Name: patch use in optimal foraging
Uploaded: 2019-01-29T11:04:46.000Z
Duration: 3 min 37 s
Channel: JoVE

K12 Standards

Next Generation Science Standards

High School

Life Science

heredity-inheritance-and-variation-of-traits

Heredity: Inheritance and Variation of Traits

HS-LS4-2

Optimal Foraging

Часто в жизни вещи, в которых нуждается человек, могут быть недоступны. Таким образом, организмы нуждаются в добывании пищи. Собирательство определяется просто как процесс поиска пищи или ресурсов в более общем смысле. Хотя еда, вероятно, является первым примером, который приходит на ум, организмы должны добывать другие ресурсы, такие как укрытие или партнеры, и животные часто идут на многое, чтобы получить то, что им нужно. Тем не менее, сам акт добывания пищи требует энергии. По сути, люди должны балансировать между сжиганием калорий и их получением. Проще говоря, поиск пищи требует определенной стратегии. Экологи создали теорию оптимального собирательства, чтобы смоделировать условия, при которых организм достигает оптимального баланса между энергией, затраченной на добывание пищи, т.е. стоимостью двух желудей и потенциальной энергией, которую он может приобрести, как шесть новых желудей. 
Одной из характеристик собирательства является то, что ресурсы не всегда равномерно распределены в пределах среды обитания. Как правило, ресурсы содержатся в заплатках, между которыми фуражиры должны перемещаться. Так как же именно собирателям следует ориентироваться на этих участках ресурсов? В 1976 году эволюционный эколог Эрик Л. Чарнов придумал теорему о предельных значениях, или MVT, чтобы объяснить, как организмы оптимизируют свои поиски пищи. У MVT есть пять основных прогнозов для оптимального кормления. Во-первых, в нем говорится, что фуражиры должны захватывать больше добычи на участках с высокой плотностью добычи, чем на участках с низкой плотностью добычи. Во-вторых, теория предсказывает, что собиратели должны тратить больше времени на охоту за ресурсами на участках с высокой плотностью добычи. Далее, фуражир должен иметь более высокий уровень захвата добычи в плотной среде с плотно прижатыми друг к другу участками, чем в разреженной среде с участками, которые разбросаны дальше друг от друга. Четвертое предсказание гласит, что фуражиры будут проводить больше времени в добывании пищи в этих плотных условиях, чем в разреженных. Наконец, фуражир должен покинуть участок, когда скорость поимки снизилась до среднего показателя по всем участкам. И вот тут-то и появляется концепция, называемая отказом от времени или GUT. Чтобы рассчитать GUT, просто вычтите время, в течение которого была получена последняя добыча, из момента, когда особь покидает участок. Следовательно, GUT должен быть одинаковым для всех участков, которые посещает фуражир. 
В этой лаборатории вы проведете моделирование добычи пищи на нескольких различных участках искусственных ресурсов, а затем выполните расчеты, чтобы оценить, как ваш класс проявил себя в качестве фуражиров и придерживались ли вы правил теоремы о предельной стоимости.

Оптимальный сбор пищи

<h4>Оптимальный сбор пищи</h4>
Организмы должны приобретать и использовать ресурсы в своей окружающей среде, чтобы выжить. В то время как пища является одним из основных ресурсов, которые организмы должны искать, особи также должны искать среду обитания, укрытие и партнеров. Этот процесс поиска ресурсов известен как собирательство, который включает в себя ряд затрат и выгод. В частности, приобретение ресурса приносит организму пользу, однако поиск и захват ресурса требует затрат времени и энергии. Таким образом, организмы применяют стратегии добывания пищи, которые максимизируют чистую прибыль до оптимального уровня, обеспечивая максимальную выгоду при наименьших затратах. Экологи разработали «Теорию оптимального кормления» для моделирования ситуаций, в которых организм достигает оптимального баланса между затратами и выгодами от добывания пищи.
<h4>Теорема о предельной ценности</h4>
Ресурсы распределены в окружающей среде неравномерно. Например, в лесной экосистеме гораздо более вероятно найти виды деревьев, собранные вместе, а не равномерно распределенные по всему лесу. Эта неоднородность в доступности ресурсов создает «участки» ресурсов. Таким образом, собиратели должны учитывать как отдачу от одного участка, так и расстояние между участками, то есть стоимость перехода на другой участок. Теорема о предельной ценности (MVT) описывает, как оптимальные собиратели используют и перемещаются между участками ресурсов в своей среде обитания 1. Существует пять основных прогнозов MVT: 
<ol class="ссылки">
	<li>Фуражиры должны захватывать больше добычи на участках с высокой плотностью добычи, чем на участках с низкой плотностью добычи.</li>
	<li>Фуражиры должны тратить больше времени на участки с высокой плотностью добычи, чем на участках с низкой плотностью добычи.</li>
	<li>Фуражиры должны иметь более высокий уровень захвата добычи на плотных участках, чем те, которые распределены дальше друг от друга.</li>
	<li>Собиратели должны проводить больше времени в плотной среде, где участки сгруппированы, чем в разреженной среде.</li>
	<li>Фуражиры должны покидать патч, когда скорость поимки снизилась до среднего показателя всех патчей.</li>
</ol>
Промежуток времени между моментом поимки последней добычи и моментом, когда фуражир покидает участок, известен как время сдачи, или GUT. В контексте MVT GUT должна быть одинаковой во всех патчах для каждого отдельного фуражира. Это было проверено в эксперименте с черношапочными синицами в большом вольере, добывающими мучного червя, спрятанного в искусственных сосновых шишках, где птицы имели одинаковый GUT для всех типов участков, что было обратно пропорционально среднему показателю отлова для всей окружающей среды. 
Чем дольше организм тратит время на поиски пищи, тем больше энергии он тратит и тем дольше он подвергается воздействию хищников и стихий, поэтому для большинства организмов важно разработать оптимальную стратегию добывания пищи для добывания ресурсов. Принципы МВТ имеют множество реальных применений для продвижения разнообразия, сохранения природы и даже поведения человека.
<h4>Оптимальный поиск пищи в изменяющихся условиях</h4>
С точки зрения разнообразия и сохранения, MVT предсказывает, что виды могут существовать только при наличии участков для адекватного удовлетворения энергетических потребностей организма, поэтому доступность и расстояние между ресурсами важны для организмов, выживание которых зависит от них. Потеря среды обитания, загрязнение и другие изменения в окружающей среде могут повлиять на способность организма оптимально добывать пищу, тем самым снижая его приспособленность. Таким образом, когда места обитания в экосистеме разрушаются, удаляются участки или целые сообщества. Это удаление ограничивает ресурсы, доступные обитателям остальной экосистемы. Меньшее количество участков с ресурсами создает более интенсивную конкуренцию и может уничтожить определенные виды. Это особенно важно для видов, находящихся под угрозой исчезновения из-за потери среды обитания, которые не смогут удовлетворить свои потребности в корме, если большая часть их среды обитания будет уничтожена. 
Люди разработали сложные способы хранения пищи, чтобы ограничить потребности в добывании пищи, однако есть много других случаев, когда сбор пищи необходим, например, поиск доступного жилья, хорошо оплачиваемой работы или поиск подходящего свидания среди прочего. В недавнем исследовании были проверены прогнозы MVT с использованием способностей врачей общей практики к поиску информации. Они обнаружили, что врачи общей практики оптимально собирают информацию при постановке диагноза пациенту; Они быстро переключались между несколькими источниками информации и использовали как источники с высокой плотностью, такие как Интернет, так и легкодоступные источники, включая своих коллег 3. Аналогичным образом, теория оптимального собирательства также применима к экономике того, как потребители совершают покупки или «собирают» продукты и информацию при совершении покупки. Эти исследования демонстрируют, как люди придерживаются предсказаний теории оптимального кормления в различных контекстах.
<h4>Ссылки</h4>
<ol>
	<li>Чарнов Е. Л. Птимальное добывание пищи: теорема о предельной стоимости. Теоретическая популяционная биология. 1976, том 9, (129-36).</li>
	<li>Джон Кребс, Джон Райан, Эрик Чарнов. Охота на ожидание или оптимальное кормление: Исследование использования пятнистых участков синицами. Поведение животных. 1974, том 22, (953-64).</li>
	<li>Мэй Дуэйри, Энтони С. Доуэлл, Жан-Клод Шталь. Применение теории поиска пищи к информационно-поисковому поведению врачей общей практики. Семейная практика BMC. 2011, Том 12, 90.</li>
	<li>Уэллс, В.К. Собирательство: экологическая модель потребительского поведения? Теория маркетинга. 2012, Том 2, 12 (117-136).</li>
</ol>

Оптимальный сбор пищи
Организмы должны приобретать и использовать ресурсы в своей окружающей среде, чтобы выжить. Хотя пища является одним из основных ресурсов, организмы должны...

Education

JoVE Lab Manual

Biology

Биология

Ecology

Экология

patch use in optimal foraging

Patch use in optimal foraging explains how organisms balance food gain against the time and energy needed to search for it. Foraging is not limited to food. Animals also search for habitats, shelter, and mates. Each choice has costs and benefits. A resource provides a benefit, but finding and capturing it takes effort. Optimal Foraging Theory models how organisms reach the best balance between those costs and gains.

A key idea in this theory is that resources are often clumped into patches rather than spread evenly through an environment. Forest trees, for example, are more likely to occur in groups than as single, evenly spaced trees. Because of this patchiness, foragers must think about both the value of a patch and the distance to the next one. Moving between patches also has a cost. The Marginal Value Theorem helps explain when an organism should keep feeding in a patch and when it should move on.

The Marginal Value Theorem predicts that foragers should capture more prey in dense patches than in sparse ones. They should also spend more time in patches with more prey, and they should have a higher prey capture rate there. In dense environments, where patches are closer together, foragers should spend more time foraging than in sparse environments. A forager should leave a patch when the capture rate falls to the average rate for the whole environment. The time between the last prey capture and leaving the patch is called the Giving-Up-Time, or GUT.

The GUT should be the same across patches for a single forager. This prediction was tested with black-capped chickadees in a large aviary. The birds searched for mealworms hidden in artificial pine cones. They showed the same GUT in all patch types, and that GUT was inversely related to the average capture rate in the environment. The result supported the Marginal Value Theorem.

Optimal foraging matters because searching takes time, uses energy, and can expose organisms to predators and the elements. It also helps explain real-world ecology and conservation. Habitat loss, pollution, and other environmental changes can disrupt foraging and lower fitness. If habitats are destroyed, patches and even whole communities may disappear. That reduces the resources available to the rest of the ecosystem and can increase competition. Species at risk of extinction may be especially affected if most of their habitat is lost.

The same ideas also apply to human behavior. Humans reduce foraging needs through food storage, but they still forage in other ways. People may search for affordable housing, a well-paying job, or a suitable date. A study of general practitioners found that they foraged for information while diagnosing patients. They moved quickly between sources and used both high-density sources, such as the internet, and easier sources, including colleagues. Optimal Foraging Theory also helps explain how consumers search for products and information when making purchases.

Patch Use in Optimal Foraging

animal behavior

Drosophila Taxis in Animal Behavior

Drosophila taxis behavior is a key part of animal behavior studies. The common fruit fly, Drosophila melanogaster, is a widely used model organism in biology. It is easy to keep in small tubes, it has a short generation time of about two weeks, and males and females are easy to tell apart because males have black coloration toward the posterior and females have banded abdomens. Scientists have used Drosophila for more than a century. Thomas Hunt Morgan and his students studied mutant flies in...

energy dynamics

Food Chain Energy Flow and Biomass

Food chain energy flow shows how energy moves through ecosystems from one organism to the next. Energy cannot be created or destroyed, so it can only change form or be passed along to another organism. When a cow grazes on grass or an osprey eats fish, energy moves to the consumer. Each transfer is part of a trophic level, and these links help explain how ecosystems stay balanced. Primary producers sit at the base of the food chain. They are autotrophs, or self-feeding organisms, because they...

measuring biodiversity

Why Biodiversity Matters in Ecosystems

Biodiversity matters because it helps keep ecosystems healthy and stable. Biodiversity is the variety of living organisms in an ecosystem, and it can be measured at the genetic, species, community, and ecosystem levels. Ecologists often focus on species richness, which is the total number of different species in a local community. They also consider evenness, which describes how similar the abundances of those species are. A community with many species is not always the most diverse if one...

extinction

Mass Extinction and the Fossil Record

Mass extinction is a major loss of species, and the fossil record shows how these events changed life on Earth. Fossils from different rock layers helped scientists see that life has a long history. In the early 19th century, that idea helped launch paleontology, the study of fossils and ancient life. At first, many scientists did not fully accept that a species could disappear forever. They thought unknown organisms seen only in fossils might still live in unexplored places on Earth. By 1859,...

species distribution and biogeography

Island Biogeography and Species Richness

Island biogeography explains why species are found in some places and not others. It looks at how biotic factors, like competition and predation, and abiotic factors, like habitat size and distance, shape birth, death, immigration, and emigration rates. For a species to avoid local extinction, births and immigration must match or exceed deaths and emigration. Edward O. Wilson and Robert MacArthur helped define this field in 1967 by studying isolated oceanic islands. Islands gave early...

population growth

Population Models and Carrying Capacity

Population ecology examines how a species population changes over time. A population is a group of individuals of the same species living in the same area at the same time. To persist, a population must grow or at least stay about the same size. Ecologists study birth rate, death rate, and age distribution to understand whether a population is increasing, declining, or at risk of extinction. Population ecologists use models to predict how population size changes. Two simple models are...

community diversity

Measuring Ecosystem Health

Ecosystem health is measured by looking at how species, habitats, and nonliving conditions interact in the same area. An ecological community includes many populations that live together and affect one another. When biotic parts, or living parts, also interact with abiotic parts, or nonliving parts, they form an ecosystem. These systems can be very small, like microbes in the human digestive tract, or very large, like a forest linked by the carbon cycle. Ecologists study ecosystem health...

climate change

Climate Change Effects on Sea Level and Species

Climate change affects Earth’s average temperature, sea level, and living things. Scientists distinguish climate from weather by time scale. Weather describes short-term conditions in one place, such as temperature and precipitation. Climate describes those same conditions over long periods, and global climate is measured using data from across the entire Earth. Researchers track climate change with help from meteorology, geography, oceanography, and computer models. Much of this work focuses...

group behavior

Hawk-Dove Strategy in Animal Populations

Hawk-dove strategy helps explain how animals compete and cooperate in populations. Organisms often face costs when they try to get food, shelter, or mates. Because of that, individuals can use different behavioral strategies to gain an advantage. This is clear in polymorphic mating systems, where one sex, usually males, uses more than one mating strategy. For example, dominant male sea lions defend groups of females on the beach. Non-dominant males stay in or near the water and try to mate...

optimal foraging

Patch use in optimal foraging explains how organisms balance food gain against the time and energy needed to search for it. Foraging is not limited to food. Animals also search for habitats, shelter, and mates. Each choice has costs and benefits. A resource provides a benefit, but finding and capturing it takes effort. Optimal Foraging Theory models how organisms reach the best balance between those costs and gains. A key idea in this theory is that resources are often clumped into patches...

sexual selection and mate choice

Mate Competition and Fitness Traits

Mate competition and fitness traits shape how organisms choose partners and pass genes to the next generation. Evolutionary fitness depends on surviving and producing offspring, and sexual selection is a major part of that process. It creates pressure on traits used in courtship and mating, such as bright colors, ornamentation, and other features that help attract a mate. These traits can also create sexual dimorphism, which means males and females of the same species look different. Sexual...

eusociality and division of labor

Honeybee Altruism and Inclusive Fitness

Eusociality is a highly organized form of animal social life. It includes division of labor, where different individuals take on different roles in the group. In these systems, some animals help others even when it comes at a cost to their own survival or reproduction. That self-sacrificing behavior is called altruism. Early evolutionary biologists used to explain fitness only at the level of the individual. Observations of eusocial species, such as honeybees, challenged that idea. W. D.

ecology

Learn how optimal foraging theory explains patch use, Giving-Up-Time, and the Marginal Value Theorem using chickadees, conservation, and human examples.

Patch Use in Optimal Foraging | JoVE K12

new-york-state-science-learning-standards

New York State Science Learning Standards

Natural Selection and Evolution

HS-LS4-1.

Подготовьтесь к преподаванию Оптимальный сбор пищи с помощью этого 3-минутного руководства для преподавателей. Охватывает ключевые этапы подготовки для лаборатории Biology на JoVE Lab Manual.

Подготовка преподавателя по Оптимальный сбор пищи в Biology - Более 1.4K просмотров | JoVE Lab Manual

Следуйте пошаговым процедурам Оптимальный сбор пищи в этом 6-минутном видео студенческого протокола. Часть коллекции Biology на JoVE Lab Manual.

Студенческий протокол по Оптимальный сбор пищи в Biology - Более 1.8K просмотров | JoVE Lab Manual

DNA as a Genetic Template

Structure of a Gene

A gene is the fundamental unit of heredity. Every individual has two copies of each gene, one inherited from each parent. Although most people contain the ...

DNA Packaging

Organization of Genes

Chromosome Structure

A functional eukaryotic chromosome must contain three elements: a centromere, telomeres, and numerous origins of replication.
The centromere is a DNA ...

The Nucleosome

DNA in a human cell is almost 2m long and it is packed inside a tiny nucleus that is only a few microns in diameter. The level of compaction of DNA inside ...

Chromatin Packaging

Each human somatic cell contains 6 billion base-pairs of DNA. Each base-pair is 0.34 nm long, which means that each diploid cell contains a staggering 2 ...

Karyotyping

Position-effect Variegation

In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and spread ...

Histone Modification

The histone proteins have a flexible N-terminal tail extending out from the nucleosome. These histone tails are often subjected to post-translational ...

Spreading of Chromatin Modifications

The histone&#160;proteins in the nucleosomes are post-translationally modified (PTM) to increase or decrease access to DNA. The commonly observed PTMs are ...

Lampbrush Chromosomes

In 1882, Flemming observed lampbrush chromosomes (LBC) in salamander eggs. Later in 1892, R&#252;ckert observed LBCs in shark egg cells and coined the ...

Polytene Chromosomes

Polytene chromosomes are giant interphase chromosomes with several DNA strands placed side by side. They were discovered in the year 1881 by Balbiani in ...

Histone Variants at the Centromere

Histone variants are the histone proteins with structural and sequence variations. These variants may be regarded as &#8220;mutant&#8221; forms that ...

Inheritance of Chromatin Structures

Epigenetics is the study of inherited changes in a cell&#39;s phenotype without changing the DNA sequences. It provides a form of memory for the ...

Euchromatin

The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions ...

Heterochromatin

chromatin-position-affects-gene-expression

Chromatin Position Affects Gene Expression

Chromatin is the massive complex of DNA and proteins packaged inside the nucleus. The complexity of chromatin folding and how it is packaged inside the ...

Genetics of Organisms

Mendelian Genetics
Evolution is caused by changes in the genetic composition of populations. In the field of population genetics, scientists model this ...

REF and WEF Fly Genetics
ExpandTo prepare for the experiment, be sure to obtain cultures of Drosophila melanogaster at least two weeks ahead of the ...

REF and WEF Fly Genetics
ExpandNOTE: At your station, you should have four vials of flies. They will be labeled as male or female. They will also be ...

Genetic Lingo

Overview

An organism is diploid if it inherits two variants, or alleles, of each gene, one from each parent. These two alleles constitute the genotype ...

Punnett Squares

Overview

A Punnett square displays the possible genotypes offspring can inherit from two parental genotypes. If a trait&#x2019;s inheritance pattern ...

Monohybrid Crosses

Overview

In the 1850s and 1860s, Gregor Mendel investigated inheritance by performing monohybrid crosses in pea plants. He crossed two plants that were ...

Dihybrid Crosses

Overview

To determine whether traits are inherited together or separately, Gregor Mendel crossed pea plants that differed in two traits. These parental ...

Trihybrid Crosses

Trihybrid Crosses
Some of Mendel&#8217;s crosses examined three pairs of contrasting characteristics. Such a cross is called a trihybrid cross. A ...

Law of Segregation

When crossing pea plants, Mendel noticed that one of the parental traits would sometimes disappear in the first generation of offspring, called the F1 ...

Law of Independent Assortment

While Mendel&#x2019;s Law of Segregation states that the two alleles for one gene are separated into different gametes, a different question of how ...

Test Cross

Alleles are different forms of the same gene. Humans and other diploid organisms inherit two alleles of every gene, one from each parent.

An allele is ...

Chi-square Analysis

The chi-square test is a statistical hypothesis test. It is used to check whether there is a significant difference between an expected value and an ...

Pedigree Analysis

Overview

A pedigree is a diagram displaying a family&#x2019;s history of a trait. Analyzing pedigrees can reveal (1) whether a trait is dominant or ...

Nature and Nurture

Many human characteristics, like height, are shaped by both nature&mdash;in other words, by our genes&mdash;and by nurture, or our environment. For ...

Probability Laws

Overview

The probability of inheriting a trait can be calculated using the sum and product rules. The sum rule is used to calculate the probability of ...

background-and-environment-affect-phenotype

Background and Environment Affect Phenotype

Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as ...

Multiple Allele Traits

The Concept of Multiple Allelism

Multiple allelism describes genes that exist in three or more allelic forms. Although diploid organisms, like humans, ...

X and Y Chromosomes

Among mammals, the gender of an organism is determined by the sex chromosomes. Humans have two sex chromosomes, X and Y. Every human diploid cell has 22 ...

Chromosomal Theory of Inheritance

In 1866, Gregor Mendel published the results of his pea plant breeding experiments, providing evidence for predictable patterns in the inheritance of ...

The Y Chromosome Determines Maleness

The Y chromosome is a sex chromosome&#160;found in several vertebrates and mammals, including humans. In addition to 22 pairs of autosomes, the human ...

Non-nuclear Inheritance

Most DNA resides in the nucleus of a cell. However, some organelles in the cell cytoplasm⁠&mdash;such as chloroplasts and mitochondria⁠&mdash;also ...

The Ratio of X Chromosome to Autosomes

In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined ...

Incomplete Dominance

Gregor Mendel&#39;s work (1822 - 1884) was primarily focused on pea plants. Through his initial experiments, he determined that every gene in a diploid ...

X-linked Traits

In most mammalian species, females have two X sex chromosomes and males have an X and Y. As a result, mutations on the X chromosome in females may be ...

Lethal Alleles

Agouti: A Lethal Allele
Lucien Cu&#233;not discovered lethal alleles in 1905 while studying the inheritance of coat color in mice. The agouti gene is ...

Sex-linked Disorders

Like autosomes, sex chromosomes contain a variety of genes necessary for normal body function. When a mutation in one of these genes results in biological ...

Epistasis

In addition to multiple alleles at the same locus influencing traits, numerous genes or alleles at different locations may interact and influence ...

X-Inactivation

The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, ...

Polygenic Traits

When more than one gene is responsible for a given phenotype, the trait is considered polygenic. Human height is a polygenic trait. Studies have uncovered ...

Dosage Compensation

In animals, gender is determined by the number and type of sex chromosome. For example, human females have two X chromosomes, and males have one X and one ...

Pleiotropy

Pleiotropy is the phenomenon in which a single gene impacts multiple, seemingly unrelated phenotypic traits. For example, defects in the SOX10 gene cause ...

Ask questions to clarify relationships about the role of DNA and chromosomes in coding the instructions for characteristic traits passed from parents to offspring. [Assessment Boundary: Assessment does not include the phases of meiosis or the biochemical mechanism of specific steps in the process.]

HS-LS3-1

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

Genome Size and the Evolution of New Genes

Gene Families

Gene Evolution - Fast or Slow?

types-of-genetic-transfer-between-organisms

Types of Genetic Transfer Between Organisms

What is Meiosis?

Meiosis I

Meiosis is the division of a diploid cell into haploid cells forming sperm and eggs in animals through differentiation. Meiosis I is the first stage of ...

Meiosis II

Meiosis II entails cell division and segregation of the sister chromatids, resulting in the production of four unique haploid gametes. The steps for ...

Meiosis vs. Mitosis

Cell division is necessary for growth and reproduction in organisms. Mitosis aids cell growth and development by dividing somatic cells. In contrast, ...

Crossing over

Nondisjunction

Replication in Eukaryotes

Overview

In eukaryotic cells, DNA replication is highly conserved and tightly regulated. Multiple linear chromosomes must be duplicated with high ...

Proofreading

Synthesis of new DNA molecules starts when DNA polymerase links nucleotides together in a sequence that is complementary to the template DNA strand. DNA ...

Mismatch Repair

Overview

Organisms are capable of detecting and fixing nucleotide mismatches that occur during DNA replication. This sophisticated process requires ...

Nucleotide Excision Repair

Overview

Exposure to mutagens can damage DNA and result in bulky lesions that distort the double-helix structure or impede proper transcription. Damaged ...

Cancer Prevention

Several factors can increase the risk of cancer in an individual. About 50% of cancer cases can be prevented by adopting a healthy lifestyle, regular ...

cancers-originate-from-somatic-mutations-in-a-single-cell

Cancers Originate from Somatic Mutations in a Single Cell

Cancer arises from mutations in the critical genes that allow healthy cells to escape cell cycle regulation and acquire the ability to proliferate ...

DNA Distortion and Damage
Cells are regularly exposed to mutagens&#8212;factors in the environment that can damage DNA and generate mutations. UV ...

comparing-copy-number-variations-and-snps

Comparing Copy Number Variations and SNPs

Sequencing of the human genome has opened up several best-kept secrets of the genome. Scientists have identified thousands of genome variations that exist ...

Gene Conversion

Other than maintaining genome stability via DNA repair, homologous recombination plays an important role in diversifying the genome. In fact, the ...

Mutations

Overview

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

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 ...

Viral Mutations

A mutation is a change in the sequence of bases of DNA or RNA in a genome. Some mutations occur during replication of the genome due to errors made by the ...

Make and defend a claim based on evidence that inheritable genetic variations may result from (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and or (3) mutations caused by environmental factors. [Clarification Statement: Emphasis is on using data to support arguments for the way variation occurs.] [Assessment Boundary: Assessment does not include the phases of meiosis or the biochemical mechanism of specific steps in the process.]

HS-LS3-2

Patch Use in Optimal Foraging

Description

Transcript

More videos by Standards