BSCI 160 Exam 2

exam 2 review (diversity)

Straitigraphy

the study of the order and correlation of Earth's rocks

Strata

layers of sedimentary rock

oldest layers are at the \________ of strata

bottom

trace fossils

imprints left in mud or volcanic ash

radiometric dating

can determine absolute age of volcanic rocks or carbon-containing material

uses isotope decay

isotope decay

the process by which an unstable atomic nucleus loses energy by radiation

-based on the half life of radioactive element
-amount of isotope remaining indicates how much time has passed since event

paleomagnetic dating

A method for determining the age of rocks based on properties relating to changes in the patterns of Earth's magnetism over time.

-earths magnetic poles move and occasionally reverse

life appeared on earth \_______ years ago

3.8 billion
prokaryote - before nucleus was formed

eukaryoute - 1.5 billion years ago, have nucleus

Precambrian

the oldest and longest span of geologic time

-diversity was limited by low O2 concentrations and extreme cold / glaciation

aerobic matabolism

Metabolism that can proceed only in the presence of oxygen.

--organisms with this replaces anaerobes

Anaerobes

do not require oxygen and may even be killed by exposure

factors influencing evolution of life on earth

-geological events (continental drift, volcanoes)

-extraterrestrial events(earth's orbit, asteroids)
-changes in oxygen concentrations
-extinctions and adaptive radiations

Evolution of chloroplasts and mitochondria

prokaryotic organisms that became part of a eukaryotic cell because of a symbiotic relationship, it gave energy to the eukaryotic cell.

(abt 1.5 billion years ago)

Alfred Wegener

A German scientist who proposed the theroy of continental drift

continental drift

The hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations

Pangaea

The name of the single landmass that broke apart 200 million years ago and gave rise to today's continents

tectonic plate theory

earths crust divided into 14 plates, contintents embedded in plates, plates float above mantle

Why do plates move?

convection currents in the mantle below move plates

-hot \= less dense(rises)
-cool \= denser atomic structure (sinks down)

why does the temperature fluctuate?

-ash
-axis of sun changing
-earths orbit changing
-creates warm and ice ages

Great Oxygenation Event

A time about 2.5 billion years ago, when a significant amount of oxygen appeared in the atmosphere

-large vascular plants evolved
-allowed for giant amphibians and gian flying insects

Geological Time Scale (GTS)

the categories of time into which Earth's history is usually divided by geologists and paleontologists: eons, eras, periods, epochs

Cambrian explosion

rapid diversification of most major animal groups marking the start of the Paleozoic era

Devonian Period

continents begin merging

age of fish

Carboniferous Period

When ferns and amphibians were dominant and coal deposits formed

Permian Period

-continents merged to form Pangaea

-amniote lineage split

Pleistocene and Holocene Epochs

Pleistocene - "ice ages" continental glaciers spread, divergence with primates, eventually leading to Homo Sapiens, many large mammal species became extinct when Homo Sapiens arrived due to hunting

what features define life

growth
respond to environment
reproduce
heredity of traits
homeostasis
metabolism
cellular

4 major steps in origin of life

1. small/mid size organic compounds

2. complex polymers 3/4) liposomes - internal environment 4/3) self -replication

formation of small/mid size oganic compounds
step 1

-simple compounds
-some energy input to create bonds and have small and mid size oganic compounds

H2, CO2, CH4, NH3 \----\>
H2CO, HCN, amino acids, sugars, nitrogenous bases

Oparin-Haldane hypothesis

simple organic compounds were changed by heat and solar radiation into more complex organic compounds

Formation of polymers
step 2

amino acids --\> proteins
nucleotides -\>nucleuic acids
monosaccharides --\> polysaccharides

formation of liposomes
step 3/4

membrane bound vesicles, lipid bilayer

can form / assemble spontaneously

provides an internal environment for chemical reactions

self-replication
step 4/3

dna information storage
protein-catalyst function

RNA world hypothesis

life based on self replicating RNA
preceded life based on DNA + protein

all organisms have

• Cell membranes and ribosomes

• Common metabolic pathways

• Semiconservative DNA replication

• DNA that encodes proteins

shared features indicate that all living organisms share a common ancestor

prokaryotes have

-naked dna
-small singular genome
-no membrane bound organelles
-few membranes
-no meiosis \= mo "sex"
-different types of "flagella"

Eukaryotes have

-linear double stranded dna with histones
-nuclear membrane
-membrane bound organelles
-endomembranes and filaments form a cytoskeleton
-mitchondria and in some Chloroplasts
-sex,meiosis
-9+2 flagella

Flagella

A long, whip-like filament that helps in cell motility. Many bacteria are flagellated, and sperm are flagellated.

"Prokaryotes" \=

Bacteria + Archaea

three primary domains

Bacteria, Archaea, Eukarya

two primary domains

Bacteria and Archaea

evolution of eukaryotic cells

Most widely accepted theory: Endosymbiotic theory
Some prokaryotes came to reside in other prokaryotes establishing a symbiotic relationship known as mutualism
Beneficial to both
Picture a large amniotic prokaryote phagocytizing other prokaryotes
Could of resulted in chloroplasts and mitochondria

phagocytosis

the ability to engulf and digest other cells

Endosymbiosis

a proteobacterium was incorporated and evolved into the mitochondrion

all mitochondria form a \_______________ group

monophyletic

Reproduction in Prokaryotes

prokaryotes divide by binary fission
asexual reproduction

ori site

origin of replication in prokaryotes

mechanisms of lateral gene transfer

transformation, transduction, conjugation

transformation

genes from environment or dead bacteria or archeae

conjugation

the transfer of genetic material from one cell to another involving cell-to-cell contact

Transduction

gene movement via virus infection

anaerobic metabolism

The metabolism that takes place in the absence of oxygen; the principle product is lactic acid.

-atp available by burning glucose
glycolysis

aerobic metabolism

Metabolism that can proceed only in the presence of oxygen.
krebs cycle

oxidative phophorylation

The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration.

Firmicutes

-group of bacteira
-produces heat - resistant endospores
-some have survived for 1000 of years
-includes staphylococci (abundant on skin)

Mycoplasma

bacteria that lack cell wall
extremely small
very small genome

Actinobacteria

gram positive
occur in branced filaments
source of antibiotics

gram positive

stains purple

Cyanobacteria

photosynthetic
blue and green pigments
can fix nitrogen

Spirochetes

spiral shaped
gram negative
provide shape and motility
many nasty parasites

chlamydias

can live only on parasites
gram-negative extremly small
various eye infections, STDS

Protobacteria

largest group of bacteria
some are photoautotrops, nitrogen fixers

seperating archaea from bacteria

-based on sequencing of ribosomal RNA genes
-archaea lack peptidoglycan cell wall and have different lipids in cell membrane, live in extreme habitats

Euryarcheota (Archaea)

more derived / specialized bacteria
live in ever conceivable habitat
can be in guts of ruminants. termites, cockroaches

Crenarcheota (Archaea)

thermophillic and or acidophillic
live in extremely hot, high pressure, cold, or acidic environments
live in places with pH of possible 2 but bodies pH still neutral

Thaumarchaeota (Archaea)

ammonia oxiders in squatic and terrestrial environments

requires less oxygen than ammonia-oxidizing bacteria

Korarchaeota (Archaea)

a phylum of Archaea that contains the hyperthermophile Korarchaeum cryptophilum

Lokiarchaeota

the "missing link"

-found near a field known as Loki's castle
-analysis saw that several genes were very similar to eukaryotic genes for cell membrane - related functions
-suggested monophyletic grouping of Lokiarchaeota with the eukaryotes

Biofilm formation

collection of microbes living on a surface in a complex community

Biofilms

dense microbial assemblages attatched to the surfaces

Viruses

-evolve
-infect all forms of life
-extremely abundant
-small genomes
-not monophyletic

Viral Replication

a virus injects genetic material into a host cell, often turning it into a virus factory

lytic life cycle

bacteriophage attaches to the host cell and injects its DNA
new phage DNA and proteins are synthesized and assembled into new phages
cell lyses

Bacteria phage

virus that attacks bacteria

phage therapy

using bacteriophages to treat bacterial infections

lysogenic life cycle

viral genome is incorporated into host cell genome and is replicated along with host genome

eukaryotes

-monophyletic group
-more closely related to Archaea than Bacteria
-acquired features from both
-major lineages diversified in the Precambrian

Protists

A eukaryotic organism that cannot be classified as an animal, plant, or fungus.

produce both sexually and asexually

budding

outgrowth of a new cell from the surface of an old one

Sporulation

formation of specialized cells that can develop into new individuals

clonal lineages

asexually reproduced groups of nearly identical organisms

Cytoskeleton

major cell organelle in eukaryotes - 3 main kinds of cytoskeletal filaments (microfilaments, microtubules. and itnermediate filamenets)

simple cytoskeletons exist in prokaryotes

Microfilaments

Long, thin fibers that function in the movement and support of the cell

intermediate filaments

Threadlike proteins in the cell's cytoskeleton that are roughly twice as thick as microfilaments. organize the internal 3 dimensional structure of the cell, anchoring organelles

microtubles

a microscopic tubular structure present in numbers in the cytoplasm of cells, sometimes aggregating to form more complex structures.

alternation of generations

a multicellular, diploid spore producing organism gives rise to multicellular haploid gamete producing organism

haploid organism, the diploid organism, or both may also produce asexually

heteromorphic

the two generations differ morphologically

isomorphic

generations look similar

Clades of Eukaryotes

8 major clades
five major clades of protistan eukaryotes w diversity
most unicellular and microscopic
multicellularity has arisen dozens of times in the eukaryotes

Protist groups

diplomonads/parabasalids, euglenozoa, alveolata, stramenoplia, rhodophyta, chlorophyta, choanoflagellida

alveolates

sacs called alveoli lie just beneath the cell membrane
all unicellular, most photosynthetic

three primary groups:
dinoflagellates
apicomplexans
ciliates

Dinoflagellates

plant-like protist that causes red tide
mostly marine
some are endosymbionts within inverterbates
some are non photosynthetic parasites within various marine organisms
can release toxins

Apicomplexans

contain apical comppelx that help invade the host tissue
parasitic, cause disease (ex. malaria)

Malarial Parasite

Two interdependent life cycles
Sexual cycle: occurs in the mosquito
Asexual cycle: occurs in the human
Knowledge of the life cycles is essential in understanding antimalarial drug treatment
Drugs are effective only during the asexual cycle

Ciliates

have numerous hairlike cilia
complex body forms
generally heterotrophic but some have photosynthetic endosymbionts

Reproduction in Paramecium

The nucleus can divide to support cell division by mitosis, reproduction is often asexual

conjugation (paramecium)

two individuals fuse and exchange micronucle; a sexual process, but not reproductive

Diatoms

single-celled organisms. found in salt and fresh water. producers. make up a large percent of phytoplankton. cell walls contain cellulose and silica (frigid and glasslike). used in silver polish, toothpaste, filter and insulation

brown algae

One of a group of marine, multicellular, autotrophic protists, the most common type of seaweed. Brown algae include the kelps.

Oomycetes

water molds