Unit 9: Population Dynamics

Organisms like humans, birds, and most trees are said to be ----------. This means that they are able to reproduce many times throughout their adult life.

Iteroparous

--------------- are long-living organisms that reproduce relatively late in their lifetime, produce few, large offspring, and care for their young for a long time. Organisms include polar bears, humans, dogs, and whales.

K - selected

------------ species are organisms that reach early reproductive maturity, live for a short time, have many small offspring, and are often semelparous. Examples are dandelions, frogs, and salmon.

R - selected

A ____________ age structure diagram narrows to a point, indicating that the number of individuals decreases rapidly with age.

Rapid growth

When a population exceeds the environment's carrying capacity—

it suffers a sudden population crash

------- growth is the best representation we have of a species population growth. It is more realistic than exponential growth.

logistic

When a species is able to grow its population quickly but eventually faces some limiting factors that keep the population from continuing to grow, it experiences _____ growth.

logistic

The global human population is closest to which of the following?

7 billion

Life Sustaining

somatic

The three largest countries in the world (in terms of population) are—

China, India, U.S.

In ecological terms, how are people distributed over the planet?

Clumped

Which of the following statements correctly characterizes the reproductive strategies of dog species?

Dogs are an iteroparous, K-selected species that reproduce sexually.

When buildings and roads are constructed, large continuous habitats are broken up into smaller, more isolated habitats

Habitat fragmentation

----------, or age structure diagrams, are a way for scientists to show the distribution of a population based on age and gender. These graphical representations can be used to predict the future of a population and to show some current issues that may be occurring within the population.

Histograms

Which of the following statements best characterizes the reproductive strategies of the human species?

Humans are an iteroparous, K-selected species that reproduce sexually.

The predator-prey interactions that occur between the moose and wolf populations on Isle Royale is an example of—

Negative feedback, the because populations regulate one another.

Which of the following is an abiotic factor that can limit the carrying capacity of a species in a specific ecosystem?

Nitrogen

When plants die, the organic matter enriches the soil with moisture and nutrients. This increases soil fertility, allowing additional plants to grow. These plants eventually die, further enriching the soil. This is an example of—

Positive feedback, because the plant population's growth rate increases over time.

------------- organisms, such as salmon or mayflies, are the opposite; they have just one reproductive event.

Semalparous

When a population overshoots its carrying capacity, it will most likely experience—

a small die-off and recovery. The population will then fluctuate around the carrying capacity.

Once a species has reached the maximum population possible for a specific habitat, it is said to have reached its—

carrying capacity

An invasive species that has just been introduced to an ecosystem and has no natural predators would likely experience—

exponential growth

The last way that we can categorize the reproductive lives of organisms is through ----------- --------, like the ones illustrated below. They show the distribution characteristics of a species, their reproductive strategies, and the life histories for the species.

survivorship curves