Flashcards in Evolution- The Broad Patterns of Evolution Deck (32)
What macroevolutionary changes does the fossil record show? (3)
1. Emergence of terrestrial vertebrates
2. Origin of photosynthesis
3. Long-term impacts of mass extinctions
What are the biases in favour of the species that have the chance of becoming a fossil?
1. Existed for a long time
2. Were abundant and widespread
3. Had hard parts
4. Lived in shallow aquatic habitats
How are rocks and fossils dated?
- The sedimentary strata reveal the relative ages of fossil
- Absolute age can be determined by radiometric dating
How are isotopes related to rocks and fossils?
- A parent isotope decays to a daughter isotope at a constant rate
- Each isotope has a known half life, the time required for half the parent isotope to decay
How are Carbon-12 and Carbon-14 useful?
- Organism accumulates carbon during life
- Ratio of 14^C to 12^C or 14^C to 14^N can be used to determine the fossils age
What are the 3 eons of the geologic record?
What are the 3 eons within the Phanerozoic eon?
1. (Pre-cambrian) Paleozoic
How are photosynthesis and the oxygen revolution related?
- Earliest types of photosynthesis didn't produce oxygen
- Oxygenic photosynthesis probably evolved in Cyanobacteria
How did the accumulation of Oxygen affect the planet?
- Resulted in a toxic challenge for most organisms
- Created an opportunity to gain an abundant energy from light and opportunities to exploit new ecosystem
What is endosymbiosis?
-Prokaryotic ancestors of mitochondria and plastids probably gained entry to host cell as undigested prey or internal parasites
- As they became more interdependent hosts, endosymbionts became a single organism
How are mitochondria and plastids related?
- Splitting resembles binary fission
- Homologous membrane structure and function
- Both have own circular DNA
- Similar ribosome structure to prokaryotes
What is the Colonial Connection?
The first multicellular organisms were colonies of prokaryotes
What is the Cambrian Explosion?
It refers to the sudden appearance of fossil resembling modern phyla in the Cambrian period. It provided the first predator-prey interactions
What is the geologic time scale?
- Cenozoic: 0-65 mya
- Mesozoic: 65-251 mya
- Paleozoic- 251-542 mya
- Pre-cambrian: 542 mya- 4.6 bya
What do plate tectonics do?
They describe how earth's crust is composed of plates floating on earth's mantle. Tectonic plates move slowly through the process of continental drift
What do oceanic and continental plates do?
They can collide, separate, or move past each other
What are the consequences of continental drift? (3)
- Deepening of ocean basin
- Reduction in shallow water habitat
- Colder and drier climate in land
What are two of the most famous mass extinctions?
What is the Permian extinction?
- Claimed 96% or marine animal species and 8/27 orders of insects
-Caused by volcanic eruptions
What is the Cretaceous extinction?
- Doomed many marine and terrestrial organisms especially non-feathers dinosaurs
- Large meteor impact
What are the consequences of mass extinctions? (3)
1. Alter ecological communities
2. Take from 5-100 million years for diversity to recover
3. Pave the way for adaptive radiations
What are adaptive radiations?
Evolution of diversely adapted species from a common ancestor upon introduction to new environmental opportunities
What are some worldwide adaptive radiations?
- Mammals underwent one after the extinction of non bird dinosaurs
-Photosynthetic prokaryotes, large predators in the Cambrian, land plants, and tetrapods
What are some regional adaptive radiations?
-Can occur when organisms colonize new environments with little competitions for example the Hawaiian islands
What do developmental genes control?
The rate, timing, and spatial pattern of changes in organisms from during development into and adult
What is heterochrony?
An evolution or a change in the rate or timing of developmental events. It can have a significant impact on body shape
What is paedomorphosis?
The rate of reproductive development accelerated compared to somatic development
What are homeotic genes?
They determine the position of basic features, such as where wings and legs develop on a bird or the arrangement of floral structures
What are Hox genes and what happens if they're expressed in the wrong location?
Hox genes provide positional info for development of fins in fish and limbs produced in tetrapods. If in the wrong location, body part can be produced in the wrong location