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Ch22 - Intro. to Evolution - Coggle Diagram
Ch22 - Intro. to Evolution
basic concepts
species-
group of related species that share
a distinctive form and are capable
of interbreeding.
breed-
plants or animals that are morphologically similar and are part of the same species
strain-
bacteria that are morphologically similar and are part of the same species
population-
individuals from the same species that occupy a certain area at a specific time
the theory of evolution
adaptation-
short-term change in genetic expression that allows an organism to adjust to an environment
evolution-
long-term permanent genetic change (mutations) that are heritable and lead to development
microevolution-
changes in a single gene in a population over time; can lead to macroevolution
macroevolution-
formation of new (groups of) species
evolution is based on two factors
variation-
heritable traits passed from parents to offspring
natural selection-
more offspring are produced than can survive; there is competition for limited resources so individuals with favorable genes will survive and reproduce
evidence for evolution
convergent evolution-
two different species becoming similar due to living in the same environment; shows how natural selection allows adaptation to a certain environment
fossil records-
comparing fossils by age can make evolutionary changes apparent
selective breeding-
traits in domesticated species have been modified by selective breeding (aka. artificial selection) where parents with favorable traits are chosen by breeders
homologies
anatomical-
anatomically similar structures due to evolution from the same ancestor
vestigial structures- anatomical structures that have no apparent functions, but resemble structures of presumed ancestors
developmental-
embryonic development analysis can point to past evolutionary relationships
similarities in the embryonic stages
molecular-
species that are related evolutionarily have more similar DNA sequences that are either expressed or silenced
Biochemical pathways
molecular pathways
Homologous genes-
2 or more genes derived from the same ancestral gene
paralog genes
occur within the same species
gene duplication can lead to a gene family which is two or more paralogs in the genome of one organism
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ortholog genes
occur in separate species
reveal molecular details of evolutionary change
two sequences that are similar but not identical due to independent accumulation of different mutations
analogous genes-
genes that have identical or similar function but don't share a common ancestor
gene transfer
horizontal
asexual
exchange of genetic material even between distantly related species
can occur between and among eukaryotes and prokaryotes (widespread among bacteria)
vertical
sexual
transfer of genetic material from parent to offspring
studies of natural selection-
looking at the development of characteristics of a population over time can highlight the changes that occurred in response to environmental changes
biogeography-
~unique species formed due to isolation in a particular area (e.g., islands) away from the rest of the world
~study of geographical distribution of modern and extinct species
endemic- naturally found only in a specific location
homology vs. analogy
homologous-
similar structure (anatomically, molecularly & developmentally), different function
analogous-
different structure (anatomically, molecularly & developmentally), similar function
evolutionary developmental biology (Evo-Devo)
what is Evo-Devo?
compares the development if different organisms to understand:
ancestral relations between them
developmental mechanisms that cause evolutionary change
involves discovery of genes that control development and the difference in their roles among different species
developmental genes
can influence:
cell division
cell migration
cell differentiation
apoptosis
interplay produces an organism with a specific body pattern
very important to the phenotypes of individuals
hox genes
found in all animals; number and arrangement differs from one animal to the other
increases in the number of hox genes may have led to greater complexity in body structure
homeotic (regulatory) genes that specify the fate of a region or segment of the body
variation of these genes may have started the formation of new body plans
evidence for the importance of hox genes
they are known to control the fate of regions along the anteroposterior axis
there is a general trend for more complex animals to have more hox genes and clusters
there are striking parallels when comparing the evolution of hox genes and animals