Video Transcript
Which of these animal species (A)
to (E) is most likely to produce offspring with a high mortality rate?
The question presents us with five
different animal species with their respective offspring and asks us to predict
which animal species will produce offspring with a high mortality rate. To do this, let’s review some
typical reproductive strategies of different species and how they relate to aspects,
such as mortality and life span.
An organism’s reproductive strategy
describes the way that they mate, and how, if at all, they raise any offspring that
are produced. There are two main groups of
reproductive strategies that form a scale from prioritizing quantity of offspring
over their quality to prioritizing quality of offspring over their quantity. Let’s see what this means by
looking at a couple of examples from the species in the question.
While whales and frogs both
typically live in aquatic environments, which are notoriously challenging
environments to live in, these animals adopt very different reproductive strategies
so are useful to compare for this question.
Whales tend to produce small
numbers of fairly large and high quality offspring. These species tend to exhibit a lot
of parental care. Mothers feed their young milk
produced by their own bodies, teach them useful skills like finding food, and
protect them from danger until they are old enough to protect themselves. Partly as a result of this, their
offspring tend to live for a fairly long time and have a low mortality rate.
Organisms like frogs, however,
which favor quantity of offspring over their quality, produce large numbers of
usually small offspring, which each require far less individual energy
investment. These species tend to exhibit
little or no parental care to their offspring, often simply leaving them to develop
and grow on their own. As a result of their high mortality
rate, these species tend to have a fairly short lifespan. This is why they opt for producing
so many offspring into which they invest little energy individually, as there is a
higher chance that at least a few of these many offspring will survive.
Based on the fact that the horse,
duck, and sheep in the images in the question labeled (A), (B), and (E) are all
shown to have only one offspring, we can assume that they follow the same
reproductive strategy of quality over quantity that the whales do, producing very
few long-lived offspring with a low mortality rate into whom they invest some or a
lot of parental care.
As the question is asking us which
of these animal species is most likely to produce offspring with a high mortality
rate, we now have enough information to answer it correctly. The species we would expect to
produce offspring with a high mortality rate is (D), the frog.
