Grade 10 Science: Chemical Reactions, Homeostasis, and Lines of Evidence for Evolution

Comprehensive question-and-answer flashcards covering chemical reaction energy changes, homeostasis and feedback systems, key mechanisms of evolution, and the main lines of evidence for evolution.

What characterizes an exothermic reaction and what are some examples of it?

An exothermic reaction releases heat to the surroundings, causing the surroundings to become warmer. Examples include the burning of wood, combustion of fuel, cellular respiration, and the rusting of iron.

What characterizes an endothermic reaction and what are some examples of it?

An endothermic reaction absorbs heat from the surroundings, causing the surroundings to become cooler. Examples include photosynthesis, melting ice, evaporation, and dissolving ammonium nitrate in water.

What is homeostasis and what are three key physiological indicators maintained by it?

Homeostasis is the maintenance of a stable internal environment necessary for survival and proper functioning. Three key indicators are body temperature (around $37\,^\circ\text{C}$), blood glucose level, and blood pressure.

How does a negative feedback mechanism maintain stability in the body?

Negative feedback detects a change and reverses it to maintain balance and prevent extreme changes, such as sweating when the body is too hot, shivering when the body is too cold, or releasing insulin when blood glucose levels are high.

What is the function of a positive feedback mechanism and what are two human body examples?

Positive feedback amplifies a change until a process is complete. Examples include childbirth (uterine contractions) and blood clotting.

How does natural selection drive evolutionary change?

Natural selection occurs when the environment acts on variation within a population, favoring individuals with advantageous traits so they are more likely to survive, reproduce, and pass those favorable traits to offspring.

What is the difference between variation and heredity in the context of evolution?

Variation refers to differences in traits among individuals in a population (such as tall versus short plants), whereas heredity is the passing of those traits from parents to offspring through genes.

How can geographic or behavioral isolation lead to the emergence of a new species?

Isolation separates populations by geographic, behavioral, or other barriers, preventing interbreeding and gene exchange, which leads to reproductive isolation and differences over time that result in a new species.

What do fossils in older versus younger rock layers indicate about evolutionary history?

Fossils in older rock layers represent organisms that lived earlier, while fossils in younger rock layers show organisms that lived more recently, providing a record of changes through geological time.

Why is Tiktaalik considered an important transitional fossil example?

Tiktaalik possessed features of both fish and early four-limbed vertebrates, providing scientific evidence for the transition from life in water to life on land.

How do the Galápagos finches demonstrate biogeographical evidence for evolution?

The Galápagos finches are closely related species that evolved from a common ancestor but developed different beak shapes (adapted for seed, insect, cactus, woodpecker, and warbler diets) after becoming geographically isolated.

What are homologous structures and what evolutionary relationship do they suggest?

Homologous structures are body structures with similar basic anatomy but different functions (such as the forelimbs of humans, bats, whales, and cats), which suggest common ancestry.

How do analogous structures differ from homologous structures?

Analogous structures have similar functions but different underlying structures and evolutionary origins, such as the wings of birds and insects allowing flight through different ancestral structures.

What is a vestigial structure and what example is found in human anatomy?

A vestigial structure is a body structure that has been reduced in size and has little or no current function compared to its role in ancestors, such as the human appendix.