As Shown in Figure 25

question 32

Essay

As shown in Figure 25.14 below, animals only appear in the fossil record about 580 million years ago, which coincides with atmospheric oxygen levels reaching a threshold needed by animals to breathe. How did the evolution of photosynthetic and heterotrophic organisms change over the last 2 billion years to support the diversity of life seen on Earth today?

---

Definitions:

Stress Reaction

The body's response to a threat or challenge, involving psychological and physiological changes to enhance coping ability.

Resilience

Denotes the ability to recover quickly from difficulties or adapt well in the face of adversity, trauma, or significant stress.

Lobotomy

A surgical procedure that involves cutting or scraping away most of the connections to and from the prefrontal cortex, once used to treat mental disorders.

Permanently Lethargic

Describes a state of continuous tiredness, a lack of energy, and general disinterest in activities, which may stem from various medical or psychological conditions.