Biodiversity
Theory of Island Biogeography: as the size of a habitatable area decreases, species diversity within that habitat will decline.
Overexploitation
Threatens species
Disrupts ecological relationships within communities
Eukaryotic Diversity
Opisthokonts: the most diverse super kingdom (animals, fungi, and some protists)
Photosynthesis was spread through eukaryotes
Genetic Variation
We can use DNA sequencing to identify differences
Selection
Artificial Selection
Natural Selection
Population
gene pool: consists of all alleles present in all individuals of the species #
Genetic variation can be measured by allele frequencies
Evolution #
the particular allele divided by the total amount of all alleles of that gene in a population (p+q=1)
supported by a large amount of evidence
genetic drift, migration, mutation, nonrandom mating
genetic drift is a kind of sampling error that results in allele frequency change by chance #
Biological Species Concept: species are groups of actually or potentially interbreeding populations that are reproductively isolated from other such groups
nonrandom mating can occur when individuals prefer mates with particular superior physical characteristics or for the individuals preference to mate with someone similar to themselves #
Reproductive Isolation #
Behaviorally Isolated meaning individuals that only mate with other individuals based solely on specific courtship rituals, songs, or behaviors #
Pre-zygotic Isolation
Post-zygotic Isolation
due to things like not ready at the same time, located in different places, or for behavioral reasons
genetic incompatibility
zygote could fail after fertilization or not be able to reproduce
the more closely related - and therefore genetically similar - the less genetically incompatibility between genomes
Evolution happens at the species level or higher #
begins when gene flow between populations is reduced or elimiated #
initially identical populations must diverge
reproductive isolation must evolve to maintain these differences
phylogenetic trees #
Hypothesis of the evolutionary expansion and relationships between organisms
monophyletic: group including all the descendents of a common ancestor
paraphyletic: group including some of the descendants of a common ancestor
polyphyletic: group including organisms from distinct groups based on shared, convergent characters, and does not include a common ancestor
Homologies
similarities based on ancestry
Analogies
can be ancestral, unique to a particular group, or present in some, but not all, of the descendants of a common ancestor
Only shared characters are useful in constructing trees
Fossil Record provides direct evidence of evolutionary history #
Remains of organisms preserved in sedimentary rocks
Radioactive decay of unstable isotopes of elements provides a means of dating rocks
Mass Extinction #
vicariance
Prokaryotes
Bacteria
size limited by diffusion
horizontal gene transfer #
Eukaryotic DNA is linear
rate of diffusion is dependent on surface area #
larger cell size, compartmentalized, sexual reproduction
membrane bound organelles increase metabolic efficiency
Cytoskeleton: internal scaffolding of proteins; can move whole cells or properties within the cell
can feed on larger cells using phagocytosis
prokaryotes then two million years were eukaryotes #
endosymbiotic theory
similarities between chloroplasts and cyanobaceria
complex multicellularity #
arose several time in evolution
can be unicellular or multicellular as well as simple and complex multicellularity
simple multicellularity: the adhesion of cells although there is little cell differentiation
complex multicellularity: requires cell adhesion, cell signaling, and differentiation and specialization among cells
movement of molecules from high concentration to low concentration
constraints imposed by diffusion can be circumvented by using bulk flow instead
plants and animals evolved complex multicellularity independently of each other
Nutrient Acquisition
Fungi
traps nematode, the digests on inside, sucks in nutrients
NOT the same as a plant
high SA:V
Good for absorbing nutrients
bad bc needs more nutrients, loses heat and water quickly
Animals
ingest then digest then absorb then eliminate
Feeding Strategies
Suspension Feeding
Substrate feeding
Fluid feeding
Bulk feeding #
all organisms need an energy source as well as a carbon source #
can be phototrophs, chemotrophs, autotrophs, or heterotrophs
Archaea
three major groups
Euryarcheota
TACK
DPANN
DNA occurs in circular form like bacteria #
membranes made by lipids
.