Lesson-1-Evidence-of-LifeLS.pdf

11TH Historical Development of GRADE the Concepts of Life Lesson 1  Objectives At the end of the lesson, the students are expected to, 1. identify the sequence of events of the history of life on earth; 2. name the pieces of evidence on the evolution of life on earth; and 3. reco...

11TH Historical Development of GRADE the Concepts of Life Lesson 1  Objectives At the end of the lesson, the students are expected to, 1. identify the sequence of events of the history of life on earth; 2. name the pieces of evidence on the evolution of life on earth; and 3. recognize the importance of knowing the history of life on earth Lesson 1 Question 1: When and where did life possibly start on Earth?  Evidence of Lifeforms During the 1800s, geologists and the naturalists Fossils found several forms of physical evidence that confirmed that Earth is very old. Rock Layers Indication of Volcanic Eruptions and Erosions  Guide Questions: 1. What is a timeline? 2. Why is creating a timeline significant?  Timeline of Appearance of Life Forms Originally formed by crystallization from a magma or in metamorphic rocks, zircons are so durable and resistant to chemical attack that they rarely go away. They may survive many geologic events, which can be recorded in rings of additional zircon that grow around the original crystal like tree rings. Like a tiny time capsule, the zircon records these events, each one of which may last hundreds of millions of years. Meanwhile, the core of the zircon itself remains unchanged, and preserves the chemical characteristics of the rock in which it originally crystallized. Stromatolite deposits are formed by sediment trapping and binding, and/or by precipitation activities of the microbial communities (Awramik 1976). It consists of layered bacteria and sediment. Consider that the Earth itself has been around for 4.5 billion years, and that Homo sapiens have only been on Earth for 195,000 years. What’s more, Stromatolites are the reason why we’re alive today! Before cyanobacteria, the air was only 1% oxygen. Then, for 2 billion years, photosynthesizing Stromatolites pumped oxygen into the oceans (like underwater trees, before trees existed). When the oceans’ waters were saturated, oxygen was released into the air, and with around 20% oxygen in the air, life was able to flourish and evolve. Eukaryotes are organisms having true nucleus. The DNA is enclosed within the nucleus whereas DNA of most prokaryotes lies enclosed in the cell’s cytoplasm. The first eukaryotes were protists.  Activity 2 Directions: Complete the paragraph by filling-in the blanks with the correct word from the box. About (1) __________, the earth was formed as the solar system came into existence with the other planets rotating around the sun. (2) __________ is said to be geologically violent because of the continuous bombardment by meteorites and volcanic eruptions. With this condition, minerals were formed from the elements and compounds contained in the molten material. The oldest material found on earth is the (3) __________ that is estimated to be 4.3 billion years old. Life on earth is believed to begin 3.5 billion years ago with single –celled prokaryotes, as discovered in sedimentary rock formations called (4) __________. As early as (5) __________,the first photosynthetic organism thrived the earth which is blue green algae called cyanobacteria. It was 2.0 billion years ago when the first eukaryotes appeared and the influx of multicellular organisms occurred 1.2 billion years ago. During the Paleozoic Era which lasted 542 to 251 MYA, the Cambrian and Ordovician Period has been known as the age of invertebrates when trilobites and cephalopods became dominant in the (6) __________. The (7) __________ is the age of reptiles that has a span of 251 to 65.5 MYA divided into Triassic, Jurassic and Cretaceous Periods. (8) __________ is the era of recent life and based on paleontological evidence (9) __________ have evolved 250 thousand years ago. (10) __________ are the only surviving species and one of the living evidence that life have existed on earth. What questions do you have? REFLECTION  Activity 3 Why Should I Study History of Life? Directions: Write at least a fifty-word reflection paper on: “Why should I study the history of life?”. Make sure to use these words in your essay; Journey Evolution Past Present Time Future