Chapters
1, 2 & 9
Big
Idea: Why am I Big & Full of Energy?
Or
Why
am I made of my grandma’s feces?
What is Biology?
§ Biology – the study of life
§ Involves many aspects: ecology, cellular biology, biochemistry,
molecular biology, genetics, evolution, zoology, botany, etc.
Characteristics of Living Things
§ Have
an orderly structure
§ Produce
offspring
§ Grow
and develop
§ Adjust
to changes in the environment
Organization
§ Cell or cells that function together
§ DNA or RNA that provides information to control life’s
processes
Reproduction
§ The
production of offspring is not essential to an individual organism, but for the
continuation of a species
§ Can
be sexual or asexual
Change During Their Life
§ Living things change during their lives
§ Growth results in an increase in the amount of living
material and the formation of new structures
§ Development is all of the changes that take place
during the life of an organism
Adjust to Environment
§ Environment – an organism’s surroundings, including
air, water, weather, temperature, and many other factors
§ Stimulus – anything in an organism’s external or
internal environment that causes the organism to react
§
Response –
reaction to a stimulus
Adjust to environment
§ Homeostasis – regulation of an organism’s internal
environment to maintain conditions suitable for survival
§ Done by using energy
Adapt and Evolve
§
Adaptation – any
structure, behavior, or internal process that enables an organism to respond to
environmental factors and live to produce offspring
l
Inherited from
previous generations
l
“Survival of the
fittest”
§
Evolution – the
gradual change in a species through adaptations over time
What is Ecology?
§ Ecology
– the scientific study of interactions among organisms and their environments.
l
Reveals
relationships among living and nonliving parts of the world
Aspects of Ecological Study
§
Biosphere – the
portion of Earth that supports life
l
Extends from
bottom of ocean to high in the atmosphere
l
If the Earth were
an apple, the biosphere would be thinner than the peel
§
Abiotic Factors – the nonliving parts of an organism’s
environment
l
Light, minerals,
temperature, air composition, soil, rocks, etc.
§
Biotic Factors –
the living organisms that inhabit an environment
l
6 Kingdoms:
• Animalae, Plantae, Fungi, Protista, Eubacteria, Archaebacteria
Levels of Organization in Ecology
§
Organism -
anything that possesses all the characteristics of life
§
Population – a
group of organisms of one species that interbreed and live in the same place at
the same time
l
Ex: All the bass
in Utah Lake, the elk near Hardware Ranch
l
They may compete
for resources, mates, etc. if there are limitations
§
Community – a
collection of interacting populations
l
Ex: everything
alive in Utah Lake or near Hardware Ranch
l
Communities may
also compete for resources, or may even be dependent on each other for food,
needed gasses, etc.
Levels of Organization in Ecology
§ Ecosystem – made up of the interactions among the
populations in a community and the community’s physical surroundings, or abiotic factors
l
Three Kinds:
terrestrial, freshwater aquatic, saltwater aquatic (marine)
l
There are all kinds of interactions in an
ecosystem
§ Biome
§
Biosphere
Organisms in Ecosystems
§
Habitat – the
place where an organism lives out its life
l
Ex: prairie dog in
a grassland, birds in a beech-maple forest
l
Habitats change
and even disappear
§
Niche – the role
and position a species has in its environment – how it meets its needs for food
and shelter, how it survives, and how it reproduces
l
Ex: under a rotting log
•
A worm gets
nutrients from organic material in soil
•
A centipede
captures and eats beetles and other animals
•
Ants eat dead
insects
•
A millipede eats
decaying leaves near the log
l
No two species can
occupy the same niche
•
If they try,
competition results
Living Relationships
§ Predator – Prey relationships
l
Are inversely
related
§ Symbiosis (means living together) – the relationship
in which there is a close and permanent association among organisms of
different species
Kinds of Symbioses
§
Commensalism – one species benefits and the other is neither
harmed nor benefited
l
Ex: bacteria on
your face, Spanish moss on branches of trees
§
Mutualism – both
species benefit
l
Ex: flowers and
bees, bacteria and plants
§
Parasitism – one
organism derives benefit at the expense of the other
l
Ex: ticks and
animals, tapeworms and animals
How Organisms Obtain Energy
§ All energy originates from the sun
§ Autotrophs – organisms that use the energy from the sun (photoautotrophs)
§
or energy stored in chemical compounds (chemoautotrophs) to
manufacture their own nutrients
Heterotrophs
§
Organisms that
cannot make their own food and must feed on other organisms
§
Herbivores – feed
on autotrophs
§
Carnivores – eat
other heterotrophs
§
Omnivores – feed
on both autotrophs and other heterotrophs
§
Scavengers – eat
animals that have already died
§
Decomposers –
break down and absorb nutrients from dead organisms
Food Chains
§ Matter & energy flow through organisms in
ecosystems (law of conservation of energy)
§
Food Chain – a
simple model that shows how matter and energy move through an ecosystem (what
eats what)
l
Give me an
example
l
There is less
energy at each successive step of the food chain
Food Web
§ Expresses all the possible feeding relationships at
each trophic level in a community
§ More realistic than a food chain because organisms
depend on more than one other species for food
§
As you draw a
food web, the arrows represent the direction of energy flow
Trophic Levels
§ Each organism in a food chain represents a feeding
step, or a trophic level, in the passage of energy
and materials
§ 1st trophic level
– autotrophs
§ 2nd trophic level
- 1° heterotrophs
l
Herbivores,
omnivores, decomposers, scavengers
§ 3rd trophic level
- 2° heterotrophs
l
Omnivores,
carnivores, decomposers, scavengers
§ 4th trophic level
- 3° heterotrophs
l
Omnivores,
carnivores, decomposers, scavengers
Ecological Pyramid
§ Shows
how energy flows through an ecosystem
§ 10%
Rule: only about 10% of all energy can be passed from one trophic
level to the next
ATP - Life’s Energy
§ Adenosine triphosphate
§ ATP stores energy in the bonds between adenosine and
three phosphates (which are charged).
§ When a bond between phosphates is broken, energy is
released
l
Stored by
creating bond
Photosynthesis
§ The process that uses the sun’s energy to make simple
sugars
l
These sugars are
then converted into complex carbohydrates
§ There are two phases to photosynthesis:
l
The light-dependent
reactions (convert light energy into chemical energy, ATP)
l
The light-independent
reactions (produce simple sugars)
§
6CO2
+ 6H20
à C6H12O6
+ 6O2
The Chloroplast & Pigments
§ Membranes in chloroplast contain pigments –
molecules that absorb specific wavelengths of sunlight
§ Chlorophyll
is the most common pigment
l
Absorbs most
wavelengths of light except green
Light-Dependent Reactions
§ Light
excites (energizes) electrons in the membranes
§ This
energy is used to form ATP from ADP (adenosine diphosphate),
which will be used in the light independent reactions
§ Electrons
then combine with some “stuff” to make something called NADPH, which will also
be used in the light independent reactions
Why is Water Needed?
§ Chloroplasts constantly need new electrons
§ Plants split water to get molecules in a process known
as photolysis (2 electrons per water molecule)
l
Oxygen is
released into the air through little holes in leaves called stomata (who uses
it?)
Light-Independent Reactions
§ The Calvin cycle (Melvin Calvin) is a series of
reactions that use carbon dioxide to form sugars
l
Uses what was
produced in light rxns & CO2 from
atmosphere (comes in through stomata)
Cellular Respiration
§ The process by which mitochondria break down food molecules to
produce ATP.
§ Three
stages:
l
Glycolysis
l
Citric acid cycle (Krebs cycle)
l
Electron transport chain
§ Glycolysis is anaerobic (no oxygen required)
§ The
other two stages are aerobic
Glycolysis
§ Glycolysis is a series of chemical reactions in the
cytoplasm of a cell that break down glucose in two
l
2 ATP are required
l
4 ATP are made
l
2 NADH are made
Citric Acid Cycle
§ Also called the Krebs cycle
§ A series of chemical reactions similar to the Calvin
cycle
§ Each pyruvate (pyruvic acid) loses a carbon and makes an ATP “on the way”
to the Krebs Cycle
§ Products per turn of cycle (2 turns per glucose)
l
3 NADH
l
2 CO2 -
then breathed out
l
1 FADH2
l
1 ATP - Usable
energy
ATP Totals from Aerobic Respiration
§
10 NADH molecules
= 30 ATP
l
Each NADH leads
to 3 ATP
§
2 FADH2
molecules = 4 ATP
l
Each FADH2
leads to 2 ATP
§
2 ATP during glycolysis
l
4 ATP are made,
but 2 are used
§
2 ATP during
citric acid cycle
l
1 per pyruvic acid
§
GRAND TOTAL = 38
ATP per glucose
Fermentation
§ Anaerobic
process
§ Follows
glycolysis and provides a means to continue producing
ATP until oxygen is available again
§ 2
major types:
l
Lactic acid fermentation (lactic acid produced -
in animals, for instance)
l
Alcoholic fermentation (ethanol & carbon
dioxide produced - yeast)
Cycles of Nature
§
Law of
Conservation of Matter