Evidences of Evolution Flashcards
remains of organisms that lived long ago
fossils
mostly found in sedimentary rocks
preserved fossils
tell us that species are not immutable
what is a geological time scale
a record of the life forms and geological events in Earth’s history
scientists develop the time scale by studying (2)
rock layers
fossils
how old is the Earth
4.5 billion years old
the earliest known cells are found in
3.5b year old rocks
earliest known eukaryotic cells date to
1.5b years
earliest multicellular animals date to
650m years
earliest land animals
450m years
earliest mammals
230m years
what happened 65m years ago
mass extinction
what happened 4.5m years ago
human family tree diverged from other apes
eras (3)
cenozoic
mesozoic
paleozoic
periods in the cenozoic era (2)
quaternary
tertiary
mesozoic era (3)
cretaceous
jurassic
triassic
paleozoic era (6)
permian
carboniferous
devonian
silurian
ordovician
cambrian
biogeography
study of the distribution of plants and animals
Philip Sclater
a bird specialist who divided the world into 6 biogeographical regions in 1857
phytogeography
study of the historical processes that may be responsible for the past to present geographic distributions if genealogical lineages
Alfred Wegner
proposed the Theory of Continental Drift in 1915
continents have undergone large movements over the past 300m years
how did continental drift affect the evolution of life on Earth
separated species. those who were able to interbreed became isolated from one another. this allowed them to acquire certain adaptations and made them incompatible or unable to work/exist together due to their differences
homologous structures
similar structure that can be found in very different animals, often pointing towards a common ancestor
analogous structures
structures that serve a similar function but are not derived from a common ancestor
vestigial structures
structures that are underdeveloped and seemingly useless, but may be fully developed and function in related organisms
molecular clocks
powerful tool for estimating the dates of lineage-splitting events
macroevolution
refers to evolution above the species level
patterns of macroevolution (2)
adaptive radiation
phyletic evolution
adaptive radiation
a single ancestor givers rise to a number of new species
phyletic evolution
gradual changes in a single lineage
other patterns of evolution (4)
divergent evolution
convergent evolution
parallel evolution
coevolution
occurs when a single lineage splits to give new forms
divergent evolution
describes evolution towards similar traits in unrelated species
convergent evolution
when two species are similar in a particular characteristic, it is only convergent evolution if their
ancestors were not similar
evolutionary pattern that is seen in groups of organisms that are closely related
parallel evolution
after organisms diverge from a common ancestor, these organisms continue to ___ because
resemble one another, they have been subjected to the same adaptive pressures
coevolution
two unrelated groups are selective agents for each other