Mixed Deck — All Ecology Topics Flashcards
100 cards from real Ecology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 20 Mixed Deck — All Ecology Topics flashcards as text
What does a survivorship curve Type II indicate about a population?
Answer: Constant mortality rate at all ages
Type II survivorship curves are linear on a log scale, indicating a constant probability of dying at any age regardless of age class.
Which pattern of population dispersion is most commonly observed in nature and often results from random resource availability?
Answer: Clumped
Clumped dispersion is the most common pattern, arising because resources are often patchy and social behaviors attract individuals to the same areas.
Which of these is a morphological adaptation?
Answer: A desert plant storing water in its leaves
A morphological adaptation refers to a structural or physical feature of an organism that helps it survive in its environment. A desert plant storing water in its leaves is a clear example of such an adaptation, as the succulent leaves are a physical modification for water conservation. These adaptations are visible and relate to the organism's body form.
How does deforestation affect the local carbon cycle?
Answer: It reduces carbon storage as trees are removed and soil carbon is released
Deforestation removes living carbon stores and often involves burning, releasing stored carbon as CO₂ while eliminating future uptake capacity.
Which sampling method is most appropriate for estimating the density of a sessile (non-moving) plant population?
Answer: Quadrat sampling
Quadrat sampling counts individuals within randomly placed plots, making it ideal for immobile organisms like plants.
A life table shows that lx drops steeply in the first week of life then levels off. This pattern corresponds to which survivorship curve?
Answer: Type III — high early mortality, low mortality thereafter
Type III survivorship curves, typical of many invertebrates and fish, show most deaths occurring very early in life with survivors having much better prospects.
What ecological term describes the ratio of net primary productivity to gross primary productivity?
Answer: Production efficiency
Production efficiency (NPP/GPP) indicates what fraction of energy fixed by photosynthesis remains after autotrophic respiration.
Which process converts atmospheric nitrogen (N₂) into ammonia (NH₃) that plants can use?
Answer: Nitrogen fixation
Nitrogen fixation, carried out by bacteria like Rhizobium, converts inert N₂ gas into ammonia that plants can absorb.
What is an 'umbrella species' in conservation planning?
Answer: A species whose protection simultaneously protects many other species sharing its habitat
Umbrella species have large habitat requirements, so protecting them creates reserves large enough to shelter many co-occurring species.
What is 'landscape connectivity' and why is it critical for conservation?
Answer: The degree to which a landscape allows organisms to move among habitat patches
Landscape connectivity enables species to disperse, colonize new areas, and maintain gene flow, which is essential for long-term population viability.
Which of the following best describes a 'sink' in a biogeochemical cycle?
Answer: A reservoir that accumulates more of a substance than it releases
A sink is any reservoir that absorbs and stores more of a substance than it releases over a given time period.
Which group of organisms is essential for returning nutrients from dead organic matter back into the soil, making them available for producers?
Answer: Decomposers
Decomposers, such as bacteria and fungi, play a critical role in ecosystem energy flow and nutrient cycling. They break down dead organisms and waste products from all trophic levels, releasing inorganic nutrients back into the environment (e.g., soil or water), which producers can then use to grow.
Which of the following is the correct definition of an 'ecological trap'?
Answer: A habitat that appears attractive to organisms but reduces their survival or reproduction
An ecological trap is a habitat where organisms preferentially settle based on misleading cues, yet suffer reduced fitness—often caused by human landscape changes.
Which of the following correctly explains why island biogeography theory is relevant to habitat fragmentation?
Answer: Fragmented habitat patches function like islands, with species richness determined by patch size and isolation
MacArthur and Wilson's island biogeography theory predicts that larger, less isolated patches (like larger habitat fragments) support more species at equilibrium.
Which of the following scenarios is an example of a density-independent limiting factor affecting a population?
Answer: A severe, late-spring frost kills a large percentage of oak tree seedlings in a forest.
Density-independent factors affect a population regardless of its density. A frost is an abiotic, weather-related event that will impact the seedlings' survival whether there are many or few in the area. The other options (disease, competition, predation) are all density-dependent factors, as their effects become more pronounced as the population density increases.
Müllerian mimicry differs from Batesian mimicry in that Müllerian mimics are:
Answer: All unpalatable species sharing a warning pattern
In Müllerian mimicry, multiple genuinely unpalatable species converge on the same warning coloration, reinforcing predator avoidance.
The 'eavesdropping' phenomenon in animal communication refers to:
Answer: Females overhearing male-male contests to assess male quality
Eavesdropping allows females to assess male quality by observing male-male contests without directly interacting, reducing their own assessment costs and risks.
Which of the following is a key assumption of the basic logistic model of population growth?
Answer: All individuals in the population are equivalent, with the same birth and death rates regardless of age or size.
The basic logistic model simplifies reality by assuming that all individuals are identical and contribute equally to the population's growth rate. It does not account for age structure, genetic differences, or spatial distribution. It also assumes a constant carrying capacity and an immediate response to density, which are often not true in nature.
Which population growth model assumes that the per capita growth rate decreases as a linear function of population size?
Answer: Logistic (Verhulst) model
The logistic model assumes a linear negative relationship between population density and per capita growth rate, dropping from r at N=0 to 0 at N=K.
Which metric is used to estimate the number of species expected to go extinct relative to habitat loss, based on species-area relationships?
Answer: Extinction debt calculation using the species-area curve
The species-area relationship (S = cA^z) predicts that habitat loss will eventually cause species extinctions proportional to the area lost, allowing estimation of 'extinction debt.'