogenics -- discuss

Characteristics of Life  1. All organisms must have cells.  2. All organisms are organized, in which specific parts like cells perform specific functions.  3. Need the right amount of energy and use it by the process of metabolism.  4. Must be able to respond to the environment by homeostasis.  What is a response?  Reaction to a stimulus – pg. 12

 5. Growth must occur by mitosis and cell enlargement.  6. Reproduction must occur in order for their genes to be passed on to the next generation.  7. Adaptation must occur in order for an organism to survive to reproduce.  Ex. Snakes with legs – vestigial organ  More fully developed in the ancestors.