Ap Biology 011- the Origin of Life-scientifice Evidence Video Review Sheet

Learning Objectives

By the end of this section, you will be able to:

• Place and describe the properties of life
• Draw the levels of system amid living things
• Recognize and interpret a phylogenetic tree

Connection for AP^® Courses

The AP^® Biology curriculum is organized around iv major themes called the Big Ideas that apply to all levels of biological organization—from molecules and cells to populations and ecosystems. Each Large Idea identifies key concepts called Enduring Understandings, and Essential Knowledges, along with supporting examples. Elementary descriptions ascertain the focus of each Large Idea: Large Idea 1, Evolution; Big Idea 2, Energy and Homeostasis; Big Idea 3, Information and Communication; and Big Thought four, Systems and Interactions. Evolution explains both the unity and diversity of life, Large Thought 1, and all organisms require energy and molecules to carry out life functions, such equally growth and reproduction, Big Idea two. Living systems also shop, transmit, and respond to information, from Dna sequences to nerve impulses and behaviors, Big Idea 3. All biological systems interact, and these interactions issue in emergent backdrop and characteristics unique to life, Big Idea 4.

The redesigned AP^® Biology course also emphasizes the investigative practices that students should primary. Scientific inquiry usually uses a series of steps to proceeds new knowledge. The scientific method begins with an observation and follows with a hypothesis to explain the ascertainment; then experiments are conducted to test the hypothesis, gather results, and draw conclusions from information. The AP^® program has identified seven major categories of Science Practices, which tin can be described by brusk phrases: using representations and models to communicate information and solve bug; using mathematics accordingly; engaging in questioning; planning and implementing data collection strategies; analyzing and evaluating data; justifying scientific explanations; and connecting concepts. A Learning Objective merges content with i or more of the seven Science Practices.

The information presented and the examples highlighted in this section support concepts and Learning Objectives outlined in Large Idea 1 of the AP^® Biology Curriculum. The Learning Objectives listed in the Curriculum Framework provide a transparent foundation for the AP^® Biology course, an inquiry-based laboratory feel, instructional activities, and AP^® Exam questions. A Learning Objective merges required content with one or more of the 7 Science Practices.

Big Idea ane	The process of evolution drives the variety and unity of life.
Enduring Understanding 1.B	Organisms are linked by lines of descent from common beginnings.
Essential Knowledge	ane.B.1 Organisms share many conserved cadre processes and features that evolved and are widely distributed amidst organisms today.
Scientific discipline Practice	three.one The student tin pose scientific questions.
Learning Objective	1.xiv The student is able to pose scientific questions that correctly identify essential properties of share, core life processes that provide insights into the history of life on World.
Essential Knowledge	ane.B.1 Organisms share many conserved core processes and features that evolved and are widely distributed among organisms today.
Science Practice	five.3 The student tin can evaluate the bear witness provided by information sets in relation to a item scientific question.
Learning Objective	1.18 The pupil is able to evaluate evidence provided by a data gear up in conjunction with a phylogenetic tree or but cladogram to decide evolutionary history and speciation.

Biology is the science that studies life, but what exactly is life? This may sound like a silly question with an obvious response, but it is not always like shooting fish in a barrel to define life. For example, a branch of biology chosen virology studies viruses, which exhibit some of the characteristics of living entities but lack others. It turns out that although viruses can attack living organisms, cause diseases, and even reproduce, they do non run across the criteria that biologists use to define life. Consequently, virologists are not biologists, strictly speaking. Similarly, some biologists study the early molecular evolution that gave rising to life; since the events that preceded life are not biological events, these scientists are likewise excluded from biology in the strict sense of the term.

From its earliest beginnings, biological science has wrestled with three questions: What are the shared properties that brand something "alive"? And once we know something is alive, how do we find meaningful levels of organization in its structure? And, finally, when faced with the remarkable diversity of life, how do we organize the dissimilar kinds of organisms so that we can better understand them? Every bit new organisms are discovered every day, biologists continue to seek answers to these and other questions.

Backdrop of Life

All living organisms share several primal characteristics or functions: social club, sensitivity or response to the environment, reproduction, adaptation, growth and development, regulation/homeostasis, energy processing, and development. When viewed together, these 8 characteristics serve to define life.

Society

Figure 1.10 A toad represents a highly organized structure consisting of cells, tissues, organs, and organ systems. (credit: "Ivengo"/Wikimedia Eatables)

Organisms are highly organized, coordinated structures that consist of ane or more cells. Even very simple, single-celled organisms are remarkably circuitous: inside each cell, atoms brand upward molecules; these in turn make up cell organelles and other cellular inclusions. In multicellular organisms (Figure 1.10), like cells class tissues. Tissues, in plow, interact to create organs (body structures with a distinct function). Organs work together to form organ systems.

Sensitivity or Response to Stimuli

Figure i.eleven The leaves of this sensitive plant (Mimosa pudica) will instantly droop and fold when touched. Afterwards a few minutes, the plant returns to normal. (credit: Alex Lomas)

Organisms respond to diverse stimuli. For example, plants can bend toward a source of light, climb on fences and walls, or reply to touch (Figure 1.11). Fifty-fifty tiny bacteria can move toward or away from chemicals (a procedure called chemotaxis) or light (phototaxis). Motility toward a stimulus is considered a positive response, while motion away from a stimulus is considered a negative response.

Link to Learning

Spotter this video to see how plants respond to a stimulus—from opening to light, to wrapping a tendril effectually a branch, to capturing prey.

Which instance almost clearly shows a way that humans can reply directly to a change in the environment?

1. We shiver when we are common cold and sweat when we are hot.

2. We walk by putting our front leg forward and pushing off with our back leg.

3. We are able to breath in and out unconsciously.

4. Our hair and fingernails grow at a constant rate over time.

Reproduction

Single-celled organisms reproduce by start duplicating their DNA, and then dividing information technology as as the cell prepares to divide to class two new cells. Multicellular organisms frequently produce specialized reproductive germline cells that volition grade new individuals. When reproduction occurs, genes containing Deoxyribonucleic acid are passed along to an organism's offspring. These genes ensure that the offspring volition belong to the same species and volition have similar characteristics, such as size and shape.

Adaptation

All living organisms exhibit a "fit" to their environment. Biologists refer to this fit every bit adaptation, and it is a event of evolution by natural selection, which operates in every lineage of reproducing organisms. Examples of adaptations are diverse and unique, from heat-resistant Archaea that live in boiling hotsprings to the tongue length of a nectar-feeding moth that matches the size of the blossom from which information technology feeds. All adaptations heighten the reproductive potential of the individuals exhibiting them, including their ability to survive to reproduce. Adaptations are not constant. As an environment changes, natural choice causes the characteristics of the individuals in a population to rail those changes.

Growth and Evolution

Organisms grow and develop following specific instructions coded for by their genes. These genes provide instructions that will directly cellular growth and development, ensuring that a species' immature (Figure 1.12) will abound up to exhibit many of the same characteristics every bit its parents.

Effigy 1.12 Although no two await akin, these kittens have inherited genes from both parents and share many of the same characteristics. (credit: Rocky Mountain Feline Rescue)

Regulation/Homeostasis

Even the smallest organisms are complex and require multiple regulatory mechanisms to coordinate internal functions, respond to stimuli, and cope with environmental stresses. Homeostasis (literally, "steady land") refers to the relatively stable internal environment required to maintain life. Ii examples of internal functions regulated in an organism are nutrient send and blood catamenia. Organs (groups of tissues working together) perform specific functions, such as carrying oxygen throughout the torso, removing wastes, delivering nutrients to every cell, and cooling the torso.

Figure 1.13 Polar bears (Ursus maritimus) and other mammals living in ice-covered regions maintain their body temperature by generating heat and reducing heat loss through thick fur and a dense layer of fat nether their skin. (credit: "longhorndave"/Flickr)

In society to part properly, cells require advisable atmospheric condition such as proper temperature, pH, and appropriate concentration of various chemicals. These atmospheric condition may, however, change from ane moment to the next. Organisms are able to maintain homeostatic internal atmospheric condition within a narrow range near constantly, despite environmental changes, past activation of regulatory mechanisms. For example, an organism needs to regulate body temperature through the thermoregulation procedure. Organisms that alive in common cold climates, such as the polar bear ([link]), take torso structures that help them withstand depression temperatures and conserve torso heat. Structures that aid in this type of insulation include fur, feathers, blubber, and fat. In hot climates, organisms take methods (such equally perspiration in humans or panting in dogs) that help them to shed excess body heat.

Energy Processing

Figure 1.14 The California condor (Gymnogyps californianus) uses chemical energy derived from nutrient to power flight. California condors are an endangered species; this bird has a wing tag that helps biologists place the individual. (credit: Pacific Southwest Region U.Southward. Fish and Wildlife Service)

All organisms use a source of free energy for their metabolic activities. Some organisms capture free energy from the dominicus and convert it into chemical energy in food; others use chemical energy in molecules they have in every bit nutrient (Figure i.14).

Evolution

The diverseness of life on Globe is a result of mutations, or random changes in hereditary material over time. These mutations allow the possibility for organisms to arrange to a changing environment. An organism that evolves characteristics fit for the environment will have greater reproductive success, subject to the forces of natural option.

Science Practice Connection for AP® Courses

Activity

Select an ecosystem of your choice, such as a tropical rainforest, desert, or coral reef, and create a representation to evidence how several organisms plant in the ecosystem interact with each other and the environment. And then, using similarities and differences among the organisms brand a hypothesis nigh their relatedness.

Consider the levels of system of the biological earth and create a diagram to place these items in order from the smallest level of organization to the most encompassing: pare prison cell, planet Earth, elephant, tropical rainforest, water molecule, liver, wolf pack, and oxygen cantlet. Justify the reason why you lot placed the items in the hierarchy that y'all did.

Think About It

Homeostasis—the ability to "stay the same"—is a feature shared past all living organisms. Yous go for a long walk on a hot 24-hour interval. Depict how homeostasis keeps your body salubrious fifty-fifty though yous are sweating profusely. And so describe an example of an accommodation that evolved in a desert found or animal that allows them to survive in extreme temperatures.

Teacher Support

The first activity is an awarding of Learning Objective one.xvi and Science Practise 6.i considering the student is justifying the claim that organisms share many features that evolved in the past and are found among organisms today.

The 2nd activity is an application of Learning Objective i.16 and Science Practice 6.1 because the student is justifying the claim that life on Earth today is organized into a hierarchy of features, from simple to complex, that evolved in the past.

The "Think virtually information technology" section is an application of Learning Objective one.xiv and Science Practice 7.ii because students are describing an example of a procedure that is shared by all living organisms, despite the environment in which they are typically found.

Ecosystems: Each system must take a common thread of producers fixing sun energy or acquiring energy from chemical reactions, feeding kickoff consumers usually herbivores or decomposers, and second consumers that are predators. The ecosystem must provide shelter, access to food and stable environment. Answers volition vary.

Levels of organization from smallest to largest: Teach students to identify the obvious answers first: atom as smallest and planet Earth at the top and then fill the gaps.

From smallest to largest:

Oxygen cantlet

Water molecule

Skin jail cell

Liver

Elephant

Wolf pack

Tropical rain forest

Planet Earth

Adaptation to dry out conditions: Stress that animals and plants use general mechanisms to preserve water in one case the transition to dry out country was made. Animals adapted to dry climates have thick pare layers to reduce water loss. Their urinary arrangement is also adjusted to concentrate urine, reducing water loss. Animals also respond to farthermost oestrus behaviorally by going out at night or when the dominicus is low. Plants develop thick waxy layers that cover, leaves in the form of thorns and open stomata (pores) at night.

Many adaptations are due to convergent evolution. The fins of dolphins are non derived from fins of fish. On the other hand, structures that look very different such as our easily and the wings of bats have the same core structure—they are limbs with the same number and arrangement of bones—simply look different because they are adapted for different functions.

Levels of Organisation of Living Things

Living things are highly organized and structured, following a hierarchy that can exist examined on a scale from minor to large. The atom is the smallest and most fundamental unit of thing that retains the backdrop of an chemical element.. It consists of a nucleus surrounded by electrons. Atoms form molecules. A molecule is a chemical structure consisting of at least two atoms held together by 1 or more chemical bonds. Many molecules that are biologically important are macromolecules, large molecules that are typically formed by polymerization (a polymer is a large molecule that is fabricated by combining smaller units called monomers, which are simpler than macromolecules). An example of a macromolecule is deoxyribonucleic acid (Dna) (Figure 1.15), which contains the instructions for the structure and functioning of all living organisms.

Effigy i.15 All molecules, including this DNA molecule, are equanimous of atoms. (credit: "brian0918"/Wikimedia Eatables)

Link to Learning

Picket this video that animates the 3-dimensional structure of the DNA molecule shown in this figure.

The give-and-take helix means spiral. What does this tell yous about the structure of DNA, which is a double helix macromolecule?

1. The nucleotides of the two strands bail together with spiral bonds.

2. A double-stranded Dna molecule has ii spiral strands bound together.

3. DNA is a double helix because it has two strands held together similar a spiral staircase.

4. Nucleotides are spiral-shaped molecules that bail together to class Deoxyribonucleic acid.

Some cells comprise aggregates of macromolecules surrounded past membranes; these are chosen organelles. Organelles are minor structures that be within cells. Examples of organelles include mitochondria and chloroplasts, which acquit out indispensable functions: mitochondria produce energy to ability the prison cell, while chloroplasts enable greenish plants to utilize the energy in sunlight to brand sugars. All living things are made of cells; the jail cell itself is the smallest fundamental unit of measurement of structure and part in living organisms. (This requirement is why viruses are not considered living: they are not made of cells. To make new viruses, they have to invade and hijack the reproductive mechanism of a living cell; only then can they obtain the materials they demand to reproduce.) Some organisms consist of a single jail cell and others are multicellular. Cells are classified as prokaryotic or eukaryotic. Prokaryotes are single-celled or colonial organisms that practise not take membrane-jump nuclei; in contrast, the cells of eukaryotes practise have membrane-bound organelles and a membrane-bound nucleus.

In larger organisms, cells combine to make tissues, which are groups of similar cells carrying out similar or related functions. Organs are collections of tissues grouped together performing a mutual function. Organs are present non merely in animals but also in plants. An organ system is a higher level of organization that consists of functionally related organs. Mammals have many organ systems. For instance, the circulatory system transports blood through the body and to and from the lungs; it includes organs such equally the heart and claret vessels. Organisms are private living entities. For example, each tree in a woods is an organism. Single-celled prokaryotes and single-celled eukaryotes are also considered organisms and are typically referred to as microorganisms.

All the individuals of a species living within a specific area are collectively chosen a population. For instance, a forest may include many pine trees. All of these pine trees stand for the population of pine trees in this forest. Different populations may alive in the same specific area. For example, the forest with the pine copse includes populations of flowering plants and too insects and microbial populations. A community is the sum of populations inhabiting a particular area. For instance, all of the trees, flowers, insects, and other populations in a forest form the woods's community. The woods itself is an ecosystem. An ecosystem consists of all the living things in a item surface area together with the abiotic, non-living parts of that environment such as nitrogen in the soil or rain h2o. At the highest level of organization (come across this figure), the biosphere is the collection of all ecosystems, and it represents the zones of life on globe. It includes land, water, and fifty-fifty the atmosphere to a certain extent.

Visual Connection

Figure 1.sixteen The biological levels of organization of living things are shown. From a single organelle to the entire biosphere, living organisms are parts of a highly structured bureaucracy. (credit "organelles": modification of work by Umberto Salvagnin; credit "cells": modification of work by Bruce Wetzel, Harry Schaefer/ National Cancer Establish; credit "tissues": modification of work by Kilbad; Fama Clamosa; Mikael Häggström; credit "organs": modification of work by Mariana Ruiz Villareal; credit "organisms": modification of work by "Crystal"/Flickr; credit "ecosystems": modification of piece of work by U.s.a. Fish and Wildlife Service Headquarters; credit "biosphere": modification of work by NASA)

Which of the following statements is false?

1. Tissues exist inside organs which exist within organ systems.

2. Communities exist within populations which exist within ecosystems.

3. Organelles exist inside cells which exist within tissues.

4. Communities exist within ecosystems which exist in the biosphere.

The Diversity of Life

The fact that biological science, every bit a science, has such a broad scope has to do with the tremendous diversity of life on earth. The source of this diversity is evolution, the process of gradual change during which new species arise from older species. Evolutionary biologists study the evolution of living things in everything from the microscopic earth to ecosystems.

The evolution of diverse life forms on Earth tin exist summarized in a phylogenetic tree (Effigy 1.17). A phylogenetic tree is a diagram showing the evolutionary relationships among biological species based on similarities and differences in genetic or physical traits or both. A phylogenetic tree is composed of nodes and branches. The internal nodes represent ancestors and are points in development when, based on scientific evidence, an ancestor is thought to have diverged to form 2 new species. The length of each branch is proportional to the time elapsed since the split.

Figure 1.17 This phylogenetic tree was constructed by microbiologist Carl Woese using information obtained from sequencing ribosomal RNA genes. The tree shows the separation of living organisms into three domains: Bacteria, Archaea, and Eukarya. Bacteria and Archaea are prokaryotes, single-celled organisms defective intracellular organelles. (credit: Eric Gaba; NASA Astrobiology Institute)

Evolution Connection

Carl Woese and the Phylogenetic Tree

In the by, biologists grouped living organisms into 5 kingdoms: animals, plants, fungi, protists, and bacteria. The organizational scheme was based mainly on physical features, as opposed to physiology, biochemistry, or molecular biology, all of which are used by modern systematics. The pioneering work of American microbiologist Carl Woese in the early 1970s has shown, however, that life on Globe has evolved forth three lineages, now called domains—Bacteria, Archaea, and Eukarya. The outset two are prokaryotic cells with microbes that lack membrane-enclosed nuclei and organelles. The third domain contains the eukaryotes and includes unicellular microorganisms together with the iv original kingdoms (excluding bacteria). Woese defined Archaea as a new domain, and this resulted in a new taxonomic tree (see this figure). Many organisms belonging to the Archaea domain live under extreme weather condition and are called extremophiles. To construct his tree, Woese used genetic relationships rather than similarities based on morphology (shape).

Woese's tree was constructed from comparative sequencing of the genes that are universally distributed, present in every organism, and conserved (meaning that these genes take remained substantially unchanged throughout evolution). Woese'southward approach was revolutionary because comparisons of physical features are insufficient to differentiate between the prokaryotes that announced fairly similar in spite of their tremendous biochemical diversity and genetic variability (Effigy one.18). Comparing rRNA sequences provided Woese with a sensitive device that revealed the extensive variability of prokaryotes, and which justified the separation of the prokaryotes into 2 domains: bacteria and archaea.

Figure one.18 These images stand for different domains. The (a) bacteria in this micrograph belong to Domain Bacteria, while the (b) extremophiles (not visible) living in this hot vent vest to Domain Archaea. Both the (c) sunflower and (d) king of beasts are part of Domain Eukarya. (credit a: modification of work by Drew March; credit b: modification of piece of work by Steve Jurvetson; credit c: modification of work past Michael Arrighi; credit d: modification of work past Leszek Leszcynski)

In which domain would a fish be classified? Why?

1. Archaea, because fish are multicellular.

2. Eukarya, because fish are multicellular.

3. Archaea, because fish are single-celled.

4. Eukarya because fish are single-celled.

Everyday Connection for AP® Courses

Phylogenetic copse tin can correspond traits that are derived or lost due to evolution. One case is the absenteeism of legs in some body of water mammals. For instance, Cetaceans are marine mammals that include toothed whales, such as dolphins and killer whales, and baleen whales, such equally humpback whales. Cetaceans are descended from even-toed ungulates and share a common ancestry with the hippopotamus, cow, sheep, camel, and squealer.

Figure 1.19

Phylogenetic trees can represent traits that are derived or lost due to evolution. Ane example is the absence of legs in some marine mammals. Ane such group is the Cetaceans, which includes toothed whales, such as dolphins and killer whales, and baleen whales, such as humpback whales. Cetaceans are descended from fifty-fifty-toed ungulates and share a mutual ancestry with the hippopotamus, cows, sheep, camel, and pig. Based on the described phylogenetic tree, which of the following beast is the most closely related to a equus caballus?

1. an armadillo

2. a camel

3. a bat

4. a true cat

Instructor Support

Employ the diagram to ask the post-obit questions:

Which animal(s) are well-nigh closely related to a duck-billed platypus? Give your reasoning.

Answer

the American opossum, least number of mutual ancestors.

Circle on i main lineage in the diagram the nodes in red, the tip of the trees in bluish and the branches in red.

Once bats were called flying mice. According to the tree, is this a valid characterization?

Respond

No, bats are more closely related to shrew and moles.

Ask students the question, how did reptiles learn how to fly?

For an exploration of the evolution of flight visit this site.

Birds are non mod solar day dinosaurs. Birds evolved from dinosaurs. Many changes took place over time.

Branches of Biological Written report

The scope of biology is broad and therefore contains many branches and subdisciplines. Biologists may pursue one of those subdisciplines and work in a more focused field. For instance, molecular biology and biochemistry study biological processes at the molecular and chemical level, including interactions among molecules such as Deoxyribonucleic acid, RNA, and proteins, as well every bit the way they are regulated. Microbiology, the report of microorganisms, is the study of the structure and function of organisms that cannot exist seen with the naked center. It is quite a wide branch itself, and depending on the field of study of report, there are likewise microbial physiologists, ecologists, and geneticists, among others.

Career Connection

Forensic Scientist

Forensic science is the awarding of science to answer questions related to the law. Biologists as well as chemists and biochemists can exist forensic scientists. Forensic scientists provide scientific evidence for utilize in courts, and their job involves examining trace materials associated with crimes. Interest in forensic scientific discipline has increased in the last few years, possibly because of popular television shows that characteristic forensic scientists on the job. Also, the evolution of molecular techniques and the establishment of Dna databases have expanded the types of work that forensic scientists can do. Their work involves analyzing samples such as hair, blood, and other trunk fluids and also processing Deoxyribonucleic acid (Figure 1.twenty) constitute in many different environments and materials. Forensic scientists also analyze other biological evidence left at offense scenes, such as insect larvae or pollen grains. Students who want to pursue careers in forensic science volition most likely be required to take chemical science and biology courses besides equally some intensive math courses.

Effigy 1.twenty This forensic scientist works in a Dna extraction room at the U.Southward. Army Criminal Investigation Laboratory at Fort Gillem, GA. (credit: United States Regular army CID Control Public Affairs)

Another field of biological study, neurobiology, studies the biology of the nervous organisation, and although it is considered a branch of biology, it is also recognized as an interdisciplinary field of study known as neuroscience. Because of its interdisciplinary nature, this subdiscipline studies different functions of the nervous system using molecular, cellular, developmental, medical, and computational approaches.

Figure 1.21 Researchers work on excavating dinosaur fossils at a site in Castellón, Spain. (credit: Mario Modesto)

Paleontology, another branch of biology, uses fossils to study life's history (Figure i.21). Zoology and phytology are the study of animals and plants, respectively. Biologists can likewise specialize as biotechnologists, ecologists, or physiologists, to proper noun merely a few areas. This is merely a small-scale sample of the many fields that biologists can pursue.

Biology is the culmination of the achievements of the natural sciences from their inception to today. Excitingly, information technology is the cradle of emerging sciences, such as the biology of encephalon action, genetic engineering of custom organisms, and the biological science of evolution that uses the laboratory tools of molecular biology to retrace the primeval stages of life on earth. A browse of news headlines—whether reporting on immunizations, a newly discovered species, sports doping, or a genetically-modified food—demonstrates the way biology is agile in and important to our everyday world.

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Source: https://openstax.org/books/biology-ap-courses/pages/1-2-themes-and-concepts-of-biology

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