Transcript 2nd Semester Final Review






A hypothesis is a “guess” about what might happen in an experiment
based on observations.
A theory is a “broad” explanation of a phenomena that has been
scientifically tested and supported.
An example of a hypothesis could be: If a plant is left in a dark closet for
a week, then it will die.
If you did indeed perform this experiment and the plant died, then
repeated the same experiment several times with the same result, you
could form a theory that plants placed in dark closets for a week will die.
Here’s the question though—did you prove without a doubt that all
plants will always die after a week in a closet?
So, how is a theory different than a law, such as the Law of Gravity?


In Biology, evolution means that a species will
evolve over time in order to insure continuance
of that species.
Can individuals evolve?


An example of natural selection are the various beak
sizes of the finches that live in the Galapagos Islands.
Short beaks can crack nuts and long beaks can reach
into deep places to get insects.
Artificial selection occurs when a species is bred for
certain traits by human beings—generally to benefit
the human population. Dachshunds were bred to
scent, chase and flush out burrowing animals.

That Earth is
very old,
about 4.54
billion years
old….
Genetic Variation in Populations


Bio means life.
Geography means
location.

Biogeography means
the location of
organisms on Earth.

Species that are
closely related will
show similarities in
embryos.
Traces of organisms that once lived on Earth.



Microevolution is
basically changes in
allele frequencies within
populations.
Macroevolution is
evolutionary change
that forms a new
species.
Which picture
represents each type of
evolution?


The organisms have a
common ancestor.
The organisms would
show similarities in
the nucleotides of
their DNA.
Gradualism takes place over a long period of
time while punctuated equilibrium happens in
“spurts”.









1. Domain: There are how many?
Three: Bacteria, Archae and Eukarya
2. Kingdom
3. Phylum
4. Class
5. Order
6. Family
7. Genus
8. Species

No, only sex cells will pass a mutation on to
offspring.


Phylogenetic trees only
show hypothesized
relationships.
Cladograms show
evolutionary history
among species.

Autotrophs make
their own food.

Heterotrophs do not
make their own food.

1. type of energy they
require

2. type of body structure

3. type of root system

4. cell type

5. type of reproduction

All of these except the type
of root system

Provides a pathway to and from the central
nervous system.

Motor Neurons


It coordinates muscle
movement,
subconscious
activities and some
balance functions.
It contributes to
coordination,
precision and accurate
timing.

The hypothalamus
regulates hunger and
thirst.


This is the cerebrum.
It receives signals and
controls movement.

Sensory neurons are
typically classified as
the neurons responsible
for converting external
stimuli from the
environment into
internal stimuli. They
are activated by sensory
input (vision, touch,
hearing, etc.), and send
projections into the
central nervous system
that convey sensory
information to the brain
or spinal cord.

As part of the
peripheral nervous
system, the autonomic
nervous system
controls involuntary
functions of the
internal organs such
as the heart rate,
digestion, respiratory
rate and perspiration.



The myelin sheath
insulates the axons and is
essential for the proper
functioning of the nervous
system.
The main purpose of the
myelin sheath is to
increase the speed at
which impulses move
along the myelinated
fiber.
Multiple sclerosis is a
disease that destroys the
myelin sheath, thus
affecting the nervous
system.


When the body feels
pain, it releases natural
painkillers called
enkephalins, but they
only last a few seconds
because the enzymes in
our bodies neutralize
them.
Narcotics mimic the
effects of enkephalins
thus relieving pain and
can be used for more
extensive periods of
time.

Communication of
information between
neurons is accomplished
by movement of chemicals
across a small gap called
the synapse. Chemicals,
called neurotransmitters,
are released from one
neuron at the presynaptic
nerve terminal.
Neurotransmitters then
cross the synapse where
they may be accepted by
the next neuron at a
specialized site called a
receptor.

Affect the CNS by
changing the activity
of the synapses by
mimicking the action
of a neurotransmitter.

It decreases the
activity of the central
nervous system.







Hormones are your body's
chemical messengers. They
travel in your bloodstream to
tissues or organs. They work
slowly, over time, and affect
many different processes,
including:
Growth and development
Metabolism - how your body
gets energy from the foods you
eat
Sexual function
Reproduction
Mood
Hormones are removed from
the blood and broken down in
the liver.


Hypothyroidism is
a condition in which
the thyroid gland
does not make
enough thyroid
hormone which
controls
metabolism.
In adults, it can
cause a lack of
energy and
unintentional
weight gain.



The pancreas is a gland
organ in the digestive system
and endocrine system. It is
both an endocrine gland and
digestive organ.
It produces hormones like
insulin, glucagon,
somatostatin and pancreatic
polypeptide.
It also secretes pancreatic
juice and enzymes that help
with the absorption of
nutrients in the small
intestine.





When cells get to be a
certain size they will
divide because:
New cells are needed
for growth.
If the cell gets too big, it
cannot transport
nutrients properly.
The DNA cannot be
copied quickly enough
for cells that are too
large.
Cells that do not
respond to checkpoints
can become cancer cells.






Bacteria reproduce
asexually. (binary fission)
Viruses reproduce
through a host cell.
Bacteria can be killed with
antibiotics.
Viruses cannot be killed
with antibiotics.
Both are considered to be
pathogens because they
cause disease.
Killed or weakened
pathogens are used to
make vaccines.



Haploid cells have only one
set of unpaired
chromosomes. These are the
sex cells and pass on
hereditary traits.
Diploid cells have two
haploid sets of chromosomes
Homologous chromosomes
contain pairs of
chromosomes that contain
genes that code for the same
traits.
Hint: It is the Powerhouse of the Cell!

The Mighty
Mitochondria!


A strand of DNA
formed by combining
DNA from two
different species.
RNA is used to join
the DNA molecules.


Genetic engineering.
By adding Bacillus
thuringiensis to
certain plants, they
are able to resist
insects.


Professor Ian Wilmut and Dolly 1997
Dolly was the first
cloned sheep and
important because
sheep had never
responded to gene
technology
procedures before.
Cloning is a process
by which science can
eliminate undesirable
traits in new
individuals.