Evolution and Adaptation

Evolution = Theory that groups of organisms change over time

Occurs over many generations due to selection and adaptation to changing environments.

Ancient living organisms looked different than the organisms living today.

The study of evolution asks: what happened to cause this shift and how did this process occur?

Scientists are interested in the relationships between groups of organisms, and explaining similarities based on shared ancestry.

Phylogeny Study of the evolutionary history of organisms. Family Tree of related organisms is called a phylogenetic tree.

http://www.onezoom.org/

How did scientists build these trees?

What is the evidence of evolution?

Fossils

Fossils are preserved remains of ancient organisms or their tracks.

best evidence of evolution

formed when plant or animal matter is changed to stone or the imprint is solidified.

Fossils found in deeper layers are older than fossils found close to the surface

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burgess-17-1Fossil record = collection of fossils that show change within a species over time (history of organisms)

Has gaps in it so it is said to be incomplete. (Transition fossils are missing)

Tarpits

Ancient organisms die and decompose forming fossil fuels.

Over time certain geological conditions have allowed the fossil fuels to seep up to the surface.

Lighter petroleum products evaporate away leaving behind sticky tar

Animals became trapped in the tar and died.

Rich source of fossil evidence.

Amber

Hardened gum/ sap of a tree

Insects or plant material become trapped and preserved.

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Flash Frozen

Organism quickly frozen and preserved during sudden change in climate or glaciation event.

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Comparative Anatomy

Similarity of structures between ancient and modern day organisms.

Embryology

In vertebrates, the early stages of development look very similar with tails and gill slits

Suggests similar ancestors embryology traces evolutionary pathway

DNA

DNA has the same chemical make up for every living thing on Earth

Scientists compare the genes of different species to determine how closely related the species are.

The more similar the sequence of bases in the DNA, the more closely related the species are.

The more similar the order of amino acids (codes for proteins) in the DNA, the more closely related the species are.

Fossilized footprint puzzle

attempting to reconstruct happenings from the geological past by analyzing a set of fossilized track

Can you tell anything about the size or nature of the organisms?

Were all the tracks made at the same time?

How many animals were involved?

Can you reconstruct a series of events represented by this set of fossil tracks?

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What can you determine is occurring from this footprint evidence?

In what directions did the animals move?

Did they change their speed and direction?

What might have changed the footprint pattern?

Was the land level or irregular?

Was the soil moist or dry on the day these tracks were made?

In what kind of rock were the prints made?

Were the sediments coarse or fine where the tracks were made?

What conditions were necessary for their preservation?

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What can you interpret what has happened?

One of the most common is that two animals met and fought. No real reason exists to assume that one animal attacked and ate the other.

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