Biology and Chemistry of Wood Ants

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Questions and Answers

What is the primary defense mechanism employed by wood ants (Formica rufa) against predators?

Releasing a cloud of pheromones to confuse predators.

Camouflaging themselves with surrounding vegetation.

Using their mandibles to bite and inflict pain.

Shooting volleys of formic acid from their abdomens. (correct)

Which of these correctly describes the composition of formic acid?

It consists of only carbon and hydrogen atoms.

It consists of carbon, nitrogen and oxygen atoms.

It consists of carbon, hydrogen, and nitrogen atoms.

It consists of carbon, hydrogen, and oxygen atoms. (correct)

What determines the identity of an atom?

The number of neutrons.

The number of bonds it can form.

The number of protons. (correct)

The number of electrons.

How many bonds can an oxygen atom typically form?

2 (B) Signup and view all the answers

What determines a compound's properties?

The types of atoms and how they are bonded together. (A) Signup and view all the answers

What causes formic acid to act as an acid, in the context of the text?

The attraction of hydrogen's electron by oxygen, releasing H+. (B) Signup and view all the answers

What role does electron distribution play in the behavior of an atom?

It determines the atom's ability to form bonds. (A) Signup and view all the answers

Why are chemical bonds considered so important?

They hold atoms together to make molecules, including those important for life. (B) Signup and view all the answers

What is the primary mechanism that drives evolutionary change according to the text?

Unequal reproductive success of individuals leading to population adaptation (D) Signup and view all the answers

Which of the following best describes the process of natural selection?

A higher proportion of individuals in a population will have beneficial traits that favor survival and reproduction over time. (B) Signup and view all the answers

What is the relationship between populations and evolution?

Populations evolve such that individuals are better adapted to their environment after multiple generations. (C) Signup and view all the answers

What is the chemical formula for formic acid, as used by wood ants?

CH2O2 (A) Signup and view all the answers

What property of an atom’s structure determines its identity?

The number of protons (B) Signup and view all the answers

Which of the following lists the components of life in order from least to most complex?

atoms, molecules, cells, organs (C) Signup and view all the answers

Which of the following best describes the role of electron distribution in chemical bonding?

It dictates the number of bonds an atom can form. (A) Signup and view all the answers

What happens when formic acid is formed?

Oxygen attracts hydrogen's electron, releasing H+ and making it acidic. (A) Signup and view all the answers

In an ecosystem, how does energy typically flow, and how do chemicals move?

Energy flows in one direction; chemicals cycle. (C) Signup and view all the answers

What is the correct order of biological organization, from least to most complex?

atoms, molecules, cells, organs (C) Signup and view all the answers

According to Darwin's theory of natural selection, what is the most accurate way to describe evolution?

Populations evolve over generations with more individuals having advantageous traits (B) Signup and view all the answers

Which statement accurately reflects the hierarchical organization of biological systems?

Cells are made up of different types of molecules. (C) Signup and view all the answers

Which of the following is a correct representation of the relationship between cells, molecules, and atoms?

Molecules are created from atoms and these molecules create cells (C) Signup and view all the answers

What is the relationship between complexity and properties in biological systems?

As complexity increases, novel properties emerge at each level that are absent from the preceding level. (A) Signup and view all the answers

What defines the difference in the movement of energy and chemicals through ecosystems?

Energy flows one way, while chemicals are recycled within the system. (B) Signup and view all the answers

What information can be determined about an atom using its electron distribution?

The atom's ability to form chemical bonds. (C) Signup and view all the answers

Which statement accurately reflects the process of evolution by natural selection, according to Darwin?

The environment selects for advantageous inherited traits, improving species over generations. (D) Signup and view all the answers

What characteristic of protons dictates an atom's identity, differentiating, for instance, oxygen from carbon?

The number of protons (A) Signup and view all the answers

How does the complexity of biological structures change from atoms to organs?

They become progressively more complex. (A) Signup and view all the answers

What are compounds made of?

Atoms joined by bonds (D) Signup and view all the answers

How do chemicals cycle within an ecosystem?

They are used, then recycled within the ecosystem. (C) Signup and view all the answers

What is the relationship between an atom’s electron distribution and its bonding capability?

The electron distribution dictates the number of bonds an atom can form. (D) Signup and view all the answers

What is the role of the environment in Darwin’s theory of evolution by natural selection?

The environment selects the most advantageous traits for survival and reproduction. (B) Signup and view all the answers

New properties emerge at each level of biological organization. How can this be best described?

Each level exhibits properties that were not present in the preceding levels. (C) Signup and view all the answers

Why is the formation of formic acid considered a chemical reaction?

Because it involves the making and breaking of chemical bonds. (D) Signup and view all the answers

Which of these is the correct flow of energy through an ecosystem?

Light to heat and is lost to the environment. (A) Signup and view all the answers

If individuals do not evolve, what is the thing that evolves according to Darwin?

The population as a whole (A) Signup and view all the answers

What relationship exists between molecules and cells?

Cells are made up of many different molecules. (B) Signup and view all the answers

How should the continuous use and recycling of chemicals in an ecosystem be best described?

As a cyclical process within the ecosystem. (B) Signup and view all the answers

What is required in the theory of evolution by natural selection for adaptation to occur?

Unequal reproductive success of the individuals. (B) Signup and view all the answers

What is the primary difference between isotopes of the same element?

Different numbers of neutrons. (A) Signup and view all the answers

If an element has an atomic number of 15, how many protons does an electrically neutral atom of that element have?

15 (B) Signup and view all the answers

Given the notation $ ^{23}_{11}Na $, how many neutrons are present in this sodium atom?

12 (A) Signup and view all the answers

Which subatomic particle primarily determines the chemical behavior of an atom?

Electrons (A) Signup and view all the answers

What is the unit used to measure the mass of atoms and subatomic particles?

Dalton (A) Signup and view all the answers

If the mass number of an atom is 31, and its atomic number is 15, how many neutrons does the atom have?

16 (B) Signup and view all the answers

What is the charge of a neutron?

Neutral (B) Signup and view all the answers

Where are protons and neutrons located within an atom?

In the nucleus. (C) Signup and view all the answers

Which of the following best describes the relative mass of an electron compared to a proton or neutron?

Much smaller (A) Signup and view all the answers

Given the isotope notation $^{14}_6C$, how many protons are in the nucleus of this carbon atom?

6 (D) Signup and view all the answers

Which particles are responsible for an atom's mass, assuming the mass of electrons is negligible?

Protons and Neutrons (A) Signup and view all the answers

What does the atomic number of an element represent?

The number of protons in the atom. (B) Signup and view all the answers

If an element has an atomic mass of approximately 32 daltons, and it has 16 protons, given the neutrons have a mass of approximately 1 dalton, how many neutrons does it have?

16 (D) Signup and view all the answers

What is the relationship between a cell and an organ?

An organ is an organized structure of many cells. (C) Signup and view all the answers

Which of the following is NOT a subatomic particle?

Atom (A) Signup and view all the answers

Which statement accurately describes energy and chemical flow within ecosystems?

Energy flows through an ecosystem, while chemicals cycle within it. (A) Signup and view all the answers

What is the electrical charge of a typical atom in its natural state?

Neutral (B) Signup and view all the answers

According to Darwin's theory of evolution by natural selection, what is the primary driver of evolutionary change?

Unequal reproductive success of individuals with favorable traits. (D) Signup and view all the answers

What is the smallest unit of matter that retains the properties of an element?

An atom (B) Signup and view all the answers

What is a key feature associated with increasing complexity in living organisms?

Emergence of novel properties not present at preceding levels. (B) Signup and view all the answers

Which statement best describes how natural selection affects a population?

It increases the proportion of well-suited individuals over generations. (C) Signup and view all the answers

Why is understanding the flow of energy important in ecological studies?

It helps determine where energy enters, exits, and transforms within an ecosystem. (A) Signup and view all the answers

What is considered a fundamental difference between how energy and chemicals are utilized in an ecosystem?

Chemicals are recycled while energy is transferred. (A) Signup and view all the answers

According to Darwin, what happens if an environment changes?

Evolution can occur in response to the environmental changes. (A) Signup and view all the answers

Which concept is a foundational aspect of Darwin’s theory of natural selection?

Populations will adapt as each generation will become well suited to the environment. (C) Signup and view all the answers

What do we mean by 'emergent properties' in the context of biological organization?

Novel characteristics arising at each level of organization. (B) Signup and view all the answers

How can we describe the flow of energy in an ecosystem?

A one-way flow, usually from light to heat. (D) Signup and view all the answers

Which statement best describes the relationship between an element and an atom?

Each element consists of certain type of atoms. (C) Signup and view all the answers

What concept did Darwin use to explain why individuals within a population are variable?

Inherited traits (C) Signup and view all the answers

What is a key assumption in Darwin's theory of evolution by natural selection?

Individuals vary in their inherited traits; and these traits impact their reproductive success. (B) Signup and view all the answers

What is the primary reason that radioactive isotopes like can be used for dating fossils?

They decay at a well-established and constant rate. (C) Signup and view all the answers

If a fossil contains 1/8 of the original amount of , how many half-lives have passed?

3 (A) Signup and view all the answers

What fraction of remains after two half-lives?

1/4 (D) Signup and view all the answers

According to the provided information, what is the half-life of $C^{14}$?

5,730 years (A) Signup and view all the answers

If a sample contains 0.0625 (or $6.25 \times 10^{-2}$) of its original quantity of how many half-lives have occurred?

4 (D) Signup and view all the answers

Why can’t be used to date fossils that are millions of years old?

After too many half-lives the amount of is undetectable. (D) Signup and view all the answers

An electron moves from the second energy level to the first. What happens to the atom's energy?

The atom's potential energy decreases. (B) Signup and view all the answers

What is the relationship between an electron's distance from the nucleus and its potential energy?

The further the electron is from the nucleus, the higher its potential energy. (B) Signup and view all the answers

If an electron moves further away from the atomic nucleus, what must occur?

The electron absorbs energy. (B) Signup and view all the answers

What are the fixed potential energy levels at which electrons can exist called?

Electron shells (B) Signup and view all the answers

Why cannot the nuclei of atoms interact during a normal chemical reaction?

Nuclei are too far away from the outer shell. (C) Signup and view all the answers

According to the text which of these subatomic particles directly participate in the chemical reactions?

Electrons (C) Signup and view all the answers

Which of these can be used to describe energy?

The capacity to cause change or do work (C) Signup and view all the answers

What does potential energy of matter depend on?

Its location or structure (C) Signup and view all the answers

Which of the these statements is supported by the text?

Matter tends to move toward the lowest possible state of potential energy. (D) Signup and view all the answers

What distinguishes stable isotopes from radioactive isotopes?

Radioactive isotopes decay spontaneously, while stable isotopes do not. (A) Signup and view all the answers

What is the outcome when a radioactive isotope's nucleus decays, causing the number of protons to change?

The atom is transformed into an atom of a different element with a different atomic number. (C) Signup and view all the answers

How are radioactive isotopes used as tracers in biological research?

They are incorporated into biologically active molecules to follow the movement of atoms during metabolism. (D) Signup and view all the answers

What is the function of PET scans in the context of diagnosing diseases?

PET scans detect location of high metabolic activity using radioactively-labelled compounds. (C) Signup and view all the answers

What determines the severity of the damage caused by radiation from decaying isotopes?

The type and amount of radiation an organism absorbs. (C) Signup and view all the answers

What is a half-life in the context of radioactive decay?

The time it takes for half the amount of a parent isotope to decay to its daughter isotope. (B) Signup and view all the answers

Which of the following best describes radiometric dating?

Measuring the ratio of parent to daughter isotopes to calculate a fossil's age. (C) Signup and view all the answers

How does the half-life of a radioactive isotope relate to its use in measuring time?

Each isotope is used to measure a particular range of time, relating to its half-life. (B) Signup and view all the answers

What is true about the half-life of a radioactive isotope?

It is not affected by environmental variables such as temperature and pressure. (A) Signup and view all the answers

What is the basis of the carbon-14 dating method?

Comparing the ratio of $C^{14}$ to $C^{12}$ in a sample to the ratio present in the atmosphere. (A) Signup and view all the answers

Why does the amount of $C^{14}$ decrease in a fossil after an organism dies?

The $C^{14}$ stops being replaced by new $C^{14}$ and continues to decay to $N^{14}$. (D) Signup and view all the answers

In the context of fossil dating, what does the ‘parent’ isotope refer to?

A radioactive isotope that decays at a constant rate. (C) Signup and view all the answers

What is the role of $C^{12}$ in carbon dating methods?

$C^{12}$ is stable and does not decay, providing a ratio to compare $C^{14}$ with. (A) Signup and view all the answers

What is the term for the isotope that a parent isotope decays into during radiometric dating?

Daughter isotope (D) Signup and view all the answers

How does the constant ratio of carbon isotopes in the atmosphere aid carbon dating?

It establishes the original ratio of $C^{14}$ to $C^{12}$ in the organism before it died. (B) Signup and view all the answers

An electron's potential energy is primarily determined by which property?

Its average distance from the nucleus. (C) Signup and view all the answers

When an electron absorbs energy, what is the typical result?

It moves to a shell farther from the nucleus. (A) Signup and view all the answers

What typically happens when an electron loses energy?

It falls back to a shell closer to the nucleus, losing energy as radiation. (A) Signup and view all the answers

The chemical behavior of an atom is primarily determined by:

The distribution of electrons in the atom's electron shells. (A) Signup and view all the answers

Which of the following best describes the trend in electron shell filling?

Electrons fill the lowest available shell first. (B) Signup and view all the answers

According to the content, how many electrons are located in the first shell of a Helium atom?

Two (D) Signup and view all the answers

What does the number of electron shells in an atom's electron distribution correspond to?

The position of the element in the periodic table rows (periods). (C) Signup and view all the answers

Based on the described process of adding electrons (and associated protons) for each element, what is the sequence of elements in each row of the table?

Corresponding to the sequential addition of electrons and protons. (A) Signup and view all the answers

How many valence electrons are present in a Silicon (Si) atom, based on its electron distribution?

4 (B) Signup and view all the answers

According to the figures in the text, how many electron shells does Sodium (Na) have?

3 (A) Signup and view all the answers

An atom has 2 electrons in its first shell and 5 in its second shell. What element is this likely to be?

Nitrogen (D) Signup and view all the answers

In the process of photosynthesis, what role does light energy play in relation to electron behavior?

It excites electrons to a higher energy level. (A) Signup and view all the answers

Which of the following represents the lowest available state of potential energy for an electron in an atom?

The first shell. (D) Signup and view all the answers

How many electrons are present in the second shell of a neutral Oxygen atom?

6 (C) Signup and view all the answers

Which of the following best describes the shape of an atom and the accuracy of the concentric circle representation of electrons?

Atoms have an irregular shape, and the simplified circular models aren't accurately representative. (A) Signup and view all the answers

Which of the following elements has a completed valence shell?

Neon (D) Signup and view all the answers

What determines the reactivity of an atom?

The number of valence electrons (C) Signup and view all the answers

How many maximum electrons can occupy the first electron shell?

2 (A) Signup and view all the answers

Which statements about the second electron shell is correct?

It can hold up to 8 electrons. (A) Signup and view all the answers

What property describes elements like helium, neon, and argon?

Inert (C) Signup and view all the answers

Which is the shape of the first electron shell orbital?

Spherical (C) Signup and view all the answers

How many valence electrons does lithium possess?

1 (C) Signup and view all the answers

What type of interactions allow atoms to complete their valence shells?

Chemical bonds (A) Signup and view all the answers

Which of the following orbitals does not belong to the second electron shell?

3p (B) Signup and view all the answers

What is the maximum number of electrons that can occupy a single orbital?

2 (B) Signup and view all the answers

Which of these atoms is likely to be chemically reactive?

Sodium (D) Signup and view all the answers

Which of the following pairs has similar chemical behavior?

Lithium and Sodium (B) Signup and view all the answers

Which orbital shape is found in the second electron shell?

Both spherical and dumbbell-shaped (A) Signup and view all the answers

Atoms with the same number of __________ in their valence shells exhibit similar chemical behavior.

electrons (C) Signup and view all the answers

What is formed when oppositely charged ions bond together?

Ionic compound (B) Signup and view all the answers

Which statement best describes the structure of an ionic compound?

Formed by a lattice of alternating cations and anions (A) Signup and view all the answers

How do ionic bonds behave differently in dry salt and in water?

They become weaker in water (A) Signup and view all the answers

What is the primary reason ammonium chloride is different from simpler ionic salts?

It contains an entire covalently bonded ion (A) Signup and view all the answers

What is a characteristic feature of the formula for ionic compounds?

Represents only the ratio of different ions (D) Signup and view all the answers

What happens to ionic bonds in salts when they are dissolved in water?

They weaken due to ion shielding by water molecules (A) Signup and view all the answers

Why are many drugs manufactured as ionic compounds?

They are stable when dry but dissociate easily in water (C) Signup and view all the answers

What effect does the environment have on ionic bonds in salts?

Interactions with water can weaken ionic bonds (B) Signup and view all the answers

Which statement accurately describes chloride ions in the context of ionic bonding?

Chloride ions are formed by gaining an electron (D) Signup and view all the answers

What is the implication of a crystal structure in ionic compounds?

They exhibit a repeating, organized pattern of ions (A) Signup and view all the answers

What type of bond is formed when two hydrogen atoms share one pair of electrons?

Single covalent bond (C) Signup and view all the answers

What is the bonding capacity of oxygen based on its need to complete its valence shell?

2 (C) Signup and view all the answers

Which model represents the actual shape of a molecule most accurately?

Space-filling model (A) Signup and view all the answers

What type of bond is formed when two oxygen atoms share two pairs of electrons?

Double bond (D) Signup and view all the answers

What indicates the structural formula of a hydrogen molecule (H2)?

H-H (A) Signup and view all the answers

In a water molecule (H2O), how many single covalent bonds are formed?

2 (D) Signup and view all the answers

Which of the following describes the interaction in ionic bonds when in aqueous solutions?

Weak interactions (D) Signup and view all the answers

What is a defining characteristic of covalent bonds?

Electrons are shared (C) Signup and view all the answers

Which formula would correctly represent a methane molecule (CH4)?

H-C-H-H-H (A) Signup and view all the answers

What visual representation shows the number of unbounded electrons in an atom in covalent bonding?

Lewis dot structure (D) Signup and view all the answers

What term describes the specific arrangement of atoms in a covalent bond graphic representing hydrogen (H2)?

Structural formula (B) Signup and view all the answers

How many pairs of valence electrons do two hydrogen atoms share in a hydrogen molecule?

One pair (C) Signup and view all the answers

In which type of bond do atoms completely transfer electrons between each other?

Ionic bond (A) Signup and view all the answers

What is the relationship between the number of valence electrons and the number of covalent bonds an atom can typically form?

They are directly proportional (A) Signup and view all the answers

What describes the valence of hydrogen atoms?

1 (B) Signup and view all the answers

What type of bond forms when one atom completely strips an electron from another?

Ionic bond (C) Signup and view all the answers

What would be the result of combining two elements with similar electronegativities?

Nonpolar covalent bond (A) Signup and view all the answers

What is the primary characteristic of a polar covalent bond?

Electrons are shared unequally (A) Signup and view all the answers

Which atom has the highest electronegativity in a water molecule?

Oxygen (D) Signup and view all the answers

What best describes the outcome when sodium and chlorine react?

Sodium becomes a cation (A) Signup and view all the answers

Two atoms connected by a double bond are often said to share:

Two pairs of electrons (B) Signup and view all the answers

In a water molecule, what does the partial negative charge indicate?

The atom is more electronegative (B) Signup and view all the answers

Which of these molecules is considered a pure element?

Oxygen (C) Signup and view all the answers

The transfer of an electron results in the formation of what type of ion?

Cation (A) Signup and view all the answers

What type of molecule is methane?

Hydrocarbon compound (C) Signup and view all the answers

What is the primary factor that determines the polarity of a bond?

Electronegativity of atoms (C) Signup and view all the answers

What effect does the unequal sharing of electrons have in a water molecule?

Results in partial charges (B) Signup and view all the answers

Study Notes

Wood Ant Defense Mechanism

Wood ants (Formica rufa) use formic acid to defend against predators like birds.
They spray formic acid from their abdomens when threatened from above.

Formic Acid Composition and Properties

Formic acid (CH₂O₂) is a compound made of carbon, hydrogen, and oxygen atoms bonded together.
An atom's identity is determined by the number of protons. Oxygen has 8 protons.
An atom's ability to form bonds depends on its electron distribution. Oxygen can form 2 bonds.
Formic acid's properties depend on how its atoms are bonded.
One oxygen in formic acid attracts hydrogen's electron, creating H+ and making it an acid, which stings.

Key Concepts

Matter is made of elements and compounds.
Element properties depend on atomic structure.
Molecular and ionic compound formation depends on chemical bonding.
Chemical reactions involve bond formation and breakage.

Study Tip (Table Structure)

A table with properties and the elements C, H, O, and N is needed alongside atomic number, electrons, neutrons, mass number, electron distribution diagrams, and valence electrons.

Biological Organization Levels

Biological organization levels, from least to most complex: atoms, molecules, cells, organs.

Energy and Chemical Flow in Ecosystems

Energy flows through ecosystems in one direction (light to heat).
Chemicals cycle within ecosystems.

Darwin's Theory of Natural Selection

Individuals with advantageous traits better suited to the environment are more likely to survive and reproduce.
Populations evolve over generations, not individuals.
Evolution is driven by unequal reproductive success in adaptation to environment.

Atomic Structure

Atoms are the smallest units of matter retaining element properties.
Atoms are composed of subatomic particles: neutrons, protons, and electrons.
Protons and neutrons are tightly packed in the nucleus. Electrons form a cloud around the nucleus.
Protons have positive charge, electrons have negative charge, and neutrons are neutral.

Atomic Number and Mass Number

Atomic number is the number of protons in an atom's nucleus.
Mass number is the total number of protons and neutrons in the nucleus.
Atomic mass is a weighted average of isotopes.
Almost all of an atom’s mass comes from the nucleus.

Isotopes

Isotopes are different forms of an element with varying numbers of neutrons.
Isotopes have the same chemical behavior because they have the same number of protons.
Some isotopes are stable, while others are radioactive (unstable).
Radioactive isotopes are used in medicine for diagnosis and research.
Radiometric dating uses radioactive decay to determine fossil ages. A parent isotope decays into a daughter isotope at a fixed rate (half-life).

Atomic Energy Levels and Electron Shells

Electrons exist in fixed energy levels (shells) around the nucleus determined by their distance from the nucleus.
Electron shell locations and potentials vary.
Electrons gain or lose energy to move between different energy levels with fixed amounts of energy.

Electron Distribution and Chemical Properties

Electron distribution in an atom’s shells and orbitals determines its chemical behavior.

Electron Orbitals

Orbitals represent 3D space where an electron spends most of its time.
An orbital can hold a maximum of 2 electrons.
Valence electrons in an atom's outermost shell determine its chemical behavior.

Covalent Bonds

Covalent bonds are formed by sharing electron pairs between atoms. This completes outer electron shells of the atoms.
Molecules are formed from two or more atoms joined by covalent bonds.
Different elements form single bonds, double bonds or other types of bonds using shared or nonpolar electron pairs.
Electronegativity relates to an atom's attraction for electrons in a covalent bond.
Nonpolar covalent bonds share electrons equally, while polar covalent bonds share them unequally, creating partial charges on the bonded atoms.

Ionic Bonds

Ions are atoms with a net positive or negative charge. They form ionic compounds (salts) through electron transfer.
Ionic compounds consist of tightly packed (lattice) ions of opposite charges. Bonds are stronger when dry.
Water weakens ionic bonds.

Weak Chemical Interactions

Weak interactions (like hydrogen bonds and van der Waals forces) are important for biological molecules.
Hydrogen bonds are weak interactions involving a hydrogen atom attracted to another atom (such as oxygen, nitrogen). Strong bonds occur when the atoms involve the transfer of electrons.

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Description

Test your knowledge on the biology and chemistry related to wood ants, including their primary defense mechanism and the properties of formic acid. This quiz covers fundamental concepts in chemistry and evolutionary biology, such as natural selection and atomic structure. Challenge yourself with questions that integrate different scientific principles.