Lesson 1 Fossil Evidence of Evolution Chapter Introduction Lesson 1 Fossil Evidence of Evolution Lesson 2 The Theory of Evolution by Natural Selection Lesson 3 Biological Evidence of Evolution Chapter Wrap-Up Chapter Menu

Lesson 1 Reading Guide - Vocab Fossil Evidence of Evolution fossil record mold cast trace fossil geologic time scale extinction biological evolution Lesson 1 Reading Guide - Vocab

The Fossil Record The fossil record is made up of all the fossils. Lesson 1-1

Fossil Formation After an animal dies, over time only bones, shells, and teeth, remain. Rarely, they become fossils. Lesson 1-2

Mineralization: After an organism dies, while it is buried in mud and sediments, water replace the organism’s original material and harden into a rock, forming fossils. Carbonization: a fossil forms when a dead organism is compressed over time and pressure drive off organism’s liquid and gas.

Fossil Formation (cont.) Organisms buried in sediment may decay or dissolve away leaving a cavity or mold. If the space is subsequently filled with sediment, an external  cast can be made.  Lesson 1-2

Fossil Formation (cont.) A trace fossil is a fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itself. Lesson 1-2

Determining a Fossil’s Age Dating means to determine the age. To date the age of fossils, scientist use relative age dating, where they date the rocks the fossils are inside in order to determine the age of the fossils themselves, as opposed to the fossils themselves. Lesson 1-3

Determining a Fossil’s Age (cont.) Absolute-age dating is measuring the age of sedimentary rock layers, by calculating the ages of igneous layers, rock formed by cooling of magma, above and below the rock layers that contain the fossils. Lesson 1-3

Lesson 1-3

Fossils over Time The geologic time scale is a chart that divides Earth’s history into different time units. Earth’s history is divided into four eons—the longest time units in the geologic time scale. Lesson 1-4

Lesson 1-4

Extinctions Extinction occurs when the last individual organism of a species dies. A mass extinction occurs when many species become extinct within a few million years or less. Extinctions can occur when environments change. Lesson 1-5

Extinctions (cont.) The fossil record contains evidence of the appearance of many new species over time. Biological evolution is the change over time in populations of related organisms. Lesson 1-5

Lesson 2 Reading Guide - Vocab Theory of Evolution by Natural Selection naturalist variation natural selection adaptation camouflage mimicry selective breeding Lesson 2 Reading Guide - Vocab

Charles Darwin A naturalist is a person who studies plants and animals by observing them. Charles Darwin was an English naturalist who, in the mid-1800s, developed a theory of how evolution works. Lesson 2-1

Darwin found that each island in the Galápagos had a different environment, and tortoises looked different depending on which island environment they inhabited. Lesson 2-1

Darwin’s Theory A variation is a slight difference in an inherited trait of individual members of a species. Variations arise naturally in populations, occurring in offspring as a result of sexual reproduction. Genetic changes to phenotype can be passed on to future generations. Lesson 2-2

Darwin’s Theory (cont.) Natural selection is the process whereby organisms better adapted to their environment tend to survive and produce more offspring. Natural selection explains how populations change as their environments change. Lesson 2-2

Adaptations Through natural selection, a helpful variation in one individual can spread to all members of a population. An adaptation is an inherited trait that increases an organism’s chance of surviving and reproducing in its environment. Lesson 2-3

Adaptations (cont.) Structural adaptations involve color, shape, and other physical characteristics. Behavioral adaptations involve the way an organism behaves or acts. Functional adaptations involve internal body systems that affect biochemistry. Lesson 2-3

Adaptations (cont.) Camouflage and mimicry are adaptations that help species avoid being eaten. Camouflage is an adaptation that enables a species to blend in with its environment. The resemblance of one species to another species is mimicry. Lesson 2-3

Lesson 3 Reading Guide - Vocab Biological Evidence of Evolution comparative anatomy homologous structure analogous structure vestigial structure embryology Lesson 3 Reading Guide - Vocab

Evidence for Evolution Lesson 3 The degree to which species are related depends on how closely in time they diverged, or split, from their common ancestor. The fossil record show many close ancestral relationships. Lesson 3-1

Evidence for Evolution (cont.) Comparative anatomy is the study of similarities and differences among structures of living species. Lesson 3-1

Homologous structures are body parts of organisms that are similar in structure and position but different in function.

Do Not Copy: The forelimbs of these species are different sizes, but their placement and structure suggest common ancestry. Lesson 3-1

Body parts that perform a similar function but differ in structure are analogous structures. Lesson 3-1

Vestigial structures are body parts that have lost their original function through evolution. Lesson 3-1

Evidence for Evolution (cont.) The science of the development of embryos from fertilization to birth is called embryology. Lesson 3-1

All vertebrate embryos exhibit pharyngeal pouches at a certain stage of their development. These features, which develop into neck and face parts, suggest relatedness. Lesson 3-1

Evidence for Evolution (cont.) Molecular biology is the study of gene structure and function. Discoveries in molecular biology have confirmed and extended much of the data already collected about the theory of evolution. Scientists can study relatedness of organisms by comparing genes and proteins among living species. Lesson 3-1

Evidence for Evolution (cont.) Scientists have found that some stretches of shared DNA mutate at regular, predictable rates. Scientists use this “molecular clock” to estimate at what time in the past living species diverged from common ancestors. Lesson 3-1

Do Not write Molecular data indicate that whales and porpoises are more closely related to hippopotamuses than they are to any other living species. Lesson 3-1

Do Not Write: Many scientists think that natural selection produces new species slowly and steadily. Other scientists think species exist stably for long periods, and change occurs in short bursts. Lesson 3-2