7.4.3.1 Reproduction

Grade: 
7
Subject:
Science
Strand:
Life Science
Substrand:
Evolution in Living Systems
Standard 7.4.3.1

Reproduction is a characteristic of all organisms and is essential for the continuation of a species. Hereditary information is contained in genes which are inherited through asexual or sexual reproduction.

Benchmark: 7.4.3.1.1 Genes & Inheritance

Recognize that cells contain genes and that each gene carries a single unit of information that either alone, or with other genes, determines the inherited traits of an organism.

Benchmark: 7.4.3.1.2 Asexual & Sexual Reproduction

Recognize that in asexually reproducing organisms all the genes come from a single parent, and that in sexually reproducing organisms about half of the genes come from each parent.

Benchmark: 7.4.3.1.3 Inherited Characteristics

Distinguish between characteristics of organisms that are inherited and those acquired through environmental influences.

Overview

Standard in Lay Terms 

All organisms need to reproduce, to pass on hereditary information and to ensure the continuation of life.

Big Ideas and Essential Understandings 

Big Idea:

Mechanisms of inheritance whether asexual or sexual, are essential for continuation of the species. Cells contain genes that are passed on to the next generation.  In asexual reproduction all genes come from one parent. Asexually reproducing organisms variation is based on the mutations that will occur within an individual organism's genome. In sexual reproduction half of the genes come from each parent. This recombination and mixing of genes creates variation within a population, in addition to the mutation rates of individual organisms.

Organisms within a population vary genetically. The variations within any population are subject to pressure from nature to survive. Nature selects which varieties survive to reproduce and pass their genes on to the next generation.

Benchmark Cluster 

MN Standard Benchmarks

7.4.3.1.1

Recognize that cells contain genes and that each gene carries a single unit of information that either alone, or with other genes, determines the inherited traits of an organism.

7.4.3.1.2

Recognize that in asexually reproducing organisms all the genes come from a single parent, and that in sexually reproducing organisms about half of the genes come from each parent.

7.4.3.1.3

Distinguish between characteristics of organisms that are inherited and those acquired through environmental influences.

THE ESSENTIALS

©Gary Larson

Correlations 
  • NSES Standards:

Life Science

Content Standard C
As a result of their activities in grade 7, all students should develop understanding of

 

1.    Structure and function in living systems

2.    Reproduction and heredity

3.    Regulation and behavior

4.    Populations and ecosystems

5.    Diversity and adaptations of organisms

AAAS Science Literacy Strand Maps

5. The Living Environment B

Now is the time to begin the study of genetic traits-what offspring get from parents. This topic can be handled as a natural part of the study of human reproduction. Students should examine examples of lineages for which breeding has been used to emphasize or suppress certain features of organisms.

By the end of the 8th grade, students should know that

  • In some kinds of organisms, all the genes come from a single parent. 5B/M1a
  • In organisms that have two sexes, typically half of the genes come from each parent. 5B/M1b*
  • In sexual reproduction, a single specialized cell from a female merges with a specialized cell from a male. 5B/M2a
  • The fertilized egg cell, carrying genetic information from each parent, multiplies to form the complete organism. 5B/M2b*
  • The same genetic information is copied in each cell of the new organism. 5B/M2c
  • New varieties of cultivated plants and domestic animals have resulted from selective breeding for particular traits. 5B/M3

Framework for K-12 Science Education

Genes are located in the chromosomes of cells, with each chromosome pair containing two variants of each of many distinct genes. Each distinct gene chiefly controls the production of a specific protein, which in turn affects the traits of the individual  (e.g., human skin color results from the actions of proteins that control the production of the pigment melanin).  Changes (mutations) to genes can result in changes to proteins,  which can affect the structures and functions of the organism and thereby change traits.


Sexual reproduction provides for transmission of genetic information to offspring  through egg and sperm cells. These cells, which contain only one chromosome of each parent’s  chromosome pair, unite to form a new individual (offspring). Thus offspring possess one instance of each parent’s chromosome pair (forming  a new chromosome pair). Variations of inherited traits between parent and offspring arise from genetic differences that result from the subset of chromosomes (and therefore  genes) inherited or (more rarely) from mutations. 8LS3.A


In sexually reproducing organisms, each parent contributes half of the genes acquired (at random) by the offspring.  Individuals have two of each chromosome and hence two alleles of each gene, one acquired from each parent. These versions may be identical or may differ from each other.


In addition to variations that arise from sexual reproduction, genetic information can be altered because of mutations. Though rare, mutations may result in changes to the structure and function of proteins.  Some changes are beneficial, others harmful,  and some neutral  to the organism. 8LS3.B


Organisms reproduce, either sexually or asexually, and transfer their genetic information to their offspring.  Animals engage in characteristic behaviors that increase the odds of reproduction. Plants reproduce in a variety of ways, sometimes  depending  on animal behavior and specialized features  (such as attractively colored  flowers) for reproduction. Plant growth can continue throughout the plant’s life through production of plant matte  in photosynthesis. Genetic factors as well as local conditions affect the size of the adult  plant.  The growth of an animal  is controlled by genetic factors, food intake, and interactions with other organisms, and each species has a typical adult  size range. 8LS1.B

Common Core Standards (i.e. connections with Math, Social Studies or Language Arts Standards): English skills will be put to use to help students label parts of cells.

Misconceptions

Student Misconceptions 
  • 7.4.3.1.1 Genetic information exists in the body part it controls but not in other places in the body (Venville, G., Gribble, S. J., & Donovan, J. (2005). An exploration of young children's understandings of genetics concepts from ontological and epistemological perspectives. Science Education, 89(4), 614-633).
  • 7.4.3.1.2 Each parent contributes genetic information for certain characteristics and not others (e.g. a child has his father's nose and his mother's eyes) Clough, E.E., Wood-Robinson, C. (1985). Children's understanding of inheritance. Journal of Biological Education. 19, 304-310).         
  • 7.4.3.1.2 In sexually reproducing organisms, genetic information or traits are inherited from only one parent (Clough, E.E., Wood-Robinson, C. (1985). Children's understanding of inheritance. Journal of Biological Education. 19, 304-310; Kargbo, D., Hobbs, E., Erickson, G. (1980). Children's beliefs about inherited characteristics. Journal of Biological Education. 14, 137-14).          

Vignette

This vignette shows how 7.4.3.1.3 could appear in a classroom.

The Flight of the Bumblebee by Nikolai Rimsky-Korsakov was playing as students walked into the classroom of Mr. R. In a flash, the students were in their seats, they knew what that music meant today.

It was the 1st pollination day of the FastPlants. The students had started the plants from seed a little over two weeks ago. In that time, the plants had germinated from the seeds, and grown to a height of a few inches. Flowers had appeared and were now ready for pollination.

FastPlants are easy to grow and have a number of identifiable mutants. Students had grown the standard (wild type) plant and were going to cross pollinate with the tall mutant. The tall plants produce an overabundance of gibberillin, causing them to be taller than the wild type.

Easy to see and easy to grow.

The day before, students had glued freeze dried bee thoraxes to the end of toothpicks. Today, they would collect pollen from one variety of flower and pollinate another in a simple Mendelian cross. Previous to this portion of the lab, students had studied flower anatomy to identify the male and female reproductive portions of the plants. A local flower shop was nice enough to donate dated flowers for the students to dissect. They had also collected pollen and observed a microscope the pollen itself germinate and the tubes grow in a sugar solution.

The pollination from one variety to another continued for several days in a row. Soon, the students could see changes in the flowers. Seed pods started to develop and over the next weeks the plants continued to grow.

Eventually, the seed pods are mature and the FastPlants die. Students gather the the seed pods, then harvest the seeds.

These seeds are the F1 generation and can be planted. Students make observations of the FastPlants. Are the plants tall or short? Are they the same as the parent plants?

Students self pollinate this generation of flowers using different bees. Students then develop and mature. The seed pods are collected again and these seeds are planted.

Students make observations of this F2 generation of plants. The number of tall and normal heighted plants are counted and placed in a data table. The parent height trait is seen again and students are able to create a Punnett Square based on the data they collect. Mendelian ratios can be studied across these generations in this model of simple inheritance.

Once the plants are up and growing, the maintenance is simple.

Students get to plant and grow several generations of plants. Making observations, drawing diagrams of the plants as they grow, pollinating the plants (cross/self pollination) is a new experience for students. The FastPlants investigation is a high interest, extended lesson and models the skills and practice of good science: careful record-keeping, inferring from evidence, quantifying data, persistence, care with procedures and planning.

Resources

Instructional Notes 

Instructional suggestions/options:

7.4.3.1.1 Cells Alive  This site is full of animations and background information about cells.

Inside a Cell This site from the University of Utah has information, animations and resources for teachers and students.

Internet access with projector or individual computers/I-pads for students

Cyto gel used with models from Flinn

Selected Labs and Lessons:

  • 7.4.3.1.1  Gene Puzzles In this lesson, students will come to understand that in sexually reproducing organisms, such as humans, typically half of the genes come from each parent.
  • 7.4.3.1.1 Southpaw Minority Why are left-handed people in the minority? In this lesson, students listen to a podcast, gather information about left-handed people and genetics.
  • 7.4.3.1.1 Pea Soup Information and background about Mendel, also an interactive pea experiment.
  • 7.4.3.1.2 Plant Parents In this lesson, students will come to understand that most plants usually reproduce sexually. Students will learn the parts of the flower and the process of sexual reproduction in plants.
  • 7.4.3.1.2 Fungal Sex To understand how sex evolved, researchers need to look back at the most primitive kinds of sexuality. That's why Duke University microbiologist Joseph Heitman is studying an ancient fungus, which comes in two varieties that aren't technically male and female, but still play distinctive roles in reproduction. Heitman and his colleagues have identified a gene that codes for a kind of protein called a transcription factor, which solely determines the fungus' sexual type.
  • 7.4.3.1.2 Reproduction and Cloning The genetic information passed from parent to offspring is contained in genes carried by chromosomes in the nucleus. Sexual reproduction produces offspring that resemble their parents, but are not identical to them. Asexual reproduction produces offspring - clones - which are genetically identical to their parents.

Plants can be cloned artificially using cuttings or tissue culture. Animals can be cloned using embryo transplants or fusion cell cloning. Genetic information from one species can be transferred to another species using genetic engineering.

  • 7.4.3.1.2 Asexual Reproduction A quick review of methods of asexual reproduction.
  • 7.4.3.1.3 Bird Beaks This lesson focuses on bird beaks, exploring the relationship between a bird's beak and its ability to find food and survive in a given environment.

Students should be encouraged to explore how various organisms satisfy their needs in the environments in which they are typically found. They can examine the survival needs of different organisms and consider how the conditions in particular habitats can limit what kinds of living things can survive. Studies of interactions among organisms within an environment should start with relationships that students can directly observe. Students should look for ways in which organisms in one habitat differ from those in another and consider how some of those differences are helpful to survival. The focus should be on different features of organisms and how these features impact the organism's chances for survival and reproduction.

  • 7.4.3.1.3 Nowhere to Hide  Through the use of an interactive activity, this lesson focuses on the concept of natural selection. By the end of elementary school, students should know that individual organisms of the same kind differ in their characteristics, and thasometimes these differences give individuals an advantage in surviving and reproducing. Further, students should be able to look for ways in which organisms in one habitat differ from those in another and to consider how some of those differences are helpful to their survival.
  • 7.4.3.1.3 Structural and Behavioral Adaptations All organisms have adaptations that help them survive and thrive. Some adaptations are structural. Structural adaptations are physical features of an organism like the bill on a bird or the fur on a bear. Other adaptations are behavioral. Behavioral adaptations are the things organisms do to survive. For example, bird calls and migration are behavioral adaptations. Adaptations are the result of evolution. Evolution is a change in a species over long periods of time.
  • 7.4.3.1.3 and 7.1.1.2 The Ringer - A straw and two loops of paper that create a flying device. Students can create investigative questions, manipulate variables, collect numerical data in the search for the 'best' Ringer. This activity can be used in conjunction with a study of evolution and natural selection, where every change constitutes a mutation, that can impact the outcome of survival of the species.
Instructional Resources 

Additional resources or links:

Wisconsin Fast Plants Activity and Resource Library Wisconsin Fast Plant resources are made available openly through the University of Wisconsin, Madison. Content created on this site is licensed under a Creative Commons Attribution NonCommercial-ShareAlike 3.0 License.

New Vocabulary 

Vocabulary/Glossary

  • cell  basic unit of all forms of life.
  • organelle  specialized structure that performs important cellular functions within a eukaryotic cell
  • cell theory  fundamental concepts of biology that states that all living things are composed of cells, that cells are the basic units of structure and function in living things and that new cells are produced from existing cells
  • cell wall strong supporting layer around the cell membrane in some cells
  • cell membrane  thin flexible barrier that surrounds all cells; regulates what enters and leaves the cell
  • nucleus   the center of an an atom which contains the protons and neutrons in cells, structure that contains the cells genetic material
  • chromosomes  threadlike structures within the nucleus that contains genetic information that is passed from one generation to the next. 
  • cell division  process by which a cell divides into two new daughter cells
  • mitosis  part of eukaryotic cell division during which the cell nucleus divides
Technology Connections 
  • Internet connections if possible for students to look up parts of cells
  • Cameras/flip videos/ students can take pictures of their models
  • Hardware cameras that connect to microscopes to images of cells in division to discuss what is happening as the cell is dividing.
Cross Curricular Connections 

English and Math will come into play with cell models.

Assessment

Students:                                            

Fully-grown adults are much larger in size than young children.  What happens to the cells of the body during the growth of a child?

1.    The cells of a growing child divide to make more cells, and those cells are each half the size as the cells were before they divided.  The cells do not grow before they divide again.

2.    The cells of a growing child divide to make more cells, and those cells grow to become the same size as the cells were just before they divided.

3.    The cells of the body of a growing child grow, but the number of cells stays the same.

4.    The size and number of cells in the body of a growing child stay the same.

What is TRUE about cells?

1.    All living things are made up of more than one cell, and all cells are the same size and shape.

2.    All living things are made up of more than one cell, but not all cells are the same size and shape.

3.    All living things are made up of cells of the same size and shape, but not all living things are made of more than one cell.

4.    Not all living things are made up of more than one cell, and not all cells are the same size and shape.

Which of the following is TRUE about the amount of genetic material in an unfertilized egg cell of an organism compared to the amount of genetic material in a fertilized egg of that same organism?(A fertilized egg cell is an egg cell that has combined with a sperm cell.)

1 An unfertilized egg cell contains half as much genetic material as a fertilized egg cell.

2.  An unfertilized egg cell contains the same amount of genetic as a fertilized egg cell.

3.  An unfertilized egg cell contains twice as much genetic material as a fertilized egg cell.

4.  An unfertilized egg cell contains four times as much genetic material as a fertilized egg cell.

Teachers:

Questions could be used as self-reflection or in professional development sessions.

Misconceptions about the history of life and how it came about are unfortunately very common. Most of these misunderstandings have to do with assumptions that evolution proceeds in a particular direction or that individual living things can choose to adapt. The following site can be very helpful University of California Museum of Paleontology

Administrators:

If observing a lesson on this standard what might they expect to see.

  • Administrators may see students being "BEE'S" and pollinating their plants. 
  • Students measuring, recording data and graphing results of their plants.
  • Students creating Punnett squares to show breeding trends of their plants.

Differentiation

Struggling Learners 

Struggling and At-Risk:

Snow, D. (2003). Noteworthy perspectives: Classroom strategies for helping at-risk students (rev. ed.). Aurora, CO: Mid-continent Research for Education and Learning.

In 2002, McREL conducted a synthesis of recent research on instructional strategies to assist students who are low achieving or at risk of failure. From this synthesis of research, McREL identified six general classroom strategies that research indicates are particularly effective in helping struggling students achieve success.

Hands on labs like the one in the vignette helps special ed students comprehend concepts better than straight book work.

English Language Learners 

Herr, N. (2007). The sourcebook for teaching science. This page contains strategies to help teachers better attend to the needs of their ELL learners. These strategies are grouped according to the following learning tasks: listening, visualization,       interpersonal communication, laboratory, demonstrations, reading and writing, instruction and vocabulary.

Hands-on science learning promotes language connections

Labeling the cell in two languages will help these students.

Being the "Bee" will help students grasp concepts

All the hands on projects listed above will help students

Extending the Learning 

G/T:

Teachers First is an educational support website that may help with G/T students

Cogito is another website that is available for G/T Students

Multi-Cultural 

Multicultural science education.  Official NSTA Position Statement.

This site hosts a English to Ojibwe and Ojibwe to English dictionary that may be used to look up meanings to vocabulary words.

Science education should include the use of culturally relevant content (Ferguson, Robert. "If Multicultural Science Education Standards' Existed, What Would They Look Like?." Journal of Science Teacher Education. 19.6 (2008): 547-564. Print.) The value of using such approaches is that they can improve the conversation about beliefs in science and hone beliefs about science for all students.

Students should be given opportunities to do science rather than read about it.  Doing science includes reasoning about science.  This kind of science emphasizes the active role of the learner in constructing knowledge. 

All the hand on projects listed above will help students

Special Education 

Technologies for Special Needs Students: In their newsletter, "Tech Trek",  from the National Science Teachers Association, there are suggestions for using technology including voice recognition software

Hands on labs like the one in the vignette helps special ed students comprehend concepts better than straight book work.

Learning experiences should be as multi-sensory as possible and safe.  Such experiences have an added benefit too.  They are effective with all learners.

Using "Bee's" to pollinate fast plants as in the vignette will help students retain

Parents/Admin

Parents 

Parents may hear about how students became a "Bee" for a day.