Test 1 Flashcards
What did Jean-Baptiste Lamarck propose?
Evolution occurs by inheritance of characteristics acquired by selective pressures
variation is acquired
What did Charles Lyell propose?
geologist that proposed uniformitarianism through the stratification of the earth’s core.
species appeared over time in the geological record, some disappeared and some modified
Alfred Wallace
developed theory of evolution through natural selection (independent of darwin)
published theories with Darwin
What is Wallace’s Line
Line between Bali and Lombok that separates the Asian Fauna from Australian Fauna
Charles Darwin
proposed that populations varied and those who were better suited to survive will pass their traits along
“On the Origin of Species”
Which animals were studied on the Galapagos
Land Tortoises
Darwin Finches
Blue-Footed Booby
Marine Iguanas
How did the Galapagos Islands allow for variation?
Islands varied in natural resources
Archipelago allowed for animals to be reproductively isolated
Natural Selection
individuals with certain alleles produce more surviving offspring than those without
increased allele presence over generations
Definition of “fitness”
measure by the number of surviving off-spring that are able to reproduce
Hardy-Weinberg Principle
genotypes will remain constant as long as
- population size is large
- mating is non-selective
- no mutations appear
- no selective pressures occur
- no im/emigration
Hardy-Weinberg Equation
p + q = 1
p - frequency of dominant allele
q - frequency of recessive allele
p^2 - homozygous dominant
2pq - heterozygous dominant
q^2 - homozygous recessive
Five Agents of Evolutionary Change
Mutation
Gene Flow
Nonrandom Mating
Genetic Drift
Selection
What is mutation?
change of an allelic proportion in a population
What is gene flow?
movement of alleles from one population to another
What is non-random mating?
mating based on a preference
inbreeding - > homozygosity
outbreeding - > heterozygosity
genetic drift
fluctuation of allele frequencies
founder effect
small population that turns into a large population quickly with out much genetic diversity
bottleneck effect
large population that decreases rapidly due to lack of genetic diversity
evolution definition
change in frequency of an allele in a population
Adaptive Selection Theory & polymorphism
animals with a common ancestor that adapted to different areas of a specific environment to avoid resource competition.
what is a transient species?
a transitional species that can allow for gaps in evolution to be explained
what is a punctuated equilibrium?
period of rapid speciation due to a change in environmental pressures
evolutionary change can be seen to move faster in smaller populations
Divergent Evolution (speciation)
evolution of different species of animals that can be traced back to a common ancestor
generally adapted to cope with new env. pressure
convergent evolution
organisms that are not from a common ancestor that independently evolve similar traits
analogous structures
features of species that are similar in function but not necessarily similar in structure / do not derive from a common ancestor
ex - flippers on dolphins and wings on penguins
homologous structures
features of a species that are similar in structure, but serve different functions / derive from a common ancestor
ex - human and dog limbs
artificial selection
favored traits that get selectively bred
vestigial structures
structures with no apparent function, but resemble ancestral structures
ex - leg bones in whales or snakes
importance of molecular record
species more closely related have more DNA similarities than those that are distantly related
Two Events necessary for speciation
reproductive isolation
genetic divergence
species definition
all individuals being capable of interbreeding and production fertile offspring
micro-evolution
change in allele frequency in a population that leads to a new species
macro-evolution
numerous species evolving simultaneously
2 Reproductive Isolating Mechanisms
prezygotic
postzygotic
prezygotic mechanism
prevention of proper zygote formation
postzygotic mechanism
form a zygote but it does not develop properly
offspring are not able to establish themselves within a niche & are unable to function
behavioral isolation
difference in behavior maintains distinctiveness
ex - mating calls
Ecological isolation
species that habit the same niche but utilize different portions / resources within that niche
Temporal Isolation
difference in mating / blooming periods
–> limits resource competition
Mechanical Isolation
structural differences that prevent mating from occuring
Prevention of Gamete Fusion
physiological mechanisms that prevent fertilization
Allopatric Speciation
geographical isolation that leads to genetic divergence
2 types of sympatric speciation
ecological
chromosomal
peripatric speciation
same as allopatric but the population can be assumed to be much smaller.
Ecological Sympatric Speciation
genetic divergence due to the exploitation of different resources / habitats within a niche
Chromosomal Sympatric Speciation
external factors that lead to an affected mutation rate. Chromatids that do not split during anaphase (mitosis I or II)
divergent speciation
single species splits into two separate species.
both can exist at same time but do not breed.
phyletic speciation
gradual change to a population that separates itself from the one that gave rise to it.
How do mammals differ?
fur, endothermic metabolism, and increased brain size.
What happened during the Permian extinction?
tectonic plate malformation that led to nuclear winter due to toxic gasses being released in the atmosphere
90% of all species became extinct
Out of Africa Theory / Adaptive Radiaion
spread of homo erectus and homo sapien populations from the great rift valley. belief that the homo sapiens were more evolutionarily fit and outlasted homo erectus
Multiregional Theory
spread of homo erectus population that evolved into homo sapeins by intermingling
neanderthals
separate species from homo sapiens that were the first hominids that provided evidence of cultural factors
ex - buried the dead with tools they’d use in the afterlife
Cro-Magnon
existed with neanderthals but outlasted them due to greater brain capacity
left records of cave paintings (cultural factors)
- means they had a higher level of mental processing and resource stability
What is the Binomial System and who Developed it?
Carolus Linnaeus developed a two-part names that are used to designate species
what is the order of the binomial system
Genus species and written in latin
Taxonomic Hierarchy
Kingdom
Phylum
Class
Order
Family
Genus
Species
Importance of 18-S ribosomal subunit
when sequenced, this subunit allows one to see when a species diverged
phylogenetics
study of ancestor-descendent relationships
what is systematics and how is it used in phylogeny
reconstruction and study of the relationship between species
monophyletic vs. para vs. poly
mono - ancestor and all descendants
para - ancestor but not all descendants
poly - convergent descendants w/o common ancestor
- evidence of convergent evolution
cladogram
aka phylogenetic tree
outgroup vs ingroup
out - organism for comparison
in - organism being evaluated
eukarya vs prokarya vs archea
nucleus vs no nucleus vs extremophils
Principle of Parsimony
explanations with fewer evolutionary steps are preferred
ex - more likely that a few species developed a trait than the idea that every species had the trait and only a few kept it
how did the Delta 32 mutation help those during the plague
recessive gene
heterozygotes got sick but were able to survive
homozygotes didn’t get sick at all
Characteristics of animals
multicellular
heterotrophic
diploid - two sets of chromosomes
reproduction by oogamy - ability to make diploid cells from haploids
key transitions in animal evolution
tissue development
body symmetry
body cavity
developmental patterns
segmentation
parazoa
sponges without defined tissue
cells will grow back together if broken apart (reaggregate)
eumetazoa
distinct, well-defined tissue
radial symmetry
symmetry along any imaginary axis
ex - cutting a pie
bilateral symmetry
mirror images
right / left & front / back
cephalization
development of a structure that holds ganglion of nerve cells in order to process information and respond
Three kinds of tissue / germ layers
ecto - outer
meso - middle
endo - inner
coelom
cavity lined with mesoderm that allows for an organ to be suspended in cavity
ex - humans
aceolom
no body cavity, gut runs through solid tissue
ex - flatowrms
psuedocoelom
false coelom that is not lined with mesoderm
ex - nematode
closed circulation
separates oxygenated & deoxygenated blood
Open circulation
Mix of oxygenated & deoxygenated blood
deuterostomes
radial cell growth / blastophore becomes anus
protosomes
spiral cell growth/ blastophore becomes mouth
