all living things are made up of one (unicellular) or more cells (multicellular). › cell -...
Post on 02-Jan-2016
216 Views
Preview:
TRANSCRIPT
Characteristics of LifeChapter 1
Organization and Cells
All living things are made up of one (unicellular) or more cells (multicellular). › Cell- smallest unit capable of performing
all life’s processes.
Organization and Cells Living organisms have organization.
› Organization- high degree of order within an organism’s internal and external parts and its interaction with the living world. Highest level of organization- organism is
made up of organ systems that carry out specific functions within the organism (Ex: digestive system).
Organization and Cells
Response to Stimuli (Responsiveness)
Living things respond to a stimulus. › Stimulus- physical or chemical changes in an
organism’s internal or external environment.› This is essential to survival.
Homeostasis Homeostasis- maintenance of a
stable internal environment despite the constant changing of an organisms external environment.
Organisms have built in system that maintains stable internal conditions, such as:› Temperature› Water content› Nutrient uptake by cell
Metabolism Energy is required to power ALL life’s
processes, such as› Growth and development› Movement› Repair
Metabolism- sum of all the chemical reactions that take in and transform energy and materials from the environment.
Metabolism
Photosynthesis › Plants, algae, phytoplankton, and some
bacteria capture and use the sun’s energy to make sugar molecules.
Organisms that cannot make their own food must get their food from other organisms.
Growth and Development
Nonliving things (Ex: icicles) grow by accumulating more of the same material (Ex: ice) of which they are made.
LIVING things grow through division and enlargement of cells. › Living multicellular organisms mature
through cell division, cell enlargement, and development.
Growth and Development Development- process by which
organisms become more adult. › Involves: cell division, cell differentiation,
or specialization. › Your body contains trillions of specialized
cells (Ex: nerve cells, blood cells, skin cells..), all of which originated from a single cell, the fertilized egg.
Reproduction Reproduction- Organisms produce
more organisms like themselves. › NOT needed for individual’s survival.
However, reproduction is ESSENTIAL to survival of a species.
Hereditary information is passed from parent to offspring through DNA. Short segments of DNA make up individual genes.
Reproduction
Two major types of reproduction:› Sexual reproduction- hereditary
information recombines from TWO organisms. Offspring are similar but not identical to either parent. Ex: Frogs
› Asexual reproduction- herditary information comes from a single parent organism. Offspring are identical to parent. Ex: bacteria
Evolution The basic GENETIC characteristics of
an individual organism do not change over their lifetime.
Populations of organisms DO change through time, or evolve.› This is critical to survival in a changing
world.› Explains the diversity of life-forms we see
on Earth today.
Themes in Biology
Diversity and Unity of Life
Living things come in many varieties (huge diversity).
Diversity and Unity of Life
Although diverse, living things are characterized by unity, or things they have in common.› Genetic code- rules governing how cells
use hereditary information.› Organelles that carry out life’s functions.
Diversity and Unity of Life “Tree of Life”- a model of the
relationships by ancestry among organisms. › Living things share certain genes, yet no
two types of organisms share all the same genes.
› Three main lineages, called domains. Organisms found on closer branches (lineages) have more similar sets of genes.1. Bacteria2. Archaea3. Eukarya - complex cells containing a
nucleus.
Less complex cells
Diversity and Unity of Life
Another system of grouping organisms divides life into six categories called kingdoms.› 4 kingdoms within domain Eukarya
Kingdoms Animalia, plantae, fungi, protista› 1 kingdom within domain Archaea
Kingdom Archaea› 1 kindom within domain Bacteria
Kingdom Bacteria
Tree of Life
Interdependence of Organisms
Ecology- study of how organisms interact with each other and the environment.› Study single species as well as
ecosystems. Ecosystems- communities of species and
their physical environment. Studies have shown that species depend on
each other and their physical environment for survival.
Evolution of Life Evolution- (decent with modification)
process in which inherited characteristics within POPULATIONS change over generations.› Can lead to genetically distinct populations
and development of new species.
Evolution of Life Theory of Evolution by Natural
Selection› Natural Selection- organisms with
certain favorable traits survive and reproduce more than those without them. Those traits that increase an organism’s
ability to survive and reproduce are called adaptations.
top related