Chapter 7. The Evolution of Living Things. Diatryma and the Rooster. Diatryma weighed about 400 pounds (182 kg.) Flightless Cenozoic Era (57-35) million years ago Over 6 feet tall Enormous Beak Sharp Claws Distant relative of the chicken. Frog Crazy. Adaptation.
The Evolution of Living Things
Adaptation – a characteristic that helps an organism survive and reproduce in its environment
Adaptations Include Structures and Behaviors for:
1) finding food
3) moving from place to place
Species – a group of organisms that can mate with one another to produce fertile offspring
Human existence is less than a hairs width at the end of the diagram
Evidence for an old universe:
Absence of short lived stars from star clusters 14-18 Ga1
Length it takes light to get to the earth from the most distant objects in the universe (10 Ga)2
Hubble expansion of the universe 7 - 20 Ga1
Evidence for an old solar system
Age of meteorites 4.4-4.6 Ga (isochron method)1
Age of moon 4.5 Ga (radiometric)1
Earth-meteorite system 4.54 Ga (lead isotope age)1
Evidence for an old earth:
Earths oldest rocks 3.8-3.9 Ga (radiometric)1
Evolution – the process by which populations accumulate inherited changes over time.
* Because of evolution scientists think that all living things and once living things, from daisies to crocodiles to humans share a common ancestor.
The fossil is a rock - Often the remains of preserved organisms are not of the organism itself but instead of minerals deposited where, especially, hard parts of the organism previously existed.
The organism is quickly
covered in sediment
A once living organism
The organism dies
The soft parts decay
The hard parts make a
mold (hollow impression)
which is replaced by minerals
There are six ways that organisms can turn into fossils, including:
1) unaltered preservation (like insects or plant parts trapped in amber, a hardened form of tree sap)
2) permineralization=petrification (in which rock-like minerals seep in slowly and replace the original organic tissues, forming a rock-like fossil - can preserve hard and soft parts - most bone and wood fossils are permineralized)
3) replacement (An organism's hard parts dissolve and are replaced by other minerals.
6) authigenic preservation
Most animals did not fossilize; they simply decayed and were lost from the fossil record. Paleontologists estimate that only a small percentage of the dinosaur genera that ever lived have been or will be found as fossils.
– the relative positions
of layers of sediment
determine the age of the
fossils found within them.
Non-radioisotope methods of direct dating: