BIOLOGY 1.1

Themes of Biology

Biology is the study of life

Every l i v i ng o rgan ism sha res p rope r t i es t ha t sepa ra te them f rom non l i v ing th ings

E v e r y l i v i n g o r g a n i s m

i s c o m p o s e d o f o n e o r m o r e c e l l s

i s a b l e t o r e p r o d u c e

c a n o b t a i n a n d u s e e n e r g y t o r u n l i f e p r o c e s s e s

w i l l m a i n t a i n a c o n s t a n t i n t e r n a l e n v i r o n m e n t

c a n p a s s o n t r a i t s t o o f f s p r i n g

c a n r e s p o n d a n d a d j u s t t o t h e e n v i r o n m e n t

w i l l g r o w a n d d e v e l o p

Properties of Life What does i t mean to be a l ive?

Cel lular organizat ion Reproduct ion Metabol ism Homeostasis Heredi ty Responsiveness Growth and development

Unifying Themes of Biology

1: cel lu lar structure and funct ion 2: reproduct ion 3: metabol ism 4: homeostasis 5: heredi ty 6: evolut ion 7: interdependence

Cellular structure and funct ion

A l l l i v i n g t h i ng s a re made o f on e o r mo re ce l l s

Ce l l s a re h i gh l y o rgan i zed , t i n y s t r uc t u res t i ny s t r uc t u res w i t h t h i n cove r i ngs ca l l ed memb rane s

O rgan i sms can ran ge f r om a s i ng l e ce l l t o t r i l l i on s o f ce l l s

T he ba s i c s t r u c tu re o f ce l l s i s t he same i n a l l o rga n i sms a l t h oug h some ce l l s a re mo re co mp le x t ha n o t he rs

Reproduction

Al l l iv ing things can reproduce

Reproduct ion is the process by which organisms make more of their own kind from one generat ion to the next

Metabolism

• L iv ing organisms carry out many d i f ferent chemical react ions in order to obta in and use energy to run thei r l i fe processes. Al l l iv ing th ings use energy to grow, to move, and to develop

Metabolism is the sum of al l the chemical reactions carried out in an organism

Homeostasis Al l l iv ing organisms must mainta in

a s table in ternal envi ronment in order to funct ion proper ly

Organisms respond to changes in thei r external envi ronment and thei r in ternal processes adjust accord ingly

The maintaining of stable internal conditions in spite of changes in the external environment is called homeostasis

Heredity Al l l iv ing th ings are able to pass on

t ra i ts to thei r o ffspr ing through genes that are passed f rom parent to offspr ing

A gene is the basic uni t o f heredi ty

The passing of trai ts from parent to offspring is cal led heredity

Sometimes damage causes genes to change

A change in the DNA of a gene is cal led a mutat ion

Evolut ion

Mutat ions cause changes in the inher i ted character ist ics of species over generat ions

Change in the inher i ted character ist ics of species over generat ions is cal led

evolut ion

A s p e c i e s i s a g r o u p o f g e n e t i c a l l y s i m i l a r o r g a n i s m s t h a t c a n p r o d u c e f e r t i l e o f f s p r i n g

I n d i v i d u a l s i n a s p e c i e s a r e s i m i l a r b u t n o t i d e n t i c a l

Individuals with genetic traits that better enable them to meet nature’s challenges tend to survive and reproduce in greater numbers causing these traits to become more common.

Charles Darwin, the 19th century British naturalist, used the term natural-selection for the process in which organisms with favorable traits are more likely to survive and reproduce

Darwin’s theory of evolution by natural selection provides a consistent explanation for life’s diversity of organisms

In terdependence

Organisms in any biological community l ive and interact wi th other organisms

A biological community is a group of in teract ing organisms

Ecology is the branch of biology that studies the interactions with one another and with the nonliving parts of their environment