Key Vocabulary Terms

Evolution - the changes in a population over time.
Lethal mutations - a mutation that results in the death of an organism.
Geographic isolation - the separation of a population into two populations that have no contact with each other, caused by a change in the environment.

Key Concepts

Evolution is the changes in populations of organisms over many generations.
Individual changes in an organism are not evolution. They may affect the organism, but they are not passed on to offspring, so they do not affect the population.
In organisms that reproduce sexually mutations are passed to offspring through sex cells or gametes.
some mutations result in traits that improve or diminish or organism's chances for survival. an organism that does not survive to reproduce will not pass the new trait on to future generations. An organism that survives in more likely to reproduce and pass the new trait on to the next generation. If it is passed on over many generations, the population will slowly change, or evolve.
There are many ways that one species might become two species, see the chart on page 356. One way this may happen would be that one part of the population has a mutation the other part lacks. If an organism with the mutation tries to mate with an organism lacking the mutation, their offspring are infertile.

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Fossil - the remains or traces of an organism that lived in the past.
Sediment - the bits of rock and mud that settle to the bottom of a body of water.
Mold - A type of fossil that is formed when a dead organism decays and leaves an empty space in rock.
Cast - a type of fossil that is formed when a mold in rock is filled with minerals that harden.
Fossil record - the history of life on Earth, based on fossils that have been discovered.
Paleontologist - A scientist who studies life in the past.
Geologic time scale - A chart that divides Earth's history into time periods.
Radioactive mineral - a mineral that gives off energy as it changes to another substance over time.
Half-life - the amount of time required for one-half of a radioactive material to decay.
Mass extinction - the dying out of large numbers of species within a short period of time.

Key Concepts

Fossils are the remains or traces of organisms that lived in the past.
Fossils take many forms two kinds would be fossil bones and teeth, stone or mineral molds and casts of bodies or body parts, animal tracks, plant imprints, preserved solid wastes, and organisms trapped in tree sap or ice.
The fossil record shows that over a period of 50 million years, the horse became larger and the structure of its front feet changed from four toes to a single hoof.
the rate at which radioactive elements decay into another substance is constant. By measuring and comparing the amount of of a radioactive element to the amount of substance it becomes, scientists can determine how long ago the stone or fossil formed.
Studying DNA may help scientists piece together the history of the Earth when they compare the DNA of modern organisms with that in fossils to observe changes that have occurred at the molecular level and similarities that suggest relationships between today's organisms and those of the ancient past.

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Investigation 14 "Making Molds" (Optional, must complete 10 total investigations)

Key Concepts and Objectives

You will use your skills of observing, communicating, inferring; organizing information, and making generalizations to find out how fossils are formed.
You will understand the process of fossil formation.

Scientific theory - a generally accepted and well-tested scientific explanation.
Hypothesis - A testable explanation of a question or problem (plural is hypotheses)
Descent with modification - the theory that more recent species of organisms are changed descendants of earlier species.
Natural selection - the process by which organisms best suited to the environment survive, reproduce, and pass their genes to the next generation.
Adaptive advantage - the greater likelihood that an organism will survive, due to characteristics that allow it to be more successful than other organisms.
Vestigial structure - A body part that appears to be useless to an organism but was probably useful to the organisms's ancestors.
Homologous structures - body parts that are similar in related organisms.

Key Concepts

A scientific theory is an explanation that has undergone many tests and is supported by many different kinds of evidence. In everyday language, a theory is usually a hunch or a guess.
Descent with modification means that present organisms are related to past organisms; they are changed descendants of past organisms.
Organisms produce many offspring. They have slight variations. Those with variations best suited to their environment are most likely to survive. Survivors pass on their traits to offspring.
The finch populations on the various islands were isolated from one another by water. Therefore, different populations bred only with each other and underwent different genetic changes.
The theory of evolution is supported by evidence other than just fossils. For example, parallel embryo development, presence of vestigial structures and homologous structures in vertebrates.

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Are you able to define the term scientific theory.
Can you state the two theories that come from darwin's work?
Are you able to give two types of evidence that supports the theory of evolution?

Primate - the group of mammals that includes humans, apes, monkeys, and similar animals.
Hominid - the group that includes humans and humanlike primates.
Homo sapiens - the species to which humans belong.
Neanderthals - Homo sapiens who lived between about 35,000 and 150,000 years ago but are not thought to be direct ancestors of humans living today.
Cro-Magnons - Homo sapiens who lived about 35,000 years ago and are direct ancestors of humans living today.

Key Concepts

Primates can see colors, have grasping fingers, and have nails instead of claws.
Hominids are those primates which have humanlike characteristics, including humans you can find examples on P376.
Scientists believe that Lucy walked upright because Lucy's skull has an opening for the spinal cord in the bottom of her skull. Her hip and leg bones show they would support her while walking upright on two legs.
The hominid brain increased in size over time although the Neanderthal brain was larger than that of modern humans.
Neanderthals, Cro-Magnons, and humans living today are all members of the species Homo sapiens, which probably descended directly from Homo erectus. However, Cro-Magnons are believed to be our direct ancestors while Neanderthals are not thought to be.

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Chapter Summary and Review

See page 382-383

Chapter 14 Review answers are