Transcript Evolution - rosedale11universitybiology

History of Life Timeline Answers
bya = billions of years ago, mya = millions of years ago
4.6 bya  Earth forms
3.5 bya  First bacteria
3.4 bya  First photosynthetic organisms
2.1 bya  First multicellular life
600 mya  first jellyfish
425 mya  first sharks
220 mya  first dinosaurs
200 mya  first mammals
180 mya  first flowering plants
90 mya  last dinosaurs
2.6 mya  First Stone tools, human use
- Homo genus been around for about 2.8 mya
- stone tools used by Australopithecus dated to 3.3 mya!!
History of Earth Timeline
Billions of years
(2016)
What is Biological Evolution?
Biological evolution is the genetic change in
a population of an organism over time.
All living organisms are thought to have descended
from a single ancestor – a one celled species.
Charles Darwin developed the Theory of Evolution to
explain how this happened. He used scientific
evidence collected in his travels.
The process of evolution occurs on a small and a large
scale. Evolution only occurs in a population NEVER in
an individual.
Example: Ladybug Evolution
Would the number of dark coloured ladybugs change
in future generations if they were better camouflaged?
How long
would this
take?
What does
“survival of the
fittest” mean?
What shell
colour alleles
do ladybugs
have?
Micro-evolution
Micro-evolution is genetic changes that occur over a
small number of generations. It is also called
evolution within a species.
Micro-evolution is when there is adaptation as a result
of natural selection of the fittest offspring.
Micro-evolution is caused by changes in allele
frequencies in a population. These changes occur to
help species better adapt to their environment.
Micro-evolution can happen in a few generations.
Micro-evolution
Moth evolution in England is an example of microevolution. During the industrial revolution black moths
were less visible to predators than white moths.
Therefore, they were more likely to survive and
reproduce. Therefore, the black allele became more
common than the white allele. Spot the black moth!
Macro-evolution
Macro-evolution is genetic change on a large
scale and takes centuries or millennia.
Macro-evolution is also known as evolution
between species and is documented in the fossil
record.
Lots of small changes or mutations can lead to
new designs like the development of the eye, or
organisms surviving in new habitats or climates.
Macro-evolution can also lead to the extinction of
species or to the rise of new species.
Macro-evolution of Whales
This is an example
of how numerous
micro-evolutionary
changes eventually
result in the
formation of a new
species by macroevolution.
There have been periods of great diversity of life on
earth followed by mass extinctions. Some
branches on the evolutionary tree have been dead
ends and there are no modern descendants living
today.
PBS video about tuberculosis (TB)
Why does evolution matter now?
https://www.youtube.com/watch?v=W-WumllRPL (9 min)
Complete the worksheets.
Also the PBS site with other videos:
www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.html