Africa Part 1 ACP Review Guide - Ecology and Energetics

Vocabulary flashcards covering ecological hierarchy, food webs and chains, predator energetics, niche dynamics, experimental design, and primary productivity from the Africa Part 1 review guide.

Species

A group of organisms capable of interbreeding and producing fertile offspring.

Population

A group of individuals of the same species living in the same geographic area at the same time.

Community

All the different populations of different species that live and interact together in a defined area.

Autotroph

An organism that produces its own organic nutrients using inorganic energy sources (e.g., grasses and small shrubs performing photosynthesis).

Heterotroph

An organism that cannot synthesize its own food and must consume other organisms for energy; primary consumers in food webs are always heterotrophs.

Scavenger

An organism, such as a vulture, that consumes dead animal carcasses and plays a functional role similar to decomposers.

Food Chain

A linear sequence illustrating the single pathway along which nutrients and energy are transferred from one organism to another.

Food Web

A complex, interconnected network of multiple food chains representing the diverse feeding pathways within an ecological community.

Food Chain Arrow

A directional indicator pointing from the organism being consumed to the consumer, demonstrating the direction of energy flow.

Ultimate Source of Energy

Sunlight, which provides the initial solar energy captured by autotrophs via photosynthesis to fuel food chains.

Lettuce-to-Cat Food Chain

A five-step food chain consisting of lettuce as the producer, greenfly as the primary consumer, ladybird as the secondary consumer (third trophic level), thrush as the tertiary consumer, and cat as the quaternary consumer.

10% Rule of Energy Transfer

The ecological principle that approximately $10\%$ of energy is passed from one trophic level to the next, while about $90\%$ is lost.

Reasons for Trophic Energy Loss

Energy is lost between trophic levels primarily as heat generated by cellular respiration and metabolism, through unconsumed body parts (e.g., bones and fur), and via excretion and undigested waste.

Pride

A social group of lions that provides benefits such as cooperative hunting of large prey, collective territory defense, and mutual cub rearing.

Optimal Foraging Strategy

The predatory behavioral model of choosing prey that maximizes net energy intake by balancing energy acquired against the caloric cost of hunting and killing.

Ecological Niche

The specific functional role, resource utilization, and environmental space occupied by a species within an ecosystem.

Competitive Exclusion Principle

The rule stating that two species competing for the exact same limiting resources cannot coexist indefinitely in the same ecological niche.

Niche Partitioning

The mechanism by which competing species divide resources (by food type, spatial distribution, or time of activity) to minimize direct competition and coexist.

Warthog Daily Energy Requirement

The caloric need of an adult warthog weighing $120\,\text{kg}$ requiring $100\,\text{kcal/kg}$ of biomass per day, calculated as $12{,}000\,\text{kcal/day}$.

Independent Variable

The variable intentionally manipulated by the researcher in an experiment, such as the hours of sunlight per day ($0$, $2$, $4$, $6$, and $8\,\text{hours}$).

Dependent Variable

The responding variable that is observed and measured for changes during an experiment, such as the growth or rate of growth of bean plants.

Controlled Variables

All conditions kept strictly constant across experimental groups, such as soil type, pot size, amount of water provided daily, and plant species.

Gross Primary Productivity (GPP)

The total amount of chemical energy or biomass created by autotrophs per unit area per unit time through photosynthesis ($4000\,\text{kcal/m}^2/\text{year}$ for the rice crop).

Net Primary Productivity (NPP)

The energy remaining in autotroph biomass after accounting for cellular respiration ($\text{NPP} = \text{GPP} - \text{Respiration}$), which represents the energy available to consumers.

Trophic Inefficiency in Food Production

The concept that eating directly at lower trophic levels (e.g., humans consuming rice sustaining $150\,\text{humans}$) supports far more individuals than eating higher trophic levels (e.g., humans eating chickens sustaining $20\,\text{humans}$) due to cumulative energy loss at each transfer.