Species and Extinction
What do we call a population of organisms that can interbreed and reproduce under natural conditions?
What is a species?
What is the combined genetic information of a particular population called?
What is a gene pool?
What pattern of growth increases by a constant amount?
What is linear growth, also called arithmetic growth?
What is a factor that prevents a population from increasing indefinitely called?
What is a limiting factor?
What term means the addition of new individuals through birth?
What is natality?
Habitat loss, pollution, disease, and over-exploitation are examples of what?
What are causes of extinction?
Two populations can no longer share genes through reproduction. What may eventually happen to them?
What is speciation, or the development of a new species?
A population adds the same number of individuals each time period. Is its growth linear or exponential?
What is linear growth?
Predators, disease, and competition usually become more influential as a population grows. What kind of factors are these?
What are density-dependent factors?
What population term describes the death rate?
What is mortality?
A forest is cleared, leaving a species with less food and shelter. Which extinction cause from the presentation best describes this change?
What is habitat loss and degradation?
A population becomes separated into two groups, and each group adapts to its environment. How can natural selection contribute to speciation?
What is by increasing differences between the separated populations over time?
Why can a population with high biotic potential grow rapidly when conditions allow?
What is because its reproductive rate and habitat requirements allow it to increase quickly?
As a population becomes more crowded, disease spreads more easily. Identify the limiting factor type and explain why.
What is density-dependent, because its effect increases as population density increases?
What does a survivorship curve show?
What is the probability of survival for a group or species?
A population is losing individuals because people harvest too many of them. Which cause of extinction is most directly involved, and why?
What is over-exploitation, because individuals are being removed faster than the population can sustain?
Compare behavioral and mechanical isolation: what prevents reproduction in each case?
What is different courtship or reproductive behavior in behavioral isolation, and incompatible reproductive organs in mechanical isolation?
Compare linear and exponential growth by describing what stays constant in each pattern.
What is a constant amount in linear growth and a constant rate of increase in exponential growth?
Compare a disease outbreak in a crowded population with a severe temperature change affecting an entire region. Which is density-dependent, and which is density-independent?
What is disease as density-dependent and the temperature change as density-independent?
Compare R and K strategists in the environments they tend to occupy and the number of offspring they produce.
What is R strategists tend to live in unstable environments and reproduce rapidly with many offspring, while K strategists tend to live in stable environments and reproduce more slowly with fewer offspring?
A species has declining numbers, and its essential habitat is being destroyed. Name one protection described in the presentation and explain how it could help.
What is designating critical habitat, which protects an area necessary for the species’ survival from destruction?
A single population is divided by a geographic barrier. Each group experiences different environmental conditions, and natural selection favors different traits. Explain a possible pathway from separation to speciation.
What is that geographic isolation limits gene sharing; different adaptations accumulate, natural selection heightens the groups’ differences, and they may eventually become separate species?
A species has a high reproductive rate and suitable habitat, so its population rises quickly. Later, resources become limited. Explain why the early J-shaped trend may not continue.
What is because the population initially grows near its biotic potential, but limiting factors eventually slow growth and may cause the population to level off near carrying capacity?
A population approaches carrying capacity while facing competition and a severe storm. Distinguish the two limiting factors and explain how each can affect the population.
What is competition is density-dependent and tends to intensify as population size increases, while the storm is density-independent and can affect populations regardless of size; both may reduce growth or population size?
A small organism lives in an unstable environment, produces many offspring, and provides little parental care. Identify its likely strategy group and survivorship type, and support your reasoning.
What are an R strategist and Type 3 survivorship, because R strategists tend to reproduce rapidly, have low parental care, and often have short life expectancy?