Download The Evolution Of Living Things

The Evolution of Living Things
Guided Notes
What you should already know…
Heredity is the passing of genetic traits from
parents to offspring.
 DNA is the genetic material that determines
the traits that a living thing inherits and needs
to live.
 Selective breeding is the process in which
humans select plants or animals to reproduce
based on certain desired traits.

What Darwin Never Knew
History of Evolution



Plato & Aristotle believed species were fixed &
could be arranged according to their complexity
Carolus Linnaeus developed a system of
classification that called binomial nomenclature
Lamarck was first to state that descent with
modification occurs and that organisms become
adapted to their environments
History of Evolution

Lamark believed in Inheritance of acquired
characteristics.
Change Over Time
Evolution is the process in which inherited
characteristics within a population change over
generations such that new species sometimes
arise.
 Evolution helps explain the variations and
adaptations that we see in organisms around
us and in evidence in the past.

Differences Among Organisms



A feature that helps an
organism survive and
reproduce in its
environment is called an
adaptation.
Adaptations may be physical,
such as a long neck or
striped fur.
Or adaptations may be
behaviors that help an
organism find food, protect
itself, or reproduce.

https://www.youtube.com/watch?annotation_id=annotation_1
2481&feature=iv&src_vid=mooMo5k2w50&v=RmzbQsIdaFw

https://www.youtube.com/watch?v=lMbDjNDD4cM
Differences Among Organisms



Living things with the
same features may be
members of the same
species.
A species is a group of
organisms that can mate
with one another to
produce fertile offspring.
Fertile offspring are
offspring that can
reproduce.
Strawberry poison frog
Smokey jungle frog
Evidence of Changes Over Time




Evidence that organisms have changed over time is
buried within the Earth’s crust.
Fossils are the traces or remains of an organism that
lived long ago.
Fossils are most commonly found in sedimentary
rock.
Body fossils form from whole organisms or from
parts of organisms. Trace fossils are signs, such as
footprints, that an organism once existed.
Evidence for Evolution




The fossil record – show biodiversity, mass extinctions
and episodic speciation
Geographic Distribution of Living Species – shows
similarities among species living on different continents
Homologous Body Structures – structures that have
different mature forms but come from the same
embryonic tissue.
Similarities in Early Development – embryos of many
vertebrates are very similar.
Fossil Evidence

Homolous Structures: structures in different organisms
that are inherited from a common ancestor and have
similar structures. (Not necessarily dissimilar functions)

Example:Vertebrate Forelimbs.
Fossil Evidence

Analogous structures are inherited from different
ancestors and have come to resemble each other because
they serve a similar function.

Bird wings and bat wings are both for flight but they are
structurally different.
Embryonic Evolution
Biochemical Evidence


Most reliable evidence for Evolution!!!!
This includes



Amino acid sequences
DNA codes
Mitochondrial DNA
Evidence of Ancestry





The fossil record is all of the fossils that have existed
throughout life’s history, whether they have been found or
not.
It provides evidence about the order in which species
have existed.
Scientists observe that all living organisms have
characteristics in common and inherit characteristics in
similar ways.
Scientists think that all living species descended from
common ancestors.
Evidence that groups of organisms have common ancestry
can be found by comparing the group’s DNA.
Walking Whales
Scientists think that the ancient ancestor of
whales was probably a mammal that lived on
land and that could run on four legs.
 Comparisons of modern whales and a large
number of fossils have supported this
hypothesis.

Walking Whales
Who Was Charles Darwin?



Charles Darwin was a
naturalist, someone who
studies nature, on the
HMS Beagle (a British
ship).
Darwin made
observations that helped
him form a theory about
how evolution happens.
Darwin observed plants
and animals from many
parts of the world,
including the Galápagos
Islands.
Charles Darwin


He studied divinity up until he was 22 when he accepted
a position on a ship for a 5 year voyage around the world.
On the Galapagos he observed two different organisms:
Darwin’s Finches
Darwin observed that the animals and plants
on the Galápagos Islands were similar to those
in Ecuador. However, they were not exactly
the same.
 The finches on each island differed from the
finches on the other islands.
 The beak of each finch is adapted to the way
the bird usually gets food.

Darwin’s Finches
Darwin’s Theory of Natural Selection

Natural selection is the
process by which
organisms that are
better adapted to their
environment survive and
reproduce more
successfully than less
well adapted organisms
do.

4 Parts of Natural Selection

Overproduction

Inherited Variation

Struggle to Survive

Successful Reproduction
Why Do Populations Change?


Environmental changes can cause populations to
change.
The factors that can cause populations to change:



Hunting – when humans hunt certain organisms, fewer
survive to reproduce.
Insecticide Resistance – insects survive insecticide
treatment and pass the resistance trait to their
offspring.
Competition for mates- organisms that reproduce
sexually have to compete with one another for mates.
Forming a New Species


The formation of a new species as a result of evolution
is called speciation.
3 events often lead to speciation:



Separation – when part of a population becomes
separated from the rest.
Adaptation – after two groups have been separated, each
group continues to be affected by natural selection.
Different environmental factors may affect each
population.
Division – over many generations, two separated groups
of a population may become very different.
The Evolution of Galápagos Finch Species
Review
1.
2.
3.
4.
5.
6.
7.
What is evolution?
Give 2 examples of an adaptation.
What is a fossil? Identify two kinds of fossils.
What did Charles Darwin observe about the finches on
the Galápagos Islands?
Define natural selection. Identify the 4 parts of natural
selection.
Identify and describe 3 factors that can cause a
population to change.
Identify 3 events that can lead to speciation.