A4.1 Evolution and Speciation Flashcards
Heritable Characteristics
Traits inherited by offspring from parents
Evolution
The change in the heritable characteristics of a population.
Darwinism
Evolution by natural selection.
Acquired characteristics
Characteristics of individual organisms that can change during their lifetimes, not necessarily inherited genetically.
Lamarckism
A theory for evolution that was based on the inheritance of acquired characteristics.
Falsification for Lamarckism
The inheritance of acquired characteristics would require specific changes to be made to genes, while mutations are unexpected changed in a DNA base sequencing.
Pragmatic Truth
A theory that predicts and explains observations, a truth that works.
The more closely related two species are in their morphology…
the fewer distances in base sequence they will have.
Evidence for evolution in base sequencing
Comparing base, amino acid, or RNA sequences of the same gene in different species.
Artificial Selection
Selecting species with desirable traits from wild species for breeding, such as a variety of crops and animal breeds grown for human society.
Evidence for Natural Selection (and therefore Darwinistic evolution you fucking moronic shitsack :))
Artificial selection has caused changes in domesticated crop species and animals over short periods of time and has caused rapid evolution, making it reasonable that natural selection has caused evolutionary changes over a much longer period of time.
Groups of vertebrates that have limbs
Amphibians
Reptiles
Birds
Mammals
Groups of vertebrates that have limbs
Amphibians
Reptiles
Birds
Mammals
Pentadactyl limb
A limb with five units that is characteristic to the four groups of vertebrates (amphibians, mammals, reptiles, birds)
Humerus
Single bone in proximal part
Carpals
group of wrist bones
Radius and ulna
Two bones in distal part
Metacarpals and phalanges
Series of bones in each five digits
Homologous structures
Structures that have structural similarities despite the differences in their function.
Adaptive radiation
Development based on different types of environments.
Analogous Structures
features of different species that are similar in function and structure and which do not derive from a common ancestral feature
Explanation for homologous structures
All 4 vertebrates share a common ancestor that had pentadactyl limbs but the limbs developed in widely different ways because they adopted different types of locomotion.
Explanation for analogous structures (convergent evolution)
They had different evolutionary origins but became similar because they perform the same or similar functions.
Example of convergent evolution so you’re not fucking screwed
Octopus and human embryos have similar early stages of eye development, but significant structural differences . The last common ancestor of mollusks and humans was eyeless, indicating analogous structures.
What’s the converse of speciation
EXTINCTION, in that it reduces the number of species on earth
What two processes are required for speciation to occur?
Reproductive isolation and differential selection.
Reproductive isolation
Two populations stop interbreeding and therefore separate gene pools and therefore diverge.
Geographical separation (EXAMPLES of causes)
Mountain ranges, Wide rivers, Stretches of oceans between islands, (Lava lizards and Galapagos)
Factors in differential selection
Climate, predation (predators), competition (resources)
An Example of speciation
Bonobos (Pan paniscus) and chimpanzees (Pan droglodytes)
- closely related,
- geographically separated by the Congo river which is probable to have fell drastically and rose again, became isolated.
- Founder population was subject to different selection pressures (food), and diverged from chimpanzees to bonobos.
Allopatric speciation
Speciation if the populations live in different areas, wherein the reproductive isolation is geological.
Sympatric Speciation
Speciation when populations live in the same area.
Temporal Reproductive Isolation
Populations of a species breed at different times.
Example: Magicicada septendecim switch from breeding every 17th year to every 13th year within the range of the species, generating a new species, Magicicada neotredecim.
Behavioral reproductive isolation
Populations of a species have differences in behavior that prevent interbreeding. Example: Fruit flies attracted to volatile compounds from hawthorn fruits to lay eggs and larvae or apple and dogwood fruits instead. (Different larval food source, different times when three fruits ripen.)
Adaptations
Characteristics that make an individual suited to its environment or way of life.
Adaptive Radiation (ONCE FUCKING AGAIN)
A pattern of diversification in which species that have evolved from a common ancestor occupy a range of ecological roles.
How many chromosomes do horses have?
64 chromos
Donkey chromos
62
Mule chromos
63
Interspecific Hybrids
Hybrids produced by cross-breeding members of different species.
Natural Interspecific Hybridization
Occurs if the ranges of closely related species overlap in an ecosystem. (Partially or fully sterile)
Examples of Barriers to Hybridization
- Proteins in the membrane of female Plasmodium, gametes prevent fertilization by sperm of a different species when a host is infected with more than one species.
- Courtship behavior is used by a bird to ensure that a partner is from the same species.
Polyploid Organism
Has more than two sets of homologous chromosomes.
Polyploidy
A whole-genome duplication, happens when the chromosomes in a cell are duplicated but the cell does not divide, results in autotetraploid.
Autotetraploid
non-hybrid tetraploid
Example that falsifies Lamarckism:
Trees’ asymmetrical shape from wind is not inherited to its offspring.
