This octopus and this surf clam both have a body structure called a mantle, which covers their soft bodies. However, the mantle is shaped differently in the two species. What best explains this?

They inherited the mantle from a shared ancestor population, but it evolved differently in different environments.

The two species evolved mantles separately with no shared ancestor.

It’s impossible to explain how structures evolve over time.

It’s a coincidence that both have mantles.

This fossil snake and this living rat both have a structure in their skull called the quadrate bone. What best explains this?

They share an ancestor population that had the quadrate bone.

They evolved the bone recently to help them survive.

It’s a coincidence both have the same bone.

The two species inherited the bone from separate ancestor populations.

This living manta ray and this fossil shark both have a skeleton made of cartilage. What best explains why both species have this structure?

They inherited the cartilage skeleton from a shared ancestor population.

Fossils are too old to explain this.

They are different species with separate origins.

It’s a coincidence that both use cartilage.

The body structures for a population of green herons were stable for a long time. Then, the herons became taller. What likely caused this change?

The environment must have changed.

The herons wanted to be taller.

It is impossible to say without more information.

Organisms naturally become taller over time.

Evolutionary History

Amplify : Evolutionary History

Checkpoint Review 2 - Evolutionary History

Checkpoint 2 - Natural Selection and Evolutionary History

LESSON 2 Early Theories on the Origin of Life • Identify the different theories on the origin of life. • Describe each theory and determine their differences What are the characteristics of living things? Before learning about the history of Earth based on geological evidence, early scientists explored the possibilities of how the first life-form existed. There are several theories about the origin of life. Theory of Catastrophism The theory of catastrophism supported by French scientists Georges Cuvier (1769-1832) and Alcide Dessalines d'Orbigny (1802-1857), is said to be a modification of the creation story of the Bible. It states that there have been several living creations from God, each encountered a catastrophe that completely destroyed them. Each new creation consisted of new life-forms, which happen to be different from the previous ones. Theory of Abiogenesis The theory of abiogenesis, or the spontaneous generation theory, states that living things were naturally created from nonliving things such as simple organic compounds. The theory supposes that abiogenesis occurred between 3.8 and 4 Gya. The experiment performed by Stanley Miller in 1953 gave way to many speculations and studies on how life on Earth really began. His research involved a simulation of the possible environment on Earth in the past. He demonstrated how an electric spark (which is a simulation for lightning) when passed through simple organic gases (similar to the early Earth atmosphere), resulted in the formation of amino acids, which are now known as the building blocks of proteins and the components of living tissues. Theory of Biogenesis The theory of biogenesis presented a strong argument against abiogenesis. This theory states that living things come from living things. Experiments of Francesco Redi and Louis Pasteur disproved the thought of spontaneous generation during their time (figure 5-1). Louis Pasteur argued that life comes from preexisting life and not from nonliving material. However, it should be noted that the "abiogenesis" or "spontaneous generation" that he opposed referred to any modern, existing, fully-formed organisms, not the original generation of life. Louis Pasteur's law of biogenesis contradicted the common belief during his time that cattle dung gives rise to flies, or old clothes with rotten food gives rise to mice. The idea of spontaneous generation was popular until near the seventeenth century. Even famous scientists of that period, such as Descartes, Galileo, and Jan Baptista van Helmont, believed in this theory. CIENCE PIONEER Francesco Redi (1626-1697). Francesco Redi is a physician, a naturalist, and a poet. His works challenged the popular theory of spontaneous generation. He disproved the idea that living things may arise from nonliving things. He also worked on toxicology using viper's venom. He discovered and worked on some parasites that caused disease in humans. SCIENCE CAREER Evolutionary Biologist An evolutionary biologist studies the descent of species and the origin of new species of living things. Working as evolutionary biologist means studying and researching species diversity, their interaction with the environment, their adaptation to change, their ancestors, and their possible origins. This career is important in the field of science because it seeks an answer to the questions about how life began on Earth.

Early society and accomplishments Origins Knowledge of the early prehistory of Southeast Asia has undergone exceptionally rapid change as a result of archaeological discoveries made since the 1960s, although the interpretation of these findings has remained the subject of extensive debate. Nevertheless, it seems clear that the region has been inhabited from the earliest times. Hominid fossil remains date from approximately 1,500,000 years ago and those of Homo sapiens from approximately 40,000 years ago. Furthermore, until about 7000 bce the seas were some 150 feet (50 metres) lower than they are now, and the area west of Makassar Strait consisted of a web of watered plains that sometimes is called Sundaland. These land connections perhaps account for the coherence of early human development observed in the Hoabinhian culture, which lasted from about 13,000 to 5000 or 4000 bce. The stone tools used by hunting and gathering societies across Southeast Asia during this period show a remarkable degree of similarity in design and development. When the sea level rose to approximately its present level about 6000 bce, conditions were created for a more variegated environment and, therefore, for more extensive differentiation in human development. While migration from outside the region may have taken place, it did not do so in a massive or clearly punctuated fashion; local evolutionary processes and the circulation of peoples were far more powerful forces in shaping the region’s cultural landscape. Technological developments and population expansion Perhaps because of a particular combination of geophysical and climatic factors, early Southeast Asia did not develop uniformly in the direction of increasingly complex societies. Not only have significant hunting and gathering populations continued to exist into the 21st century, but the familiar cultural sequences triggered by such events as the discovery of agriculture or metallurgy do not seem to apply. This is not to say that the technological capabilities of early Southeast Asian peoples were negligible, for sophisticated metalworking (bronze) and agriculture (rice) were being practiced by the end of the 3rd millennium bce in northeastern Thailand and northern Vietnam, and sailing vessels of advanced design and sophisticated navigational skills were spread over a wider area by the same time or earlier. Significantly, these technologies do not appear to have been borrowed from elsewhere but were indigenous and distinctive in character. Austronesian languages Austronesian languagesMajor divisions of the Austronesian languages. These technological changes may partially account for two crucial developments in Southeast Asia’s later prehistory. The first is the extraordinary seaborne expansion of speakers of Proto-Austronesian languages and their descendants, speakers of Austronesian (or Malayo-Polynesian) languages, which occurred over a period of 5,000 years or more and came to encompass a vast area and to stretch nearly half the circumference of Earth at the Equator. This outward movement of people and culture was evolutionary rather than revolutionary, the result of societal preference for small groups and a tendency of groups to hive off once a certain population size had been reached. It began as early as 4000 bce, when Taiwan was populated from the Asian mainland, and subsequently it continued southward through the northern Philippines (3rd millennium bce), central Indonesia (2nd millennium bce), and western and eastern Indonesia (2nd and 1st millennia bce). From approximately 1000 bce on the expansion continued both eastward into the Pacific, where that immense region was populated in a process continuing to about 1000 ce as voyagers reached the Hawaiian Islands and New Zealand, and westward, where Malay peoples reached and settled the island of Madagascar sometime between 500 and 700 ce, bringing with them (among other things) bananas, which are native to Southeast Asia. Thus, for a considerable period of time, the Southeast Asian region contributed to world cultural history, rather than merely accepting outside influences, as frequently has been suggested. The second development, which began possibly as early as 1000 bce, centred on the production of fine bronze and the fashioning of bronze-and-iron objects, particularly as they have been found at the site in northern Vietnam known as Dong Son. The earliest objects consisted of socketed plowshares and axes, shaft-hole sickles, spearheads, and such small items as fishhooks and personal ornaments. By about 500 bce the Dong Son culture had begun producing the bronze drums for which it is known. The drums are large objects (some weigh more than 150 pounds [70 kg]), and they were produced by the difficult lost-wax casting process and decorated with fine geometric shapes and depictions of animals and humans. This metal industry was not derived from similar industries in China or India. Rather, the Dong Son period offers one of the most powerful—though not necessarily the only or earliest—examples of Southeast Asian societies transforming themselves into more densely populated, hierarchical, and centralized communities. Since typical drums, either originals or local renditions, have been found throughout Southeast Asia and since they are associated with a rich trade in exotics and other goods, the Dong Son culture also suggests that the region as a whole consisted not of isolated, primitive niches of human settlement but of a variety of societies and cultures tied together by broad and long-extant trading patterns. Although none of these societies possessed writing, some displayed considerable sophistication and technological skill, and, although none appears to have constituted a territorial centralized state, new and more complex polities were forming.

Revolutionary History

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