Evolution, Themes of Biology, and Chemical Context of Life

Comprehensive practice flashcards for Chapter 1 (Themes of Biology, Scientific Inquiry, Evolution) and Chapter 2 (Chemical Context of Life).

How does E.O. Wilson define biology through the concept of biophilia?

E.O. Wilson describes biophilia by stating, "Biology is a human endeavor that results from our attraction to life in all its forms."

What are the seven characteristics of life shown in Chapter 1?

The seven characteristics of life are Order, Energy processing, Growth and development, Regulation, Reproduction, Response to the environment, and Evolutionary adaptation.

What are the structural differences between prokaryotic and eukaryotic cells regarding the nucleus and organelles?

A prokaryotic cell lacks a nucleus (DNA is distributed throughout) and has no membrane-enclosed organelles. A eukaryotic cell contains a membrane-enclosed nucleus holding DNA and has membrane-enclosed organelles.

What are the ten levels of biological organization ordered from highest to lowest?

1. The Biosphere, 2. Ecosystems, 3. Communities, 4. Populations, 5. Organisms, 6. Organs and Organ Systems, 7. Tissues, 8. Cells, 9. Organelles, 10. Molecules.

What anatomical modification is present in bat wings, and what metabolic record do hummingbirds hold?

Bat wings are modified tetrapod forelimbs with arms, hands, and fingers specialized for flight. Hummingbirds have the highest metabolism of any homeothermic animal.

What is the unifying theory of biology, and how did Charles Darwin define natural selection?

The unifying theory of biology is Evolution (descent with modification). Darwin defined Natural Selection as the principle by which each slight variation, if useful, is preserved.

What eukaryotic structure is cited as an example of unity underlying the diversity of life?

The architecture of cilia in eukaryotes.

What are the three domains of life, and which groups belong to Domain Eukarya?

The three domains are Domain Bacteria, Domain Archaea, and Domain Eukarya. Domain Eukarya includes Kingdom Animalia, Kingdom Plantae, Kingdom Fungi, and Protists.

What is a chemical compound, and how do its emergent properties relate to its constituent elements?

A compound is a substance consisting of two or more elements in a fixed ratio (such as $NaCl$ or $CO_2$). A compound has emergent properties that are distinct from those of its individual elements.

How are atomic mass and atomic number defined, and what are the relative natural abundances of carbon isotopes?

Atomic mass is the sum of protons and neutrons (\text{Atomic Mass} = \text{\textnormal{\textnum{P}}} + \text{\textnormal{\textnum{N}}}), while atomic number is the number of protons (\text{Atomic Number} = \text{\textnormal{\textnum{P}}}). Carbon-12 ($^{12}C$) accounts for $99\text{\%}$ of carbon, whereas Carbon-13 ($^{13}C$) and unstable, radioactive Carbon-14 ($^{14}C$) combined make up $1\text{\%}$.

What determines an atom's chemical reactivity, and what does the Octet Rule state?

Valence electrons in the outermost shell determine chemical reactivity. The Octet Rule states that atoms are most stable when their outermost electron shell contains 8 electrons (or 2 for Hydrogen and Helium).

How do cations and anions differ, and how do they interact in an ionic bond?

A cation is a positively charged ion formed when an atom loses an electron, while an anion is a negatively charged ion formed when an atom gains an electron. An ionic bond is an attraction between an anion and a cation.

What is the key difference between non-polar and polar covalent bonds?

In non-polar covalent bonds, electrons are shared equally (e.g., $H_2$, $O_2$, $CH_4$). In polar covalent bonds, electrons are shared unequally due to differences in electronegativity, creating partial positive ($ ext{ extdelta}^+$) and partial negative ($ ext{ extdelta}^-$) charges (e.g., $H_2O$).

Why does a water molecule ($H_2O$) form polar covalent bonds?

Oxygen (8 protons) is more electronegative than Hydrogen (1 proton), pulling shared electrons closer to oxygen. This creates a partial negative charge ($ ext{ extdelta}^-$) on oxygen and partial positive charges ($ ext{ extdelta}^+$) on the hydrogens.

What is a hydrogen bond, and how does its individual strength compare to its collective strength?

A hydrogen bond occurs between two molecules when a Hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom. Hydrogen bonds are individually weak, but collectively strong.

What are the reactants and products in the chemical reaction that forms water?

The reactants are $2H_2$ and $O_2$, and the product is $2H_2O$, represented by the reaction equation $2H_2 + O_2 \rightarrow 2H_2O$.