QUARTER 2-MODULE 3 IN GENERAL BIOLOGY 2- GRADE 11 STEM PDF

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LEARNING MODULE – Grade 11 (General Biology 2 - STEM)Name: _____ Year & Section: _____ModuleEvolution and Origin of BiodiversityEvery living organism, from bacteria to monkeys to blueberries, evolved from a different species at some point. Although it may appear that living things today remain l...

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LEARNING MODULE – Grade 11 (General Biology 2 - STEM)

Name: _________________________________________

Year & Section: _____________

Module #3 Evolution and Origin of Biodiversity INTRODUCTION

Every living organism, from bacteria to monkeys to blueberries, evolved from a different species at some point. Although it may appear that living things today remain largely unchanged, this is not the case; evolution is a continuous process. The theory of evolution is biology's unifying theory, which means it serves as the framework within which biologists ask questions about the living world. The theory of evolution provides direction for predictions about living things that are born out in experiment after experiment. You have learned already from your lower earth science subjects about Earth and how it is formed, how it was evolved to be like the present Earth that we live in today. Our planet Earth has been subjected to a number of geological and biological challenges t hat have altered not only its landscape but also its inhabitants. You have learned already from your lower earth science subjects about Earth and how it is formed, how it was evolved to be like the present Earth that we live in today. Our planet Earth has undergone a series of geological and biological challenges that have changed not only its landscape but also its inhabitants.

OVERVIEW

This module will look at evolution and how changes over time have resulted in the emergence and diversification of species. However, the lessons in this module are limited to the geologic time scale's description of the history of life on Earth, the characteristics of these living organisms during different periods of Earth's history, and the various mechanisms that produce changes in these living organisms from one generation to the succeeding generations.

This module is composed of the following:  Introduction  Diagnostic Test  Expectations  Learning Activities  Activities  Assessment

OBJECTIVES: MELC’s:

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Describe general features of the history of life on Earth, including generally accepted dates and sequence of the geologic time scale and;

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characteristics of major groups of organisms present during these time periods

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Explain the mechanisms that produce change in populations from generation to generation (e.g., artificial selection, natural selection, genetic drift, mutation, recombination)

To check your previous knowledge about our lesson, try to answer the diagnostic test below. Good luck! 1. Which organism was the first to dominate the Earth? a) Dinosaurs

b) Fishes c) Plants d) bacteria 2. The Mesozoic era is called the Age of reptiles, how about the Cenozoic era?

a) Age of mammals b) Age of humans c) Age of birds d) Age of Technology 3. What is the longest part of Earth‟s history which covers 88% of the Earth‟s history? a) Precambrian b) Paleozoic c) Mesozoic d) Cenozoic 4. The geologic time scale is subdivided into four groups. What is the correct sequence if you will arrange them from the largest to the smallest? a) Eon, period, epoch, era b) Eon, era, period, epoch c) Eon, era, epoch, period d) Era, eon, period, epoch 5. Coronacollina acula is a fossil that represent the oldest animal with hard body parts that was discovered recently in South Australia. Scientist believed that this animal existed during ___________. a) Precambrian b) Paleozoi c) Mesozoic d) Cenozoic

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The Earth is around 4.5 billion years old. What was Earth like million years ago? When did the first living organism evolved? By studying the Earth‟s geological timeline, we will be able to trace the processes by which fossils and living organisms have evolved since the time that life started until the present day

The Earth‟s history is divided into eons, eras, periods and epochs. The geologic time scale is a record of the life forms and geological events in Earth‟s history. Scientists developed the time scale by developing by studying the rock layers and fossils worldwide. Radioactive dating was used to determine the absolute divisions in the time scale. THE GEOLOGICAL TIME SCALE

EON

ERA

MILLIONS OF YEARS AGO

PERIOD

EPOCH

Quatemary

Holocene

0.01

Historicsl Time

Pleistocene

2.6

Ice ages, origin of homo

Pilocene

5.3

Bipedal human ancestor appear

Miocene

23

Mammals and angiosperms continue to diversity

Oligocene

33.9

Origins of primates

Cenozoic Neogene

Phanerozoic

Palegene

Mersozoic

MAJOR EVENTS

Eccene

55.8

Angiosperms, dominate, mammals diversify

Paleocene

65.5

Mammals, birds, insects diversify

Cretaceous 145.5

Angiosperm diversify, dinosaurs extinct at end period

Jurassic 199.6

Dinosaurs abundant, first bird appear, gymnosperms

dominate

Paleozoic

Triassic 251

Dinosaurs evolve, origin of mammals, gymnosperms dominate

Permian 299

Reptiles diversidy, major extinction of many marine organisms

Carboniferous 359.2

Devonian 416

Silurian

First seed plants appear, origin of reptiles, amphibians dominate Bony fishes diversify, insects and first amphibians appear First vascualar plants

The Earth‟s geological life may simply be subdivided this way;

1. The Precambrian life (Hadean, Archean and Proterozoic eras)  The Precambrian life covers approximately 88% of the Earth‟s history. It is during this time that the Earth was transformed from a ball of gas and dust to liquid rock enveloped with hot, non-breathable gases mostly composed of carbon dioxide, nitrogen, and sulfur. The molten rock cooled down to form the earth‟s crust and with that, the gases also changed providing a cooler temperature composed mostly of nitrogen. The Earth become more conducive to life and allowed single-celled cyanobacteria to exist.

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It was believed that soft bodied creatures lived during Precambrian but with this discovery, an organism with individual skeletal body parts possibly appears before the Cambrian. It is therefore the oldest animal with hard parts-they would have been structural supports. This also signals that initiation of skeletons was not sudden in the Cambrian as was thought, that Ediacaran animals are part of the evolutionary lineage of animals. This recent discovery shows that Ediacaran animals were not extinct just before the Cambrian. Another recent fossil discovery may represent the earliest animal species ever found. These fossils from South Australia date back 650 million years. Until this

discovery, most scientists believed that there was no animal life prior to the Ediacaran period. Many scientists now believed that animals may in fact have evolved during the Cryogenian period.  The latter part of Precambrian life, the Proterozoic era, was greatly affected by the movement of tectonic plates forming the supercontinent Rodinia. Many species of bacteria and protists were killed by the presence of higher concentration of oxygen. New types of organisms evolved using biochemical adaptations enabling them to survive the presence the presence of oxygen. This allowed the domination of aerobic eukaryotes, the first multicellular organisms. 2. Paleozoic Era

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This era known as “Old Life”, started more than 540 million of years ago and lasted for more than 300 million years. This era is divided into six periods: Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian. Geological processes during this era began with the break-up of supercontinent Rodinia into continents Gondwana and Laurentia. These two continents were located near the equator that subsumed much of the current day landmasses in a different configuration. At this time, sea levels were very high, probably at a level that hasn‟t been reached since.

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Towards the latter part of Paleozoic era, however, the largest mass extinction in history also occurred, wiping out approximately 90% of all marine animal species and 70% of land animals. When the continents were rejoined as Pangaea, lower sea levels increased volcanic activity, and climate change are the possible causes of the mass extinction during this era.

3. The Mesozoic Era or the “middle life” 

It started 245 million years ago and lasted for 180 million years. It is subdivided into three periods; Triassic, Jurassic and cretaceous periods. These are the major geological events that happened during this era; movement of the tectonic plates like the gradual rifting of the supercontinent Pangae a. This split Pangaea into two northern continents (North America and Eurasia) and Laurasia and a southern continent. Gondwana (South America, Australia, Antarctica and the Indian continent. During the Triassic period, Pangaea still formed one massive continent.

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This era is known also as the era of dinosaurs because its predominated by reptiles because of their ability to withstand dry climates. Small mammals and birds also thrive d in this era because of being warm-blooded and hair or feathers to protect them from the changing climate. Gymnosperms were most abundant during this era

because their seeds were protected to endure the dry weather. Cretaceous period ended with a mass extinction event thought to be brought about by the collision of an asteroid or comet with Earth. 4. The Cenozoic Era or „recent life‟

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This era started 65 million years ago and continues up to the present time. It is divided into three periods: Paleogene, Neogene and Quaternary. The world‟s great mountain ranges were built during this era. The main Alpine orogeny, which produced the Alps and Carpathians in southern Europe and the Atlas Mountains in northwestern Africa, began roughly between 37 to 24 million years ago. The Himalayas were formed during sometime after the Indian plate collided with the Eurasian plate. The formation of these mountain ranges contributed to the cooling down of the climate in this era.

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Animals during this era had to adapt with the rise and fall of the oceans caused by melting glaciers. Among marine life-forms, the mollusks became highly diversified.

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This era is also known as the Age of Mammals.

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This era is the development and proliferation of perissodactyls and artiodactyls.

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Paleolithic hunters are considered by the scientists as more likely the cause of the disappearance of these mammals.

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Changes in the environment often creates new niches (living spaces) that contribute to rapid speciation and increased diversity

When we try to understand the history of the Earth and how our planet changed over time as describes on our geological timeline, we also try to understand how biological processes that take place have caused disruptions in the organismal equilibrium. These biological changes that happens through the course of geological events that shaped our planet until today is explained through the process of evolution

BASIC MECHANISM OF EVOLUTION The thought that species change had been suggested and debated well even before Charles Darwin began to explore the idea on evolution. Plato writings explained about evolutionary ideas. James Hutton proposed also that geological change occurred gradually by the accumulation of small changes from processes operating like they are today over long periods of time. This view of Hutton was supported by a geologist named Charles Lyell

who became a friend to Darwin. This idea became influential to Darwin‟s thinking. In the Early nineteenth century, Jean Baptiste Lamarck published a book that detailed a mechanism for evolutionary change referred as „inheritance due to acquired characteristics by which modifications in an individual are caused by its environment or the use or disuse of a structure during its lifetime could be inherited by its offspring and thus bring changes in a species. Although Lamarck idea was discredited, his ideas were an important influence on evolutionary thought. These forces known as the mechanism of evolution are said to have caused disruptions in the equilibrium. These are natural selection, mutation, genetic drift, gene flow (migration) and recombination.

1. Natural selection

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This mechanism of evolution was proposed two naturalists- Charles Darwin and Alfred Russell Wallace in the mid-nineteenth century. These two naturalists spent time exploring the natural worlds on expeditions to the tropics from 1831 to 1836 (Darwin) and from 1848 to 1852 (Wallace). Darwin‟s journeys in the Malay Archipelago included stops at several island chains, the last being the Galapagos Islands (west of Ecuador) where he observed species of organisms on different islands that were clearly similar yet had distinct differences. Wallace and Darwin both observed similar patterns in other organisms and independently conceive a mechanism to explain how and why such changes could take place. Darwin called the mechanism natural selection

To see more of Darwin‟s Voyage, you can visit this website http//www.archive.org/details/journalofresea00darw.

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Natural selection was governed with these three principles. - First, the characteristics of organisms are inherited, or passed from parent to offspring. - Second, more offspring are produced than are able to survive (resources for survival and reproduction are limited). Thus, there is a competition for those resources in each generation. - Third, offspring vary among each other in regard to their characteristics and those variations are inherited.

Out of these three principles, Darwin and Wallace reasoned that offspring with inherited characteristics that allow them to best compete for limited resources will survive and have more offspring than those individual with variations that are less able to compete. Since characteristics are inherited, these traits will be better represented in the next generation. These will 9 lead to change in populations over generations in a process that Darwin called “descent with modification”. These principles were presented on the book of Darwin “On the Origin of Species” which was published in 1859. Importantly, these differences must have some genetic bases; otherwise, selection will not lead to change in the next generation. A heritable trait that aids the survival and reproduction of an organism in its present environment is called an adaptation.

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Adaptation is a “match” of the organism to the environment. Adaptation to an environment comes about when a change in the genetic variation occurs over time that increases or maintains the match of the population with its environment. Darwin observed that beak shape varies among finch species.

He postulated that the beak of an ancestral species had adapted over time to equip the finches to acquire different food sources. The same traits do not always have the same relative benefit or disadvantage because environmental conditions change. For examples, finches with large bills were benefited in one climate, while small bills were a disadvantage; in a different climate, the relationship could be reversed 2. Mutation  This is a change in the DNA sequence of the gene.  Mutation is a source of new alleles in the population.  A mutation can change one allele into another, but the net effect is change in frequency. The change in frequency resulting from mutation is small, so its effect on evolution is small also unless it interacts with one of the other factors such as selection. The outcomes or effect of mutation in an organisms‟ phenotype or appearance are as follows; a) It may affect the phenotype of organism in a way that gives it reduced fitness- lower likelihood of survival, resulting in fewer offspring. b) It may produce a phenotype with a beneficial effect on fitness. c) Neutral mutations will have no effect on fitness. Harmful mutations are removed from the populations by selection and will generally only be found in very low frequencies equal to the mutation rate. Beneficial mutations will spread through the populations through selection, although that initial spread is slow.

Whether or not a mutation is beneficial or harmful is determined by whether it helps an organism survive to sexual maturity and reproduce. Mutation is the ultimate source of genetic variation in all populations- new alleles, and, therefore, new genetic variations arise through mutation. 3. Genetic Drift

 It is simple the effect of change. It is most important in small populations because drift would be completely absent in a population with infinite individuals.

 Genetic drift occurs because the alleles in an offspring generation are a random sample of the alleles in the parent generation.

 Genetic drift can also be magnified by natural or human-caused events, such as disaster that randomly kills a large portion of population, which is known as the bottleneck effect results in a large portion of genome suddenly being wiped out. 4. Gene Flow

 The flow of alleles in and out of the population resulting from the migration of individuals or gametes. While some populations are fairly stable, others experience more flux.

 Gene flow can occur when an individual travels from one geographic location to another and joins a different population of the species

Patterns of Descent with Modification .

Species  

Ernst Mayer‟s definition: “Species are groups of interbreeding natural populations that are reproductively isolated from other such groups.” Is a closely related organism that is very similar and capable of producing fertile offspring.

Reproductive Isolating Mechanism  

The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offspring are sterile. These barriers maintain the integrity of a species by reducing gene flow between related species

1. Pre-zygotic isolation mechanisms  Prevent fertilization and zygote formation.  happens before fertilization occurs between gametes 1.1 Geographic or ecological or habitat isolation  Occurs when two species that could interbreed do not because the species live in different areas.  The two species live in different habitats and will not encounter one another: each is isolated from the other species.

1.1 Temporal or seasonal isolation 

Different groups may not be reproductively mature. For example, two populations of plants may produce flowers in different seasons, making mating between the populations impossible.

Western meadowlark

Eastern meadowlark

1.2 Behavioral isolation

 Patterns of courtship are different. For example, eastern & western meadowlark songs differ.

1.3 Mechanical isolation 

Differences in reproductive organs prevent successful interbreeding. Mechanical isolation occurs when mating is...