Determinism: Flashcards
When did the Ordovian-Silurian mass extinction occur?
440 mya
What were the major outcomes of the Ordovician-Silurian mass extinction?
- 85% of marine species went extinct
- rapid recovery - many surviving groups experienced rapid diversification
- rise of fish groups - survival of Cartilagenous fish, bony fish, and armoured fish
When did the end Devonian extinction happen?
365 mya
What were the major survivors and extinctions of the end of the Devonian mass extinction?
Survivors: ray-finned fish, early tetrapods, sharks, conodonts
Extinct: placoderms (apex predators), many jawless fish, acanthodians
When did the end Permian mass extinction occur?
250 mya
What were the major survivors and extinctions that happened at the End Permian mass extinction?
Survivors: therapsids, early archosauromorphs, ancestors of modern amphibians, cynodonts
What were the major survivors and extinctions that happened at the End Permian mass extinction?
Survivors: therapsids, early archosauromorphs, ancestors of modern amphibians, cynodonts
Extinctions: primitive synapsids, large Temnospondyls
When was the Triassic-Jurassic mass extinction?
210 mya
What were the major outcomes of the Triassic-Jurassic mass extinction?
- dinosaurs adapted and became dominant terrestrial vertebrates
- pterosaurs survived and continued to diversify
- early mammals survived by occupying diverse niches
Extinctions: conodonts, ammonoids, non-mammalian therapsids, large Temnospondyls amphibian
How did mammals survive the K-T extinction, and what advantages did they have?
- Small size protected them from abiotic factors
- Generalist diets
- Endothermic adaptation allowed temperature regulation
- Diverse abilities (climbing, burrowing, swimming, gliding)
- Ability to quickly fill vacant niches
What are the main reasons for survival after mass extinctions?
- Adaptability to changing environmental conditions
- Occupation of diverse niches
- Size advantage (smaller animals often had better survival rates)
- Habitat flexibility
- Dietary flexibility
Why did apex predators often go extinct during mass events?
- specialisation
- resource requirements
- population dynamics
- position in food chain
- size
How can mass extinctions be used to argue for determinism in evolution?
- Victims of extinctions share common traits, indicating predictability in extinction patterns
- Extinction events can accelerate evolution by increasing evolvability
- Creation of ecological opportunities and new niches for survivors to radiate into
How does the convergent evolution of powered flight support the argument for determinism?
- Flight evolved independently in pterosaurs (230 mya), birds (150 mya), and bats (50 mya)
- Highlights a deterministic trend towards exploiting aerial niches
- Suggests predictable evolutionary outcomes under similar environmental pressures
What are the key points about the convergent evolution of endothermy?
- evolved independantly in mammals (200-280 mya) and birds (150-160 mya)
- provides advantages in maintaining stable body temperatures
- suggest a deterministic trend towards active lifestyles across diverse environments
What were the major key innovations during the Cambrian explosion (540 mya)?
- Notochord: pikaia (first basal chordate)
- bilateral symmetry
- complex eyes
- shells and exoskeleton
- appendages
- segmentation
How did the evolution of jaws impact animal diversity?
- first occurred in placoderms and acanthodians (450 mya - Silurian)
- led to diversification in feeidng behaviours
- allowed exploitation of different resources
- prompted further innovations (e.g., pharyngeal jaws in wrasses and cichlids)
What was the significance of the amniotic egg as a key innovation?
- evolved 310-320 mya
- allowed tetrapods to become fully terrestrial
- enables radiation into habitats far form water bodies
- opened up new ecological opportunities
- deterministic solution to terrestrial reproduction
- did not have to evolve again as it allowed for rapid diversification
How can key innovations be used to argue for determinism in evolution?
- Functional constraints lead to predictable evolutionary outcomes
- Provide significant adaptive advantages under similar environmental pressures
- Conservation of body plans and Hox genes suggests deterministic solutions
- Physical and biological constraints channel evolution towards certain innovations
- Enhance performance and fitness, favoring survival through natural selection
- Lead to predictable ecological shifts when opportunities arise
Why did rapid diversification occur in the Cambrian explosion (540 mya)?
Predators started to evolve true to key innovations, which forced prey to also evolve -> evolutionary arms race
Why did Pikaia survive the Cambrian?
They remained small but had a notochord that allowed them to move fast and away from prey without the constraints of having a large body
What was a major event that happened during the Carboniferous period (360-300 mya)?
Emergence and diversification of early amphibians
What major events happened during the Cambrian:
- rapid diversification of animal life - most major animal phyla appeared in the fossil record
- evolution of hard body parts
- Piakaia evolved and survived (505 mya)
What major events happened in the Ordovician period (490-440 mya)?
- significant increase in marine diversity
- evolution of fish
- cephalopods became the dominant predators in the ocean
- end of the Ordovician = major extinction event
