103, BSCI Spring 2012
Lecture Notes Exploring life
Chapter 1
All life forms have common features
All living things have order organized structures that work together
Regulation living things control their internal environment which can be very different from the external
environment
Growth and development genes direct these processes, all living things have DNA with heritable units
called genes
Energy processing living things take in energy and use it to grow and develop
Response to environment living things respond to stimuli from the environment
Reproduction Living things produce their own kind
Evolutionary adaptation Species change over time
Levels of organization
Biosphere all of earths environments that support life living earth
Ecosystem- all organisms living in an area + nonliving components soil, water, atmosphere pine barrens
Community-all organisms inhabiting an ecosystem - all living things in the pine barrens
Population all members of the same species living in the pine barrens
Organism an individual living thing - Tony Soprano
Organ system several organs that work together - Tony Sopranos circulatory system
Organ-structures composed of several tissues that work together to perform a function Tonys heart
Tissue group of similar cells cardiac muscle in Tonys heart
Cells unit of living matter separated from the environment by a membrane muscle cell
Organelle a structure that performs a specific function within a cell - mitochondria
Molecule cluster of atoms held together by chemical bonds myosin in the cell
Atoms the smallest particles of ordinary matter a carbon atom in myosin
Living organisms interact with their environments to exchange matter and energy - food webs
Producers plants and other photosynthetic organisms trap energy and use it to make sugars from CO2
and H2O.
Consumers eat plants and each other and release CO2 and H2O.
Decomposers breakdown dead living things and recycle molecules
Ecosystems have two major dynamic processes nutrient cycles and energy cycles
Cells are the structural and functional units of life
Lowest level of organization that can perform all functions of life reproduction, movement, respiration,
control of internal environment
The of levels organization have emergent properties novel activities and functions as they interact
Individual components at level interact to form systems e.g. ecosystems, organ systems
Two kinds of cells exist
o Prokaryotes small simple cells like bacteria lacking a nucleus and organelles
o Eukaryotes larger more complex cells with internal structures like membranes and organelles
All cells use DNA to store genetic information
Life can be arranged in three domains
Taxonomists are biologists that name and classify living things
Kingdoms of life historically life was classified into five kingdoms animals, plants, fungi, protists, etc.
Domains scientists agree that three domains of life exist
o Bacteria consists of prokaryotes, single celled organisms found in many places
o Archaea also prokaryotes, single celled organisms found in extreme environments - thermal
vents
o Eukaryotes cells with a nucleus and organelles divided into kingdoms such as plants, fungi,
animals, and protists
Protists a diverse group of eukaryotes several kingdoms that live in moist and aquatic habitats amoeba,
algae, diatoms
Plants make their own food
Fungi break down dead organisms
Animals eat other organisms
Evolution - A theory that explains the unity and diversity of life
o Organisms alive today descended from earlier life
o Natural selection is the mechanism that explains this change
o Two observation led Darwin to this
o Individual variation
o Overproduction and competition
o From this Darwin inferred
o Unequal reproductive success this leads to natural selection
o Heritable traits lead to differential reproductive success some live, others do not
Scientists use two main approaches to learn about nature
o Discovery science observations and measurements, some data quantitative, some qualitative,
collecting and analyzing observations uses inductive reasoning
o Hypothesis based science
o Hypothesis pose an answer to a question
o They use deductive reasoning logic that flows from general to specific
o Coral snake king snake experiment
Scientific method
o Observation Question Hypothesis Prediction Experiment Result Accept
or reject hypothesis
o Scientists share results through publications and electronic delivery