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1 McMaster BIO 1M0 EXAM LATEST ACTUAL EXAM
QUESTIONS AND CORRECT ANSWERS 2024 -2025
ALREADY GRADED A+
How did complex/adaptive foraging promote cooperation? - ANSWER-- Male-female cooperation → primate child care not suited for hunting lifestyle
- Cooperation between people with two different skills → gather food at different times
- Cooperation between hunters → hunting success highly variable
- Cooperation in teaching and learning → teaching young how to forage
Give two examples of how reuniting can create new species - ANSWER-- Hybridization (new species)
- Allopolyploidy (polyploids from 2 different species)
Why are underground organisms more likely to fossilize? - ANSWER-Habitat bias. Underground organisms more likely to fossilize because of active sediment deposits (also occurs in swampy areas)
What type of bias is responsible for the fossilization of snails and not slugs? - ANSWER- Taxonomic bias. Hard things are more likely to fossilize because they are less prone to decay compared to soft-bodied organisms.
What type of bias is responsible for more fossils from the Cenozoic era (more recent) being found compared to the Paleozoic era? - ANSWER-Temporal bias. More recent fossils likely to be found due to less time to decay/destroy
How does abundance bias relate to taxonomic, temporal, and habitat bias? - ANSWER- Abundance bias → abundant organisms = higher chance to fossilize. Abundant fossils ≠ abundant organisms Hard, swampy/underground, recent fossils more likely to fossilize/be found. This does not mean they were abundant when alive. 1 / 4
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What organisms were primarily responsible for creating oxygen in the Precambrian era? - ANSWER-Photosynthetic bacteria (cyanobacteria)
We are in the Phanerozoic eon. What are the three eras within this eon, and what epoch are we in currently (technically and proposed)? - ANSWER-Paleozoic (includes Cambrian period, ends with Permian extinction), Mesozoic (ends with extinction of dinosaurs), Cenozoic → presently in Holocene epoch, suggested Anthropocene
What is the sister taxon to Canis? - ANSWER-Lutra, Mephitis
What are possible triggers for adaptive radiation? - ANSWER-- Ecological opportunity → empty niches, new climate
- Co-evolution → evolution of one species leads to evolution in other species
- Morphological innovation → evolution of a key trait (new body plans from Hox genes)
How did the angiosperm explosion impact other organisms? - ANSWER-Opened up new opportunities for other organisms to undergo co-evolution
What were some factors that led up to the Cambrian explosion in the Paleozoic era? - ANSWER- Higher oxygen levels, evolution of predation, new niches, new body plans (from new genes)
In what sense do the principles of evolution apply directly to modern humans? - ANSWER- Differential reproductive success due to heritable variation in traits → people with desirable traits are having more sex/children than people with undesirable traits
What distinguishes modern humans from other evolved organisms? How does it affect how adaptive principles are applied to us? - ANSWER-Language, technology, complex thought, culture. Due to our complex brains and differing culture, it is hard to link variation in fitness to heritable traits
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3 How does a changing environment promote adaptations, whereas a constant environment hinders adaptations? - ANSWER-Changing environments provide opportunities for new combinations and directions for natural selection to go. Constant environments can lead to organisms to becoming 'stuck' due to lack of variation needed (eg, vertebrae eyes)
How can geographic changes lead to allopatric speciation? - ANSWER-Geological changes lead to environmental change. This can lead to mountains forming, rivers changing, etc. This changes how two populations may interact, without changing how they live. If they overcome gene flow and adapt independently to different environments, speciation may occur
Species interaction is key in evolution. What are two ways that taxa can be affected by changes in other taxa? - ANSWER-- Colonization → other species change due to arrival of an organisms (invasive species
- Evolution → environment changes due to changes in organisms (leads to co-evolution)
How can competition (intraspecific and interspecific) lead to adaptive contraction? - ANSWER- Interspecific: competition from other clades can lead to extinction of one (eg, dinosaurs vs therapsids) Intraspecific: competition from a successful member from your own clade leads to extinction of a particular species (eg, humans vs hominins)
What are some adaptations primates have? - ANSWER-- Stereoscopic vision
- Versatile limbs → grasping hands/feet, unspecialized digits
- Large brains
- Teeth → unspecialized flat teeth
How did the angiosperm explosion lead to adaptive radiation in primates? - ANSWER- Processing and handling of angiosperm fruit and flowers leads to complex foraging → ability to switch between types of food and learn how to use new foods
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4 What factors likely lead to the development of upright posture in primates? - ANSWER-- Transition from forest to grassland environments
- Free up hands for harvesting/carrying food
- Effort to stay cool (now in grasslands)
- Adaptation for long-term migration
What are apes very good at? What are they shit at? - ANSWER-Apes are well-adapted for swinging through trees (versatile limbs). Apes are good at hanging, bad at sitting.
If ape radiation had never happened, what might've been the fate of humans? - ANSWER-There would be less diversity between the surviving apes (not replaced by monkeys) and likely no humans
Why are scientists interested in teeth? - ANSWER-Molar development (milk → adult) suggests long development. Long development suggests elaborate sociality.The amount of dental enamel left suggests length of maturing
What inferences can be made if a fossil has forward-facing eyes, vs large far apart eyes? - ANSWER-Forward-facing → forager → better for precise tasks, 3D vision Far apart eyes → prey → peripheral vision, better for night vision
Greater variation in male reproductive success requires... - ANSWER-More sexual dimorphism, more male-male competition for female mating
Why might Homo sapiens have dominated the world? Do we have evidence for it? - ANSWER- Might have been due to our large brains, but this is not reflected in fossils
How do archaeologists determine posture and diet from fossils? - ANSWER-Diet → teeth, jaws Posture → Knees, hips, backs, skulls
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