Transcript Change Over Time

Change Over Time
Mrs. Horn 5th Grade 1st
Nine Weeks
Our Goals for This Unit
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Define adaptation and identify how they help
organisms survive in their environment
Identify specific types of adaptations (physical and
behavioral)
Identify an organism’s environment by studying its
physical features
Define fossil and explain how they show change in
an environment
Explain reasons for extinction of organisms
Adaptations
What is an Adaptation
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Anything that helps an organism survive in its
environment
Adaptations may be physical features on an
animal’s body
Adaptations may be things animals do
Structural Adaptations
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Adjustments to internal or external physical features
Examples: webbed feet help ducks survive in water,
snakes and other reptiles have scales that help
prevent water loss in dry environments
May help protect an organism or enable it to hunt
better
Examples: turtles have hard shells to protect them
from predators, sharks have excellent sense of smell
and sharp teeth that help them catch food
Behavioral Adaptations
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An adjustment in an organism’s behavior
Example: wolves travel in packs because
together they can hunt larger animals that a
single wolf alone can not capture
Migration
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Movement of animals to find food, reproduce
in better conditions, or find a less severe
climate
Birds, butterflies, fish, and mammals such as
manatees migrate
Hibernation
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A period of inactivity during cold weather;
animal remains inactive until warmer
temperatures return
Bats, snakes, bear, and frogs hibernate to
escape the cold
Desert Animal Adaptations
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Long eyelashes protect eyes from strong,
sandy wind.
Nostrils can be closed and opened at will.
During a sandstorm, the camel closes its
nostrils.
Padded feet help it to walk comfortably on the
soft sand.
Long legs keep its body much above the hot
sand.
Toes are joined together to prevent sinking into
the sand.
Hump stores excess amount of food as fat.
Due to scarcity of water only few plants grow
in a desert. When food is available, a camel
eats plenty of it. Excess amount of food is
converted into fat and is stored in the hump. It
is used when food is scarce, that is why it is
able to live without eating food for several days.
It drinks plenty of water to recover water lost
from body, when water is available. A camel
can live without water for many days.
Adaptations of Grassland Animals
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Strong legs help them to cover
long distances in search of
food.
The body color merges with
the color of the dry grass
(camouflage). This helps
animals like the deer to escape
from their enemies and animals
like the lion to remain unnoticed
till the prey is close enough to
hunt.
They also have a keen sense
of smell and sharp eyesight.
Adaptations of Cold Region Animals
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The body is covered with a thick layer of
hollow hair that traps air and keeps the
bear warm. There is also a thick layer of
fat below its skin. These features keep
the bear comfortably warm even when
the temperature goes below -30 degree
Celsius in winter.
The polar bear is a good swimmer. This
adaptation helps it to catch seal for food
when ice melts in warmer months.
The polar bear also has a peculiar habit.
In winter, when the weather turns
extremely cold and food is difficult to find,
it goes to sleep (hibernation) and
wakes up only after a few months when
the weather warms up. This is how the
largest meat-eating land animal on
Earth survives in cold conditions without
food for many months.
Adaptations of Animals Living on
Mountains
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The body is covered with a
thick growth of hair that
touches the ground and this
keeps the animal warm.
Yaks have more red blood
cells than any other animals.
This helps them to obtain
enough oxygen from the air.
At some places deep holes are
covered with just a thin layer of
ice. Herds of yak travel on
snow in a single file, carefully
stepping on the footprints left
by the lead yak.
Plant Adaptations
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Scented flowers that attract pollinators
Leaves that catch sunlight
Roots that soak up water
Rain-forest plants have pseudobulbs that store water
Drip-tip leaves that have adapted to constant wet conditions in a rain
forest and drain excess water
Cacti in the desert have thick, waxy stems that prevent water loss;
also have dense, shallow roots that soak up rain quickly
Oak trees loose leaves in the winter to prevent water loss
Aquatic plants’ stomata are located on the top of their leaves rather
than the bottom because the float on water
Other plant adaptations include producing chemicals that taste bad
and some produce poisonous chemicals to deter predators
Evidence of Change Over Time
Fossils
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Any remains, traces, or imprints of organisms
that lived long ago.
How Are Fossils Formed?
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Dead organism is covered by sediment
the soft parts of the body decay but the
skeleton is preserved
the skeletal parts are then replaced by
minerals in the sediment
surrounding sediment hardens into rock
How Are Fossils Formed?
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An insect may become trapped in tree sap.
Over time, the sap hardens into amber and
preserves the insect
An animal may walk across wet sand or soil.
If the footprint is quickly covered by
sediment, the footprint can be preserved.
What Fossils Tell Us
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Provide clues that tell us how environments
have changed
Help scientists determine the past climate of
an area
Provide clues about what organisms were
like in the past and how they have changed
How has Earth Changed?
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Earth’s history is measured in long stretches
of time called eras
Eras are described by the kinds of life that
were dominant at that time
Precambrian
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Earliest part of Earth’s
history
Earth became
hospitable to life
Paleozoic
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Life became abundant
Trilobites, fish, insects,
amphibians, and
reptiles appeared
Many organisms
became extinct at end
of this era
Mesozoic
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Appearance of
dinosaurs, mammals,
birds, and flowering
plants
Rocks from the end of
this period suggest that
many forms of life
become extinct at the
end of this era
Cenozoic
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Era in which we live
Fossils show that early
mammals were very
large
Most recent ice age
occurred during this
period of time or era
Test Prep
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A squirrel is born with white fur instead of
the normal gray fur color. How would
environmental conditions have to change to
increase this squirrel’s chance of survival?
A city dump is built nearby.
Volcanic ash covers the forest.
The climate gets cold enough to snow.
An earthquake causes the land to shift.
Test Prep
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A.
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An environment suddenly becomes colder.
Which adaptation would MOST LIKELY give
some animals a better chance of survival
than others?
Long tails
Long ears
Small eyes
Thick fur coats
Test Prep
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A.
B.
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What adaptation would make it difficult for a
brow bear to get food in a polar bear’s
habitat?
Its brown fur
Its sharp claws
Its large body
Its sharp teeth