module 13 Flashcards
(40 cards)
Senescence
progressive deterioration of physiological function with increasing age
age dependent increase in mortality and decline of fecundity
What does evolution of death do? (Weissmann) (3 pts)
ensures removal of less fit individuals from population to make room for reproductively prolific individuals
long lived individuals have more offspring than short lived which selects against death
acquisition of mutations with age selects for death
Mutation accumulation hypothesis
MA suggests that selection weakly impacts mutations results in late-onset degeneration
- loci can acquire more neutral mutations via drift with age
- only detectable if individuals survive long enough and express symptoms of aging
Antagonistic pleiotropy hypothesis
AP results in strong selection for mutations beneficial early in life but deleterious later in life - aging is a maladaptive byproduct of survival and reproduction during youth
Disposable soma hypothesis
Investment in optimization of somatic cell repair and maintance (for indefinite survival) is not worthwhile since extrinsic mortality will prevent realization - investment in reproduction is more quickly realized.
Transcription/translation in germ line cells evolved towards fidelity and error-checking meiosis.
somatic cells selected for growth
plant senescence
annuals can devote energies towards seed prodctuion - pernnials have a head start on annuals - reduced genetic diversity in perennials subject to rapid environmental/predation changes
self pruning due to low nutrient productivity and accessiblity for pollinators
minimizes abiotic and biotice effects on the plant
major transitions
occurrences in time that set the stage for the evolution of cellular and multicellular forms
Biological ontogeny take homes
- biomolecules could be generated abiotically
- catalytic rnas can transmit information and self-replicate
- cells compartmentalize key biomolecules and increase their encounter frequency
miller-urey exp
showed that mimicking prebiotic conditions in teh lab could result in the production of the 20 most common amino acids
what are the major transitions
molecular replication, information storage and transmission, segregation of 1 and 2, prokaryotes to eukaryotes, unicellular to multicellular, solitary life to multigenerational colonies
transition 3 take homes
Endosymbiosis was fundamental for the emergence of eukaryotes Genetic analyses revealed the bacterial origins of mitochondria and chloroplasts Other forms of endosymbiosis exist Gene and/or metabolite exchange between endosymbiotic partners helps to maintain the relationship
evidence for symbiosis?
separate circular genomes, similar cell size to bacteria, independent replication, genes resemble those form bacteria
Hominoidea
Apes (Hominoidea) are a branch of Old World tailless simians native to Africa and Southeast Asia.
Hominini
or hominins, form a taxonomic tribe of the subfamily Homininae (“hominines”). Hominini includes the genus Homo (humans), but excludes the genus Gorilla (gorillas).
Sahelanthropus
an extinct species of the Homininae (African apes) dated to about 7 million years ago, during the Miocene epoch. The species, and its genus Sahelanthropus, was announced in 2002, based mainly on a partial cranium, nicknamed Toumaï, discovered in northern Chad.
Ardipithecus
is a genus of an extinct hominine that lived during the Late Miocene and Early Pliocene epochs in the Afar Depression, Ethiopia.
Australopithecus
one of the longest-lived and best-known early human species
Kenyanthropus
is a 3.5 to 3.2-million-year-old (Pliocene) hominin fossil discovered in Lake Turkana, Kenya in 1999 by Justus Erus,
Homo naledi
an extinct species of hominin, which anthropologists first described in September 2015 and have assigned to the genus Homo.
Homo ergaster/erectus
extinct chronospecies of the genus Homo that lived in eastern and southern Africa during the early Pleistocene, between about 1.9 million and 1.4 million years ago. Originally proposed as a separate species, H.
Homo heidelbergensis
extinct species or subspecies of archaic humans in the genus Homo, which radiated in the Middle Pleistocene from about 700,000 to 300,000 years ago, known from fossils found in Southern Africa, East Africa and Europe. African H. heidelbergensis has several subspecies.
Homo floresiensis
, dubbed “the Hobbit,” was an ancient hominin that lived until at least 17,000 years ago. Scientists discovered the first H. floresiensis fossil, along with stone tools and animal remains, in 2003 in the Liang Bua (LB) cave on the remote Indonesian island of Flores, according to a 2004 Nature paper.
Homo neanderthalensis
are our closest extinct human relative. Some defining features of their skulls include the large middle part of the face,
lactase persistance
is the continued activity of the lactase enzyme in adulthood. Since lactase’s only function is the digestion of lactose in milk, in most mammal species, the activity of the enzyme is dramatically reduced after weaning.
