YAY more DAT biology

taxonomy

science of classifying animals

3 domains

archaea: single-celled prokaryotes, no peptidoglycan, ether-linked

eubacteria: single-celled prokaryotes, yes peptidoglycan, ester linked

eukarya: contain membrane-bound organelles, multicell or unicell

kingdoms

archaea

eubacteria

protist

fungi

plantae

animalia

prokaryotes

no membrane bound organelles

store genetic info in nucleoid region

either archaea or eubacteria domains

Archaea are more closely related to Eukarya than Eubacteria

Archaea possess unique genetic, biochemical, and evolutionary traits that distinguish them from Eubacteria and link them more closely to Eukarya

endospores

preserve genetic material during harsh conditions

extremophiles

Usually archaea

can survive very harsh conditions

peptidoglycan

make up bacterial cell walls

made of sugars and amino acids

capsule of bacteria

protective coating

virulence factor

gram positive bacteria stain color

purple

gram positive bacteria traits

thick, no outer membrane

no LPS

teichoic acid that connects peptidoglycan to the membrane

exotoxins: toxic proteins

gram negative bacteria stain color

pink

gram negative bacteria traits

thin peptidoglycan layer

periplasmic space filled with periplasmic fluid

Lipopolysaccharides (LPS): endotoxins released when bacteria dies

secretes exotoxins

no teichoic acid

prokaryote characteristics

no membrane bound organelles

smaller

no steroids in the membranes

nucleoid region

origine of replication: 1 in eubacteria, many in archaea,

ribosomes 70S (50S+30S)

only flagella, no cilia

glycolysis, pyruvate oxidation, Krebs cycle in cytosol, electron transport chain in cell membrane

eukaryote traits

membrane-bound organelle

cell wall only in plants and fungi

larger

steroids in the cell membrane

nucleus

no plasmids

many origins of replication

ribosomes 80S (60S and 40S)

glycolysis in cytosol, pyruvate oxidation in mitochondrial matrix, Krebs cycle in mitochondrial matrix, electron transport chain in mitochondrial inner membrane

protists

mostly unicellular eukaryotic organisms

1) fungus-like protists

2) plant-like protists

3) animal-like protists

fungus-like protists

lack a cell wall made of chitin

move via cilia or flagella

saprophytic: feed on decaying organic material via phagocytosis

reproduce via asexual and sporulation

plant-like protist

primary producer

produce oxygen

algae have chloroplast and photosynthesis

others are diatoms and dinoflagellates

animal-like protists

protozoa

Food vacuoles with digestive enzymes

amoeba and paramecium

heterotrophic

move via flagella or cilia

often parasitic

Fungi

kingdom under domain Eukarya

mushrooms, molds, yeasts

heterotrophic

saprophytic: eat decay matter

life cycle is haploid

cell wall is chitin

hyphae: branched filaments come together to form a system of mycelium

reproduction: alternate between asexual and sexual (asexual in favorable conditions via budding and sporulation by mitosis) (sexual in unfavorable conditions switch between haploid and diploid phases)

Lichens

symbiotic autotrophs where fungus is paired with algae or cyanobacteria

fungus: protects and provides water and nutrients

algae/cyanobacteria: photosynthesis to provide fungi with food

animalia

eukaryotic, diploid, multicell, heterotrophic, aerobic

phylum: porifera, cnardia, Platyhelminthes, nematode, rotifera, annelida, mollusca, arthropoda, echinodermata, chordata

coelomates

organisms possessing fluid filled cavity called coelom, mesoderm surrounds coelom completely

• annelida, mollusca, arthropoda, echinodermata, chordata → most specialized

acoelomates

do not possess coelom

platyhelminthes: least specialized

pseudocoelomates

partially surrounded coelom

nemotoda and rotifera

schizocelomates

coelom begins and splits in mesoderm

Holoblastic cleavage (even), spiral cleavage, determinate cleavage

protostomes: mouth develops first, before anus (from blastopore)

enterocoelomates

coelom begins as lateral out pockets of the archenteron

radial cleavage, indeterminate cleavage, totipotent

deuterostomes: blastopore becomes anus

phylum porifera (under kingdom animalia)

simple, multicell, porous sponges

earliest animal

body asymmetry

parazoan: no tissue organization and no coelom type

sessile: non-mobile

aquatic

cnidaria (phylum under kingdom animalia)

ex: jellyfish, hydra, corals

radial body symmetry

diploblastic: 2 cell layers, ectoderm and endoderm

aquatic

platyhelminths (phylum under kingdom animalia)

ex: flatworms, tapeworms

non-segmented, parasitic worms

bilateral symmetry

cephalization: “sense of head”

triploblastic: 3 germ layers

acoelomate: lack coelom

protostomes

nematoda (phylum under kingdom animalia)

ex: roundworms

non-segmented, parasitic worms

bilateral symmetry

triploblastic

protostomes

pseudocoelomates

rotifera (phylum under kingdom animalia)

non-segmented, aquatic zooplankton

bilateral symmetry

triploblastic

pseudocoelomates

protostomes

annelida (phylum under kingdom animalia)

ex: earthworms, leeches

first to develop segmentation

closed circulatory system: multiple aortic arches and distinct arteries and veins

bilateral symmetry

triploblastic

coelomates

protostomes

mollusca (phylum under kingdom animalia)

ex: snails, squids, octopus

soft bodies, mostly aquatic

bilateral symmetry

triploblastic

coelomates

protostomes

arthropoda (phylum under kingdom animalia)

organisms with segmented bodies and jointed appendages

most diverse phylum, greatest number of species

class insecta: ants, grasshoppers

class arachnida: spiders, scorpions

class Crustacea: lobsters, crayfish, crab

bilateral symmetry

triploblastic

eucolomates

protostomes

exoskeleton made of chitin

open circulatory system: fluid doesnt stay in, hemolymph is fluid, flows into open body cavity called hemocoel

echinodermata (phylum under kingdom animalia)

ex: starfish, and sea urchin

closest to chordates

radial body symmetry

triploblastic

coelomates

deuterostomes: anus forms first from blastopore

chordata (phylum under kingdom animalia)

segmented bodies

vertebrates and invertebrates

bilateral symmetry

triploblastic

coelomates

deuterostomes

chordates

dorsal hollow nerve cord: develops into CNS

notochord: cartilaginous rod derived from mesoderm

pharyngeal pouch (slits): form pharynx, gills, feeding structures, or head and neck

post-anus tail: dissolved in humans

invertebrates

lack vertebrate

ex: lancelets and tunicates

vertebrates (sub phylum) evolutionary path

1. early jawless fish

2. chondrichthyes: cartilaginous, jawed fish

3. osteichthyes: bony fish

4. lobe-finned fish: bony fish whose fins first resembled limbs

5. amphibians: first tetrapods, proper limbs with digits

6. mammals: most evolved vertebrates

class mamalia

closed circulatory system

4-chambered heart (birds also)

lungs

hair

mammary glands (milk)

diaphragms

paleontology

study of fossils

biogeographic evidence

distribution of species around the world

embryology

study and comparison of the developmental stages of embryos in related organisms

comparative anatomy

compares body parts of animals

homologous structures

may or may not perform same the same function but they share an ansestor

analogous structures

same function but not common ansestor

vestigial structures

sever no purpose, homologous to functional structures in other organisms

biochemical methods

DNA sequence comparisons, common pathways like the Krebs Cycle

Catastrophism

mass extinctions in certain areas leads to local populations that are shaped by the organisms that survivied

George Cuvier

Use and Disuse Theory

Jean-Baptiste Lamarok

inheritance of acquired traits: traits acquired through either the use or disuse and then passed to offspring

incorrect theory

Natural Selection Theory

gradual, non-random process where allele frequencies change as result of environmental interactions

random genetic variations amongst individuals can lead to better fitness

Charles Darwin

survival of the fittest

individuals with higher fitness survive and pass on DNA to future generations compared to less fit individuals

fitness: ability to survive and produce fertile offspring

evolution of populations, not individual

Requirements for Natural Selection

• Resource demand exceeds supply

• variation of traits within a population

• variation in traits must be genetically influenced (heritable)

• trait variation must be influential for reproduction or fitness

Stabilizing selection

average is favored

normal bell curve

directional selection

one extreme is favored

disruptive selection

rare trait is favored, average is not favored

sexual selection

non-random mating between males and females

females want quality

males want quantity

artificial selection

humans effect the rate of change

Hardy - Weinberg Equilibrium

allele frequency: p + q = 1

genotype frequency: p² + 2pq + q² = 1

Hardy - Weinberg Equilibrium Requirements

large population: minimize genetic drift

random mating

no mutations

no natural selection

no migration

microevolution

gene frequency changes over a few generations

non-random mating

mutations

natural selection

gene flow: movement and mixing alleles between populations via migration and inbreeding

genetic drift

random changes in allele frequencies

has a stronger effect on small populations

bottleneck effect

sudden reduction in population size causing a loss of some alleles

founder effect

a few individuals are separated from a large population with different alleles

sources of genetic variation

• non-fatal mutations

• sexual reproduction

• polyploidy: multiple chromosomes introduce variety

balanced polymorphism

maintains a variety of phenotypes within a population

types:

• heterozygous advantage: 2 parents produce offspring with better fitness

• minority advantage: rare phenotypes offer high fitness. cycles between high and low frequency

• neutral advantage: may be beneficial if environment changes

Macroevolution

large scale over a large amount of time

species are reproductively isolates with little to no gene flow between them via prezygotic and postzygotic isolation mechanisms

prezygotic isolation mechanisms

barriers that prevent fertilization

• habitat isolation

• temporal isolation: reproduce at different times of year

• mechanical isolation

• behavioral isolation

• gamete isolation

postzygotic isolation mechanisms

reduce organisms success of survival after zygote is formed

• hybrid mortality: zygote forms but doesn’t survive development or birth

• hybrid sterility: hybrid is infertile

• hybrid F2 breakdown: F1 generation survives and is fertile, F2 generation does not survive

speciation

how new species are formed

begins with reproductive isolation, populations gradually diverge into two species

allopatric speciation

geographical barriers

adaptive radiation: many species arise from one ancestor to adapt to different environments

specialize to fill different niches within an environment

sympatric speciation

without geographical barrier

due to:

• balanced polymorphism: occurs when different phenotypes are maintained within the same area

• polyploidy: chromosome duplication

• hybridization: hybrids more fit

Phyletic Gradualism

evolution works by small changes over time

FALSE

Punctuated equilibrium

evolution works through short spurts of change with long periods of stasis

divergent evolution

species come from a common ansestor

convergent evolution

unrelated species adapt to similar environments, analogous structures

parallel evolution

species come from a common ancestor and undergo similar changes

coevolution

two species impart selective pressure on each other

hummingbirds and flowers

camouflage

aposematic colorations: warning colors

mimicry

Resembling other species

Batesian: non-harmful species resemble harmful species

Müllerian: two harmful species resemble each other

root of phylogenetic tree

most common ansestor

node of phylogenetic tree

branch point, group splits from one

polytomy of phylogenetic tree

internal node leads to more than 2 tips

clade (monophyletic group) of phylogenetic tree

cluster with an ancestor and all of its descendants

paraphyletic group of phylogenetic tree

an ancestor and some but not all descendants

cladogenesis of phylogenetic tree

divergence of evolutionary lineages from new clades

anagenesis of phylogenetic tree

gradual evolution of interbreeding population without splitting

parsimony of phylogenetic tree

the simpler the evolutionary explanation, the better