Biology 150 exam 1

reducing atmosphere hypothesis

miller urey experiment; an experiment conducted to test pre life conditions and see if organic molecules could have spontaneously appeared. They found that in an environment with NH3 O2 N2 and H2O organic molecules could have formed

deep sea vent hypothesis

supposes organic molecules could have formed inside hydrothermal deep sea vents that could have provided energy, heat, and mineral catalysts

extraterrestrial hypothesis

supposes organic molecules could have arrived on a meteor or from outer space

step 2 - origins of life

simple into complex molecules. these organic molecules would have polyermerized into more complex compounds, likely aided by mineral surfaces such as clay

Step 3 - origins of life

becoming cell structures. the complex molecules began distinguishing the external from internal by producing boundaries

protobiont

prebiotically produced molecules that acquired a boundary like a lipid bilayer

Step 4 - origins of life

the cell structures gain chemical activity. RNA is thought to be the first macromolecule in protobionts bc it can store info, catalyze (using its ribosomes), and can self replicate.

How did RNA evolve

it had 2 traits it needed to develope: ability to make new RNA (1) and ability to speed up ribonecleotide synthesis (2).

1A: a mutation that coded for replication occured in the RNA

1B: that mutation made the RNA with that gene multiply quicker and eventually beat out the rest of the RNA

2A: a mutation that let RNA catalyze a step in ribonucleoside sequencing production

2B: same thing occured where those RNAs were more fit to reproduce more and outlast the other RNA

whats the origin of eukaryotic cells?

2 methods:

Endosymbiosis - one structure “lives” inside another for a mutually beneficial relationship

Invagination: membrane of a cell folds inward and traps outer material and bacteria (lead to nuclear envelope)

Fossil dating

technique used to determine specimen age

what are the factors of fossil dating

tissue, location,size, species abundance, human bias

how is fossil dating done

by measuring percentage of radioisotope decay

when was the first prokaryote, cyanobacteria, eukaryote, multicellular eukaryote, invertebrate, and when was the Cambrian explosion

3.5 -3.8, 3.5, 2.5, 1.5, 0.6, 0.5 (Billion years ago)

traits used for phylogenetic trees and define

morphological - organisms physical attributes

molecular - DNA sequences

embryonic - developemental similarities

what is phylogeny/ phylogenetic tree

a representation of evolutionary history, visually represented in a tree

define each parts of this phylogenetic tree

Node: where lineage splits

Branch: evolving lineage

clade

an organism and all its decendents

paraphyletic clade

ancestor+group but some decendents are missing

homologs

features in different species that share a common ancestor

paralogs

genes in same species evolved through duplications

orthologs

genes in different species evolved from a common ancestors gene through speciation

evolution

heritable change in 1 or more characteristics of a population or species from 1 generation to another

6 pieces of evidence for evolution

1. fossils

2. selective breeding

3. vestigial structures

4. convergent evolution

5. homologies

6. biogeography

processes of evolution - gene duplication

Gene duplication is a process where a segment of DNA is copied and results in the presence of additional copies of that gene in the genome. This can lead to new functions and greater variability among species.

processes of evolution - mutations

random changes in gene sequences that increase variation

processes of evolution - exon shuffling

process in evolution where genes coding regions (Exons) are mixed through recombination events leading to new proteins and functions

processes of evolution - horizontal shuffling

Horizontal gene transfer is a process where genetic material is transferred between organisms in a manner other than traditional reproduction, allowing for the acquisition of new traits and increased diversity

what can alter allele frequency

1. natural selection

2. genetic drift

3. migration

genetic drift

random shifts in alleles based on random events, usually occurs in small populations

types of genetic drift

founder effect - a few individuals from a population start a new population

bottleneck effect - individuals that survive an event (I.e tornado) have different allele frequencies that the og population

microevolution

changes in gene patterns in a population resulting in character changes

macroevolution

microevolution but over a long period of time resulting in a new species

biolological species concept

that a group of individuals can breed

ecological species concept

species occupying specific ecological niches

evolutionary species concept

each species has its own evolutionary lineage

what does it mean to be a species

organisms share common characteristics, interbreed succesfully, and share evolutionary history.

cryptic species

look similar and have been classifies as one species but are different

anagenesis

process where species goes through gradual change over time leading to new traits, transformation of single lineage

cladogenesis

species evolves into 2 or more distinct lineages or species, occurs when a single ancestor lineage splits into multiple decendants

what are the processes of speciation

genetic changes / microevolution

adaptive changes

reproductive isolation

types of reproductive isolation

pre-zygotic and post-zygotic

types of pre-zygotic reproductive isolation

temporal isolation - organisms aren’t awake at the same time so they can’t reproduce

geographical isolation - organisms are in different locations so they can’t reproduce

behavioral isolation - having different mating calls for ex

gametic - can have intercourse but not reproduce

mechanical isolation - physically cannot reproduce (I.e different genetalia)

types of post-zygotic reproductive isolation

hybrid sterility - can reproduce but the result is infertile (mules)

hybrid inviability - zygote becomes unviable post fertilization

allopatric speciation

physical separation of 1 species that diverge into 2 species

hybrid zones

if there is overlap between the 2 species

adaptive radiation

when species break off into ecological niches

sympatric speciation

adaption to environment and different behaviors

polyploidy

common in plants, change in chromosome number

sexual selection

traits one gender finds more attractive, helps with mate selection

evo-devo (evolutionary development)

different gene expression can lead to developmental differences

what does gremlin do and what does BMP4 do

gremlin inhibits BMP4 and BMP4 causes apotosis

what is apotosis

cellular suicide, method of removing cells

give an example of gremlin and BMP4 being used

both a chicken and a duck had BMP4 but only the duck had gremlin which is why they look different

archea

single celled microorganisms, extremophiles (can live in extreme conditions)

what type of archea likes high salt conditions

halophiles

connections between archea and eukaryotes

histones associated with DNA, 30 or more ribosomal proteins