Science - Natural Selection

Make a prediction: In an environment of Cold Level 1, what would happen to this environment 200 generations in? (with mutations) Ostrilope population (trait - fur; 50 generations in): 5 Level 3 ostrilopes, 2 level 4s, 25 level 5s, 30 level 6s, 35 level 7s, 35 level 8s, 15 level 9s.

200 generations in: 80 level 7s, 50 level 8s, 90 level 9s, 130 level 10s.

Feature

A characteristic that all members of a species have.

Histogram

A graph that uses bars to show how characteristics or values are distributed within a group.

Generation

A group of individuals born and living at about the same time.

Species

A group of organisms of the same kind (in one or more populations) that do not reproduce with organisms from any other group.

Population

A group of the same type of organism living in the same area.

Most lobsters in the wild are seen to have greenish-brown colored shells. However, in approximately 1 in 2 million, there is a blue-colored shell lobster. How is having a blue shell a neutral mutation to a blue lobster?

A lobster having a blue shell is a neutral mutation since it isn't an adaptive or non-adaptive trait. Studies shown that the normal lobster and a blue lobster have about the same survival rate in the wild; so, a neutral mutation trait wouldn't become a less common or more common trait over generations.

Chromosome

A long piece of DNA that contains many genes.

What is a neutral mutation?

A neutral mutation is when an organism has a mutated trait that is neither adaptive or non-adaptive in the environment.

Remember this:

A population can be described by the traits present and by the number of individuals who have each trait.

Mutation

A random change to a gene that sometimes results in a new trait.

Ancestor

A related organism from a previous generation.

Effect

A result or change that happens because of an event or process.

Trait

A specific characteristic of an individual organism.

Gene Version

A specific form of a gene that provides instructions for making a particular protein molecule.

How can a sudden change in in Earth's climate impact an animal species?

A sudden environmental change, like hotter weather can quickly kill out organisms of populations. Sometimes, organisms would die out to quickly to adapt to the new environment, causing extinctions.

Non-Adaptive Trait

A trait that makes it less likely that an individual will survive in a specific environment.

Adaptive Trait

A trait that makes it more likely that an individual will survive in a specific environment.

Protein Molecule

A type of large molecule that performs important functions inside organisms.

DNA

A type of molecule that genes and chromosomes are made of.

Camouflage

A way of hiding by looking the same as the background.

Predator

An animal that hunts and kills other animals for food.

Prey

An animal that is hunted or killed by another animal for food.

Cause

An event or process that leads to a result or change.

Gene

An instruction for making a protein molecule.

Offspring

An organism produced as a result of reproduction.

Variation

Any difference in traits between individual organisms.

As cane toads are big-eaters, they compete with each other for food. Whenever there is no more food to be found in an area, they go to other areas to find food. The first toads to reach new areas get most food, while slower ones get whatever is left. How might having bigger, stronger legs allow toads to adapt better than regular toads?

Bigger legs allow toads to outrun other toads to get more food in new areas, being an adaptive trait. They will then have better chances at getting food, making survival easier.

Environment

Everything (living and nonliving) that surrounds an organism.

True or False: Reproduction always creates individuals with adaptive traits.

False

Situation: A population of moths live on a type of tree with light-colored bark, so moths that have the light color wing trait used the tree to hide. Over many years, the bark of trees turned darken in color due to pollution. How would the distribution of traits change?

First, light-colored moths would start having a hard time to hide, as they have a non-adaptive trait. The few moths that have dark-colored wings would be able to hide much easier. Therefore, the distribution of traits will shift from mostly light-color moths to dark-colored moths.

How do genes determine an individual's traits?

Genes are instructions for making protein molecules and protein molecules determine traits.

Extinct

Having died out completely and no longer alive anywhere on Earth.

How can histograms help us describe a population?

Histograms can help us describe a population by the number of bars seen telling us a population's variation and the bar height telling us the distribution of each trait.

What are some human activities that are causing temperatures to increase? How can this very small increase affect animal species?

Human activities including burning fossil fuels, raising farm animals, and deforestation cause global temperatures to increase. This can melt Arctic ice sheets where polar bears hunt, make it too warm for some trees in the mountains to survive, and kill corals that become reefs that many other species depend on.

You've discovered that newts in a population started to have increased levels of poison as snakes (predators) entered their environment over many generations. Why is this claim wrong to why the newts became more poisonous?: Claim: Individual newts became more poisonous because they wanted to.

In this environment, newts in this newt population wanting to become more poisonous didn't cause the newts to become more poisonous as they cannot control how high their poison level traits are. As this newt population has a high variation of poison traits, with the introduction of snakes, if newts are able to change their poison levels to high poison levels, being adaptive traits, low levels of poison, being non-adaptive traits and medium poison levels would most likely become nonexistent or less common as the distribution of traits will shift so that there are only high poison newts, decreasing variation of poison traits.

If this claim is incorrect (card 50), how is this claim correct?: Claim: The newt population became more poisonous because the snakes in the environment caused poison to be an adaptive trait.

In this environment, the presence of snakes caused this newt population to become more poisonous, as higher poison traits became adaptive traits. As this newt population had a high variation of poison traits, snakes came into their environment as generations passed, causing the distribution of traits to shift from mostly low poison traits to high poison traits. High poison levels prevented snakes from eating newts, allowing high poison in newts to become more common, while newts with low poison traits will more likely be eaten, becoming less common, being non-adaptive traits.

Organism

Living things, such as plants, animals, and bacteria.

How can mutations help make a population better able to adapt to a changing environment?

Mutations can introduce new traits, which increases the chance that one of the new traits will be adaptive to an environmental change. This trait will then become more common over generations until another environmental change.

Based on knowing that 200 and 50 generations ago in this environment, there weren't any snakes and a high distribution of low level poison newts and low distribution of high poison level newts, explain using the previous flashcard: Explain how your model answers the question: How did a poison-level trait that wasn't always present in the newt population become the most common trait? (refer to your notes and key concepts)

My model answers this question because it shows that 200 generations ago in an environment without snakes and level 10 poison traits, no poison levels were adaptive as there were no predators, but the level 10 poison trait was then introduced from mutations 50 generations ago in the environment. Then 40 generations ago in the environment with snakes, poison became an adaptive trait to allow newts to less likely be eaten by the snakes, and the new trait poison level 10 is the most poisonous trait in this population, so newts with this trait will more likely survive longer and reproduce more than other newts, passing down the genes for poison level 10, causing the poison level 10 trait to become the most common trait after many generations into today's population.

If a newt has to be eaten to defend itself, how do they become more common than less poisonous newts? What are the two circumstances?

Newts become more common than less poisonous newts because in one circumstance, a predator who tries to eat a poisonous newt might turn sick from the newt's tetrodotoxin before the newt gets killed, allowing the newt to escape and survive, and in another circumstance predators licks the newt to decide whether to eat the newt, where predators are less likely to eat more poisonous newts.

What are two ways the number of individuals with each trait in a population can change?

One way is by environmental change: the population members with the adaptive trait will become more common over time, while ones with the non-adaptive trait will become less common. Another way is by two organisms having a baby which has a mutation in its genes for a different trait.

What would happen to these two ostrilope populations? (without mutations) - Cold environment Ostrilope population 1: Variation - low, distribution - 30 level 1 fur trait ostrilopes, 25 level 2 fur trait ostrilopes. Ostrilope population 2: Variation - high, distribution - 20 level 1s, 15 level 2s, 13 level 3s, 10 level 4s, 5 level 5s, 3 level 6s, 2 level 7s.

Ostrilope population 1 will die out and go extinct as they don't have the fur traits to survive. Level 1 and 2 fur traits are too little fur, so the ostrilopes are going to freeze and won't be able to reproduce. Ostrilope population 2 will survive as they have the fur traits to survive. After many generations, Level 6s and 7s will become the most common fur traits as they are the highest are the most likely to survive out of all of the traits in the population.

What would happen to an ostrilope population with a high distribution of high level fur traits living in a cold climate, but all the sudden, the climate turns humid/hot?

Ostrilopes consisting of the high-level fur trait will overheat and die out quickly as their high levels in fur are non-adaptive traits. The high-level fur trait will then become less common over generations and the distribution will dramatically decrease.

Where do the genes that determine an individual's traits come from?

Parents pass their genes down to their offspring.

What are ways plants can defend themselves?

Plants can defend themselves by being poisonous, have sharp thorns or spines, and have tough bark.

Situation: A population of poisonous snakes (red/yellow) live in an area with sand and dirt, but no grass, where they are hunted to eagles. As generations passed, the environment changed to having grasses and various plants growing there. What mutation would make the snake population better able to adapt to this environmental change so that they are able to hide from the eagles (predators)?

Snakes giving birth to an offspring with a mutation in its genes for the green color trait would help this snake population to adapt. The green color trait would allow the offspring to live long enough to pass down this trait, making it harder for eagles to spot the snakes.

Can mutations introduce non-adaptive traits, or can they only introduce adaptive traits?

Some mutations can introduce non-adaptive traits. This is because as mutations are random changes to genes, an offspring has a chance to either adopt a mix of its parent's genes, or have a mutation which would be adaptive, non-adaptive, or neutral.

Selection Pressure

Something in the environment that affects an individual's chances of surviving.

What is TTX poison (tetrodotoxin)? How is this an adaptive trait to newts?

Tetrodotoxin is a lethal, quick-acting poison which can kill in seconds or minutes. This is an adaptive trait to newts because as garter snakes are predators in their environment, the more tetrodotoxin a newt has, the less likely a snake is going to eat that newt as it can taste and smell how strong the poison is.

Over many generations, it is seen that the newt population in a park seemingly increased in poison traits. This means the newts became much more poisonous over time. What could be the cause to this?

The cause to this could've been that a baby with a mutation in its genes for a higher level poison trait could've been born. Over time, higher poison level traits became more common over time as they were adaptive traits, making high poison newts more common.

Based on this information, why did the distribution of traits change in these populations? (Ostrilopes): Starting Population (A): Low fur level traits, medium variation. Ending Population (A): Medium fur level traits, medium variation. Environment (A): Changed to cold temperature. Starting Population (B): Low fur level trait, low variation. Ending Population (B): None (extinct) Environment (B): Changed to cold temperature.

The distribution of traits changed in these populations because as generations passed in this environment, in Population A, the variation of traits decreased as the distribution of traits shifted so that there was only medium level fur traits, and as Population B completely died out. In Population A, higher levels of fur traits became adaptive traits, so ostrilopes with medium fur traits were more likely to survive the cold environment and live longer, but in Population B, there were only low level fur traits, so ostrilopes died out quickly as they froze, being non-adaptive traits.

Based on this information, why did the distribution of traits change in this population? (Ostrilopes): Starting Population - Many color traits, high variation. Ending Population - All Level 7 traits (yellow), no variation Environment - Changed to Yellow Level 7 color, includes predators.

The distribution of traits changed in this population because as generations passed in this environment, the distribution of traits shifted so that the high variation of color traits would change to only Yellow Level 7 traits as they are adaptive traits. Yellow Level 7 color traits help ostrilopes hide better from any predators, but blue, green, or higher levels of the yellow color trait allow ostrilopes to be seen by predators and die out faster, being non-adaptive traits.

Based on this information, why did the distribution of traits change in this population? (Thornpalms): Starting Population: Mostly low, some medium, and some high water storage traits, high variation. Ending Population: High (Level 9) water storage traits, no variation. Environment: Changed to low rainfall.

The distribution of traits changed in this population because as generations passed in this environment, the distribution of traits shifted so that the high variation of water-storage traits changed to only Level 9 water-storage traits, being adaptive traits. Level 9 water-storage traits can store the most water out of this thornpalm population, allowing thornpalms to live longer, but with low rainfall, thornpalms that have lower water-storage traits won't be able to store as much water, making them live shorter, being non-adaptive traits.

Remember:

The number of individuals with each trait in a population can change over time.

Distribution

The number of individuals with each trait in a population.

How can an individual be born with an adaptive trait?

The parents had genes for the adaptive trait, which they passed down to the individual.

Natural Selection

The process by which the distribution of traits in a population changes over many generations.

Sexual Reproduction

The process in which two parents pass on their genes to create offspring.

Answer the Scientific Argument Question "How did the trait for increased poison level become more common in the newt population?"

The trait for increased poison level became more common in the newt population because as snakes entered the newt population's environment, the distribution of traits shifted from most newts having low levels of poison to most newts having high levels of poison. The snakes were able to use their smell and taste senses to decide if a newt is too poisonous to eat, so this made them more likely to eat Poison Level 1 and low levels of poison newts as they had non-adaptive traits and were less likely to reproduce. Level 10 poison and high levels of poison newts were too poisonous for snakes to eat, so they were given more time to live for more reproduction to pass on their genes for higher poison level traits.

Look at these claims: - Claim: The newt population became more poisonous because the snakes in this environment caused poison to be an adaptive trait. - Revised Claim Addition: Poison Level 10 is the most common because the newts with this trait were able to live longer and reproduce more than other newts. Use Reasoning to connect the piece of evidence to the combined claim. Correctly complete the sentences. Evidence: From "The Deadly Dare": "Even more important, predators can smell and taste TTX poison. The main predator of rough-skinned newts is the garter snake. Scientists have found evidence that garter snakes use their senses of smell and taste to tell whether a rough-skinned newt is too poisonous to eat."

This matters because as garter snakes are able to decide whether a newt is too poisonous to eat with smell and taste, they can easily distinguish the low level poison newts from the higher level poison newts, allowing the snakes to eat low level poison newts as Level 10 Poison newts and high poison newts are too poisonous to eat, allowing high level poison newts to live longer to pass on their genes for higher poison levels.

Look at these claims: - Claim: The newt population became more poisonous because the snakes in this environment caused poison to be an adaptive trait. - Revised Claim Addition: Poison Level 10 is the most common because the newts with this trait were able to live longer and reproduce more than other newts. Use Reasoning to connect the piece of evidence to the combined claim. Correctly complete the sentences. Evidence: Sometime between 50 generations ago and today, snakes became part of this newt population's environment.

This matters because as snakes enter this newt population's environment, they will be predators to the newts and eat the newts, which caused the distribution of traits to change so that newts with adaptive traits of more poison become more common and were able to live longer and reproduce more, while newts with non-adaptive traits of less poison become less common and won't be able to live very long and won't get to reproduce.

Look at these claims: - Claim: The newt population became more poisonous because the snakes in this environment caused poison to be an adaptive trait. - Revised Claim Addition: Poison Level 10 is the most common because the newts with this trait were able to live longer and reproduce more than other newts. Use Reasoning to connect the piece of evidence to the combined claim. Correctly complete the sentences. Evidence: 50 generations ago, some newts had each of the poison-level traits. Today, no newts have the trait for Poison Level 1.

This matters because as snakes relied on newts for food, the snakes were more likely to eat the newts with lower poison levels, causing variation of the newt population to decrease as Poison Level 1 newts were all eaten up and went extinct. As higher poison level newts had adaptive traits and were able to reproduce more, Poison Level 1 newts were very likely to be eaten by the snakes since they had the lowest levels of poison, which prevented genes of low poison levels to be passed on.

Look at these claims: - Claim: The newt population became more poisonous because the snakes in this environment caused poison to be an adaptive trait. - Revised Claim Addition: Poison Level 10 is the most common because the newts with this trait were able to live longer and reproduce more than other newts. Use Reasoning to connect the piece of evidence to the combined claim. Correctly complete the sentences. Evidence: 50 generations ago, most newts had the trait for Poison Level 1. Today, most newts have the trait for Poison Level 10.

This matters because many generations ago without snakes as predators, Poison Level 10 traits weren't seen as adaptive traits as lower levels of poison were more common, but due to the snakes in today's environment, newts with higher levels of poison were able to defend themselves from snakes better than newts with lower poison levels, so Poison Level 10 poison newts had more time for more reproduction than other newts as they had the highest level of poison.

For good measures...

To answer a scientific question, use CER. CER: Claim - A statement that answers the question. Evidence - The scientific data and details that support your claim. Reasoning - Explains "how" or "why" the evidence supports the claim. (Also known as scientific rule.)

How do you place trait labels on a histogram?

To correctly place trait labels on histograms, place +o and +s (more likely to have offspring/more likely to survive) on the traits that will survive due to reproduction. Put -o and -s on the traits which will become extinct due to not being able to give off enough offspring. Then, place m to which traits were introduced by mutations.

How do you form a scientific argument?

To create a scientific argument... - Begin with a question - Make a claim that presents an answer to the question - Have evidence that supports the claim - Use reasoning/clearly explain how the evidence supports the claim.

Inherit

To receive genes from a parent.

Ex: Correctly label the "40 Generations Ago" traits. 40 Generations Ago (newts/poison level traits); environment changing from no snakes to snakes (predators): 50 poison level 1s, 30 level 2s, 23 level 3s, 20 level 4s, 15 level 5s, 11 level 6s, 10 level 7s, 7 level 8s, 7 level 9s, 4 level 10s (introduced by mutations.) Population Today; environment with snakes: No levels 1, 2, and 3; 10 level 4s, 15 level 5s, 20 level 6s, 25 level 7s, 32 level 8s, 36 level 9s, 46 level 10s.

Trait labels for "40 Generations Ago": Poison level 1: -o, -s Poison level 2: -o, -s Poison level 3: -o, -s Poison level 4: +o, +s Poison level 5: +o, +s Poison level 6: +o, +s Poison level 7: +o, +s Poison level 8: +o, +s Poison level 9: +o, +s Poison level 10: +o, +s, m

True or false: Mutations allow populations to survive environmental changes.

True; as the environment changes, mutations are needed in a population as they can introduce new adaptive traits for better chance of survival in an environmental change.

How can we describe this population?: 10 low fur ostrilopes, 30 medium fur ostrilopes, and 50 high fur ostrilopes.

We can describe this ostrilope population by saying that most ostrilopes are high in fur, but there is some variation with less medium fur and low fur ostrilopes.

How do mutations in genes occur?

When organisms reproduce, they pass copies down of their genes to their offspring. As genes are being duplicated changes can occur. The majority of these changes are very small, but occasionally, mutated genes lead to instructions that make a new protein molecule that leads to a new trait in the offspring.

How do you tell if a trait is adaptive or not?

You can tell if a trait is adaptive or not based on the environment. It doesn't matter if a trait is most common during a period of generation; it matters if the trait allows the organism to more likely survive longer than other organisms.