Transcript Evolution * the genetic change in a species over time

Evolution – the
genetic change in
a species over time
Recent Evolution in Humans

Evolution is very much still happening today — and it's happening to
us.

Right here, right now.

Our genes constantly change over time thanks to the power of
selection.
Recent Evolution in
Humans
1. Drinking milk as adults

All mammals (besides humans) stop
producing lactase after weaning.

Lactase is needed to breakdown lactose
(milk sugar) in the body.

This means that they will no longer be able to
digest milk when they get older.
Recent Evolution in
Humans
1. Drinking milk as adults

Scientists have discovered a mutation that
first appeared on the plains of
Hungary about 7,500 years ago, that allowed
some humans to digest milk into adulthood.

The ability to digest protein-rich, caloriedense, dairy products was a definite
evolutionary advantage.
Recent Evolution in Humans
1. Drinking milk
as adults

We still see evidence of this genetic
change today.

This is why more than 75% of humans
are lactose intolerant.
2. Disease resistance

Any genetic mutation that leads to an
advantage for survival, will continue in
future generations.

Sickle-Cell Anemia prevents Malaria.

Sickle-Cell Anemia is most common in
people of African descent (7%), and
other areas where malaria is prevalent.
2. Disease resistance

About 10% of Europeans have a
genetic mutation that protects them
from HIV infection.

This genetic mutation (known as
CCR5-Ä32) prevents the virus from
entering the cells .
13 People Identified As Immune To
Genetic Diseases, But Researchers
Can't Find Them
http://www.iflscience.com/health-andmedicine/thirteen-people-identified-immune-geneticdiseases-researchers-cant-trace-them/
http://what-when-how.com/acp-medicine/hiv-andaids-part-2/
Blue Eyes - a
Mutation
New
research shows that people with blue
eyes have a single, common ancestor.
Scientists
have tracked down a genetic
mutation which took place 6,000-10,000
years ago and is the cause of the eye color
of all blue-eyed people.
Blue Eyes - a
Mutation
"Originally,
we all had brown eyes," said
Professor Hans Eiberg from the Department
of Cellular and Molecular Medicine. "But a
genetic mutation affecting the OCA2 gene
in our chromosomes resulted in the creation
of a "switch," which literally "turned off" the
ability to produce brown eyes.“
Super Site
 An
unknown number of women may
perceive millions of colors invisible to the
rest of us.
Blue Eyes - a
Mutation
This
affectively varied the amount of
melanin produced by the eye.

Indigenous
Tibetans, who
live at altitudes
above 10,000
feet in the
Himalayan
highlands,
have blood
that produces
more of the
oxygentransporting
hemoglobin
protein.
Breathing at
High Altitudes
Blind Cave Fish and Deep Sea Creatures


Named for the feature that it
lacks: eyes. Originally from
deep caves in Mexico, it has no
need for eyesight.
It uses sonar and other
heightened senses to navigate
and to avoid bumping into
other fish.
HELP!
I CAN’T
SEE!!
https://www.youtube.com/watch?v=YVvn8dpSAt0
https://www.youtube.com/watch?v=Sd7lvPpDDUg
Blind Cave Fish and Deep Sea Creatures


Named for the feature that it
lacks: eyes. Originally from
deep caves in Mexico, it has no
need for eyesight.
It uses sonar and other
heightened senses to navigate
and to avoid bumping into
other fish.
HELP!
I CAN’T
SEE!!
https://www.youtube.com/watch?v=YVvn8dpSAt0
https://www.youtube.com/watch?v=Sd7lvPpDDUg

Many people are
born without wisdom
teeth.

A few thousand years
ago, a mutation
popped up that
prevented wisdom
teeth from growing at
all. Now one in four
people are missing at
least one wisdom
tooth.
Wisdom Teeth
Wisdom Teeth

Humans stopped needing wisdom
teeth after humans begin cooking
food and developed
agriculture thousands of years ago.

This switch to softer foods,
decreased the size of our jaw
muscles.

Cave men would wear out their
molars and have room for the
wisdom teeth to replace the.

Most people don’t have room for
them.
Shrinking Brains
 We
think pretty highly of
our brains, but it turns out
they've actually been
shrinking for more
than 20,000 years.
 The
total change adds
up to a piece the size of
a tennis ball in an adult
male.
Vestigial Traits

We all have traits or behaviors that suited our ancestors just fine, but
no longer make any sense — but we just can't seem to get rid of
them.

The Appendix - once aided our primate ancestors with the digestion
of cellulose-rich plants once aided our primate ancestors with the
digestion of cellulose-rich plants

Your coccyx, better known as your tailbone, is the very last part of
your vertebrae, and is the remnant of a lost tail.

“When you're cold or
stressed out, your
arrector pili are the
smooth muscle fibers
that contract
involuntarily to give
you "goose bumps."

this can provide
warmth

This can make you
look bigger

No longer makes
sense for us to have.
Arrector Pili (goose
bumps)
http://io9.gizmodo.com/5829687/10-vestigial-traitsyou-didnt-know-you-had
Plato (428-348 BC) on Evolution

Plato believed that the structure and form of organisms could be
understood from their function.

He believed the function of the organism was designed to achieve
ultimate goodness and harmony.
I’m
HUNGRY!!
Aristotle (the father of biology)on Evolution
Aristotle (384-322 BC)

Aristotle, was the first to come
up with the idea of evolution.

His idea was that organisms
changed over time striving
toward what he called “the
telos” (an ultimate object or
aim).
Aristotle (the father of biology) on Evolution
- the "scale of nature"
Humans
Develop a "scale of nature," in which he arranged
the natural world on a ladder commencing with
inanimate matter to plants, invertebrates, and
vertebrates.
Mammals
Birds
Reptiles
Fish
Insects
Jellyfish
Plants
Rocks and Minerals
Among the vertebrates, he placed the fish at the
lowest rung of the ladder and humans on the highest
rung. This "scale of nature" represents a progression
from the most imperfect to the most perfect.
Goethe (1749-1832),

Goethe (1749-1832) believed that the origin of each
level of organism was based on a fundamental
“primitive plan” from which the more complex
features and organisms developed.
https://en.wikipedia.org/wiki/Evolution_of_biological_complexity
Natural Selection

Darwin proposed that inherited traits that were advantageous to
survival, had a higher probability of being propagated to future
generations.

The result would be adaptation, evolutionary modification of a
population that improves each individuals’ chances of survival and
reproductive success in the environment occupied by the
population.
Natural Selection

The trait that that increases the
survival of that species that
evolved over generations is
called an ADAPTATION.
https://www.youtube.com/watch?v=YVvn8d
pSAt0
http://listverse.com/2014/03/18/10-totally-weirdcreature-adaptations/
Evolution by Natural
Selection

As a result of natural selection, the
population changes over time; the
frequency of favorable traits increases in
successive generations, and unfavorable
traits decrease or disappear.

1800 moths in London - video
https://www.youtube.com/watch?v=aTftyFboC_M
Evolution by natural
selection results from
four natural
conditions:
#1
High reproductive capacity.
Each species produces more
offspring than will survive to maturity.
#2 Heritable variation.
Evolution
by natural
selection
results
from four
natural
conditions
:
#2
The individuals in a population exhibit variation.
Some traits improve the chances of an
individual’s survival and reproductive success.
The variation necessary for evolution by natural
selection must be inherited so that it can be passed to
offspring.
Evolution by natural selection results from four natural
conditions:
#3
Limits on population growth, or a
struggle for existence.
Only so much food, water,
light, growing space, and so on
are
available to a population,
and organisms compete with
one
another for the limited
resources available to them.
Other limits on population
growth include predators and
diseases.
Evolution by natural selection
results from four natural conditions:
#4
Differential reproductive success.
Reproduction is the key to natural selection:
The best-adapted individuals reproduce most successfully,
whereas less fit individuals die prematurely or produce
fewer or less viable offspring.
In some cases, enough changes may accumulate over
time in geographically separated populations (often with
slightly different environments) to produce new species.
Charles Darwin

Charles Darwin visited the Galápagos Islands off the coast of
Ecuador.

Among the species he studied, he studied 14 different finch species
found on the island.

Each finch species was unique with special adaptations that helped
it survive it its environment.

These adaptive traits were different from finches living on the South
American mainland.
Charles Darwin

The finch species, although similar in color and overall size, exhibit
remarkable variation in the shape and size of their beaks, which are
used to feed on a variety of foods.
Darwin realized that the 14 species of Galápagos finches descended
from a single common ancestor—one or a small population of finches
that originally colonized the Galápagos from the South American
mainland. Over many generations, the surviving finch populations
underwent natural selection, making them better adapted to their
environments, including feeding on specific food sources. The
evolution of these finches continues to be actively studied by
researchers.
Darwin’s
Finches

Each species’
beak was
specially
adapted to find
and eat a
specific diet.
Trying to Organize Organisms

Until the invention of the microscope in late 1590’s (by Zacharias
(son) and Hans (father) Jansen), scientists thought there were only 2
broad categories of organisms on Earth; 1) Plants and, 2) Animals.

Scientists had to rethink this idea when they discovered bacteria
(prokaryotic cells). Bacteria were distinctly different and separate
from plant or animal cells.

Bacteria have a prokaryotic cell structure: They lack organelles
enclosed by membranes, including a nucleus.
There are 2 sub-divisions of
prokaryotes

The prokaryotes fall into two groups that are sufficiently distinct from
each other to be classified into two kingdoms, Archaea and
Bacteria.

The archaea frequently live in oxygendeficient environments and
are often adapted to harsh conditions; these include hot springs
(like Old Faithful, at Yellowstone), salt ponds, and hydrothermal
vents

Raven, Peter H.; Hassenzahl, David M.; Hager, Mary Catherine; Gift,
Nancy Y.. Environment, 9th Edition (Page 86). Wiley. Kindle Edition.
There are 2 sub-divisions of
prokaryotes

The archaea frequently live in oxygen-deficient environments and
are often adapted to harsh conditions; these include hot springs
(like Old Faithful, at Yellowstone), salt ponds, and hydrothermal
vents (see Case in Point: Life Without the Sun, in Chapter 3).

The thousands of remaining kinds of prokaryotes are collectively
called bacteria.
Eukaryotes

The eukaryotes, organisms with eukaryotic cells.

Are divided into four kingdoms of living things,

1) plants,

2) animals,

3) protists, and

4) fungi,
Eukaryotes

Eukaryotes are made up of eukaryotic cells
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Eukaryotic cells
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1) Have a nucleus

2) Membrane-bound organelles (compartmentalization)
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3) Are highly structured

Are divided into four kingdoms of living things,

1) plants

2) animals

3) protists

4) fungi
Eukaryotes

Are divided into four kingdoms of living things,

1) plants - photosynthesis

2) animals – ingest food and digest it in their bodies.

3) protists (Unicellular or relatively simple multicellular eukaryotes, such as
algae, protozoa, slime molds, and water molds, are classified as members of
the kingdom Protista.

4) fungi (molds and yeast) - secrete digestive enzymes into their food and
then absorb the predigested nutrients.

Now on to population ecology
Play the
Survival
Game

http://www.sciencech
annel.com/gamesandinteractives/charlesdarwin-game/