Download 5.10B Key Concepts

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.