MIDDLETOWNHIGH SCHOOL SOUTH

Biology

Booklet 2

nAME: ______

cLASS: ______

Learning Outcomes

The Evolution of Man

Describe what a hominid is.

Describe why discovering Lucy was important to evolutionary biology.

Understand and describe the difference between the terms evidence and inference.

Be able to make inferences based on evidence presented to you.

Understand that the fossil record can identify what organisms are the oldest and youngest.

Understand that strata or layers can help to identify the age of fossils based on their position in the strata.

Give an example of an organism that has evolved over a long time period and discuss the changes that have occurred.

Define a homologous structure and explain its significance in evolutionary terms.

Define a vestigial structure and explain its significance in evolutionary terms.

Explain the significance of a common embryonic origin.

Describe the term adaptation.

Understand and describe the term adaptive radiation.

Describe the term species.

Describe how those organisms best suited to their environment will survive and be able to reproduce.

Describe what natural selection is.

Give examples of organisms have undergone natural selection.

Give an example of the high speed evolution of organisms such as antibiotic resistant bacteria and the black peppered moth.

Describe the term selective breeding.

Understand the difference between natural selection and selective breeding.

Be able to draw conclusions from data in experiments

Give examples of organisms that have been selectively bred

Understand the economic significance of selective breeding to humans

The Evolution of Man – Finding Lucy

Your teacher will show you a short movie clip

  • Hominids are erect-walking primates that include modern humans, earlier human species and early human-like species.
  • Evidence refers to information / data / physical objects that prove or disprove something.
  • Inference refers to conclusions that follow logically from direct evidence.
  • Lucy is the name of the nearly complete skeleton of anAustralopithecus afarensis.
  • She was the first nearly complete skeleton recovered for the species, found in1974 in the Afar TriangleofEthiopia.
  • Lucy is about 3.18 million years old and is not the only earlyhominid found at Hadar. Many more A. afarensis hominids were found in the local area.
  • Lucy's skeleton was clearly different from other primates. Her knees were able to lock, her femur slanted inward and her large toe was in line with her other toes, allowing her to walk upright.
  • The discovery of Lucy surprised palaeontologists because although she was unquestionably bipedal, she was remarkably apelike -- with a brain about the size of a chimpanzee's.

Why do we study bones?

  • Anthropology is the study of humans, past and present.Biological (Physical) anthropologists seek to understand how humans adapt to diverse environments.
  • In addition, they are interested in human biological origins, evolution and variation. They give primary attention to investigating questions having to do with evolutionary theory, our place in nature, adaptation and human biological variation.
  • To understand these processes, biological anthropologists study other primates (primatology), the fossil record (paleoanthropology), prehistoric people (bioarchaeology), and the biology (e.g., health, cognition, hormones, growth and development) and genetics of living populations.

Task 1: Understanding the role of a physical anthropologist.

In this activity you will be comparing the bones of a modern human and a modern chimpanzee with unknown bones.

  1. Study carefully the bones for all three animals.
  2. List each Mystery bone in the table below.
  3. Complete the table by writing down if you think each Mystery bone is more like human bone, more like chimpanzee bone or not like either.

Mystery Bones / Primate Comparisons
Tick() the appropriate box and give a reason for your selection
Jaw / Human
Primate
Pelvis / Human
Primate
Femur / Human
Primate
Foot / Human
Primate
  1. Based on your observations in the table, what is a reasonable inference about how the mystery fossil bones might have related to humans or chimpanzees? Explain your answer.

Inference______

Reason ______

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ChimpanzeeUnknownHuman

The Role of the Paleontologist

  • Paleontologists study the forms of life exisiting in prehistoric or geologic times, as represented by fossils of plants, animals and other organisms.
  • Strata – geologists use an indirect method of dating rocks and fossils called stratigraphy. Stratigraphy is the study of strata on Earth. Strata are layers.

Task 2: Study the diagram below and answer the questions that follow.

  1. Which layer is the oldest and why?
  1. These strata are layers of the Earth’s surface. What can you deduce about the relationship of the depth of the layer and how much time has passed?
  1. Label the strata diagram to show the oldest to youngest layers.

The horse

  • One of the few animals for which we have a fairly complete evolutionary record is the horse. All the main stages of the evolution of the horse have been preserved in fossil form.
  • Over 60 million years, the horse evolved from a dog-sized creature that lived in rainforests into an animal adapted to living on the plains and standing up to 2 metres high.
  • In the process its multi-toed feet, that were adapted for walking across the forest floor, evolved into single-toed hooves more suited for running over open country.

Task 3: Study the diagram above and answer the questions that follow.

The diagram shows the evolution of the horse over the last 60 million years. List 5 ways that the body has changed over time.

  1. ______
  1. ______
  1. ______
  1. ______
  1. ______

Homologous structures

  • Homologous structures are structures derived from a common ancestor or same evolutionary or developmental origin.
  • Homologous structures may not necessarily perform the same function but they share a common ancestral origin.
  • For example, the forelimbs of humans and bats are homologous structures. Although they are used differently, the basic skeletal structure is the same and they are derived from the same embryonic origin.
  • Their similarity in this regard could indicate a likely evolution from a common ancestor.

Task 4: Study the diagram above and answer the questions that follow.

  1. Name two similarities between the above structures
  1. Name two differences between the above structures
  1. Explain why the bat wing is similar to the human hand. Use the diagram above to help you explain this.

5. Using the key at the side of each diagram to help you, colour in each part of the animal limbs in different colours. Do you notice any similarities?

Developmental Biology

  • Embryology is a branch of developmental biology that focuses on the early development of organisms before they are born or hatched.
  • These developing organisms are known as embryos.
  • Embryology is particularly useful in studying organisms that can be grouped together as having a common ancestor and therefore finds out more about their evolutionary past.

Task 5: Study the diagram above and answer the questions that follow.

  1. Using different coloured pens / pencils / highlighters, group together the organisms that you think share a common ancestor.
  1. What do you think embryo similarities tell scientists about how closely organisms are related?
  1. Complete the sentence by underlining the correct word.

The ththat the embryos of two animals remain the same the

recently they shared a common ancestor.

Vestigial Structures

  • Vestigial structures refer to organs or parts of organs which are greatly reduced from the original ancestral form and are no longer functional or are of reduced or altered function. E.g. the human appendix.
  • Vestigial structures provide a clue to the evolutionary history of a species because they are remnants of structures found in the ancestral species.

Your teacher will show you a short movie clip from a documentary called “Inside Nature’s Giants”

HOME RESEARCH TASK

Task 6: Study the diagrams below and answer the questions that follow.

  1. The diagrams below describe vestigial structures in humans. Explain why these organs are considered vestigial and what their purpose was in the evolutionary past.
  1. Give two further examples of vestigial structures from different organisms that have not been discussed in class.
  1. For the vestigial structures that you found, give their use in the evolutionary past.

DNA Evidence for Evolution

Deoxyribonucleic acid (DNA) codes for proteins that your body needs to live. Two of those proteins are the alpha and beta hemoglobin proteinsthat occur in your blood. These proteins carry oxygen and carbon dioxide as they circulate in your bloodstream.

Other animals’ blood alsocontains α and β hemoglobin proteins. However, not all of these proteins are identical. The differences between α and β hemoglobin proteinsare caused by differences in the DNA that codes for them.

One reason why developmental biologists are interested in comparing the DNA and proteins of organisms is to learn about relatedness.

The more similar two organisms’ DNA are, the more likely it is that the organisms are closely related.

Process and Procedures

The following sequences of letters stand for the DNA bases from portions of the genes that code for alpha and beta hemoglobin proteins.

1. Compare the DNA sequences from the αhemoglobin for two different primates. Calculate the percent for how similar the bush baby αhemoglobin DNA sequence is to Homo sapiens.

% similar = (numb. DNA bases the same ÷ total numb. DNA bases) × 100

2. Compare the DNA sequences from the β hemoglobin of four different primates. Calculate the percent for how similar each βhemoglobinDNA sequence is to Homo sapiens.

Charles Darwin and the Theory of Evolution

Your teacher will show you a short movie clip on Charles Darwin

  • Charles Darwin was born on February 12, 1809 in Shrewsbury, England. Darwin was born on the same day as Abraham Lincon. He was the British naturalist who became famous for his theories of evolution and natural selection.
  • Like several scientists before him, Darwin believed that all life on Earth evolved (gradually developed) over millions of years from a few common ancestors.
  • The book that Darwin published based on his experiences and an observation of various living organisms was titled “The Origin of Species By Means of Natural Selection” (1872). This
  • Charles Darwin visited the Galapagos Islands and recorded his findings about the different species of finch.
  • He found that:
  • On each Island, the landscape and food source for the finches was different;
  • The finches had adapted to their environment by changing their body size and beak shape so that they could eat food and survive;
  • This resulted in 13 different species being formed over millions of years.
  • An adaptation is a feature of an organism which enables it to survive successfully in its habitat.
  • A species describes organisms that can successfully interbreed to produce fertile offspring.

The diagram below illustrates how the finches of the Galapagos Islands adapted to suit their environment. Discuss this with your class before you go onto the next activity.

Study the diagram above. Discuss what this tells you about the evolutionary process. What conclusions can you come to about all of these finches?

Scientists often use the term “adaptive radiation” when talking about the evolution of new species. What do you think this term means? Research this phrase and write down the definition in the space provided.

Adaptive radiation: organisms changing slowly to form new species that are well suited to their new environment so that they survive and can breed.

Task 7: Your teacher will demonstrate an experiment illustrating the adaptations of finches to suit their environments. You will then carry out this experiment yourself.

Table 1

Name of person with this “beak” type
Finch 1: Large Spoon
Finch 2: Knife
Finch 3: Tweezers
Finch 4: Fork

Table 2

White beans / Yellow beans / White seeds / Green beans / TOTAL number of food particles collected
Finch 1 / 55 / 2 / 1 / 0 / 58
Finch 2
Finch 3
Finch 4
Total
Average

Task 8: Complete the following questions.

  1. Write down a summary of what you learned from this activity. What did it show you about adaptations?
  1. From your data in the table, which bird would have survived? Give a reason for your answer.

Adaptations in the cactus plant

  • The desert is a hot, dry environment where water is in limited supply.
  • Cactus plants have adapted to this environment by employing the following mechanisms:
  • Leaves have been reduced to spines to limit water loss via evaporation because of the smaller surface area.
  • Root network is extensive to absorb water when it does rain.
  • The green stem of the plant has a thick, waxy cuticle to reduce water loss.
  • The stems and leaves are succulent and fleshy to store water.

Natural Selection

•All individuals in a species are different from each other in subtle ways - some possess a physical appearance (phenotype) better suited to their environment.

•It is more likely that organisms with these phenotypes will survive to maturity and reproduce.

•When there is very little environmental pressure, organisms produce more offspring than their environment can support.

•Predation, competition, overcrowding and disease resistance will limit the number of offspring surviving to maturity. This keeps the population in check.

•The offspring that survive these environmental pressures often resemble their parents.

•Beneficial characteristics are passed on to offspring e.g. Ability to hide from predators.

•The population in the species that lacks this beneficial characteristic will get smaller and smaller as they die off.

•This process of organisms with favourable characteristics living and those with unfavourable characteristics dying is repeated generation after generation.

•Organisms with the more favourable phenotype are “selected” and survive.

•These organisms eventually become predominate in the population.

•This is known as SURVIVAL OF THE FITTEST

Summary

  • Natural selection is the process by which only organisms best adapted their environment survive and transmit their genetic characteristics in increasing numbers to their offspring while those less well adapted tend to become eliminated.

Examples of Natural Selection - The Peppered Moth

  • Before the industrial revolution in Britain, most peppered moths were of the pale variety. This meant that they were camouflaged against the pale birch trees that they rest on.
  • Moths with a mutant black colouring were easily spotted and eaten by birds. This gave the white variety an advantage, and they were more likely to survive to reproduce.
  • Airborne pollution in industrial areas blackened the birch tree bark with soot. This meant that the mutant black moths were now camouflaged, while the white variety became more vulnerable to predators.
  • This gave the black variety an advantage, and they were more likely to survive and reproduce.
  • Over time, the black peppered moths became far more numerous in urban areas than the pale variety.

Task 9: Your teacher will take you through a computer simulation of the peppered moth story.

Data and Analysis of Moth Simulation

1. Complete the data table below for both types of moth after running the simulation.

Percentage of Light Moths / Percentage of Dark Moths
Light Forest
Dark Forest

Present this information in the form of a bar graph on the grid below:

2. Explain how the colour of the moths increases or decreases their chances of survival in the different environments.

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3. Explain the concept of "natural selection" using your moths as an example.

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4. What would happen if there were no predators in the forest? Would the colours of the moths change over time? Explain your answer.

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HOME LEARNING TASK

Task 10: Using the information that you have learned in class and other resources available to you, create a story board of the story of the peppered moth. Your story board should include both words and pictures to illustrate what happened to both moths during the industrial revolution. You should also include the phrase “natural selection”.

Antibiotic-resistant bacteria

  • Microorganisms such as bacteria and viruses reproduce very rapidly and can evolve in a relatively short time.
  • One example is the bacteriumE. coli. Its DNAcan be damaged or changed during replication, and most of the time this causes the death of the cell. But occasionally, the mutation is beneficial - for the bacteria.
  • For example, it may allow resistance to an antibiotic. When that antibiotic is present, the resistant bacteria have an advantage over the bacteria that are not resistant. This is another example of natural selection.
  • Antibiotic-resistant strains of bacteria are an increasing problem in hospitals.

Selective Breeding