Semester 2 Review:
Genetics/Heredity
Inside the nucleus of our cells you will find _________chromosomes_________. We have ___23__ pairs of
chromosomes in our body cells. We get _____23_____ from mom and _____23_____ from dad. Our chromosomes
are made up of ______DNA_____. If I look at a section of that DNA on the chromosome, that would be called a
______gene______ for one of the traits I hold. I get 2 alleles for each trait I hold. Those alleles can be either
____dominant_____ or _______recessive________.
I can use a punnett square to see all the ways that my _______alleles________ can combine.
Define:
Asexual reproduction- One parent organism produces offspring without meiosis and fertilization. All offspring
are identical to the parent because they inherit all their DNA from that one parent.
Sexual reproduction- When the genetic material from two different cells combines, producing a new, unique
offspring.
Heterozygous- 2 alleles in a gene that are different (Tt)
Homozygous-2 alleles in a gene that are the same (TT or tt)
Alleles- Each member of a gene pair, you receive one from each parent, it produces variations in a trait
(represented by a single letter).
Genotype- the actual genetic make up represented by letters (TT, tt, Tt)
Phenotype- the physical appearance (short, tall, brown eyes, blue eyes)
Heredity- the physical appearance (short, tall, brown eyes, blue eyes)
In asexual reproduction ___one____ cell makes an exact copy of itself and its DNA.
In sexual reproduction __two___ cells combine to make an entirely new cell with similar traits of the parent cells, but
this combination makes an entirely new organism with new DNA (more variety.)
Why would an organism created through sexual reproduction have an even number of chromosomes in each of their
cells? Because there are chromosomes from the offspring come from TWO parents.
DNA is made of 4 base pairs. Correctly pair the following:
Adenine pairs with Thymine
Guanine pairs with Cystine
What is the difference between a learned trait and an inherited trait? Learned traits are behaviors that result from
the influence of one's environment, as opposed to inherited traits, which are passed down automatically in
one's DNA.
Identify the following and choose the best answer choice:
Is it a PHENOTYPE or GENOTYPE, HOMOZYGOUS RECESSIVE, HETERZYGOUS, or
HOMOZYGOUS DOMINANT
GG
Genotype, Homozygous dominant
GG, Gg, gg, BB, Genotype Homozygous Dominant – GG, BB Heterozygous Dominant – Gg, Bb
Bb, bb
Homzygous Recessive – gg, rr
Green Eyes
Phenotype
Bb
Genotype – Heterozygous Dominant
Dominant or
Dominant – H Trait that is expressed any time it is present (represented by the capital letter,
always written first in a sequence).
Recessive
Recessive – h - trait that does not show unless there are 2 alike alleles (tt), represented by the
lower case letter, always written second in a sequence.
Gg
Blue Eyes
Dd
Dd, Tt, RR, Gg,
HH, TT
Genotype – Heterozygous Dominant
Phenotype
Genotype – Heterozygous Dominant
Genotype Homozygous Dominant – RR, HH, TT Heterozygous Dominant – Dd, Tt, Gg
Homzygous Recessive – none
Define:
natural selection- (survival of the fittest)- the traits that are naturally passed down and are best suited to
survive their environment allowing them to reproduce as well.
Selective breeding- deliberate breeding of plants or animals for desired traits.
Adaptation- an inherited trait that increases an organism’s chance of surviving in a particular environment.
Give an example of natural selection: Race horse, drought resistant plant, bug-resistant vegetable, Labradoodle
(Labrador crossing with a Poodle)
Identify the following as either selective breeding or natural selection:
Situation
A. A White rabbit thrives in a snowy environment and
passes the trait on to offspring.
B. Farmer trying to reproduce a chicken that produces
many eggs.
C. A farmer planting the seeds of a corn stalk that
produces large ears of corn.
D. Brown beetles blend in with leaves on trees, so survive
and continue to pass on to offspring.
Natural Selection or Selective Breeding
Natural Selection
Selective Breeding
Selective Breeding
Natural Selection
What is a punnett square? used by scientists to predict the possible traits of an offspring by crossing the known
genotypes
Identify which of the following is an adaptation that would increase an organisms chance or survival, circle the correct
answer choice:
A bear hibernating during the winter.
A giraffe with a short neck.
An orange beetle on a green tree.
Brightly colored cardinal that attracts mates.
Yes
Yes
Yes
Yes
or
or
or
or
NO
NO
NO
NO
Cross a heterozygous tall man with a heterozygous tall lady. What are the possible genotypes and phenotypes of the
offspring?
T= Tall
t = Short
T
t
Genotypes:
T
____25_____% homozygous tall
____50_______% heterozygous tall
____25_______% homozygous short
t
Phenotypes:
____75_______% tall
____25_______% short
Cross a heterozygous brown rabbit with a homozygous white rabbit. What are the possible genotypes and
phenotypes of the offspring?
B = Brown
b = White
B
b
Genotypes:
b
_____0______% homozygous brown
_____50_______% heterozygous brown
_____50______% homozygous white
b
Phenotypes:
_____50______% brown fur
_____50______% white fur
All animals/humans need ___oxygen___ to make energy from food. The body then gives off
__carbon dioxide__ as a waste product. This is the exact opposite for what type of organism? Plants
List characteristics of our solar system that allow life here on Earth
1. Proximity to the Sun contributes to temperature ranges experienced by a celestial body. Distances that are too
close or too far from that Sun create extreme temperature conditions that are considered inhospitable to life.
2. The presence and composition of an atmosphere contributes to the ability of life to exist. Atmospheric gases help
regulate extreme temperature variations and ozone in the atmosphere shields living things from harmful ultraviolet
radiation.
3. Earth is known as the water planet with about 70% of its surface covered by water. All life on Earth depends upon
the presence of water. There is geological evidence that liquid water was once present on the surface of Mars
Identify each of the following tree leaves using the dichotomous key above.
I.____birch______________________ II.___buckeye____________________ III. pecan_________________________
IV._______sweet gum_______
V._____red bud_______ VI._____magnolia____________________
VII.______locust__________________
Ecology
In the catastrophic events chart below, describe what type of effects that event could have on an
ecosystem. List at least 3 for each.
Name of
Effect of that event (3)
Name of
Effect of that Event (3)
Event
Event
Tornado
Secondary succession,
Earthquake
displacement of species,
Tsunami
Wipes out shallow water
ecosystems, erodes beaches
Secondary succession occurs
Pollution
Affects water quality, photosynthesis,
may destroy species,
Drought
Hurricane
Define/ Describe:
Composting- Decomposing of organic matter by fungi and bacteria transforming it into nutrient rich soil.
Watershed- An area of land where the surface water and groundwater drain into a particular body of
water; separated from other watersheds by drainage divides.
Weathering- chemical and physical break down of rocks into sediment
Erosion- the movement of sediment from one place to another
Deposition- the placement of sediment after being carried from place of origin
Succession- Process of change in a living community in which the community changes the
physical environment to eventually establish an ecosystem which is as stable.
Migration-organism moving from place to place because of climate changes, lack of food or reproduction.
What type of things could be put in a compost bin?
Does a compost bin give off heat? If so, why? Yes, the fungi and bacteria give off energy (heat) as they break
down the organic material
What types of effects do humans have on watersheds?
What would happen if a large tanker of oil accidentally crashed? Where would it go? Oil spill and the tanker
could sink to the bottom of the ocean creating an artificial reef
What are the Texas ecoregions?
Piney Woods, Blackland Prarie and Oak Woods, Western Gulf Coastal Plains, South Texas Plains, Edward
Plateau LLano Uplift, Rolling Plains (Panhandle), High Plains, Trans-Pecos
OUR Ecoregion here in Texas is the Blackland Prairie & Oak Woods
List 3 things that can trigger succession and tell me whether it would be primary or secondary.
1. Volcanic eruption - primary
2. Glacier - primary
3. Flooding/Fire - secondary
Describe why biodiversity is important.
Allows for species survival
Why do animals/plants develop adaptations?
To increase an organism’s chance of surviving in a particular environment
Give me some examples of adaptations and tell me how that helps the animal survive and prosper to keep
a high level of biodiversity.
1. Beak adaptation – get food better.
2. Thicker fur – better survive cold winters
3. Sleep pattern during winter – conserve energy
Why might animals/fish migrate?
To find food, destruction of habitat, reproduce
What is the above diagram called?
Food chain
What does the above diagram show?
Transfer of energy
What is another name for Primary Consumers?
Herbivore
What do they eat? Producers
What is another name for Secondary Consumers? _Carnivore___
What do they eat? Herbivores
What is the diagram to the right called?
Food Web
What do the arrows represent?
Direction of transfer of energy
Name some organisms from the diagram that use
radiant energy from the sun to make food?
Flowers, Ferns, Corn, Carrots
List 2 primary consumers from the diagram:
1. Cows or rabbits
2. Squirrel or deer
Name two organisms from the diagram that the wolf takes in the energy from.
Cows and rabbits
Name two organisms from the diagram that the squirrel takes in the energy from.
Flowering Plants
List the planets in order closest to the sun to farthest away.
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto (dwarf planet)
What accommodations do we need in order for humans to explore space?
Life support systems
Radio and communication/data systems (electrical)
Exercise
What is Work and what is the formula for determining how much work is being done? the amount of force
required to move an object a distance while applying force. Work formula - F (N-newtons) x d (m –meters) W = Fd