Name: heritability and the environment
Uploaded: 2024-10-24T14:03:06.000Z
Duration: 1 min 6 s
Channel: JoVE

K12 Standards

Arizona Science Standards

High School

Life Science

HS+B.L3

HS+B.L3U1.10

Heritability

תורשתיות מודדת את ההשפעה הגנטית על תכונות או מאפיינים פיזיים כגון גובה או צבע עיניים.
תורשתיות יכולה להשתנות בהתאם לקבוצה ולתנאים שבהם הם חיים.
לדוגמה, גובה האדם הוא 90% תורשתי, אבל חומרים מזינים ופעילות גופנית משפיעים עליו באופן משמעותי.
כאשר כולם בקבוצה, כמו כל הילדים במשפחה זו, חיים בסביבה דומה, הבדלים בתכונות שלהם, כמו גובה או אישיות, נוטים יותר לנבוע מהגורמים הגנטיים שלהם.
לעומת זאת, אם אחד הילדים פעיל יותר מבחינה גופנית ובעל תזונה בריאה יותר, ההבדלים בין המאפיינים הפיזיים של האחים עשויים לנבוע מגורמים סביבתיים ולא גנטיים.
נתונים היסטוריים על תכונות פיזיות ממחישים עוד יותר את השפעת הסביבה. לדוגמה, הגובה הממוצע העולמי של גברים ונשים כאחד עלה בכ-10 ס"מ במהלך 100 השנים האחרונות, מה שמשקף שיפור בתזונה ובבריאות.

תורשתיות

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תורשתיות היא מונח סטטיסטי המתאר את המידה שבה הבדלים גנטיים בין פרטים תורמים לשונות בתכונה מסוימת בתוך אוכלוסייה. זהו מושג בסיסי בגנטיקה, אך לעיתים קרובות יש לו פירושים שגויים. תורשתיות מבוטאת באחוזים ומשקפת את שיעור השונות בתכונה מסוימת בתוך אוכלוסייה שניתן לקשר להבדלים גנטיים. עם זאת, חשוב להבין שתורשתיות אינה קובעת עד כמה תכונה היא "גנטית", והיא אינה קבועה באוכלוסיות שונות או בהקשרים סביבתיים שונים.

התורשתיות של תכונה יכולה להשתנות בצורה משמעותית בהתאם לאוכלוסייה הנבדקת ולתנאי הסביבה הספציפיים הקיימים. שינויים אלו מדגישים את ההקשר תלוי-הסביבה של התורשתיות. לדוגמה, באוכלוסייה שבה רוב הפרטים חיים בתנאים סביבתיים דומים, הבדלים בתכונה כמו גובה נוטים להיות מוסברים על ידי שונות גנטית, מה שיביא לאומדן תורשתיות גבוה. לעומת זאת, באוכלוסייה שבה קיים מגוון רחב של תנאים סביבתיים, אותה תכונה עשויה להראות תורשתיות נמוכה יותר, משום שלתנאים הסביבתיים יש השפעה משמעותית יותר על השונות הנצפית.

יתר על כן, תורשתיות גבוהה אינה מצביעה על כך שההתפתחות של תכונה אינה מושפעת מגורמים סביבתיים. גם תכונות בעלות מרכיב תורשתי משמעותי, כמו מנת משכל (IQ), יכולות להיות מושפעות בצורה ניכרת משינויים בתנאים הסביבתיים. מצב זה מדגיש את האינטראקציה הדינמית בין גנטיקה לסביבה. לדוגמה, תוכניות חינוך מועשרות עשויות לשפר את היכולות הקוגניטיביות, מה שמעיד ששינויים סביבתיים יכולים להשפיע על תכונות בעלות בסיס גנטי חזק.

שינויים היסטוריים בתכונות כמו גובה ממחישים גם הם את הרעיון הזה. הגובה הממוצע באוכלוסיות שונות עלה במהלך המאה ה-20, בעיקר בשל שיפורים בתזונה ובשירותי הבריאות ולא בשל שינויים גנטיים באוכלוסיות אלו. עלייה של כ-8.89 סנטימטרים בגובה הממוצע מהשנים 1896 עד שנות ה-90 מדגימה את ההשפעה המשמעותית של שיפורים סביבתיים על תכונה שיש לה מרכיב גנטי משמעותי.

בנוסף, מחקרים על אנשים עם רקע גנטי דומה שגודלו בתנאים סביבתיים שונים, החל מתמיכה מינימלית ועד לתמיכה מרבית, מראים שונות רבה בתכונותיהם. מחקרים אלו מדגימים שהגנטיקה מספקת את הבסיס, אך הגורמים הסביבתיים מעצבים במידה רבה את התכונות הפיזיות וההתנהגותיות של פרטים. הבנת הדינמיקה בין גנטיקה לסביבה היא חיונית להבנה של תורשתיות ותפקידה בפיתוח תכונות באוכלוסיות שונות.
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תורשתיות מודדת את ההשפעה הגנטית על תכונות או מאפיינים פיזיים כגון גובה או צבע עיניים.
התורשתיות יכולה להשתנות בהתאם ...

Education

JoVE Core

Introduction to Psychology

מבוא לפסיכולוגיה

Unit 1

יחידה 1

Biopsychology

ביופסיכולוגיה

KEY TERMS AND CONCEPTS

מונחים ומושגים מרכזיים

heritability and the environment

Heritability describes how genetic differences contribute to trait variation in a population. It is a statistical measure, so it shows how much of the spread in a trait can be linked to genes across a group. It does not tell you how “genetic” a trait is in an individual person.

Heritability is usually expressed as a percentage. That percentage can change depending on which population is studied and what environmental conditions are present. This means heritability is context-dependent, not fixed for every group or setting.

When people in a population live in very similar environments, genetic differences may explain more of the variation in a trait. In that case, the heritability estimate can be higher. Height is one example often used to show this pattern.

When a population has wider environmental differences, the same trait may show lower heritability. Environmental factors then play a larger role in the variation that is seen. A high heritability estimate still does not mean the trait is untouched by the environment.

Traits with strong heritable components can still change when the environment changes. IQ is one example, because enriched educational programs can improve cognitive ability. The transcript also notes that average height has increased over the last century mostly because of better nutrition and healthcare, not because of genetic change.

The rise in average height was about 3.5 inches from 1896 to the 1990s. Studies of people with similar genetic backgrounds also show large differences when they grow up in environments that range from minimal to highly supportive. These examples show that genes set a framework, but the environment helps shape the final trait.

Heritability and the Environment

introduction to biological bases of psychology

introduction-to-biological-bases-of-psychology

Biological Factors Shaping Behavior and Mind

Biopsychology connects biology and psychology by showing how the body influences behavior and mental processes. It focuses on the nervous system, neurotransmitters, hormones, genetics, and evolutionary ideas. Together, these areas help explain why people think, feel, and act the way they do. The nervous system is the main foundation of biopsychology. It has two parts: the central nervous system, or CNS, and the peripheral nervous system, or PNS. The CNS includes the brain and spinal cord and...

nervous system

Nervous System: CNS, PNS, and Reflexes

The nervous system helps the body sense, move, and respond. It works through a network of nerve cells that carry signals around the body. This system has two main parts: the central nervous system and the peripheral nervous system. The central nervous system, or CNS, includes the brain and spinal cord. The brain acts as the body’s control center. It processes sensory information and helps coordinate responses. The spinal cord serves as a major pathway for signals between the brain and the rest...

neurons as communicators of the brain

Neuron Parts and Signal Transmission

Neurons are the cells that carry information through the brain and nervous system. They use electrical and chemical signals to help control body functions, from heartbeat regulation to complex thinking. Their structure is built for fast, efficient communication. The cell body, or soma, is the neuron’s control center. It contains the nucleus, which holds the cell’s genetic material and helps maintain the neuron’s health and function. The cytoplasm around it contains organelles that make...

neuronal communication

How Neurons Send Signals

Neurons send signals through electrochemical communication that supports brain and nervous system function. A key part of this process is the action potential, a rapid electrical change that starts when the neuron’s internal charge rises above a threshold. That signal then travels along the axon to the axon terminal, where it is ready to pass to another neuron. The connection point between two neurons is called a synapse. Synapses can be electrical or chemical, and each type moves information...

neurotransmitters

Brain Chemicals That Shape Mood and Movement

Neurotransmitters are chemical messengers that help neurons communicate. They play a major role in nervous system function, as well as in mood, movement, sleep, and social behavior. Serotonin is made in the brain and intestines. It is linked to well-being and happiness, and it helps regulate mood, appetite, and sleep. When serotonin levels are out of balance in the brain or in peripheral sites, depression and sleep problems can occur. Dopamine is produced in several brain areas, including the...

cerebral hemispheres

How the Brain’s Two Halves Work

The brain’s two cerebral hemispheres work together to process information and control the body. The left and right hemispheres are linked by the corpus callosum, a large bundle of nerve fibers. This connection lets the two sides share sensory and motor information, with each hemisphere controlling the opposite side of the body. The hemispheres are also specialized for different tasks. This is called lateralization, which means certain functions are handled more strongly by one side than the...

lobes of the cerebrum

How Brain Lobes Shape Perception

The cerebral cortex is divided into two hemispheres, and each hemisphere has four lobes: frontal, parietal, temporal, and occipital. Together, these lobes support the brain’s main cognitive and sensory jobs. They work as a team to help you think, feel, move, and respond to the world. The frontal lobe sits behind the forehead and acts as a control center for personality, intelligence, and voluntary muscle movement. It also contains the prefrontal cortex, a region that helps with planning,...

spinal cord

Spinal Cord Nerves and Reflexes

The spinal cord is a major part of the central nervous system. It runs from the base of the brainstem to the lumbar region of the vertebral column. It helps keep the body stable and carries signals between the brain and the rest of the body. The spinal cord sits inside the bony spine for protection. It is divided into 30 segments that match the vertebrae. Each segment connects to a specific body region through paired spinal nerves. These spinal nerves are grouped by where they leave the...

lateralization

Brain Hemisphere Specialization

Brain hemisphere specialization divides mental tasks between the left and right sides of the brain. This split can improve neural efficiency and support more complex human abilities. Each hemisphere tends to handle the work it does best, which helps cognitive processing run more smoothly. The left hemisphere is especially strong in logic and language-related tasks. It supports analytical thinking, which means breaking a problem into parts and solving it step by step. This is important for...

human genetics

Genes, Behavior, and Mental Health

Human genetics explains how genes can influence behavior, emotions, and mental health. It also shows how a person’s genetic code can shape physical traits and the risk of disease. Each individual carries a unique set of genes, so the effects can be subtle or more noticeable. Genes help direct how the brain, hormones, and cells work. These body systems are all shaped by genetic instructions, and they help produce differences in thoughts and behavior. Human genetics therefore links biology with...

genetic material

Chromosomes, DNA, and Inherited Traits

Chromosomes, DNA, and inherited traits explain how genetic information is organized in the human body. Each cell contains a nucleus, and the nucleus holds 46 chromosomes arranged in 23 pairs. These chromosomes are tightly coiled structures made of DNA, which carries the instructions passed from parents to offspring. An individual inherits one set of chromosomes from the mother through the egg and one set from the father through the sperm. This combination creates a unique genetic makeup. Of...

genetic variation

How Alleles Shape Inherited Traits

Genetic variation helps explain why individuals in the same species can look and act differently. It comes from differences in DNA sequences. This diversity matters because it helps a species survive and adapt when the environment changes. Variation starts at fertilization, when an egg and sperm cell join. Each of these cells carries 23 chromosomes, so the fertilized egg can have up to 46 chromosomes. Chromosomes are long DNA strands that contain genes, which are the basic units of heredity. <br...

behavioral genetics and its designs

How Behavior Genetics Studies Inheritance

Behavior genetics studies how inherited genes influence human behavior. It looks at how genes passed from parents to offspring help shape behavioral traits and tendencies. The field also examines how inherited factors and environmental influences work together. Researchers use family studies, twin studies, and adoption studies to separate genetic and environmental effects. Family studies track traits within biological families to find possible genetic patterns. They have helped identify...

organization of the brain

Brain Regions and Their Key Functions

The brain is the main control center of the nervous system. It processes sensory input, makes decisions, and directs body actions. Its structure is divided into the hindbrain, midbrain, and forebrain, and each part supports important functions. The hindbrain sits at the base of the brain. It helps regulate automatic life processes. The medulla oblongata controls involuntary functions such as heartbeat, breathing, and blood pressure. Nearby, the pons acts as a bridge between brain regions,...

evolutionary psychology

Evolutionary Psychology and Human Behavior

Evolutionary psychology explains human behavior and mental processes through natural selection. It uses Darwin’s idea that traits can spread when they help survival and reproduction. In this view, some common behaviors may be adaptations that were useful to our ancestors. One clear example is fear of snakes. This fear is nearly universal, which suggests that early humans who avoided snakes were more likely to survive deadly encounters. Over many generations, that caution could be passed on and...

neuroplasticity

How the Brain Rewires Itself

Neuroplasticity is the brain’s ability to change its structure and function in response to learning, experience, or injury. It allows neural circuits to reorganize over time. This flexibility supports lifelong development and adaptation. One part of this change begins when dendrites and axons grow. Dendrites receive signals, and axons send them. As they grow, the brain’s circuitry becomes more complex and can support more connections. Next, synaptogenesis occurs. Synaptogenesis is the...

brain imaging

Brain Scanning Techniques

Brain scanning techniques help scientists and doctors see the structure and activity of the human brain. These methods support the diagnosis, study, and treatment of neurological and psychiatric disorders. The main techniques include computerized axial tomography, or CT, positron-emission tomography, or PET, magnetic resonance imaging, or MRI, functional magnetic resonance imaging, or fMRI, and transcranial magnetic stimulation, or TMS. CT scans use X-ray technology to build detailed...

the endocrine system

Endocrine Glands and Hormone Signals

The endocrine system is a network of glands that send hormone signals through the body. Hormones are chemical messengers that help control many body functions. They enter the bloodstream and travel to cells with the right receptors, or target sites, so the signal can be received. Because of this, hormone effects are widespread, unlike the more localized effects of neurotransmitters. This signaling helps the body keep a stable internal environment, called homeostasis. Several major glands...

somatosensory, motor, and association cortex

somatosensory-motor-and-association-cortex

Brain Cortex Areas for Sensation and Movement

The brain cortex uses separate areas for sensation, movement, and higher thinking. The somatosensory cortex is in the parietal lobes. It helps the brain interpret touch, temperature, and proprioception, which is awareness of body position. The somatosensory cortex has an organized map of the body. Neurons at the top of this region mainly process signals from the lower body. Neurons at the bottom handle input from the upper body. This layout helps the brain locate sensory input with precision.

major hormones and their functions

Hormone Imbalances and Their Effects

Hormones are chemical messengers made by endocrine glands. They help control body functions and keep internal conditions stable. When hormone levels shift too far up or down, normal body processes can be disrupted. Several major hormones have clear roles in the body. Oxytocin is made in the hypothalamus and released by the pituitary gland. It supports social bonding, childbirth, and lactation. Low oxytocin can affect social interaction and stress response, and it may contribute to depression.

inheritance

Genes, Traits, and Mendel's Rules

Genes, traits, and Mendel's rules explain how characteristics pass from parents to offspring. Gregor Mendel's pea plant experiments changed how scientists understand heredity. His work showed that traits are controlled by discrete units inside organisms called genes. Genes usually come in pairs. One gene is inherited from each parent, and together they make a person's genotype. Genotype is the genetic blueprint for potential traits. Examples include blood type, eye color, and inherited...

gene-environment interactions

How Environment Shapes Gene Expression

Environmental factors can change how genes are expressed. Gene expression is a dynamic process, and traits can differ even in people with the same DNA. Radiation, temperature, behavior, nutrition, and stress all help shape the final outcome. The reaction range helps explain this process. It means genes set a possible range for a trait, while the environment helps decide where a person falls within that range. For example, genetics may allow a height range from 5'5" to 6'1", but nutrition,...

heritability

Heritability describes how genetic differences contribute to trait variation in a population. It is a statistical measure, so it shows how much of the spread in a trait can be linked to genes across a group. It does not tell you how “genetic” a trait is in an individual person. Heritability is usually expressed as a percentage. That percentage can change depending on which population is studied and what environmental conditions are present. This means heritability is context-dependent, not...

natural selection and adaptation

Adaptation in Changing Environments

Natural selection explains how organisms become better suited to their environments over time. It favors individuals with traits that improve survival and reproduction. Adaptation is the result. It includes genetic changes that help an organism function in specific conditions, such as extreme cold or thinner air at high altitudes. Adaptation is not only physical. Psychological adaptation also helps organisms, especially humans, succeed in their surroundings. These responses come from both...

natural selection and mating preferences

How Selection Shapes Mate Choice

Natural selection and mating preferences work together to shape how organisms survive and reproduce. Natural selection favors traits that help an organism fit its environment. Mating preferences are part of sexual selection, which influences who mates with whom and how genes are passed on. Evolutionary psychologists argue that these preferences are tied to instincts that support reproduction. For females, conception, pregnancy, and nursing create a strong need to choose mates who can offer...

criticisms of the evolutionary perspective

criticisms-of-the-evolutionary-perspective

Social Learning vs. Evolutionary Psychology

Social learning theory and evolutionary psychology offer two different ways to explain sexual behavior. A study in which strangers gave students compliments and then asked for casual sex showed a clear gender gap. None of the women said yes, while 70% of the men agreed. Evolutionary psychology explains this result by arguing that natural selection may have shaped women to be more selective about sexual partners. From this view, selectivity can help improve survival and reproductive success. It...

key terms and concepts

Learn how heritability measures genetic differences in a population, why it changes with environment, and how nutrition, education, and healthcare affect traits.

Heritability and the Environment | JoVE K12

JoVE Core Introduction to Psychology offers an engaging learning experience on the fundamental principles of psychology through concise video lessons. Students will explore important topics such as cognitive processes, emotional regulation, and neural mechanisms, establishing a strong foundation in the study of the mind and human behavior. This series provides an accessible and captivating approach to grasp the essential concepts of the discipline.

introduction to psychology

Florida Department of Education

SC.912.L.14

SC.912.L.14.6

new-york-state-science-learning-standards

New York State Science Learning Standards

Natural Selection and Evolution

HS-LS4-3.

What is Population Genetics?

A population is composed of members of the same species that simultaneously live and interact in the same area. When individuals in a population breed, ...

Hardy-Weinberg Principle

Diploid organisms have two alleles of each gene, one from each parent, in their somatic cells. Therefore, each individual contributes two alleles to the ...

Mutation, Gene Flow, and Genetic Drift

In a population that is not at Hardy-Weinberg equilibrium, the frequency of alleles changes over time. Therefore, any deviations from the five conditions ...

Genetic Variation

Genetic variation stems from differences in DNA sequences among individuals, which are essential for species adaptation and evolution.
Genetic variations ...

Heritability measures the genetic influence on traits or physical characteristics such as height or eye color.
Heritability can vary depending on the ...

Natural Selection and Adaptation

Natural selection drives evolution by supporting organisms that are best adapted to their environments, enhancing their survival and reproduction rates.
...

Natural Selection and Mating Preferences

The principle of natural selection suggests that organisms better adapted to their environment are more likely to survive and reproduce.
Evolutionary ...

Use mathematics and computational thinking to explain the variation that occurs through meiosis and calculate the distribution of expressed traits in a population.

Genomic DNA in Prokaryotes

The genome of most prokaryotic organisms consists of double-stranded DNA organized into one circular chromosome in a region of cytoplasm called the ...

Genomic DNA in Eukaryotes

Eukaryotes have large genomes compared to prokaryotes. To fit their genomes into a cell, eukaryotic DNA is packaged extraordinarily tightly inside the ...

The DNA Helix

Overview

Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most ...

DNA Packaging

Overview

Eukaryotes have large genomes compared to prokaryotes. In order to fit their genomes into a cell, eukaryotes must pack their DNA tightly inside ...

Organization of Genes

Overview

The genomes of eukaryotes can be structured in several functional categories. A strand of DNA is comprised of genes and intergenic regions. ...

Karyotyping

Describing the number and physical features of chromosomes can reveal abnormalities that underlie genetic diseases. This description is facilitated by ...

RNA Structure

Overview
The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. Although most RNA is single-stranded, it can form ...

RNA Stability

Intact DNA strands can be found in fossils, while scientists sometimes struggle to keep RNA intact under laboratory conditions. The structural variations ...

Types of RNA

Overview
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs ...

MicroRNAs

MicroRNA (miRNA) are short, regulatory RNA transcribed from introns&mdash;non-coding regions of a gene&mdash;or intergenic regions&mdash;stretches of DNA ...

Transcription

Overview
Transcription is the process of synthesizing RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene ...

Translation

Lesson: Translation
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following ...

Bacterial Transformation

In 1928, bacteriologist Frederick Griffith worked on a vaccine for pneumonia, which is caused by Streptococcus pneumoniae bacteria. Griffith studied two ...

What is Gene Expression?

Overview
Gene expression is the process in which DNA&nbsp;directs the synthesis of functional products, that is, proteins. Cells can regulate gene ...

The Central Dogma

Overview

The central dogma of biology states that information encoded in the DNA is transferred to messenger RNA (mRNA), which then directs the synthesis ...

Transcription Factors

Tissue-specific transcription factors contribute to diverse cellular functions in mammals. For example, the gene for beta globin, a major component of ...

Construct an explanation for how the structure of DNA and RNA determine the structure of proteins that perform essential life functions.

HS+B.L3U1.11

Mutations

Mutations are changes in the sequence of DNA. These changes can occur spontaneously or they can be induced by exposure to environmental factors. Mutations ...

genome-size-and-the-evolution-of-new-genes

Genome Size and the Evolution of New Genes

evolutionary-relationships-through-genome-comparisons

Evolutionary Relationships through Genome Comparisons

Genome comparison is one of the excellent ways to interpret the evolutionary relationships between organisms. The basic principle of genome comparison is ...

Genome Copying Errors

DNA replication is a well-evolved process that copies millions of base pairs with high fidelity during each cell division. Occasionally a wrong base or a ...

Multi-species Conserved Sequences

Next-generation sequencing technologies have created large genomic databases of a variety of animals and plants. Ever since the human genome project was ...

Gene Duplication and Divergence

The seminal work of Ohno in 1970 popularized the idea of gene duplication and divergence. DNA sequence comparison studies reveal that a large portion of ...

Exon Recombination

The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new ...

Analyze and interpret data on how mutations can lead to increased genetic variation in a population.

HS+B.L3U1.12

Heritability and the Environment

Description

Transcript

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