CHAPTER 6 Macroevolution Flashcards
- refers to evolution above the species level
- encompasses the grandest trends and transformations in evolution and are generally what we see when we look at the largescale history of life
MACROEVOLUTION
Mechanisms of Macroevolution
mutation
sexual reproduction
gene flow
genetic drift
natural selection
+
3.8 billion years = macroevolution
Patterns in Macroevolution
According to the University of California, Berkeley (2021)
- STASIS
- CHARACTER CHANGE
- LINEAGE – SPLITTING (or SPECIATION)
- EXTINCTION
- All of the changes, diversifications, and extinctions that happened over the course of life’s history are the patterns of macroevolution.
Patterns in Macroevolution
- they don’t change much for a long time
- Some lineages have changed so little for such a long time that they are often called living fossils
Stasis
In 1938, scientists thought that coelacanths went extinct 80 million years ago. But they discovered a living coelacanth in the Indian Ocean; the coelacanth lineage exhibits about 80 million years’ worth of morphological stasis.
Patterns in Macroevolution
- Lineages can change quickly or slowly.
- Can happen in a single direction, or it can reverse itself.
- Can occur within a single lineage or across several lineages.
- This may include:
1. -
2. -
Character Change
* Adaptive Radiation
* Co-evolution
Patterns in Macroevolution; Character Change
- Species evolved into several different forms that live in different ways
- is evolution of many diversely adapted species from a common ancestor.
- an event in which a lineage rapidly diversifies, with the newly formed lineages evolving different adaptations.
Adaptive Radiation
Patterns in Macroevolution; Character Change
Causes of adaptive radiation
1. -
* usually means an adaptation that allows the organism to
evolve to exploit a new niche or resource.
2. -
* results into character displacement
3. -
* Lineages that invade islands may give rise to adaptive
radiations because the invaders are free from competition
with other species.
- Key Adaptation
- Competition
- Invasion of vacated/ new niches
Patterns in Macroevolution; Character Change
- Refers to a kind of interaction between species which is described as reciprocal interaction
- An evolutionary change in one species may constitute a new selective force on another.
- direct genetic change in one species is attributable to genetic change in the other.
Co-evolution
Patterns in Macroevolution; Character Change
Types of Coevolution
- Parasitism
- Mutualism
- Competition
- Predation
- Predator-Prey
- Herbivore-Plant
Patterns in Macroevolution:
- can be identified by constructing and examining a phylogeny.
- phylogeny might reveal that a particular lineage has undergone:
Lineage-splitting (or speciation)
Patterns in Macroevolution:
- Patterns of long, stable periods are interrupted by brief periods of more rapid change.
- A catastrophic event or major genetic change occurs, rapid evolution and speciation occurs
- Differs with Gradualism which are patterns of slow, gradual change
Punctuated Equilibrium
Patterns in Macroevolution:
An evolutionary process in which unrelated organisms evolve structures, traits, or morphological features that have the same function (unrelated organisms come to resemble one another)
Convergent Evolution
Patterns in Macroevolution: Convergent Evolution
refers to the trait acquired by unrelated species as a result
of same adaptive response to a similar environment. It arises from convergent evolution in which different species evolved analogous traits.
structure look similar but distantly related
homoplasty
Patterns in Macroevolution:
- is extremely important in the history of life.
- It can be a frequent or rare event within a lineage, or it can occur simultaneously across many lineages (mass extinction).
extinction
- Every lineage has some chance of becoming extinct, and
overwhelmingly, over 99% of the species that have ever lived on Earth have gone extinct.
Patterns in Macroevolution: Extinction
Causes of Extinction
- asteroid strikes
- loss of habitat
- invasive species
- lack of food
- climate change
- lack of genetic diversity
- better-adapted competition
- disease
- human predation
- pollution
