The Fossil Record Quiz

The Fossil Record

• Fossils are preserved remains of ancient organisms.
• The study of fossils is called paleontology.
• Fossils reveal organisms that lived on Earth during different time periods.
• Fossils form through gradual replacement by mineral deposits of the remains of buried organisms.
• The formation of fossils is rare because most bodies decompose quickly when oxygen is present.
• Hard-bodied organisms are more likely to fossilize than soft-bodied organisms.
• Organisms can be preserved in amber, volcanic ash, and ice.
• Cuvier noted that fossils of complex organisms are found in younger rock layers and fossils from deeper rock layers are less similar to modern organisms.
• Lyell noted that geological change occurs gradually over time.
• Fossils show intermediate links between groups of organisms.
• Archaeopteryx, a fossil from 150 million years ago, shows characteristics from both reptiles and birds, suggesting that birds evolved from reptiles (or dinosaurs).

Biogeography

• Biogeography studies the geographical distribution of organisms based on living species and fossils.
• Species that are geographically close are more closely related than those that are geographically separated, regardless of environment.
• Darwin observed that remote islands became populated by species that arrived by water or air, which later evolved into new species.
• Lemurs are only found in Madagascar, but fossils show they once existed across Africa.

Anatomy

• Bone structure and function can provide evidence for evolution.
• Homologous Structures have a similar developmental origin, and similar bone, muscle, ligament, tendon, and blood vessel arrangements.
• Similarities in embryonic development also reveal evolutionary relationships through homologous features.
• Analogous Structures perform similar functions but do not have a common evolutionary origin. For example, bird wings vs. insect wings.
• Vestigial Structures are functional in ancestral organisms but have no current function. For example, the pelvic bones of whales are non-functional because they lack hind limbs.

Competition

• Competition exists between individuals of the same species as some individuals are favored by nature over others.

Molecular Biology

• Evolutionary relationships are reflected in the DNA of species.
• Comparing DNA sequences can determine relatedness.
• The more similar the DNA sequences of two species are, the more closely related they are.

Modern Theory of Evolution

• Modern theory expanded on Darwin's original theory of evolution.
• Darwin did not understand how traits were inherited from one generation to the next.

Modern Genetics

• Genetic traits are passed on from one generation to the next.
• Evolutionary change is described as the changes in allele frequencies within a gene pool.
• Natural selection favors some alleles over others.
• Mutations cause genetic variation.

Pseudogenes

• Pseudogenes are vestigial genes that no longer serve a purpose.