Chapter 10 Notes
A. What is Heredity?
1. Heredity is the passing on of traits from one
generation to another.
B. Who was Gregor Mendel and what did he do?
1. Studied the traits of pea plants because they
could self-pollinate.
2. Traits are inherited forms of characteristics,
such as white and purple flower color
3. He discovered that some traits are hidden, or
recessive and that some traits always appear, or
are dominant.
4. Also determined that each parent donated a set
of instructions for each trait. These later were
called genes.
5. Alleles are different forms of each gene.
C. What is a Punnett Square?
1. A Punnett Square is a diagram that shows all
possible combinations of alleles, or the
genotype, from the parents.
2. Dominant trait represented by a capital letter,
recessive trait represented by a lower case letter.
3. The male alleles are listed across the top, while
the female alleles are list down the side.
4. The recessive trait will only appear when two
recessive alleles are present.
5. The actual appearance of the organism is its
phenotype.
D. What are exceptions to Mendel’s conclusions?
1. Incomplete dominance occurs when one trait is
not completely dominant over another trait.
2. Incomplete dominance creates pink flowers from
red and white flowers.
3. One gene can influence many traits for example
white tigers fur gene also controls the tiger’s
blue eyes.
4. Many genes can influence one trait or example
eye color and height.
5. Environment affects traits such as eating healthy
and practicing a talent.
E. What are genes and DNA?
1. Genes are passed from one generation to
another.
2. Genes are part of DNA
3. Rosalind Franklin took pictures of DNA using
X-ray diffraction.
4. Photographs revealed that DNA was spiraled.
5. James Watson and Francis Crick described DNA
as being a double helix, or shaped like a twisted
ladder.
F. Natural Selection is the process by which
individuals with favorable traits survive and
reproduce.
1. It was proposed by Charles Darwin who
thought that traits accumulated in a
population through natural selection.
2. Favorable traits make an organism better
adapted to its environment.
3. A population is a group of organisms of the
same species
G. There are four basic steps in natural selections:
1. Overproduction – organisms have more
offspring than can survive to become adults
(strongest survive)
2. Genetic Variation – some organisms have
traits that improve their chances of survival
while other traits lower survival chances. No
two individuals have the same traits.
a. Adaptations are traits that improve the
chances for survival and reproduction.
These traits are passed on to future
generations.
b. Some traits may be favorable for one
environment, but harmful in another.
3. Struggle to Survive- Survival of the fittest.
a. In natural environments, all organisms
in a population may not be
supported.
b. Organisms must compete for food,
water, living space, and mates
c. Organisms must also battle disease
and predators
d. Only some organisms are born to
survive long enough to reproduce
4. Successful Reproduction – Individuals who
are better suited to an environment are more
likely to pass on their traits.
a. Individuals who are not well suited to
an environment are likely to die early
with few or no offspring.
b. Organisms must also have the right
traits to attract a mate such as the
peacock tails and large deer antler.
H. Watching natural selection
1. Populations respond to changes in their
environment. If the changes are big enough,
it may affect the survival of the population.
2. Those that survive will pass their traits on to
the next generation.
3. Examples: Peppered moth, Insects and
insecticides, bacteria and antibiotic
medications
I. Heredity or Environment – Which plays a greater
role in the development of an individual?
1. Both genes and the environment play a part
in the development.
2. Grown in different conditions – change in
environment
3. Chemistry of the individual body – the arctic
fox produces chemicals in the fox’s skin that
are sensitive to temperature.
4. Temperature
5. Soil chemistry (hydrangea)
J. Learned Behavior
1. Genes influence behavior as well as
appearance
2. Instincts are inherited behaviors
3. Some behaviors are learned from experience
or watching others
4. Human ability to speak is inherited, but
language is learned.
5. Dog tricks are learned
6. The instinct to hunt is inherited, but the actual
hunting is learned (cats, dogs, wolves)
K. Types of Interactions
1. Ecosystems – all the populations that live in
an area plus everything, living and nonliving,
that affects them
a. All living things must interact with
their ecosystem
2. Interactions with the Environment
a.Limiting factors: things that limit the
size of the population such as
predators, food, water, living space,
temperature, climate, and water. Any
single resource can be a limiting factor.
b.Carrying Capacity – the largest
population that can live on the land.
As a population grows, more pressure
is put on the ecosystem to supply food,
land, etc.. The limiting factors help
keep a population in check. When a
population grows larger than the
ecosystem carrying capacity, the
limiting factors will cause the
population to decline.
3. Interactions among Organisms
a. Community – all the species living in
an area – a population living in a
specific area or habitat
b.Four ways that organisms in a
community interact with each other:
competition, predator-prey, symbiosis,
long-term interaction
1) Competition – when two or
more individuals or
populations use the same
resources and must compete
for these resources (food,
water, space, sunlight).
2) As the ecosystem's resources
are limited, it leaves less for
others to use.
3) Can happen between
different populations (trees
competing for sunlight) or
within the same population
(elk in Yellowstone
competing for food).
L. Predator - Prey Interactions: animals compete for
food where the prey is eaten and the predator does the
eating
1. Predator adaptations - must be able to adapt
to catch their prey, ability to run, trap and
camouflage
2. Prey adaptation - must be able to run, stay in
groups, camouflage, have protective coloring,
or mimicky markings such as moths with
large black spots that look like owl eyes.
M. Symbiosis - close long term relationship between
two species which may or may not be harmful to the
species involved.
1. Mutualism - both organisms are helped
a. humans and intestinal bacteria
b. clown fish and sea anemone
c. coral and certain algae
2. Commensalisms - one is helped, but the other
is neither helped nor harmed.
a. sharks and remoras: remoras ride on
the backs of sharks to eat the food left
behind by the shark.
3. Parasitism - one (parasite) is helped while the
other (host) is harmed.
a. ticks, tapeworms
N. Long term Interactions - may cause changes in
response to the other
1. ant and acacia tree - ant protects trees from
herbivores, tree provides food for ants
2. pollination - some pollinators have adapted
very specialized beaks to gather nectar from
plants. If plant were to become extinct then
the animal would also become extinct