descent with modification part 2 Flashcards
basic premise of the theory of evolution
organisms are descendants of a common ancestor
divergence
structure found in common ancestor that is modified throughout generations (diverge from ancestral structure)
homologous structures
similar physical structures arranged in different ways (look different, built alike)
convergence
unrelated organisms with similar lifestyles develop similar structures
analogous structures
characteristics that result from shared lifestyle, not shared ancestry
Convergent evolution shows how species have evolved separately but have similar ____ structures
(analogous)
Divergent evolution demonstrates how species can have common _____ anatomical structures which have evolved for different purposes.
(homologous)
vestigial traits
Traits that do not seem to have a function in the current organism but has function in some related species
anatomical similarities- evolution weaknesses
some complex structures evolved more than once
-complex structure did not exist in common ancestor
-must have appeared after common ancestor
anatomical similarities- recent creation perspectives
God created similar organisms to fill similar roles
anatomical similarities- progressive creation perspectives
God may have created several broad types of organisms
-evolutionary descendants display homologies due to common ancestry
-homologies do not prove that they all came from one single ancestor
anatomical similarities: creation weaknesses regarding convergence
why didn’t God reuse structures in species that share a similar lifestyle but are not closely related
anatomical similarities: creation weaknesses regarding vestigial traits
why would God include a structure if it didn’t do anything?
what do evolutionists believe about developmental similarities
-Genetically related organisms go through similar developmental stages
-Organisms result from editing a common set of instructions
developmental similarities: evolution weaknesses
-strctures are not as similar as we thought
-different genes may be responsible for features that appear homologous
what do recent creationists believe about developmental similarities?
God chose to use common developmental themes to create related organisms
what do progressive creationists believe about developmental similarities?
God created common ancestor for different groups of organisms
* Later, God modified common ancestor into several new forms, but did not modify the embryonic form
developmental similarities- creation weaknesses
why would God put genes in an organism if he didn’t plan to use them?
molecular similarities: evolution perspective
-same genes found in many species
-genes with identical function can have slightly different DNA
-closely related species have fewer differences
-animals often arrange into groups based on physical similarities and DNA confirms these groupings
molecular similarities- evolution weaknesses
-some surprises in groups that look similar that are not genetically related
-genes don’t always back up physical similarities
molecular similarities: recent creation perspectives
God made small changes in genes for variety without altering function
*the mutation rate was high after flood ? no evidence
molecular similarities: progressive christian perspectives
God created several types of organisms
-diverged via evolution to form multiple species with genes that are similar
-organisms descending from different types God created are less similar
molecular similarities: creation weaknesses
-if earth is young, genes must have mutated at an incredibly rapid rate
-why would God make the same gene in similar species different if the ONLY advantage of genetic variety is enhanced adaptation via natural selection?
biogeography
study of where different organisms live on the earth
similar habitats in various parts of world are populated by
unrelated organisms (similar traits, not genetically similar)
example: habitat is populated by nearby organisms that adapted to live in that habitat
Islands have plants and animals similar to the nearby mainland
adaptive radiation
single species adapts to many roles in empty environment
adaptive radiation creates
many closely related species
marsupials
Located almost exclusively in Australia and the surrounding islands
biogeography- recent creation perspective
God created different animals in different parts of the world for diversity
biogeography- progressive creation perspective
no conflict with evolutionary perspective
biogeography- creation weaknesses
To get on the ark, how did marsupials get to the idle east and then back to Australia without leaving fossils anywhere?
why didn’t the violent mixing in the flood spread fossils all over the world?
continental drift is caused by
plate tectonics
overview of plate tectonics
Earth’s crust made of plates that can move around
Plates formed by volcanic ocean ridges
Plates eventually forced back down into earth’s interior
continents were all connected in the ___ era
Pangea
evidence of continents being close together in Pangea era
Identical fossils are found on different continents (they could NOT have crossed ocean, continent were just nearby)
continental drift- evolution weaknesses
It is not known for sure what forces cause crust movement (there are only some hypothesis)
continental drift- creation weaknesses
o Plates would have to move very rapidly during the flood
Huge amounts of heat generated by friction
Would have boiled away all of Earth’s oceans
o Huge energies needed to start and stop rapid plate movement
o Why are plates still moving?
radiometric dating
using radiometric decay to determine how old rocks are
radioactive atoms are…
not stable
misconception: radiometric decay may have been much faster in the past
Scientists have never been able to artificially change the rate of decay
fossils
the remains of an organism left in soil or rock
where are fossils found?
sedimentary rock
-sand and sediment deposited into water and later turned into rock
a fossil is formed when an organism is buried…
Must not be eaten first or decompose
Soft parts decompose quickly
Requires specific conditions
Forming a fossil is difficult and unlikely
There is an order to the fossil record with ___ organisms at the bottom and ___ organisms near the top
extinct; living
what fraction of species are preserved as fossils
10%
almost all major animal groups suddenly appear when?
Cambrian explosion
____ changes are more likely to be preserved in the record
small
why does the Cambrian explosion not fit in Darwins evolutionary model of SLOW and STEADY change?
Organisms can suddenly look very different with little evidence of how or why they changed so quickly
fossil record- recent creation perspectives
-fossils created during the flood and associated events
-order may be due to how well organisms float
-order may be due to how soon environments were flooded
-God may have created fossils to give the earth apparent age
fossil record- progressive creation perspectives
No conflict with evolutionary perspective for most of the fossil record
Large jumps in the record are when God created new forms
fossil record- creation weaknesses (pollen argument)
Today, pollen is found everywhere on earth. Why does pollen first appear in the fossil record near the same time as flowering plant fossils first appear?
-If everything was created at the same time, why is there a lot of mud that does not have pollen in it?
transitional fossils are found where?
right where you would expect them
___ is a link between birds and dinosaurs
Archaeopteryx
transitional fossils- evolutionary weaknesses
o Some transitional fossils are missing
o Some transitional fossils have some characteristics that are not transitional
Brings the transitional interpretation into question
transitional fossils- creation weaknesses
o Why transitional organisms appear in the correct order in the fossil record
Not a weakness for a progressive creation
o Why you can predict where to find transitional organisms
there are __ species of hominins with characteristics more similar two humans than any other type of animal
20
homo ergaster
was primarily bipedal with a large brain
homo neaderthalensis lived primarily in
Europe
humans did Not descend from Neanderthals, they
reproduced with each other
humans vs Neanderthals
neanderthals are stronger and have larger brains
what %of human DNA may be from Neanderthals?
1.5-2%
___________ is supported by evidence from many different areas of science
Common descent model
