Title: Characteristics of Living Things
1The Keys to Life Characteristics of Living
Things
2What is Life?
- "In an organism, a condition in which there is
reproduction, growth, development, metabolism,
use of energy, excretion, response to stimuli and
composition of cells."
3Characteristics of Living Things
- Made up of units called cells
- Grow and develop
- Maintain a stable internal environment
homeostasis - Respond to the environment
- Can reproduce
- Obtain and use materials and energy
- Taken as a group, change over time (evolution)
- Based on a universal genetic code (DNA)
4Cell Structure and Function
- Cells have specialized structures that carry out
the cells life processes
5Cells Make Up Organisms
- Cells have specialized structures that carry out
the cells life processes - Two types of organisms Prokaryotic Eukaryotic
- Prokaryotes
- lack membrane bound organelles
- Eukaryotes
- contain membrane bound nucleus and organelles
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7Cell Theory
- Formed from the works of Hooke, van Leeuwenhoek,
Schleiden, Schwann, Virchow - Three main premises
- All living things are made up of at least one
cell. - Cells are the basic unit of structure and
function - All cells come from existing cells
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8Reproduction
- All species of organisms have the ability to
reproduce - Organisms reproduce like organisms.
- Life comes only from life. -- BIOGENESIS
- Two Types sexual and asexual
- Sexual-involves 2 parts of one
- organism or from 2 different
- organisms of the same species
- Asexual-does not combine heredity info from
different organisms of the same species
9Reproduction
- Transmission of hereditary information (DNA) to
offspring - Essential for the continuation of a species
- DNA deoxyribonucleic acid
- Shape double helix
- Composed of nucleotides
10Reproduction
- Nucleotide consists of sugar, phosphate group and
base - Uprights of ladder are alternating deoxyribose
units and phosphate groups 4 bases make up
rungs adenine, thymine, cytosine, and guanine
A---T, C---G - Read in 3 letter combos at a time -- CODONS
11Structure of DNA nucleotides are repeating
units
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12Growth and Development
- All living things grow
- Growth is a result of cell division and cell
enlargement - To grow is to change in size.
- Cell division is the formation of 2 or 4 cells
from an existing cell (mitosis and meiosis) - Newly divided cells enlarge to the size of a
mature cell
13Growth and Development
- An adult organism arises from the process of
development - Occurs due to repeated cell divisions and cell
differentiation - To develop is to change in shape and form.
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14Obtain Materials and Using Energy
- How organisms obtain, use, and transfer energy
for life - All living things use energy in a process called
metabolism - The sum of all the chemical
- processes that occur in the organism
15Obtain Materials and Using Energy
- Two basic pathways
- 1. Cellular respiration takes in food, breaks
it - down into glucose, converts to ATP
(energy) - 2. Photosynthesis uses sunlight, water, and
- carbon dioxide to make glucose (then, the
- photosynthetic organisms go through
cellular - respiration)
16Obtain Materials and Using Energy
- Almost all energy for life on earth derived from
photosynthesis - Autotrophs produce their own energy by making
their own food - EX. Plants
- Heterotrophs must take in food to meet energy
needs - EX. Herbivores, carnivores, omnivores,
scavengers, detrivores
17Obtain Materials and Using Energy
- Living things are set apart by their complexity
- All living things are highly organized at both
the molecular and cellular levels - Most multicellular organisms have cells and
groups of cells organized by function
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18Environmental Response
- Response a reaction to a stimulus
- Ex. Plant responding to light will move its
leaves to maximize exposure for photosynthetic
processes.
Boy, that water sure looks cool and refreshing
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19Homeostasis
- Organisms are looking for HOMEOSTASIS
- process where organisms try to reach a steady
state or balance - Please add this comment to your notes as it is
not on your handout!
20Homeostasis
- All living things maintain stable internal
conditions - Includes regulation of temp, water content, food
intake, etc. - Most multicellular organisms have gt1 systems
maintains important internal controls - Keep in mind that living orgs NEVER reach a
perfect balance it is a constant balancing act
of overshooting and undershooting the goal
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21Change over time -- Evolution
- Change over time evolution
- EVOLUTION is the gradual accumulation of
adaptations over time that help a group of
organisms survive and be able to produce new
offspring that would demonstrate the BEST
combination of adaptations - SURVIVAL OF THE FITTEST!!!
22Change over time -- Evolution
- Populations of organisms gradually change
(evolve) over generations - Process of natural selection important to
evolution process - Survival of the fittest
- Survivors pass favorable traits on to offspring
23Changes in beetle populations over time
24Evolutionary benefits can be due to better
camouflage
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