Download Evolution: Change over Time

Evolution: Change over Time
Mrs. Paparella
May 2012
Honey Creepers of the Hawaiin Islands
• http://www.york.ac.uk/news-andevents/features/honeycreepers/
Similarities to Darwin’s Finches
• Heather Lerner, an assistant
professor of biology at Earlham
College, added: “Some eat
seeds, some eat fruit, some eat
snails, some eat nectar. Some
have the bills of parrots, others
of warblers, while some are
finch-like and others have
straight, thin bills. So the
question that we started with
was how did this incredible
diversity evolve over time?”
Family Tree of “ Darwin’s Finches”
Burst of new evolution is called a
“Radiation”
• These birds evolved between 4 million and 2.5
million years ago after the formation of
specific Hawaiin Islands.
How and Why did the species evolve?
How does this demonstrate
geographical isolation?
• “Each island that forms represents a blank
slate for evolution, so as one honeycreeper
species moves from one island to a new
island, those birds encounter new habitat
and ecological niches that may cause them to
adapt and branch off into distinct species.”
Why is this such an important
discovery?
• Professor Hofreiter, of the Department of
Biology at the University of York, said:
“Honeycreepers probably represent the most
impressive example of an adaptive radiation in
vertebrates that has led to a number of beak
shapes unique among birds. In our study we
are, for the first time, able to resolve the
relationships of the species within this group
and thereby understand their evolution."
What is the role of genetics in evolution?
• Random mutations that are advantageous to the
survival of an organism when environmental
conditions change over time are passed on to
future generations.
• Offspring that have those new characteristics are
able to survive and pass those changes on to
their offspring.
• New species evolve because of those changes
becoming consistently seen in future generations.
What bird is the ancestor of the
honeycreeper?
• “Using genetic data from 28 bird species that
seemed similar to the honeycreepers
morphologically, genetically or that shared
geographic proximity, the researchers
determined that the various honeycreeper
species evolved from Eurasian rosefinches.
Unlike most other ancestral bird species that
came from North America and colonized the
Hawaiian Islands, the rosefinch likely came
from Asia, the scientists found.”
What is the current status of the
honeycreeper species?
• More than half of the known 56 species already
extinct. The researchers focused on the 18 surviving
honeycreeper species but of those, six are considered
critically endangered by the International Union for
Conservation of Nature, four are considered
endangered and five are vulnerable.
• Professor Hofreiter said: “It is a tragedy that most
species from this unique group of birds, one of the
best examples of the power of natural selection we
have on earth, are extinct or on the brink of
extinction. We still have time to take actions to
conserve the diversity that is left.”
What is the next step for researchers?
• They will “ use museum specimens and
subfossil bones to determine where the
extinct species fit into the evolutionary family
tree, or phylogeny, to see if the new lineages
fit into the overall pattern found in the current
study.”
And now for something completely
different……….
• Cartoons are often an easy way to get a point
across to a reader.
• Take a look at the following 3 cartoons and
explain the role of evolution.
100 Million Years Ago
• What event caused
Larry to evolve into
a snake?
The Platypus and the Spiny Anteater
• The ant eater and the platypus
are “distant cousins”.
• The spiny ant eater and the
platypus are known as
echidna.
• These animals are
monotremes (egg-laying
mammals).
• Monotremes live only in
Australia and New Guinea.
• What role does geographical
isolation have in the
explanation of where the
species are found?
What do all living things have in
common????
The end?????????
• really only a transition---------imagine how we
might evolve in another million years------What characteristics might we develop that
allow us to adapt to changing environmental
conditions?????
• How would those new traits come about???