Learning Activities Grade 7

Suggested Learning Activities for Grade 7 students during the COVID-19 school closure.

Seattle Public Schools is committed to making its online information accessible and usable to all people, regardless of ability or technology. Meeting web accessibility guidelines and standards is an ongoing process that we are consistently working to improve.

While Seattle Public Schools endeavors to only post documents optimized for accessibility, due to the nature and complexity of some documents, an accessible version of the document may not be available. In these limited circumstances, the District will provide equally effective alternate access.

Due to the COVID-19 closure, teachers were asked to provide packets of home activities. This is not intended to take the place of regular classroom instruction but will help supplement student learning and provide opportunities for student learning while they are absent from school. Assignments are not required or graded. Because of the unprecedented nature of this health crisis and the District’s swift closure, some home activities may not be accessible.

If you have difficulty accessing the material or have any questions, please contact your student’s teacher.

Middle School Math Grade 7

Topic 8 Lesson 8-1 & 8-2

Solve Problems Involving Geometry

How to Access & Use Pearson Bounce Pages

The Bounce Page app is a place where you can access Virtual Nerd videos. These are interactive tutorial videos that go over the fundamental math concepts of each lesson.

You can download Pearson Bounce Pages from your Android or Apple store.

TIPS FOR USING BOUNCE PAGE

1. AIM the camera so the FULL page is easily viewable on your screen. For best results, flatten thepage, or if scanning a screen be sure the entire page is visible on your phone screen.

2. TAP the screen to scan the entire front of the page. Scan the ENTIRE page. Scanning a singleproblem will not work. Scan the page BEFORE students write on the page.

3. BOUNCE the page to life by clicking your Bounce Pages program icon.

4. Update the operating system on your device and the Bounce Pages app as needed.

Copyright © by Savvas Learning Company LLC. All Rights Reserved. 7

Name Reteach to Build Understanding

8-1

In the scale drawing shown, the room is 3 centimeters long. What is the actual length of the room?

3 m1 cm = x m

3 cm Use the scale 3 m1 cm to write

a proportion.

3 # 31 = 3 # x

3 Multiply both sides by 3.

9 = x Simplify.

The actual length of the room is 9 meters.

The garden in the scale drawing is 0.75 inch long.

What is the actual length of the garden?

1. Write the scale as a ratio: ∣ ∣ ft

∣ ∣ in.

2. Write the ratio of the garden’s actual length to its length in the drawing. Use the variable x to represent the unknown measurement.

3. Use the ratios determined in Exercises 1 and 2 to write a proportion.

4. By what number are both sides of the proportion multiplied to find x?

5. What is the actual length of the garden?

On the Back!

6. On a scale drawing, a park is 4.5 inches long. The scale is 0.5 inch = 10 feet. What is the actual length of the park?

Room

Scale: 1 cm = 3 m

1 2 4 51 2 3 4 5cm

Garden

Lawn

Scale: 1 in. = 10ft

1in.

R 8-1

TUTORIALPRACTICE

1 cm = 1.7 feetThe gridlines are spaced 1 cm apart.

3 inches

A

B

Name:

8-1 Additional Practice1. What is the actual length of the truck? 2. A portion of a map with cities A and B

is shown. The map uses a scale of 1 inch to 30 miles. A new map has a scale of 2 inches = 15 miles. How far apart are cities A and B on the new map?

3. A 12-foot wall measures 2.5 inches on a scale drawing. In the drawing, a second wall is 9 inches long. What is the actual length of the second wall?

4. In a scale drawing, the length of a rectangular room is 6 inches, and the width is 3 inches. The actual length of the room is 18 feet.

a. What is the scale of the drawing?

b. In a new scale drawing of the same room, the length of the room measures 4 inches. What is the scale of the new drawing? Explain.

5. On a scale drawing of a fence, 3.75 inches represent 24 feet.

What is the actual length of a fence that is 2.8 inches long in the drawing?

8-1 Solve Problems Involving Scale Drawings 97Go Online | PearsonRealize.com

Scan for Multimedia

The gridlines are spaced 1 cm apart.1 cm = 4 feet

Bedroom

BathroomDeck

LivingRoom

width

DiningRoom

Study

Foyer

LivingRoom

Kitchen

4.0 in. 6.0 in.

6.0 in.

4.0 in.

2.0 in.

8.0 in.

4.0 in.

length

length12 in.

width8 in.

6. Higher Order Thinking If carpet costs $1.50 per square foot including the cost of installation, how much will it cost to carpet the entire living room floor of the cabin shown at the right?

7. On the floor plan shown at the right, 1.25 inches represents 2 feet.

a. What is the actual length of the entire floor?

b. What is the actual area of the entire floor? Explain how you found the area.

8. An architect is recreating the blueprint for a deck with an existing scale factor of 1 in. = 2 ft, shown at the right. The architect is using a different scale so that the length of the deck on the new blueprint measures 8 inches.

PART A

What is the scale factor of the new blueprint?

PART BWhat is the width of the deck on the new blueprint?

Assessment Practice

98 8-1 Solve Problems Involving Scale Drawings Go Online | PearsonRealize.com

Copyright © by Savvas Learning Company LLC. All Rights Reserved. 7

Name Reteach to Build Understanding

8-2

The floor of a closet is 4 feet long and 2 feet wide and has four right angles. Make a scale drawing of the floor using a scale of 1 cm = 1 ft.

Use a ruler to draw a horizontal line segment that measures 4 centimeters. This represents the 4-ft side. Then use the corner of the ruler to draw a right angle.

Use the ruler to extend the vertical side of the right angle to a length of 2 centimeters. This represents the 2-ft side. Repeat the process to complete the drawing.

The scale drawing shows that the floor is in the shape of a rectangle.

Yolanda cuts fabric into geometric shapes to make quilt pieces. She plans to make a four-sided fabric piece that has a 1-inch side that is adjacent to a 3-inch side, with the included angle between these two sides measuring 120°. She wants opposite sides of the shape to have the same length. Draw the quadrilateral that represents Yolanda’s fabric piece.

1. Use a ruler to draw a side that measures 3 inches.

2. The side you drew in Exercise 1 will be one side of a 120° angle. Use a protractor to draw the other side of the angle and extend the line segment to measure exactly 1 inch.

3. Use a protractor to draw an angle that measures 60º. One side of the angle should be the side you drew in Exercise 2. Extend the new side to measure 3 inches in length, and then use a ruler to draw the last side of the quadrilateral. What is the length, in inches, of the last side?

4. Use a protractor to find the measure of the obtuse angle adjacent to the last side of the quadrilateral.

On the Back!

5. Yolanda also needs a fabric piece that is a square in which each side measures 4 inches. Make a drawing of this fabric piece.

1 2 3 4 5cm

Rightangle

4 cm

2 cm

R 8-2

TUTORIALPRACTICE

Name:

8-2 Additional Practice1. What quadrilateral can be drawn that has

exactly two pairs of perpendicular sides?2. What geometric shape may describe a

quadrilateral that has two sides with length 8 cm and two sides with length 5 cm?

3. A four-sided sandbox has exactly two right angles, two side lengths 5 ft, and two side lengths 6 ft. What geometric shape best describes the shape of the sandbox?

4. A park has a pond shaped like a quadrilateral with all sides 18 feet long and at least one right angle. What geometric shape best describes the shape of the pond?

5. What geometric shape may describe a quadrilateral that has exactly two pairs of parallel sides and no right angles?

6. A playground is shaped like a quadrilateral with all sides 27 feet long, with two angle measures of 65° and two angle measures of 115°. What geometric shape best describes the shape of the playground?

7. Draw a quadrilateral with one angle that measures 25° and one pair of parallel sides, with the shorter parallel side measuring exactly 5 units in length.

8. Use computer drawing software to construct a quadrilateral with two pairs of parallel sides and two angles measuring 125°. What geometric shape describes this quadrilateral?

8-2 Draw Geometric Figures 99Go Online | PearsonRealize.com

Scan for Multimedia

9. Higher Order Thinking Draw a quadrilateral using geometry software with all sides 2 units long and at least one angle that measures 40°. What is the specific name of the quadrilateral?

10. Rachel correctly constructs a quadrilateral given the following conditions.

Two sides measure 2 units in length. Two sides measure 3 units in length. All angles are right angles.

Which quadrilateral does Rachel construct?

𝖠

3 units

2 units 𝖡 2 units

3 units

𝖢

2 units

3 units

𝖣

11. A 4-sided picture frame is formed by connecting identical quadrilaterals on each side. For each quadrilateral, the top angles have equal measure, while the bottom angles have equal measure. Use geometry software to construct a possible side of the frame and label each angle inside the figure. What is the name of the quadrilateral that you constructed?

Assessment Practice

3 units

3 units

100 8-2 Draw Geometric Figures Go Online | PearsonRealize.com

Grade 7 Science Learning Activity

April 28-May 1, 2020

Populations & Resources Unit

Lessons 7 & 8 Instructional Materials

Name ___________________________________

School___________________________________

Class Period ______________________________

Teacher __________________________________

Hello Families,

We hope you and your family are well and safe during this time. During this unprecedented out-of-school

time, the SPS middle school science team will be offering instructional opportunities for students that align

with the district’s adopted middle school science instructional materials.

This investigation packet is part of a series of district-aligned lessons for middle school science developed by

AmplifyScience and adopted by SPS in 2019. While Amplify Science lessons are designed to be done in the

classroom with peers, there are some activities that students can complete at home.

In this packet you will find activities to accompany the lesson videos being aired this week through Seattle’s

Public television programming on SPS TV (local channel 26). The videos and packets are also posted to the,

SPS Science webpage under their corresponding grade level. These lesson videos, developed in collaboration

between SPS teachers, Denver Public Schools teachers, and Amplify Science, feature teachers going through

the information in the lessons. The work in this packet is intended to be completed alongside the viewing of

the video of the corresponding videos.

Closed captioning for the videos is available many home languages if this helpful to your family.

○ Click CC (bottom right of video)

○ Click Setting (the gear next to CC)

○ Click Subtitles/CC

○ Click Auto-translate

○ Choose your language

For students who have access to the internet and the following devices and browsers may wish to log-in to

their AmplifyScience account from home are welcome to do so. Chrome and Safari are the recommended

browsers to use for full functionality of the Amplify digital tools and features.

Sincerely, Seattle Public Schools Science Department

AMHARIC

ጤና ይስጥልኝ የ SPS የመካከለኛ ደረጃ ት / ቤት ቤተሰቦች ፣

በዚህ ጊዜ እርስዎ እና ቤተሰብዎ ደህና እንደሆኑ ተስፋ እናደርጋለን። በአሁኑ ባልተጠበቀ ከትምህርት ቤት ውጭ መሆን፣ የ

SPS የመካከለኛ ደረጃ ት/ ቤት የሳይንስ ቡድን በዲስትሪክቱ ከፀደቀው የመካከለኛ ደረጃ የሳይንስ ማስተማሪያ ቁሳቁሶች ጋር

የሚጣጣሙ የትምህርት ዕድሎችን ለተማሪዎች ይሰጣል ፡፡

ይህ የጥናት ፓኬጅ በአምሊፋይሳይንስ( AmplifyScience) የሚዘጋጅ፣ ከዲትሪክቱ ጋር የሚጣጣም ከትምህርት ቤት ውጭ

የሚሰጥ ተከታታይ የርቀት ትምህርት አካል ነው። አምሊፋይሳይንስ( AmplifyScience) ተማሪዎች በክፍል ውስጥ

ከእኩዮቻቸው ጋር እንዲከናወኑት የተነደፉ ቢሆኑም፣ተማሪዎች በቤት ውስጥ ሊያከናውንዋቸው የሚችሉ አንዳንድ

ተግባሮች አሉ። በዚህ ፓኬት ውስጥ በሲያትል የህዝብ ትምህርት ቤቶች የቴሌቪዥን ፕሮግራም በ SPS TV (local channel

26) አማካኝነት በዚህ ሳምንት ከሚተላለፉት የትምህርት ቪዲዮዎች ጋር አብረው የሚሄዱ የትምህርት ተግባሮችን ያገኛሉ።

እንዲሁም ቪዲዮዎቹ እና ፓኬጆቹ በሚከተለው በ SPS ድረ-ገጽ ላይ ይገኛሉ ።

https://www.seattleschools.org/academics/curriculum/science.

ይህ ለቤተሰብዎ ጠቃሚ ከሆነ፣ቪዲዮዎቹ በተለያዩ ቋንቋዎች የፅሁፍ መግለጫ ማግኘት ይችላሉ።

○ CC (የቪዲዮው ታችኛው ክፍል ቀኝ) ጠቅ ያድርጉ

○ Setting (ከ CC አጠገብ ያለው ጊር) ጠቅ ያድርጉ

○ Subtitles/CC ጠቅ ያድርጉ

○ Auto-translate ጠቅ ያድርጉ

○ ቋንቋዎን ይምረጡ

ኢንተርኔት እና የሚከተሉትን መሳሪያዎች እና ብራውዘሮች( browsers) ያላቸው ተማሪዎች ከቤት ወደ

አምሊፋይሳይንስ(AmplifyScience) መለያቸው መግባት ይችላሉ።

o Desktops and Laptops (Chrome & Safari) o Chromebooks o iPads that support iOS11.3+ (iPad5+) - Suggested browser: Safari

ከሠላምታ ጋር ፣

ሲያትል የህዝብ ትምህርት ቤቶች ሳይንስ ዲፓርትመንት SIMPLIFIED CHINESE 你好 SPS 初中家庭,

希望您和您的家人在这段时间内过得安好。在这段空前未有的停课期间, SPS 中学科学团队将为学生提

供教学机会, 这些课程与校区采用的中学科学教学材料是一致的。

此学习包是 AmplifyScience 开发的一系列与校区一致的遥距校外课程的一部分。虽然 Amplify Science课

程的设计目的是与同伴在课堂上完成, 但学生也可以在家中完成一些活动。在此学习包中, 您将找到一些

活动,以配合本周通过 SPS TV在西雅图的公共电视节目播放的教学视频 (本地频道 26台)。 视频和学习

包也会发布 SPS 网页上,https://www.seattleschools.org/academics/curriculum/science.

如果有助您的家人, 可以多为他们提供种语言的视频隐藏字幕。

○ 点击 CC (视频右下角)

○ 点击 Setting (CC 旁边的齿轮)

○ 点击 Subtitles/CC

○ 点击 Auto-translate

○ 选择你的语言

可以上互联网以及有以下设备和浏览器的学生可以在家中登录其 AmplifyScience 帐户。

o 座台式和笔记本计算机(Chrome & Safari)

o Chromebooks o 支援 iOS11.3+ 的 iPads (iPad5+)- 建议的浏览器: Safari

真诚的

西雅图公立学校科学系

SPANISH Hola Familias de Secundaria de las Escuelas Públicas de Seattle, Esperamos que usted y su familia estén bien y seguros durante esta temporada. Durante este tiempo sin precedentes fuera de la escuela, el equipo de ciencias de la escuela secundaria de SPS ofrecerá oportunidades de instrucción para los estudiantes, que se alinean con los materiales de instrucción de ciencias de la escuela secundaria adoptados por el distrito. Este paquete de investigación es parte de una serie de lecciones extraescolares remotas alineadas con el distrito, desarrolladas por AmplifyScience. Si bien las lecciones de Amplify Science están diseñadas para realizarse en el aula con sus compañeros, hay algunas actividades que los estudiantes pueden completar en casa. En este paquete encontrará actividades para acompañar los videos de las lecciones que se transmiten esta semana a través de la programación de televisión pública de Seattle en SPS TV (canal local 26). Los videos y paquetes también se publican en la página web de SPS, https://www.seattleschools.org/academics/curriculum/science. Los subtítulos para los videos están disponibles en muchos idiomas caseros si esto es útil para su familia.

○ Presione CC (abajo a la derecha del video) ○ Presione Setting (el engrane cercano a CC) ○ Presione Subtitles/CC ○ Presione Auto-translate ○ Escoja su lenguaje

Los estudiantes que tienen acceso a Internet y a los siguientes dispositivos y navegadores pueden iniciar sesión en su cuenta AmplifyScience desde casa.

o Computadoras de Escritorio y Laptops (Chrome y Safari) o Chromebooks o iPads con iOS11.3+ (iPad5+) – Navegador sugerido: Safari

Sinceramente, Departamento de Ciencias de las Escuelas Públicas de Seattle SOMALI Qoysaska Dugsiga Dhexe SPS , Waxaan rajeyneynaa adiga iyo qoyskaada in aad caafimaad iiyo nabadgelyo qabtaan waqtigaan lagu jiro . Dg Inta lagu jiro waqtigan aan caadiga aheyn ee dugsiga dibadiisa, kooxda sayniska ee dugsiga dhexe ee SPS waxay soo bandhigayaan fursado waxbarid isla markaana ardayga oo la waafajineysa agabka tacliinta sayniska ee dugsiga dhexe ee degmadu qaadatay Xirmadan barista sayniska waa qeyb ka mid ah taxane ah oo dugsiyada degmada inkastoo casharada Amplify Sayniska loogu talagalay in lagu sameeyo fasalka dhexdiisa ardayda , waxaa kale oo jira howlo qaarkood oo ay ardaydu ku dhamayn karaan guriga warqadahaan xirmada ah dhexdeedaIn casharada muqaalka ah waxaad ka heleysaan sitimaanka barnaamijka talefishinka Dugsiyada Dadweynaha Seattle SPS TV (kanaalka gudaha 26). Xirmada warqadaha iyo fiidiyowga waxaad ka heleysaa shabakada SPS websaydhka, https://www.seattleschools.org/academics/curriculum/science.

Waxaad halkan ka heli kartaa sawiro qaar iyo luqado hadii ay tahay mid ku caawineysa qoyskaada. ○ guji CC (bottom right of video) ○ guji Setting (the gear next to CC) ○ guji Subtitles/CC ○ guji Auto-translate ○ Dooro luqadaada

Ardayga heysta Khadka internet raacana tilmaanta isticmaalka ka dibna ay galaan koontadooda AmplifyScience guriga .

o Desktops and Laptops (Chrome & Safari) o Chromebooks o iPads that support iOS11.3+ (iPad5+) – talo isticmaal : Safari

Mahadsanid, Dugsiyada Dadweynaha Seattle Waaxda Sayniska VIETNAMESE Kính gửi các gia đình của học sinh cấp 2 SPS, Chúng tôi hy vọng quý vị và gia đình đều được khỏe mạnh và an toàn trong thời gian này. Trong thời gian nghỉ học chưa từng xảy ra này, nhóm khoa học của các trường cấp 2 SPS sẽ mang đến cho các em học sinh cơ hội học tập phù hợp với tài liệu giảng dạy khoa học dành cho cấp 2. Tập bài học kiểm nghiệm này là một phần của một loạt các bài học dựa theo và được phát triển bởi AmplifyScience. Trong khi các bài học Khoa học Amplify được thiết kế để thực hiện trong lớp học với các bạn học, nhưng cũng có một số hoạt động mà học sinh có thể hoàn thành tại nhà. Trong tập bài học này, quý vị sẽ tìm thấy các hoạt động đi kèm với video bài học được phát sóng trong tuần này thông qua chương trình truyền hình công cộng Seattle trên SPS TV (kênh địa phương 26). Các video và tập bài học cũng được đăng lên trang web SPS, https://www.seattleschools.org/academics/curriculum/science. Phụ đề cho các video có sẵn qua nhiều ngôn ngữ nếu điều này giúp ích cho gia đình của quý vị.

○ Nhấp CC (dưới cùng bên phải của video) ○ Nhấp vào Setting (biểu tượng hình bánh răng bên cạnh CC) ○ Nhấp vào Subtitles/CC ○ Nhấp vào Auto-translate ○ Chọn ngôn ngữ của quý vị

Học sinh nào truy cập vào internet và các thiết bị và trình duyệt sau có thể đăng nhập vào tài khoản AmplifyScience của các em từ nhà.

o Desktops and Laptops (Chrome & Safari) o Chromebooks o iPads that support iOS11.3+ (iPad5+) - Suggested browser: Safari

Trân trọng, Seattle Public Schools Science Department

Lesson 7

How does competition affect different populations?

To the right is a food

web of the six

populations.

Competition: Some populations use the same resource, such as eat the same resource population (or food).

This makes them in competition with one another.

Which two populations are in competition?

________________________________________________________and ______________________________________________________________

We have observed in a previous lesson that the furbil population could be increased by increasing the number

of births that the furbils had.

We did this by increasing the number of weebugs and therefore increasing the number of energy storage

molecules available!

In this new population setting a competitor has been introduced, the Stingwings!

Do you think a change in the Stingwing population could affect the Furbils?

Yes No

Explain your thinking:

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

Plan an investigation to test your hypothesis above:

I plan to increase / decrease the number of Stingwings.

1. Launch the Populations and Resources Sim and go to 6 Populations mode.

2. Let the Sim run for 40 time units.

3. Make the change to the stingwings that you selected above.

a. (Remember that making a bigger change will cause a bigger effect!) Note: You can lock the

furbil population.

4. Press Play and let the Sim run for another 40 time units.

5. Go to Analyze and use the range window to observe the population sizes after the change.

Observations before the change Be sure to make observations about the stingwing, furbil and Greenleaf populations

Observations after the change Be sure to make observations about the stingwing, furbil and Greenleaf populations

Annotate the food web for the stingwing, weebug and furbils populations with or arrows to show a visual

representation of whether the populations increased or decreased after your change.

Was your hypothesis correct or incorrect? Why do you think you observed what you did?

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Jelly Population Explosions

Jelly Population Explosions

In some ecosystems, the

population of jellies has increased so

much over a short period of time that

people call it a population explosion.

Ecologists, fishermen, and many other

people around the world are concerned

about jelly population explosions. In

some places where jelly populations

are getting bigger, the increase in

population can affect human activities

and the ecosystems we depend on:

masses of jellies damage fishing nets,

clog water pipes for power plants, and

drive swimmers away from beaches.

Scientists around the world are hard at

work trying to understand why these

population increases occur and how we can avoid causing

them.

Two Jelly Populations

To understand what can cause jelly populations to increase, a

team of ecologists studied two ocean ecosystems near the

southwestern coast of Africa—Northern Benguela and

Southern Benguela. Northern Benguela is off the coast of

Namibia, while Southern Benguela is off the coast of South

Africa. A strong ocean current divides Northern Benguela

from Southern Benguela. These two ecosystems are very

similar: both include populations of jellies, zooplankton, and

fish such as sardines and anchovies, as well as African

penguins and Cape fur seals. Humans have fished in both of

these ecosystems for a long time.

The team of ecologists studying the two jelly populations

analyzed data that had been collected over the last 50 years

by other scientists and by fishermen. Based on the samples of

jellies counted in each region, they determined that the jelly

population increased in Northern Benguela, but not in

Jelly population explosions can happen all over the world. This photo

shows lots of jellies in a shallow part of the ocean near Denmark.

Northern Benguela and Southern Benguela

are two ocean ecosystems off the coast of

Africa.

Active Reading Strategies

• Title Pre-Think and Pre-Scan

• Highlight unit science words

• Circle unfamiliar words and ideas and write definitions/ notes about them that you find out in the text

• Write in the margins to identify questions, and “a-ha!” moments

• Underline evidence that helps us answer the question: How can competition affect a population?

Southern Benguela. Today, the population of jellies in Northern

Benguela is much larger than has ever been recorded there before. Yet in

Southern Benguela, the jelly population has remained relatively stable.

In comparing these two ocean ecosystems, the ecologists found

an important difference: laws prevented people from catching too many

fish in Southern Benguela. In the 1950s, commercial fisheries began to

catch large numbers of sardines and anchovies from both Northern and

Southern Benguela. However, starting in the 1970s, people passed laws

that limited the number of sardines and other fish that could be caught

each year in Southern Benguela, in an effort to protect the fish

populations there. In contrast, there were no limits placed on fishing in

Northern Benguela.

Without laws limiting the number of fish they could catch in

Northern Benguela, people caught huge numbers of sardines and other

fish there, causing the fish populations to decrease. By the early 2000s,

the fish populations returned to near-normal levels in Southern

Benguela, but had dropped to record low numbers in Northern

Benguela.

Competition for Food

In this ecosystem, the jellies do not eat fish, and the fish do not eat

jellies. So why did a decrease in the size of the fish populations in

Northern Benguela affect the jelly population? Let’s look at the sardine

population as an example. Jellies and sardines eat the same food:

zooplankton. The relationship between jellies and sardines is called

competition because they are competing for the same resource population.

When the sardine population decreased due to unlimited fishing in Northern Benguela, fewer sardines were

around to eat zooplankton. With fewer zooplankton eaten by the sardines, the zooplankton population

increased—leaving more zooplankton for the jellies to eat. Having a larger resource population made more

energy storage molecules available to the jellies. This allowed them to reproduce more. More reproduction led

to more births than deaths, so the jelly population increased. This is how the change in the sardine population

was able to affect the jelly population, even though jellies are not

directly connected to sardines on the food web. A change to the

sardine population caused the zooplankton population to change,

which caused the jelly population to change. This is an example of an

indirect effect, the result of a chain of causes and effects, where one

cause leads to an effect that then causes another effect.

In Southern Benguela, the jelly population did not increase. Because

of limits on fishing, the fish population in Southern Benguela was

relatively stable. This meant the fish consumed the same number of

zooplankton as usual, leaving the same number of zooplankton for

jellies and not causing any change to the jelly population. In a

stable ecosystem, biodiversity—the number of different kinds of

living things in the ecosystem—also stays the same. Biodiversity

is a measurement of how healthy an ecosystem is. When an

ecosystem becomes less biodiverse, it is because the ecosystem is

so unstable that entire populations

Fishing with a net like this red one

can catch thousands of sardines and

anchovies at a time. People catch

these fish for food.

Jellies and sardines are not directly connected

on the food web, but they both eat

zooplankton. This relationship is called

competition because both populations are

competing for the same resource population.

are dying out. In order to maintain healthy

ecosystems, people need to come up with plans

like Southern Benguela’s fishing limits to help

keep ecosystems stable and maintain their

biodiversity.

Looking at lots of population data helped ecologists

figure out what caused the jelly population increase

in Northern Benguela. However, jelly populations are

increasing in other ecosystems all over the globe.

Since every ecosystem is unique, other jelly increases

may have different causes.

Questions

1. What was the key difference between the situation in North Benguela and South Benguela?

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2. The sardines are not the jellies’ resource population or consumer population, but they still caused the

jelly population in North Benguela to increase. How did this happen?

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3. Do you think the government should be able to place laws and restrictions on things like hunting and

fishing? Explain your thinking:

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This diagram shows an indirect effect of overfishing

in Northern Benguela: a jelly population increase.

After Overfishing in Northern Benguela

Lesson 8

What do you think would happen to the

lion population if the hyena population

increases in size? Assume that the

populations were stable before this

change (circle one)

The lion population would increase

The lion population would decrease

The lion population would not change

Explain your thinking:

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Last time we collected evidence about how populations that are in competition for a resource population can affect

one another. What ideas do you have about other forms of competition between populations of organisms?

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To the right is a food web of the six

populations.

Plan and conduct an investigation in the digital model to collect evidence about whether organisms that are not directly affecting one another could cause changes to a population.

Can populations that are not directly connected on a food web still affect one another?

Collect evidence on each scenario and record your observations.

Scenario Observations

The clawcats have no consumer population. Find two ways you could cause a decrease in their population.

1.

2.

The greenleafs have no resource population. They are something called producers and make their own energy from the sun! If the sun is constant all year round, find two ways that you could decrease the weebug population.

1.

2.

Key Concept

Applying this to the Moon Jelly Problem:

Pick one of the following populations to write about and explain how a change in that population could have

caused a change in the moon jelly population:

• Algae

• Orca

• Walleye Pollock

Vocabulary Bank:

• Consumer Population

• Resource Population

• Energy Storage

Molecule

• Births

• Deaths

• Reproduction

• Direct Effect

• Indirect Effect

Try to use some of our science vocabulary words in your response!

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