unit 9

taxonomy, systematics, and the animal kingdom

biodiversity

biodiversity

the variety living organisms, or all of the living species in an area

taxonomy

the discipline of classifying the diverse organisms and assigning them universally accepted scientific names

taxon

the group or level of organization in which organisms are classified

systematics

the science of classifying organisms based on their evolutionary relationships

why do we classify organisms

to make sure scientists are talking about the same organism

how do we assign scientific names

genus and species (latin)

why do scientists use latin for scientific names

its a dead language, which means it will never evolve. also tradition and the fact that European scientists used the “educated” language. in addition to regionalism.

carolus linnaeus

came up with the taxonomic system we know today, adopted binomial nomenclature

8 taxa

domain, kingdom, phylum, class, order, family, genus and species

what is a species

the classification of organisms that have the potential to breed together and produce a viable, fertile offspring

sub-species

variations of a species that live in different geographical locations

hybrid

the infertile offspring between two different species

domain

bacteria, archaea, & eukarya

kingdom

eubacteria, archaebacteria, protista, fungi, plantae, Animalia

cell type

prokaryote or eukaryote

cell structures

-cell walls w/ or w/o peptidoglycan

-cell walls w/ cellulose

-cell walls w/ chitin

-no cell walls

number of cells

unicellular or multicellular

mode of nutrition

autotroph, heterotroph, or both

classification of living things

domain, kingdom, cell type, cell structure, number of cells, & mode of nutrition

homologous structures

structures the are similar in a different species of common ancestry

analogous structures

structures that are similar in different species due to convergent evolution (body of sharks and dolphins)

Robert Whittaker

expanded the number of kingdoms from 3 to 5

Carl Woese

expanded it to 3 domains and 6 kingdoms

what is the problem with traditional classification

species can be similar because of evolution or “coincidence”

the modern classification system

naming and grouping organisms by their evolutionary relationships

phylogenetic tree

branching diagram that represents what is believed to be the evolutionary relationships among organisms or their phylogeny

molecular clock

model that uses DNA sequence comparisons to estimate the length of time that two species have been evolving independently

cladistics

method involving the use of evolutionary innovations (new characteristics that arise as lineages evolve) for classification

cladogram

diagram that shows the evolutionary relationships among group of organisms

clade

group of organisms that include the ancestor and all of the descendants

shared characteristic

feature that all members of a group share

derived characteristic

appears in recent parts of a lineage, but not in older members

ernst Mayer

came up with the biological species concept

limitations to the biological species concept

extinct species or asexually reproducing organisms

phylogeny is based on…

structural similarities, patterns of embryonic development, and similarity among genes

evolutionary tree

branching diagram that shows the evolution of modern species

extinct species…

are included in the evolutionary tree

evolutionary trees show

the timeline in which species shared a common ancestor

using the fossil record…

the tree compare extinct species to modern ones

mutations in genes

are used in the molecular clock as a way to show the passing of time in species

mutations occur at a steady rate but…

different genes have different mutations rates

more conserved regions…

have less a chance for mutation because they are critical to life

Willi Hennig

came up with cladistics

LUCA

last universal common ancestor

monophyletic

each clade should only include the ancestor and all its descendants

polyphyletic

groups that are not recognized by the strict interpretation of cladistics, come from two lineages

paraphyletic

A group composed of a collection of organisms, including the most recent common ancestor of all those organisms

molecular biology

using genetic similarities instead of structural similarities, more closely related means a more recent common ancestor

asymmetrical

no symmetry

bilateral symmetry

when an organisms can be cut into two identical pieces across only one plane

radial symmetry

when an organisms can be cut into identical pieces across many planes

endoderm

the inner most layer of the embryo

mesoderm

the middle layer (if present) of the embryo

ectoderm

the outer most layer of the embryo

notochord

flexible rod of tissue that extends along the dorsal surface of the body

protostomes

the blastopore forms the mouth (one way)

deuterostomes

the blastopore forms the anus (two way)

determinate cleavage

at the 8-16 stage, each cell has already specialized down a path to a specific part of the body

indeterminate cleavage

early cells are not yet specialized to a specific body part

coelom

the body cavity between the digestive tract and outer body wall

acoelomates

do not have a cavity, it is completely filled with mesoderm tissue

psuedocoelomates

have a cavity, but its not surrounded by mesoderm tissue, outer body wall has mesoderm but there is none surrounding the endoderm digestive tract

coelomates

have a cavity that is completely surrounded by mesoderm. along both the outer body wall and inner digestive tract

intracellular digestion

digest food inside of a specific cell type

nematocysts (cnidaria)

venom barbed spear used to capture prey

colloblasts (Ctenophora)

cells that squirt a glue-like substance to capture prey

cephalization (platyhelminthes)

showing a distinct head region

tripoblastic

three germ layers, ectoderm, mesoderm, and endoderm

Porifera

sponges

cnidaria

jellyfish, corals, sea anemones

cnetophora

comb jellies

Platyhelminthes

flatworms

Rotifera

rotifers, or “wheel animals”

nematoda

roundworms

annelida

earthworms, leeches, tubeworms

Mollusca

octopi, snails, clams

Cephalopoda

head-foot; squid and octopi

Gastropoda

stomach-foot; snails and slugs

bivalvia

two shells; clams, mussels, oysters

arthropoda

spiders, ants

crustacea

10 legs, crabs

chelicerae

8 legs, spiders, scorpions, ticks

insecta

6 legs, ants, butterflies, bees

incomplete metamorphosis

the larval form and adult form look similar

complete metamorphosis

larval form and adult form look completely different

chondrichthyes

sharks, skates, and rays emergence of jaws and paired appendagescartilaginous skeletonuse gills for breathing

osteicthyes

bony fish emergence of calcified bone in the skeletal systememergence of limbs in lobe-finned fish (gave rise to tetrapods)emergence of lungs in lungfish (gave rise to amphibians)

amphibia

salamanders, frogs, toads jelly-like eggsmetamorphosisfirst vertebrates to move to landlimbsmoist skin that aids in respiration

reptilia

snakes, turtles, lizards, crocodiles amniotic eggstypically a leather shellemergence of scales which allowed a true break from water

aves

birds emergence of feathers (some dinosaurs had them as well)capable of flighthardened, oval shell

two ways a molecular tree can be organized

by molecular comparisons or body plan