Download Traits - Net Start Class

Traits
Explanation:
Students will explore the difference between physical appearances passed down as
inherited traits, and responses to the environment that are learned, not inherited.
Key Concept 1: Some traits are inherited from parent to offspring, while other
behaviors are learned during an organism’s lifetime.
Organisms resemble their parents and have behaviors that help them survive within
their environments. Physical likenesses between parents and offspring are inherited,
passed from generation to generation, such as feather color or shapes of leaves in
plants. Other likenesses are learned, such as table manners, reading a book, or seals
balancing balls on their noses. Organisms that have well-adapted bodies and useful
behaviors are the ones to survive.
Key Concept 2: Inherited characteristics are things such as hair color, the shape
of a beak, and spines on a cactus.
Most of the physical characteristics of an organism are inherited from its parents
through reproduction. The genetic code (cell blueprint) from parents is transferred to the
cells of the offspring as part of its heredity. A tiger kitten will resemble its parents’ four
legs, two ears and eyes, a tail, and fur. It will breathe air and need water and food just
like its parents. Some characteristics will not be physically evident, but are inherited just
the same. The tiger kitten will also inherit being a carnivore (meat eater) and being an
instinctive hunter.
A new crop of flowers in a flowerbed will be easily identifiable because they will reflect the traits
they inherited from the parents. A young daffodil plant will have the same root system, stem,
leaf form, and flower color as its parents that supplied the seed from which it grew. It will have
the same needs for sunlight, water, and soil, and possess about the same life span. All of these
genetic characteristics are called inherited traits, having been passed from generation to
generation.
Key Concept 3: Acquired characteristics can include learned behaviors, such as a
child riding a bicycle or animals learning tricks, but can also include physical
characteristics, such as a scar.
Acquired means to obtain a characteristic after an organism is born by learning the
behavior, such as riding a bike, or being affected physically after birth, such as getting a
cut that leaves a scar. Beyond the inherited traits that an organism receives from its
parents, nature has given an organism the ability to respond to changes in an
environment. These changes by organisms to the surrounding environment are not
physical changes, but are changes in behavior. These changes in response to the
environment are called “learned or acquired characteristics.”
Learned characteristics in animals can be taught or come through experiences in the
environment. The tiger kitten is an instinctive hunter and carnivore, but it does not know
how to hunt from birth. Many animal parents, such as lions, tigers, and wolves, teach
their young how to hunt and how to work in packs to bring down prey. A human infant
has all the physical characteristics of the parents, but has to be taught a language,
proper human behavior, and how to ride a bicycle. Other learned characteristics can
come through interaction within the environment. A bear, hunting for salmon along a
river, learns the best place to catch fish and will fight to keep other bears away from his
favorite spot. Yellowstone National Park in Wyoming has a continual problem with bears
that invade campsites. Once a bear discovers scrap food in a trashcan in the
campground, it can abandon its usual foraging and rely on campers for food.
Yellowstone has had to implement a policy of capturing the bears and transporting them
miles into the wilderness away from campers to get them to return to their usual feeding
habits. Bear-proof garbage bins are used in many parks to avoid teaching bears that
human trash is a food source.
Acquired traits in plants are responses to the environment. In hydrangea flowers,
soils of different pH (acidity) will cause the plant to produce different colored flowers,
ranging from pink to blue. The structures of the hydrangea are inherited, but the specific
color of the flowers is a response to soil conditions. When a plant responds to its
environment and grows in a certain way, that response is an acquired trait. For
example, gravity pulls roots to grow downward and the plant stems respond and grow
upward. If a plant is tipped on its side, the stem will still curve to grow upward. Some
plants, such as sunflowers, respond to the direction of sunlight and have learned to
grow toward the light.