Phylogenies
Vocabulary
Biological Fitness
Natural Selection
100
What is measured on the left side of this phylogeny?
Time in Millions of Years
100
A phenotype that can be passed down from ancestors to descendants because it is partly/mostly caused by DNA.
Heritable Trait
100
Explain why a virus that hurts only baby rabbits might affect the biological fitness of all rabbits?
Because they are unable to grow up and mate/replace the dying rabbits
100
What does it mean when a trait is "selected for"?
A: things with that trait are more likely to survive
B: things with that trait are less likely to survive
A: more likely to survive
200
Why doesn't Archaeohippus (center) have a line coming out of the top of it?
Because it is extinct
200
A species that is still alive (1+ individuals) is called this.
Extant
200
If two penguin families exist at the same time and compete for the same food (no sharing!), which penguins would have lower fitness: the penguins who eat, or the penguins who don't?
The penguins who cannot eat will have lower fitness (starve and likely not have kids)
200
What does it mean if a trait is "selected against"?
A: things with that trait are more likely to survive
B: things with that trait are less likely to survive
B: less likely to survive
300
What does it mean when Parahippus's line connects into Merychippus 15 million years later?
Parahippus was the ancestor of Merychippus
300
A measure of an individual or a species’ ability to find reproductive success (have kids).
Biological Fitness
300
Two penguin families have slightly different beaks because of genetic variation (one is longer, the other is shorter). The longer beak ones are able to hold more squid on their travel back to the nest, where they feed their kids. How does that affect their fitness?
The longer beak penguins have higher fitness because they are able to feed their kids more.
300
The three principles of Natural Selection are 1) Offspring cannot all survive, 2) Not all offspring are the same as each other, and 3)...?
The most biologically fit offspring will survive and reproduce
400
What is the common ancestor of all of the listed species?
Crown Reptilia
400
Embryology studies...?
Bonus: what is the first root word and its meaning?
Embryos and their development/growth.
an embryo is a not-fully developed offspring
400
Two penguin families of different sizes (4 ft tall and 3 ft tall) are both alive during a global winter. The global winter has pushed predatory seals farther south, and seals prefer bigger penguins. Which species is more fit in this scenario?
The small penguins will survive and have kids more often, because they are ignored by seals more often.
400
66 MYA the Chicxulub meteor changed the world a LOT--plants died, temperatures dropped, and lots of animals died shortly after. That meteor event selected for smaller, feathered dinosaurs. Why did they survive better than the others?
Feathered dinosaurs better survived the global winter because the feathers kept them warm. The non-feathered ones froze or starved.
500
Without fossil evidence, what three types of evidence do scientists use to organize extant species?
Embryology, DNA, and comparative anatomy
500
"Survival of the fittest" is the shortest definition of this term.
Natural Selection
500
Were the ancestors of humans biologically fit? Why?
Yes, because they were able to reproduce and have kids. Us existing is evidence that our ancestors were biologically fit!
500
When something goes extinct, it is often because of a changing world and natural selection--there were no individuals of that species that could survive when the world changed. What are two causes of extinction that we covered in class?
-Temperature: Freezing/overheating
-Starvation/Thirst
-Overhunting: none of the animals could escape
-Unable to have kids