Science Q2 Final Topics - FINAL REVIEW+ PDF

1 What is the definition of a fossil? The remains or imprints of once-living organisms (mostly in sedimentary rocks). 2 What is the definition of fossil record? All of the fossils that have been discovered and provides evidence about the order in which species have existed through time, and how they...

1 What is the definition of a fossil? The remains or imprints of once-living organisms (mostly in sedimentary rocks). 2 What is the definition of fossil record? All of the fossils that have been discovered and provides evidence about the order in which species have existed through time, and how they have changed over time. 3 What are the steps of forming a fossil? 1) Fossils commonly form when a dead organism is covered by a layer of sediment or mud. 2) Over time, more sediment settles on top of the organism. 3) Minerals in the sediment may seep into the organism and replace the body's material with minerals that harden over time. 4) This process produces a cast fossil. Many familiar fossils are casts of hard parts, such as shells and bones. 5) If the organism rots away completely after being covered, it may leave an imprint of itself in the rock. What evidence supports evolution? Similar structure -Similar DNA - Unused 4 body structures 1) Common Structures: scientists have found that related organisms share structural traits. Structures reduced in size or function (unused structures) may have been complete and functional in the organism's ancestor. Also, similar structures with different functions. 2) Similar DNA: The genetic information stored in an organism's DNA determines the organism's traits. Because an organism's DNA stays almost exactly the same throughout its entire lifetime, scientists can compare the DNA from many organisms. The greater the number of similarities between the molecules of any two species, the more recently the two species most likely shared a common ancestor. 5 How can we tell the age of a fossil by relative dating and absolute dating? Relative dating determines whether a fossil formed before or after another fossil. When an organism is trapped in mud or sediment, the resulting fossil becomes part of that sedimentary layer of rock. In rock layers that are not disturbed, newer fossils are found in layers of rock that are above older fossils. Absolute dating: estimates the age of a fossil in years. Estimations are based on information from radioactive elements in certain rocks near the fossil. 6 What is extinction and mass extinction? An extinction happens when every individual of a species dies. A mass extinction occurs when a large number of species go extinct during a relatively short amount of time. Gradual environmental changes can cause mass extinctions. Catastrophic events, such as the impact of an asteroid, can also cause mass extinctions 7 What is the geologic time scale? The geologic time scale is the standard method used to divide Earth's long 4.6-billion- year natural history into manageable parts. Paleontologists adjust and add details to the geologic time scale when new evidence is found. 8 What are the 4 divisions that make up the history of life in order? 1) Precambrian era 2) Paleozoic era 3) Mesozoic era 4) Cenozoic era 9 What major events happened in the Precambrian era? 1) Life began to evolve and oxygen increased. 2) The earliest prokaryotes lived without oxygen (cyanobacteria). 3) Life began during this time. 4) Mass extinction: Increased oxygen was followed by the evolution of some organisms, but the extinction of others. For some organisms, oxygen is toxic. 5) Multicellular organisms evolved (eukaryotes). 6) Prokaryotes (single-celled organisms without a nucleus) were the dominant life form. 7) The early Prokaryotes lived in the ocean. 8) Less is known about its life than life in more recent time intervals, because microscopic organisms did not preserve well in the fossil record. 9) Cyanobacteria use sunlight to make their own food. This process releases oxygen. 10 What major events happened in the Paleozoic era? 1) Rocks from this era are rich in fossils of animals such as sponges, corals, snails, and trilobites. 2) Oceans were completely changed. 3) Crawling insects were among the first animals to live on land, followed by large salamander-like animals. 4) By the end of the era, forests of giant ferns covered much of Earth. 5) It is called “ancient life”.  6) The largest known mass extinction took place at the end of this era as many as 96% of marine species had become extinct & many other species of animals and plants also became extinct. 7) Plants, fungi, and air-breathing animals colonized land. 8) Life moved onto land. 9) All major plant groups except flowering plants appeared. 10) Fish, the earliest animals with backbones, appeared during this era, as did sharks. 11) By the end of the era reptiles and winged insects appeared. 11 What major events happened in the Mesozoic era? 1) It is called “middle life”. 2) In this era, a great variety of dinosaurs lived on Earth, and giant marine lizards swam in the ocean 3) Because of the abundance of reptiles, the era is commonly called the “Age of Reptiles”. 4) Mass extinction: an asteroid hit Earth around this time causing giant dust clouds and worldwide fires. With sunlight blocked by dust, many plants would have died. 5) In total, about two-thirds of all land species went extinct. 6) The most important plants during the early part of the era were conifers, or cone-bearing plants, which formed large forests. 7) The first birds and mammals also appeared. 8) Flowering plants appeared later in this era. 9) The climate has changed many times during this era. 12 What major events happened in the Cenozoic era? 1) It is called “recent life”. 2) Plants and Mammals dominate Earth. 3) Primates evolved (a group of mammals that includes humans, apes, and monkeys). 4) Humans appeared during this era. 5) Early mammals were small, but larger mammals appeared later. 6) More is known about this era than about previous eras, because the fossils are closer to Earth's surface and easier to find. 7) Extinction: During ice ages, many organisms migrated toward the equator. Other organisms adapted to the cold or became extinct. 8) We currently live in this era. 13 What characteristics do scientists use to classify living things? A) Physical Characteristics: Scientists look at physical characteristics, such as skeletal structure. They also study how organisms develop from an egg to an adult. For example, animals with similar skeletons and development may be related. B) Chemical Characteristics: Scientists can identify the relationships among organisms by studying genetic material such as DNA and RNA. They study mutations and genetic similarities to find relationships among organisms. Organisms that have very similar gene sequences or have the same mutations are likely related. Other chemicals, such as proteins and hormones, can also be studied to learn how organisms are related. 14 What is the definition of a species? A species is a group of organisms that are very closely related. They can mate and produce fertile offspring 15 What does a scientific name tell us about an organism? Each species has its own scientific name. A species is a group of organisms that are very closely related. They can mate and produce fertile offspring. The genus name includes similar species. A scientific name always includes the genus name followed by the specific name. The first letter of the genus name is capitalized, and the first letter of the specific name is lowercase. The entire scientific name is written either in italics or underlined. 16 What is the definition of taxonomy? Taxonomy is the science of describing, classifying, and naming living things. 17 What are the names and characteristics of the 3 domains? Domain Bacteria: All bacteria belong to Domain Bacteria. They are also up of prokaryotes. They lack a nucleus in their cells. They are single-cell organisms. They reproduce by cell division. They live in almost any environment, soil, water, and even inside the human body! Domain Archaea: They are also up of prokaryotes. They lack a nucleus in their cells. They are single-cell organisms. They reproduce by cell division. They differ from bacteria in their genetics and in the makeup of their cell walls. They live in harsh environments, such as hot springs and thermal vents, where other organisms could not survive. Some are found in the open ocean and soil. Domain Eukarya: They are eukaryotes. They are made up of cells that have a nucleus and membrane-bound organelles. The cells of eukaryotes are more complex than the cells of prokaryotes. For this reason, the cells of eukaryotes are usually larger than the cells of prokaryotes. Some eukaryotes, such as many protists and some fungi, are single-celled. Many eukaryotes are multicellular organisms. Some protists and many fungi, plants, and animals are multicellular eukaryotes. Domain Eukarya is made up of all eukaryotes. 18 How can classification change over time? Millions of organisms have been identified, but millions have yet to be named. Many new organisms fit into the existing system. However, scientists often find organisms that don't fit. Not only do scientists identify new species, but sometimes these species do not fit into existing genera or phyla. In fact, many scientists argue that protists are so different from one another that they should be classified into several kingdoms instead of one. Classification continues to change as scientists learn more about living things. 19 What is a cladogram and how can I interpret them? Scientists often use a type of branching diagram called a cladogram. A cladogram shows relationships among species. Organisms are grouped according to common characteristics. Usually, these characteristics are listed along a line. Branches of organisms extend from this line. Organisms on branches above each characteristic have the characteristic. Organisms on branches below lack the characteristic. 20 What is a dichotomous key and how can I interpret them? A dichotomous key uses a series of paired statements to identify organisms. Each pair of statements is numbered. When identifying an organism, read each pair of statements. Then choose the statement that best describes the organism. Either the chosen statement identifies the organism, or you will be directed to another pair of statements. By working through the key, you can eventually identify the organism. 21 What are the names of the 6 kingdoms? 1) Kingdom Protista. 2) Kingdom Plantae. 3) Kingdom Fungi. 4) Kingdom Animalia. 5) kingdom Archaebacteria. 6) kingdom Archaebacteria. 22 What are the characteristics of the kingdom Archaebacteria? / Domain Archaea 1) They are also up of prokaryotes. 2) They lack a nucleus in their cells. 3) They are single-cell organisms. 4) They reproduce by cell division. 5) They differ from bacteria in their genetics and in the makeup of their cell walls. 6) They live in harsh environments, such as hot springs and thermal vents, where other organisms could not survive. 7) Some are found in the open ocean and soil. 23 What are the characteristics of the kingdoms Eubacteria? / Domain Bacteria 1) All bacteria belong to Domain Bacteria. 2) They are also up of prokaryotes. 3) They lack a nucleus in their cells. 4) They are single-cell organisms. 5) They reproduce by cell division. 6) They live in almost any environment, soil, water, and even inside the human body! 24 What are the characteristics of the kingdoms Protista? They are single-celled or multicellular organisms. They include algae and slime molds. Protists are very diverse, with plant-like, animal-like, or fungus- like characteristics. Some protists reproduce sexually, while others reproduce asexually. Algae are autotrophs, which means that they make their own food. Some protists are heterotrophs. They consume other organisms for food. 25 What are the characteristics of the kingdoms Fungi? They get energy by absorbing materials. use digestive juices to break down materials around them for food. They have cells with cell walls but no chloroplasts. They are single-celled or multicellular. They include yeasts, molds, and mushrooms. They reproduce sexually, asexually, or in both ways, depending on their type. 26 What are the characteristics of the kingdoms Plantae? They consist of multicellular organisms that have cell walls, mostly made of cellulose. Most plants make their own food through the process of photosynthesis. Plants are found on land and in water that light can pass through. Some plants reproduce sexually, such as when pollen from one plant fertilizes another plant. Other plants reproduce asexually, such as when potato buds grow into new potato plants. While plants can grow, they cannot move by themselves. 27 What are the characteristics of the kingdoms Animalia? They contain multicellular organisms that lack cell walls. They do not have chloroplasts like plants and algae, so they must get nutrients by consuming other organisms. Therefore, they are heterotrophic. Animals have specialized sense organs, and most animals are able to move around. Birds, fish, reptiles, amphibians, insects, and mammals are just a few examples of animals. Most animals reproduce sexually, but a few types of animals reproduce asexually, such as by budding. 28 What are the differences between Eukaryotic and Prokaryotic cells? Eukaryotes are made up of cells that have a nucleus and membrane-bound organelles. The cells of eukaryotes are more complex than the cells of prokaryotes. For this reason, the cells of eukaryotes are usually larger than the cells of prokaryotes. Some eukaryotes, such as many protists and some fungi, are single-celled. Many eukaryotes are multicellular organisms. Prokaryotes usually have a cell wall and reproduce by cell division. Prokaryotes are single-cell organisms that lack a nucleus in their cells. 29 What are the differences between heterotrophic & autotrophic organisms? Autotrophic they make their own food through the process of photosynthesis. Heterotrophs consume other organisms for food. 30 What is common ancestor? A common ancestor is the most recent species from which two different species have evolved.