Transcript Evolution Presentation Evolution_2016_ELLx

Evolution
• Change over time.
Many things change over time including:
• Fashion
• Music
• Technology
Biological Evolution:
• A change in the genetic characteristics of a
population over time.
• Changes in life on Earth over long periods of
time (millions and billions of years) through
process of natural selection resulting in new
species.
• All living things are related or have a common
ancestors (organism share a common
descent).
History
• The theory of evolution
was originally proposed by
Charles Darwin in the
book ‘Origin of Species’ in
1859
• Darwin was influenced by
many ideas and people of
this time.
Darwin was influenced by other scientists and
mathematicians of his time.
Charles Lyell
Thomas Malthus
Alfred Wallace
Darwin was influenced by is observations
of animals that are bred, such as dogs.
• Selective Breeding (Artificial Selection):
Change in a population through breeders selecting organisms
with desired traits.
Artificial Selection
Video: https://www.youtube.com/watch?v=F-XTUpLmhPc
Watch video to review artificial selection of dogs.
Darwin was influenced by is his voyage and
explorations to South America and especially
the Galapagos Islands
There were many
things that Darwin
didn’t understand
about evolution,
but ever since he
proposed the
theory the evidence
in support of
biological evolution
has grown.
The lines of evidence used to determine
evolutionary relationships between organisms:
• Fossils
• Biogeography: the distribution of species
• Comparative Anatomy
• Homologous Structures
• Vestigial Structures
• Comparative Embryology
• Molecular Evidence: DNA and proteins
Fossils
• Fossils are the remains or impression of a
prehistoric organism.
• Fossils can be preserved bones or other body parts,
an impression or mold of a living thing, or a trace of
an animal (such as a footprint).
• Fossils provide evidence of ancient life forms.
• Fossils are formed in a number of different ways, but most are formed when
a plant or animal dies and is buried in mud and silt. Soft tissues quickly
decompose leaving the hard bones or shells behind. Over time sediment
builds over the top and hardens into rock.
Fossil Formation
Watch Video:
http://www.pbslearningmedia.org/resource/tdc02.
sci.life.evo.becfossil/becoming-a-fossil/
Explain why only a small fraction of life on Earth is
preserved as fossils.
How do scientists use fossils to determine
evolutionary relationships?
• Scientists use fossils to determine how living things are related by….
Biogeography
The distribution of species.
Species that are geographically
isolated (i.e. on islands) will be
uniquely adapted to their
environment, but show
similarities to one another
providing evidence of their
common ancestor.
Biogeography
Example: Giant tortoises of the Galapagos
Islands show similarities:
• Hard shell
• Dry skin
• Long necks
But the tortoise species on each island are
slightly different because each has adapted
to different environmental conditions.
Biogeography
Homologous
Structures:
Similar structures in a
variety of different
organisms
A shared trait (structure)
between two or more
organisms that provides
evidence that the
organisms shared common
ancestor.
Forelimbs of humans, cats,
whales, and bats all have
similar parts/bones but
different shapes.
Vestigial Structures
A trait that was useful to an ancestor and has been passed down
through generations in a modified and reduced form because it is
not useful to the current organism
Human Tailbone
Hind Leg Bones in Whales
Vestigial Structures in humans
• https://www.youtube.com/watch?feature=youtu.be&v=rFxu7NEoKC8
&app=desktop
• Watch the video to learn about some of the vestigial structures in the
human body and provide under the definition (#3b) section of your
booklet