Ch. 7 The Evolution of Living Things

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Transcript Ch. 7 The Evolution of Living Things

Science 7 th
Hoyman, Jackson, Ely
Students will examine the evolution of living organisms
through inherited characteristics that promote survival of
organisms and the survival of successive generations of
their offspring.
a) Explain that physical characteristics of organisms have
changed over successive generations.
b) Describe ways in which species on Earth have evolved due
to natural selection.
c) Trace evidence that the fossil record found in sedimentary
rock provides evidence for the long history of changing
life forms.
Charles Darwin – ship’s naturalist aboard the “HMS Beagle”
that sailed in 1831. (naturalist – studied the natural world –
plants and animals). Darwin had many ideas about how
organisms changed over time. These ideas have helped
shape today’s Theory of Evolution.
Darwin’s vocabulary
1. Species – similar organisms that can mate and produce
fertile offspring.
2. Adaptations – traits that help an organism to survive and
3. Evolution – theory that species change gradually over
time to become adapted to new conditions.
 Natural Selection – process where organisms that
are better adapted to their environment are more likely
to survive and reproduce. 4 steps…
1) overproduction – producing more offspring
than can possibly survive.
2) inherited variation – every individual has its
own traits. Similar, but not identical to parents.
3) struggle to survive – some individuals have
traits better adapted to environment.
4) successful reproduction - better adaptations
are passed down to next generation.
Selective Breeding is when
humans select plants or
animals for breeding based
on desired traits.
Natural Selection or Selective Breeding
Dark moths are eaten by
birds more than speckled
2) Corn bred for better taste
and insect resistence
3) Birds with tougher beaks
are able to break open
nuts for food.
Natural Selection
Selective Breeding
Natural Selection
Darwin’s Theory of Natural Selection
1. Define and explain the 4 parts of “natural selection.”
Genetics and Evolution & Changes in Populations
2.Where does variation in a species come from?
3.What are 3 examples of things that cause changes in
populations? Name and briefly describe each
Change over Time (pages 166-169)
5.How is the fossil record useful to scientists?
6. What things do scientists look at to determine
common ancestry (who is closely related)?
Fossils and the Age of Fossils (page 194-195)
7.Describe the most common way fossils are made.
8.Which type of dating (relative or absolute) is more
accurate? Explain why.
1) Separation – part of a population is separated from the
rest by a mountain range, islands, etc.
2) Adaptation – separate groups of a species are affected
by natural selection in different ways.
3) Division – the two separated populations become so
different from each other that they are no longer able
to mate and reproduce.
 Scientists compare Fossils (preserved remains of
organisms) and living creatures to show that certain
organisms may be related to each other.
 How fossils form:
 1) fossil is buried
 A) buried by ash from a volcano
 B) covered by tar or ice
 C) buried by sediment ***
 2) bones & other hard body parts harden to rock
 3) erosion uncovers the fossils
Yes or No
Deer tracks in sand?
Seashell on a beach?
Crocodile dies on bottom of river?
Jellyfish in ocean?
Animal caught in a tar pit?