Transcript Evidence of Evolution Notes (15.2)

Evidence of Evolution (15.2)
State Standard
SB5C. Explain how fossil and biochemical
evidence support the theory
Chapter 15
Evolution
15.2 Evidence of Evolution
The Fossil Record
 Fossils provide a ____________ record of species that
lived long ago.
 Only the ____________ parts of an organism are likely
to leave fossils – ex: shells, bones, thick cell walls.
 Very few fossils capture the details of ____________
or internal ____________.
 Sometimes ____________ are left behind in
sediments along rivers and lakes.
Chapter 15
Evolution
15.2 Evidence of Evolution
The Fossil Record cont’d
 Fossils show that ancient species share ____________
with species that now live on Earth.
 One problem w/ the fossil record is the lack of any
“____________” or transition forms. This could be due to
many organisms being too ____________ or due to fossils
being ____________ by the erosion or pressure.
Glyptodont
Armadillo
Chapter 15
Evolution
15.2 Evidence of Evolution
Determining Fossil Age
 Biologists use ____________ dating to determine the
approximate age of fossils.
 The isotopes act as ____________ for measuring time.
 To use this method, scientists must know:
1. The ____________ of the isotope being measured.
2. how much of the isotope was ____________ present in
the fossil or in the rock containing the fossil.
3. how much of the isotope is ____________..
 Half-life is the amount of time it takes for half of the isotope
to ____________.
Chapter 15
Evolution
15.2 Evidence of Evolution
Determining Fossil Age Cont’d
 Biologists most often use
____________ for radioisotope
dating, but its half-life is
relatively ____________.
 Other isotopes like Uraniaum
235 are often used to help
determine the age of older
fossils.
 Relative dating determines the
relative age of rocks/fossils by
____________ them to known
older or younger layers.
Chapter 15
Evolution
15.2 Evidence of Evolution
Comparative Biochemistry
 Common ancestry
can be seen in the
complex metabolic
____________ that
many different
organisms share.
Chapter 15
Evolution
15.2 Evidence of Evolution
Comparative Biochemistry Cont’d
 Comparisons of the similarities in these
molecules across species reflect evolutionary
____________ seen in comparative anatomy
and in the fossil record.
 Organisms with closely related ____________
features have more closely related
____________ features.
Chapter 15
Evolution
15.2 Evidence of Evolution
Comparative Embryology
 Vertebrate ____________ exhibit homologous
structures during certain phases of
development but become totally
____________ structures in the adult forms.
 Many scientists believe this is evidence that all
vertebrates ____________ a common
____________.
Chapter 15
Evolution
Anatomical Evidence
Homologous Structures
• ____________ similar
structures that may or
may not have the same
____________.
• Indicate possible
____________ ancestry
Chapter 15
Evolution
Anatomical Evidence
Analogous Structures
 Similar in function but
__________ in __________
so they do not indicate
shared ancestry
 Show that
functionally similar
features can evolve
independently in
__________
environments
Chapter 15
Evolution
Anatomical Evidence
Vestigial Structures
 Structures that are the
____________ forms of
functional structures in
other organisms.
 Evolutionary theory
predicts that features of ancestors that no
longer have a function for that species will
become ____________ over time until they
are lost.
Chapter 15
Evolution
Anatomical Evidence
Adaptations
 An adaptation is an ____________ trait
that may increase an organism’s survival
and reproductive success.
 ____________ is a measure of the relative
contribution an individual trait makes to the
next generation.
Chapter 15
Evolution
Anatomical Evidence
Adaptations Cont’d
Camouflage
Leafy sea dragon
 Allows
organisms to
become almost
____________
to predators
 All about
____________
Chapter 15
Evolution
Anatomical Evidence
Adaptations Cont’d
Mimicry
 One species evolves to ____________ another
species.
 All about ____________/warning (not hiding).
Western coral snake
California kingsnake
Chapter 15
Evolution
15.2 Evidence of Evolution
Geographic Distribution
 The distribution of plants and animals that
Darwin saw first suggested evolution to Darwin.
Rabbit
Mara
Chapter 15
Evolution
15.2 Evidence of Evolution
Geographic Distribution Cont’d
 The Mara & Rabbit fill the same ____________
on 2 different continents.
 Darwin observed that the Mara was more
____________ to other South American
species than it was to the rabbit, and vice
versa.
Rabbit
Mara
Chapter 15
Evolution
15.2 Evidence of Evolution
Phylogenetic Trees
 A ____________ is a
description of the line of descent
of a group of organisms.
 Fossil collections are often not
____________ enough to
determine any evolutionary
patterns or traits, so biologists
will ____________ likely
phylogenies by comparing
morphological features, DNA
sequences, and chromosomal
characteristics.
 ____________ is the permanent
loss of a species.
Chapter 15
Evolution
15.2 Evidence of Evolution
Types of Characters (traits)
 ____________ traits are newly evolved
features, such as feathers, that do not appear
in the fossils of common ancestors.
 ____________ traits are more primitive
features, such as teeth and tails, that do
appear in ancestral forms.
 Anatomically similar structures inherited from
a common ancestor are called ____________
structures.
Cladogram - a
diagram showing
possible
relationships
between
organisms based
on shared traits
(characters)
How to Read – if
the organism is
above the trait, it
has the trait. If it
is below the trait,
it doesn’t have it.
Ancestral
Character –
shared by all
species on the
diagram.
Derived
Character- only
shared by some
Outgroup – least
in common
Homologous or Analogous?
Bat Wing
Human Arm
Homologous or Analogous?
Bat Wing
Bird Wing
Homologous or Analogous?
Dragonfly Wing
Hummingbird Wing
Homologous or Analogous?
Dragonfly Wing
Bumblebee Wing