Well-adapted species have many offspring.
Conditions in an organism’s environment ensure its survival.
Birds and reptiles share a number of inherited characteristics.
Tigers are so different from cheetahs.
The work of Charles Lyell.
The work of Gregor Mendel.
His collection of specimens.
His trip on the H.M.S. Beagle.
Useful support for his theory.
Evidence that Earth was very young.
Interesting but unrelated to the evolution of modern species.
Evidence that traits are acquired through use or disuse.
Evolved from sea stars.
Evolved before sea stars.
Belong to the same species as sea stars.
Share a common ancestor with sea stars.
The nearly universal genetic code.
The presence of vestigial structures.
A tendency toward perfect, unchanging DNA in various species.
The transmission of acquired characteristics by DNA.
The color of their feathers
The length and shape of their wings
The size and shape of their beaks
The curve of their claws
Completely unrelated species on each of the islands.
Species exactly like those found in South America.
Species similar to mainland South American species.
Species completely unrelated to those found in South America.
Earth is several million years old.
Earth is several thousand years old.
All fossils were formed in the last 1000 years.
All rocks on Earth contain fossils.
Inheritance of natural variations.
Inheritance of acquired characteristics.
Survival of the fittest.
Possession of adaptations developed through use.
Lack of competition within the species.
Possession of inherited adaptations that maximize fitness.
Choices made by plant and animal breeders.
Tendency towards perfection
Where species and their ancestors live.
How extinct species can be related to living species.
How different species can interbreed.
How animals that live in the same area are closely related.
Examples of fossils.
Examples of natural variation.
Intermediate fossil forms
Being preserved as fossils.
Providing humans with food.
Surviving in the environments in which they lived.
Swimming from South America to the Galápagos Islands.
If species living on different islands had once been members of the same species
If finches and tortoises had originated from the same ancestral species.
If all birds on the different islands were finches.
Why all tortoises on the different islands were identical.
Tendency towards perfection
The human population will outgrow the available food supply.
All populations evolve through natural selection.
Earth is a few thousand years old.
Past geological events must be explained in terms of processes observable today.
The actions of organisms as they use or fail to use body structures.
An unchanging local environment.
Continual increases in population size.
The natural variations already present within the population of organisms.
The majority of a species’ offspring die.
Without certain checks on population size, there would soon be insufficient food for the growing human population.
In the 1700s, England needed more housing.
In the human population, people die faster than babies are born.
Descent with modification.
Fitness varies among individuals.
Population size is very large.
There is heritable variation among members of the population.
More offspring are born than can survive.
They transmit characteristics acquired by use and disuse to their offspring.
They tend to produce fewer offspring than others in the population.
They are the ones that are best adapted to survive in their environment.
They will perpetuate unfavorable changes in the species.