Missed Questions Review Notes

Keystone Species Prioritization: In conservation biology, keystone species are prioritized because their loss can lead to the collapse of the entire food web. These species play a crucial role in maintaining the structure and stability of their ecological communities.

Type III Survivorship Curve: Species exhibiting high juvenile mortality typically follow a Type III survivorship curve. This curve indicates a high death rate early in life, with a greater proportion of individuals surviving to older ages once they reach a certain maturity threshold.

Description: Biological magnification refers to the phenomenon where toxins become increasingly concentrated in the bodies of organisms at higher trophic levels in a food web. Top predators are most affected because they consume prey that have already accumulated toxins, leading to high concentrations in their own tissues.

Factors Limiting Elephant Carrying Capacity: The carrying capacity of elephants in a savanna ecosystem is most directly limited by the availability of essential resources such as water and space. These resources are crucial for their survival and reproduction.

Importance of Nitrogen Fixation: Nitrogen fixation is critical in ecosystems because it converts atmospheric nitrogen ( $N<em>2$ ), which is unusable by most organisms, into usable forms like ammonia ( $NH</em>3$ ) or ammonium ( $NH_4^+$ ). This conversion is essential for plant growth and overall ecosystem productivity.

Deserts at 30 Degrees Latitude: Deserts are commonly found at 30 degrees latitude due to the pattern of atmospheric circulation. At these latitudes, descending dry air absorbs moisture from the land surface, resulting in arid conditions.

Redefinition: Biological magnification is the concentration of toxins in top predators due to the consumption of prey with accumulated toxins.

Limits to Food Chain Length: The length of food chains in ecosystems is ultimately limited by the inefficiency of energy transfer between trophic levels. Energy is lost as heat during metabolic processes at each level, resulting in less energy available for higher levels.

Biggest Threat: According to the H.I.P.P.O. acronym (Habitat Loss, Invasive Species, Pollution, Population Growth, Overexploitation), the biggest threat to biodiversity is habitat loss. The destruction and fragmentation of habitats reduce the amount of available space and resources for species, leading to population declines and extinctions.

Survivorship curves depict the mortality rates of a population across different ages. The three primary types are:

Type I Curve: Characterized by high survival rates during early and middle life, with a significant drop in survival in older age (e.g., humans, large mammals).
Type II Curve: Features a constant mortality rate throughout life, indicating equal chances of dying at any age (e.g., some birds, lizards).
Type III Curve: Exhibits high mortality rates in the early stages of life, with fewer individuals surviving to adulthood (e.g., many fish, amphibians).