8.3 Evolution As An Ongoing Process Flashcards
Coevolution definition
The process in which one species evolves in response to changes in another species
Co-evolution example (caribou & wolf)
e.g. caribou evolve to run faster away from wolves; only the quickest wolves will catch enough prey to survive and reproduce
Co-evolution example (frog & predators)
e.g. poison-dart frog’s warning coloration adaptation and the avoidance behaviour of its predators
Mutualism
a symbiotic relationship wherein both organisms benefit from the interaction
How do flowers and insects co-evolve?
-Plants that produce big, bright, fragrant flowers
attract more pollinators
-Pollinators that are attracted to those flowers get
more nectar and are more likely to survive
How do plants and herbivorous insects co-evolve?
-Many plants have evolved defence mechanisms in
order to reduce herbivory
-E.g. spines, thorns, toxins
-Natural selection enabled some insects to adapt to
poisons and actually benefit from them, allowing
the insects to also become poisonous to their
predators
Mimicry Definition
One species (mimic) evolves to resemble another (model) – may or may not be closely related species
List the 2 type of mimicry
batesian and mullerian
Batesian mimicry
harmless species evolves to mimic a harmful species
Mullerian mimicry
two harmful species mimic each other (additional warning signs)
How can complicated structures evolve over time?
through cumulative selection
Cumulative selection
the evolution of a simple structure into something more complex through a number of small adaptations
Why do some structures stay simple?
“survival of the fittest” – that’s why some organisms still don’t have complex eyes (or any); they don’t need them
How can the environment impact structures?
As the environment changes, specialized structures can adapt to new functions
Give an example of how specialized structures can adapt to new functions (chitin)
E.g. Chitin is the main component of exoskeletons in arthropods like lobsters
-However, in terrestrial arthropods such as scorpions, the exoskeleton also helps prevent water loss and provides support to the body
Give an example of how specialized structures can adapt to new functions (wings)
Natural selection has remodelled penguins’ wings into powerful flippers for swimming and hunting small fish and other prey.
How can evolution explain the range of
complexity of eyes in modern organisms?
Cumulative selection explains the range of
complexity of eyes in modern organisms
-it’s the evolution of a simple structure into a
more complex structure through a series of small
adaptations
Give an example of evolutionary remodelling
of an existing structure to perform a new
function.
multiple functions of chitin (a main
component of arthropod exoskeletons)
-The exoskeleton of a marine arthropod such as a
reef lobster helps protect the animal from
predators.
-On land, the arthropod exoskeleton of this scorpion fulfills additional functions: resisting water loss and supporting its body on dry land.
-Chemical changes to this material made it even
more watertight as the animals became adapted
to living on land
Define co-evolution and provide two examples.
Co-evolution is the process in which one species evolves in response to the evolutionary changes in another species
e.g. the poison-dart frog’s warning-coloration adaptation and the avoidance behaviour of its predators
e.g. milkweed plants produce toxic chemicals and so they are not eaten by most insects. However, the monarch caterpillar has not only managed to develop tolerance to the milkweed’s toxin, but has found a way to store the toxin in its tissues to make itself poisonous to others.
Analyze the advantages and disadvantages of
remodelling an existing structure to perform a
new function
in penguins:
advantages: can get away from aquatic predators faster
disadvantages: unbalanced on land, can’t fly, and can’t escape land predators as fast
Describe the process that has led to the
following situation. The old-world swallowtail
caterpillar feeds on the fringed rue plant, despite
the toxic oil contained in the plant’s leaves
-the caterpillar didn’t evolve in response to the rue plant’s evolutionary changes, which has made the plant toxic
Examine the images of the less aggressive
aardwolf (top) and the aggressive striped
hyena (bottom).
(a) Suggest a reason why some people believe
that the aardwolf is a mimic.
because it resembles the model (hyena) and it mimics it in order to gain survival advantage
Examine the images of the less aggressive
aardwolf (top) and the aggressive striped
hyena (bottom).
(b) Are there any disadvantages to the model
(the striped hyena) in having a mimic that is less
aggressive?
the striped hyena’s predators might think that the hyena is less aggressive and will try to kill it
(c) The striped hyena does not live in southern
Africa but the aardwolf does. The aardwolf
lives in the same areas in southern Africa as
the brown hyena, which has a blotchy brown
coat. Does this information contradict the
idea that the aardwolf is a mimic? Explain
yes because this hyena is much different from the aardwolf, so it’s not a mimic for this species of hyena because it doesn’t resemble it
(d) Propose an alternative explanation for the
similar striped patterns in the two species
if they had to adapt to similar environments, that’s why they might have similar adaptations/features
-e.g. camouflage - both developed stripes
Explain how you would provide evidence that
the human hand evolved through cumulative
selection
i would use the first humans’ simple hand structures as evidence of how it evolved and became more complex over time due to a series of small adaptations
Some people may assume cumulative selection
makes some species “better” than others.
Explain why this is not accurate
“survival of the fittest” is why some organisms still don’t have complex structures because they don’t need them, simple structures are all they need for their environment
