therefore ensure that that male reproduces more successfully. If the trait/attribute
has a heritable feature then its offspring will have that feature too. Ex: large
heavy deadly antlers of the male deer. Male deer (stags) sometimes compete
against other male deer to compete for female deer (does). The larger your
armour the better equipped you are to fight, the better equipped you are to fight
the more chances of securing mates; Given that the antlers have a genetic basis
the more successful males (largest antlers) pass them onto their male offspring.
There is a cost to having these heavy antlers. Having the heavy antlers
(advantages) might outweigh the costs it causes given their prevalence in the deer
•Intersexual selection: Often it is the males who are competing against each other
for access to the females. Females are in the position to choose their mate. If the
female population of a given species has some consensus about what’s desirable
in the males of a species, then those males that have the trait that is desirable will
be chosen as mates more often given that those attributed males get chosen more
often, they reproduce more often and produce more offspring. Ex: the more
brilliant the plumage is, the more likely it is to secure a mate, and therefore the
more likely it is to pass the plumage off to his offspring. This process has
occurred long enough for all the male population of the peacock to have the
•There are these evolutionary processes (natural selection processes, sexual
selection processes, intrasexual competition, intersexual selection etc.
•All of which are helping to shape the design properties and design features of all
species. Out of these evolutionary processes, some products emerge. 3 of the
products that are discussed are 1. adaptations; 2. spandrels; and 3. random effects.
1. Adaptations: those design processes selected and coordinated towards
solving recurrent problems. They are usually species specific – virtually
all members of the species have them. Ex: long neck of giraffe, large
brain in human.
2. Spandrels – are design properties that are not contribute directly to
adaptation. Rather they are linked at a genetic level to adaptations. So they get
carried along the evolutionary process. They can seem like adaptations but
are not. There are things can look species – specific but are not. They are
instead by-products of adaptations. These are design properties that are not
adaptive but rather are linked to adapted features/adaptive design properties.
They become incidentally incorporated into the design of an organism. Ex:
ears are adaptations. Ear lobes are not adaptations. They are spandrels – they
are things that happen to co-occur with ears. So they are typical of the human
species. Although all humans have earlobes, it doesn’t make them adaptive.
It just means that earlobes are connected to ears, and ears are adaptive; B/c
ears exist for the final significance, we all have earlobes as well. They are the
by-products of adaptations. It doesn’t mean they have any final significance