Chapter 3 Lsn 2 & 3

An ________ is a characteristic of a species that enables the species to survive in its environment.

Adaptation

_______ ______ are body parts that perform a similar function but differ in structure. The wings of flies and birds are examples.

Analogous structure

Darwin thought all the Galapagos tortoises shared a common _______ that came to one of the islands millions of years ago.

Ancestor

Living species that are closely related share a common _______.

Ancestor

For this reason, Darwin called selective breeding __________ selection.

Artificial

_________ _________ explains and supports Darwin's theory.

Artificial Selection.

_____________ adaptations involve the way organisms act; hunting at night is an example of this type of adaptation.

Behavioral

If a variation ________ a tortoise, allowing it to compete for food better than other tortoises, the tortoise lived longer, reproduced more, and passed on its variations to its _______.

Benefited, offspring.

A structural adaptation that aids members of a species in blending in with their environment is called _______________.

Camouflage

The existence of analogous structures indicates that the species are not ______ related.

Closely

The more similar two structures are to each other, the more likely it is that the species have evolved from a recent _____ _____.

Common ancestor.

The study of similarities and differences among structures of living species is called _______ ______.

Comparative anatomy

Studies in molecular biology have shown that some stretches of ______ that are common to many species change through time at steady, predictable rates like a kind of molecular clock.

DNA

How closely related two species are depends when they ______, or split, from their common ancestor.

Diverge

Scientists use this molecular clock to estimate the time in the past when living species ______ from common ancestors.

Diverge

______ is the study of the development of embryos from fertilization to birth.

Embryology

Studying the development of _____ can also provide scientists with evidence that certain species are related.

Embryos

Charles Drwin was a ________, a person who studies plants and animals by observing them.

English naturalist

The living and nonliving parts of the ______________ are always changing: species that cannot ________ to such changes will become extinct.

Environment, adapt.

Darwin was not the first to develop a theory of _______, but his theory is the one best supported by evidence today.

Evolution

The continuous discovery of new _______ that have features of species that lived before and after them is strong evidence of evolution of species.

Evolution

______________ adaptations involve internal body systems that affect organisms' biochemistry; expanding blood vessels that cool a jackrabbit's blood is an example of this type of adaptation.

Functional

Scientists today are studying how _____ can be recognized in simple ways that cause dramatic changes in organisms.

Genes

The existence of _____ provides evidence of evolution because they have been shown to be the source of variation upon which ______ _____ acts.

Genes, Natural selection

The more closely related two species are, the more similar their _____ and _______ are.

Genes, proteins

Darwin didn't know about _______, but he realized that ________ in populations could help explain how the different species of Galapagos tortoises and other organisms evolved.

Genes, variations.

The similarities in location and function of the _____ _____ is a sign that the vertebrate species share a common ancestor.

Gills + glands

Body parts of organisms that are similar in position but different in function are called _______ ______-. The forelimbs of different mammals are examples.

Homologous structure

Scientific studies of fossils, anatomy, embryology, and molecular biology have provided evidence of relatedness among ______ and _____ species.

Living, extinct

The species of tortoise that lived on an island with tall cacti has _____ necks; the species of tortoise that lived on an island with lots of short grass had _______ necks.

Long, short.

An adaptation in which species resembles another species is called ______.

Mimicry.

The study of gene structure and function is called _______ ______.

Molecular biology

Though scientists now study evolution at the ______ level, the basic principles of Darwin's theory of evolution by natural selection have remained unchanged for more than _______ years.

Molecular, 150

Darwin's theory of evolution by _________ __________ predicts that species will develop adaptations and, therefore, eventually closely match Earth's changing environments.

Natural Selection

____________ is the process by which populations of organisms with variations that help them survive in their environments live longer, compete better, and reproduce more than populations that do not have _________.

Natural Selection, variations.

In _______________, nature causes the changes in the species; in __________________, humans cause the changes in the species.

Natural breeding, selective breeding.

If species have homologous structure, this suggests that the species are _______.

Related.

Evolution does not occur in a straight line with one species __________ another in a series of orderly steps.

Replaced

___________________ is the breeding of organisms for desired characteristics.

Selective Breeding

Darwin realized that ___________ and ______________ are similar processes.

Selective breeding, natural breeding

Darwin noticed that there was a relationship between each ________ and the food source of the island it lived on.

Species

The type of tortoise, mockingbird, and finch that live on each of the Galapagos islands was slightly different; Darwin later figured out that some varieties were different enough to be classified as different _________.

Species

____________ adaptations involve shape, size, color, and other physical features; the length of a Galapagos tortoise species' neck is an example of this type of adaptation.

Structural

Scientists classify adaptations into ______ categories.

Three

All species of ________ have pharyngeal pouches at some stage during their development.

Vertebrate

The best explanation for ______ ______ is that the species that have vestigial structures are _______ to ancestral species that still use the structures for a specific purpose.

Vestigial Structure, related

Whales have a tiny _____ _____ bone, which is a vestigial structure for walking on land.

Vestigial pelvic

Body parts that have lost their original function through evolution are called ______ ________. The ______ of flightless birds are an example.

Vestigial structure, wings

Since the publication of Darwin's theory, scientists have _______, refined, and _____ his work.

confirmed , extended