Microevolution Flashcards
Evolution-
genetic change in a
line of descent over the generations`
Microevolution-
how populations of organisms change from generation to generation and how new species originate
Macroevolution-
patterns of changes in groups of related
species over broad periods of time- determine phylogeny, or evolutionary relationships among groups of
species–how different species are related
Jean-Baptiste Lamarck–theories
Use and disuse, Inheritance of acquired characteristics, Natural transformation of species
Natural transformation of species-
because of the two above,
each generation of a species is transformed into a slightly different
more complex form
Ex- giraffe developed long neck from
stretched over time bc of necessity and this trait was passed to offspring
Inheritance of acquired characteristics
features that are
acquired during the lifetime of an organism can be passed on to offspring
Use and disuse
body parts of organisms develop more when used more, and unused parts weaken
Charles Darwin–explanation
Because of strong check on populations because of limited food
supply, inherited variations that are favorable to survival will be preserved, others eliminated. (Adaptations.) Natural Selection.
Ex- Galapagos finches- 13 different species all descended from
one single species, but because of the different environment on each island, different
traits selected for, different species evolved
Adaptations
evolutionary modification that improves chances of survival in specific environment
Natural Selection definition
better adapted organisms are more likely to survive, therefore population changes over time
Charles Darwin–aspects
Variation, Overproduction, Limits on population growth, Differential reproductive success,
Variation
individuals of a population exhibit variations,
some of which improve chances of survival and others which do not
Overproduction
every generation of a species has the
capacity to produce more offspring than can survive
Limits on population growth
struggle for existence
between individuals of a species because of limited resources
Differential reproductive success-
individuals that are
best adapted to the environment (contain most favorable
traits) are more likely to survive and reproduce,
therefore their traits will pass on and others will die off
Modern synthesis-
combines Darwin’s theory and Mendel’s theory to explain how these traits are passed on
Explains that variation is caused by mutations
Paleontology
studies fossils-remains or traces left in sedimentary rock by previously existing organisms.
Oldest layer at the bottom, upper layers are successively younger- allows scientists to place events recorded in rocks in their correct sequence.
Evidence of human life begins 100k years ago
halflife
halflife--amount of time it takes half of substance to decay after 2 halflives, 25% will be left. after 3, 12.5,
Comparative anatomy-
in comparing structures from one organism to the next, scientists can discover how closely related they are
Homologous features/ homology- (+ex)
features that are derived from the same structure in a common ancestor
Ex- human arm, cat forelimb, whale front flipper, and a
bat wing all have a similar arrangement of bones, muscles, and nerves,
even though they are all used for different types of locomotion
Homoplastic features (analagous)/ homoplasy-
structurally
similar features that are not homologous but have similar functions that evolved independently in distantly related organisms
can lead to convergent evolution
Ex- wings of insects and birds evolved in order to function in flight, but each evolved from different ancestors.
Convergent evolution + ex
independent evolution of similar structures in distantly related organisms
Ex- aardvarks, anteaters, and pangolins all resemble one
another in lifestyle and structural features. All have strong, sharp claws, elongated snouts, long, sticky tongues, but each evolved from a different order
Vestigial structures- + ex
organs that are nonfunctional or
undersized. These are remnants of more developed structures that were functional in ancestral organisms
Ex- in humans, the coccyx (fused tailbones), wisdom teeth, muscles that move our ears. (Usually not eliminated entirely)
Biogeography-
study of past and present geographic distribution of
organisms, which affects their evolution. Unrelated species can
therefore look alike when found in similar environments
can occupy different niches but if they live in the same habitat
placental v marsupial
humans–placental–placenta forms, organ of exchange between
mother and baby, meaning all development happens in utero in amniotic sac
marsupial–give birth to immature baby which crawls out and up into the pouch, filled with tissue