Evolution and Speciation Flashcards
What is Evolution?
A change in the heritable characteristics of a population
Darwin’s theory
All species of organisms have evolved from a small number of original species
Lamark’s theory
Physical changes that occur during a lifetime can be passed on to the offspring (false)
Heritable characteristics
Traits that are passed on by genetic information
Inheritable characteristics
Traits that you get during your life time and cannot be passed on to an offspring
How are base sequences in nucleic acids and amino acids evidence for evolution?
Similarity in the base sequences indicate common ancestry. Fewer differences in the base sequence –> supports the theory of evolution by natural selection
Selective Breeding
Artificial breeding, whereby man intervenes in the breeding of species to produce desired offspring. (Causes rapid evolution)
What is an example of selective breeding?
Dog breeding. For example, beagles were bred to be smaller to enter fox holes
Homologous Structure
It has a similar structure and a different origin. Has a divergent evolution and adaptive radiation. It becomes different when performing different functions and is a natural classification.
Analogous Structure
It has a different structure and similar function. It has a convergent evolution and becomes similar through performing a similar function. An artificial classification
What is an example of a Homologous structure?
Mammals, reptiles, amphibians, and birds have a pentadactyl limb. They all have a similar arrangement of bones in their appendages based on a five-digit limb
What is an example of an Analogous Structure?
Wings are found in birds and insects. Fins are found in whales and fish.
Gradualism
Species change by steady and gradual transformations
Punctuated Equilibrium
Species remain stable for long periods before undergoing abrupt and rapid change
How does speciation occur?
Through reproductive isolation (geographical barriers) and differential survival.
What is an example of a reproductive barrier?
Bonobos and common chimpanzees are separated by the congo river
Allopatric Speciation (HL)
Speciation ccurred due to geographical barriers
Sympatric Speciation (HL)
Speciation due to behavioural isolation or temporal isolation
Adaptive Radiation (HL)
A pattern of diversification in which species that have evolved from common ancestors occupy various ecological roles. This increases diversity. (One ancestor –> evolves to like 5 species)
Interspecific Hybrids (HL)
Produced by cross-breeding members of different species.
Polyploidy (HL)
When an organism has more than two sets of chromosomes in every cell. It is caused by non-disjunction in the meiosis.
Autopolyploidy (HL)
When a polyploid offspring is derived from a single parental species (usually via self-fertilization)
Allopolyploidy (HL)
When a polyploid offspring is derived from two distinct parental species
Prezygotic Isolation (HL)
Type of reproductive isolation where it occurs before fertilization can occur (no offspring are produced)
