MS-LS1-5: Genetic and Environmental Growth Factors

MS-LS1-5
Genetic and Environmental Growth Factors

Middle School

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Learning Objectives

• Explain how environmental factors like light and water influence how organisms grow.

• Describe how genetic factors determine an organism’s potential for growth and its traits.

• Explain how growth is a result of interactions between genes and the environment.

• Analyze how selective breeding in wheat shows the interplay of genes and environment.

Key Vocabulary

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Environmental Factors

Environmental factors are local conditions, such as the amount of water, that affect an organism's growth.

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Genetic Factors

Genetic factors are the inherited genes that determine the potential traits and characteristics of an organism.

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Organism

An organism is any individual living being, such as a plant, animal, or single-celled life form.

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Breeding

Breeding is the process of mating selected organisms to produce offspring with specific desired traits.

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Soil Salinity

Soil salinity refers to the amount of salt content present in the soil where plants grow.

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Salt Tolerant

A salt-tolerant organism has the special ability to survive and grow in soil with high salinity.

Key Vocabulary

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Photosynthesis

This is the essential process where plants use sunlight, water, and carbon dioxide to create their food.

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Vacuoles

These are storage pockets inside cells that hold water, food, and other important waste products for the cell.

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Environmental Factors on Growth

• An organism’s growth depends on factors in its environment.

• These include the availability of light, water, space, and nutrients.

• For example, fertilizer adds nutrients to soil, helping plants grow larger.

• Fish in a large pond often grow bigger than in a small pond.

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Multiple Choice

What is the primary role of environmental factors like light, water, and nutrients for an organism?

• They determine its growth.

• They change its color.

• They help it communicate.

• They decide its age.

Multiple Choice

Why does adding fertilizer to soil typically result in larger plants?

• Because fertilizer provides the plant with more space.

• Because fertilizer increases the amount of water available.

• Because fertilizer supplies the plant with essential nutrients.

• Because fertilizer gives the plant more access to light.

Multiple Choice

If one group of fish is raised in a small pond and another group is raised in a large pond, which group is likely to grow bigger and why?

• The fish in the small pond, because there is less competition.

• The fish in the large pond, because they have more space to live and find food.

• The fish in both ponds will grow to the same size.

• The fish in the small pond will have better access to light.

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What Are Genetic Factors?

• Genetic factors are DNA instructions that set the potential for an organism's growth.

• These instructions are passed down from parents to their offspring through genes.

• Large-breed cattle have genes that allow them to grow much larger.

• Different types of grasses have unique genes for their height and color.

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Multiple Choice

What are genetic factors?

• They are the DNA instructions that determine the potential for an organism's growth.

• They are the nutrients an organism gets from its environment.

• They are the behaviors an organism learns to survive.

• They are the messages sent between cells in an organism.

Multiple Choice

How does an organism receive its genetic factors?

• They are inherited from parents through genes.

• They are developed by an organism over its lifetime.

• They are absorbed from the food an organism eats.

• They are created by the environment in which an organism lives.

Multiple Choice

If two large-breed cattle have a calf, what is the most likely reason the calf will also grow to be large?

• The calf inherited genes for large size from its parents.

• The calf will eat the same type of grass as its parents.

• The calf will live in the same environment as its parents.

• The calf learned how to grow large by watching its parents.

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Interaction of Environmental and Genetic Factors

• An organism's growth depends on the interaction between genes and the environment.

• For example, dwarf fruit trees have genes that limit their potential size.

• However, their actual height is influenced by factors like water and nutrients.

• Not every seed from a tall plant will grow to the same height.

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Multiple Choice

What determines an organism's growth?

• The interaction between its genes and its environment

• Only the genes it receives from its parents

• Only the amount of water and nutrients it receives

• The number of seeds the parent plant produces

Multiple Choice

How do environmental factors like water and nutrients affect a dwarf fruit tree that has genes for a small size?

• They change the tree's genes to make it taller

• They have no effect on a tree with dwarf genes

• They only determine the color of the fruit

• They influence the actual height the tree reaches

Multiple Choice

If two seeds from the same tall plant are grown in different conditions, one with rich soil and plenty of water, and the other with poor soil and little water, what is the most likely outcome?

• The plant in the nutrient-rich soil will likely grow taller.

• Both plants will grow to the exact same height.

• The plant in the poor soil will grow taller.

• Only the plant in the nutrient-rich soil will grow.

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The Global Problem of Soil Salinity

• Wheat is a critical food source, providing 20% of all human calories.

• A major problem called soil salinity, or high salt, threatens wheat farms.

• This issue affects about 20% of the world’s farmland.

• It is caused by drought or when irrigation water leaves salt behind.

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Multiple Choice

What is soil salinity?

• A high level of salt in the soil

• A type of healthy soil for growing plants

• A method for watering crops

• A shortage of wheat in the world

Multiple Choice

What is the relationship between farming practices and soil salinity?

• It is caused by events like drought or irrigation methods.

• It is a problem that only affects wheat farms.

• It improves the quality of the soil for farming.

• It helps crops get more calories from the sun.

Multiple Choice

A region that provides a large amount of calories through wheat farming experiences a severe, long-lasting drought. What is the most likely outcome?

• The region's food supply would be threatened because the soil would become too salty for wheat.

• The drought would cause the wheat to grow larger and provide more calories.

• The amount of farmland affected by salt would decrease globally.

• The salt in the soil would be washed away, improving crop growth.

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Genetic Factor: Natural Salt Tolerance

Modern Bread Wheat

• ​This plant uses a barrier method to stop salt from entering its roots from the soil.

• ​​A specific gene creates a barrier that blocks the salt at the surface of the roots.

• ​This defense mechanism is effective only in soil with low levels of salt.

Barley

• ​Barley uses a different strategy, allowing salt to enter but then storing it safely inside.

• ​​A special gene helps the plant capture and move the salt into cell pockets called vacuoles.

• ​This keeps the salt locked away from sensitive parts of the leaf, protecting the plant from damage.

Multiple Choice

What is the primary role of the special genes found in both modern bread wheat and barley?

• To provide the plant with a way to handle salt in the soil

• To help the plant absorb more water from the soil

• To make the plant's leaves grow larger

• To change the color of the plant's flowers

Multiple Choice

How does the strategy for handling salt in modern bread wheat differ from the strategy used by barley?

• Wheat blocks salt from entering its roots, while barley lets salt in and stores it.

• Barley blocks salt from entering its roots, while wheat lets salt in and stores it.

• Both plants use a barrier to stop salt from entering their roots.

• Both plants capture salt and move it into special cell pockets.

Multiple Choice

Based on the plant's defense mechanism, what would most likely happen if modern bread wheat was planted in soil with a very high salt concentration?

• The salt barrier would likely fail, allowing salt to enter and harm the plant.

• The wheat plant would adopt barley's strategy of storing salt in vacuoles.

• The plant's genetic barrier would become stronger to block the extra salt.

• The plant would be unaffected and continue to grow normally.

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Breeding Salt-Tolerant Wheat

• Durum wheat, used for making pasta, struggles in salty soil.

• An ancient relative, einkorn wheat, has a salt-tolerant gene.

• Scientists used breeding to create a new durum wheat variety.

• This new wheat has the protective gene to grow in salty fields.

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Multiple Choice

What was the primary purpose of creating a new variety of durum wheat?

• To make pasta taste better

• To allow it to grow in salty soil

• To create a wheat that needs less water

• To make the wheat grow faster

Multiple Choice

How did scientists solve the problem of durum wheat struggling in salty soil?

• By adding special fertilizer to the soil

• By breeding it with an ancient relative that has a salt-tolerant gene

• By giving the durum wheat more sunlight

• By removing a harmful gene from the durum wheat

Multiple Choice

If a farmer planted both the new salt-tolerant durum wheat and the original durum wheat in a field with high salt content, what would be the most likely outcome?

• The new durum wheat would grow well, while the original durum wheat would struggle.

• Both types of wheat would grow equally well in the salty soil.

• The original durum wheat would grow better than the new variety.

• Neither type of wheat would be able to grow in the salty soil.

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Common Misconceptions

Misconception	Correction
An organism's growth is determined only by its genes.	Growth results from both an organism's genes and its environment.
Adding more water to salty soil always helps a plant.	In very salty soil, salt can pull water out of a plant’s roots.
Salt-tolerant crops are completely artificial.	Salt tolerance is a natural trait that scientists can breed into other crops.

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Summary

• An organism's growth is influenced by its genes and the environment.

• Genes set the potential for growth, and the environment determines its extent.

• High soil salinity is a major threat to crops as it hinders water absorption.

• Developing crops that resist environmental stressors is essential for global food security.

Poll

On a scale of 1-4, how confident are you about explaining how environmental and genetic factors affect plant growth?

• 1

• 2

• 3

• 4