What are the different TYPES of evolution?
Allopatric and sympatric speciation
What are the different PATTERNS of evolution?
Divergent evolution, convergent evolution, co-evolution, Sequential evolution, Parallel evolution
What is divergent evolution? what is the evidence for it?
- when an ancestral species evolves into two or more species that have become specialised to occupy different ecological niches
- homologous structures
What are homologous structures? What is an example?
- A feature seen in closely related species (e.g. had a common ancestor that is recent) that is similar in structure but used for different species
- eg the pentadactyl limb is seen in all mammal species but used for different things (e.g. swimming, flying, walking etc.)
What is adaptive radiation? what causes it?
- When from a common ancestor, many new species evolve due to the SUDDEN availability in niche’s
- Caused generally by a sudden die off of the species that used to occupy these niche’s
What is convergent evolution? what is the evidence for it?
- when two or more species evolve from different ancestors but develop similar features due to similar selection pressures
- analogous structures
What are analogous structures? what is an example of it?
- a feature seen in distantly related species (e.g. had a common ancestor a long time ago) that is similar in structure and function
- eg sharks, dolphins and penguins all have same streamlined body in order to swim fast to catch and avoid prey and predators
Why does convergent evolution happen?
There are only a finite number of effective solutions to some challenges and because of this they emerge independently of each other
What is co-evolution?
when 2 different species are ecologically intimate and influence each others evolution
What are examples of types of ecologically intimate relationships? How do they influence each other?
- Mutualism: evolve together to work harmoniously together
- Parasitism: host evolves to remove it while parasite evolves to stay in/on it
- Predator/prey: predator evolves to catch prey while it evolves to avoid it
- Mimicry: mimicking species changes in order to match its copy species
- Interspecific competition: evolve to avoid each other
What is sequential evolution?
When the population of an entire species changes so much over time on a genetic level WITHOUT a split that organisms of each population in time would not be able to reproduce (however the old population has been replaced so is impossible to tell FYI)
What is parallel evolution? How does it occur?
- The evolution of similar anatomical or physiological features by related groups of organisms independently of each other, these features were not present in the ancestral population
- Due to similar selection pressures in each environment
What is a cladogram?
A diagram that classifies organisms according to their evolutionary relationship based on structural evidence (e.g. morphological and physiological evidence)
What is a phylogenetic tree?
A diagram that classifies organisms according to their evolutionary relationship based on genetic evidence (e.g. mtDNA, amino sequence comparisons etc.)
What are the two types of evolution rates that can occur?
- punctuated equilibrium
- gradualism
What is punctuated equilibrium?
It is when a species undergoes a long period of stasis (period of no evolutionary change) but then undergoes rapid speciation in a short period of time
What causes punctuated equilibrium?
A period of environmental stability which is then punctuated by a short period of rapid environmental change
How can you tell from fossil records that punctuated? Why is this?
- There may be a sudden physiological change in the fossil records with no transitional species
- the change in the physical structures of a species was so sudden and the transitional species existed for a very short time
What is gradualism?
It is the slow process of divergence between different populations by the slow process of changing allele frequency and mutation
How does gradualism occur?
By slowly changing selection pressures
What types of evaluation rates do most species undergo?
Punctuated equilibrium