BISC 1112: MA2

polyploidy

polyploidy

an individual getting one or more additional sets of chromosomes; occurs most often in plants

autopolyploid

an individual that has more than two chromosome sets, all derived from a single species

hybrid zones

a geographic region in which members of different species meet and mate, producing at least some offspring of mixed ancestry

adaptive radiation

a period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities

Linnean system of classification

(most inclusive) domain, kingdom, phylum, class, order, family, genus, species (most exclusive); mnemonic:

Dear King Philip Came Over For Good Soup

phylogenetic tree

an evolutionary tree that shows the evolutionary relationships between different groups of taxa

cladistics

the study of resemblances among clades

cladogram

a depiction of patterns of shared characteristics among taxa

monophyletic clade

a group of taxa that consists of a common ancestor and all of its descendants

paraphyletic clade

a group of taxa that consists of a common ancestor and some, but not all, of its descendants

polyphyletic clade

a group of taxa that includes distantly related organisms but does not include their most recent common ancestor

how old is the Earth?

4.6 billion years old

when did life begin?

4 billion years ago

when did humans emerge?

300,000 years ago

what is the first evidence of life?

stromatolites: layered deposits formed by cyanobacteria

Miller-Urey experiment (1953)

simple inorganic compounds transform into organic ones by mimicking an ancient atmosphere

what was the first genetic material?

RNA; RNA molecules called ribozymes have been found to catalyze many different reactions

know the extinctions

oxygen in the atmosphere

in the beginning, there was little or no oxygen in the atmosphere; autotrophic organisms started around 4 billion years ago and with that, photosynthesis (making organic compounds from inorganic ones)

endosymbiotic theory

theory that mitochondria and plastids originated as prokaryotic cells engulfed by a host cell; the engulfed cell and its host cell then evolved into a single organism; Lynn Margulis

mass extinctions

decreased biodiversity drastically

Cambrian explosion

refers to the sudden appearance of fossils resembling modern phyla in the Cambrian period (535 to 525 million years ago); possible causes: new predator-prey relationships, rise in atmospheric oxygen, evolution of the Hox gene

Hox gene

embryophytes

multicellular, dependent embryo; apical meristems; walled spore (in sporangia) protected by sporopollenin (a polymer); multicellular gametangia and sporangia; alternation of generations

apical meristems

sporopollenin

covers the outer layer of pollen

gametangia

sporangia

life cycle of a moss

animals

multicellular; heterotrophic eukaryotes; have tissues that develop from embryonic layers

animal characterization

symmetry (radial, bilateral, or no symmetry); germ layers (diploblastic or triploblastic); cleavage/coelom formation/blastopore fate (protostome or deuterstome)

radial symmetry

the body is shaped like a pie or barrel (lacking a left side and a right side) and can be divided into mirror-imaged halves by any plane through its central axis

bilateral symmetry

a central longitudinal plane divides the body into two equal but opposite halves (types: dorsal, ventral, anterior, posterior)

describe animal embryonic development

zygote → cleavage → blastula (hollow ball of cells) → gastrulation (blastula-stage embryo folds inward) → gastrula (formation of three layers: ectoderm, mesoderm, and endoderm)

ectoderm

outer germ layer; forms skin and nervous system

mesoderm

middle germ layer; forms muscles, organs, and red blood cells

endoderm

innermost germ layer; forms digestive system

coelomates

posses a true coelom (body cavity)

pseudocoelomates

have a body cavity

acoelomates

lack a coelom (body cavity)

blastopore

in a gastrula, the opening of the archenteron that typically develops into the anus in deuterostomes and the mouth in protostomes

protostomes

mouth forms first from blastopore

deuterostomes

anus forms first from blastopore

characters that distinguish humans from other apes

upright posture and bipedal locomotion; larger brains; language capabilities and symbolic thought; the manufacture and use of complex tools; shortened jaws; shorter digestive tract

evidence for early bipedalism

fossilized footprints at Laetoli, Tanzania

Hox genes

family of regulatory genes that encode transcription factors and are essential during embryonic development

incomplete metamorphosis

each nymphal stage looks like a small version of the adult but getting slightly bigger with age

complete metamorphosis

the larval body is always markedly different in form from that of the adult

retrieval practice

self-quizzing; retrieving knowledge from memory

spaced out practice

studying information more than once over time

interleaving

mixing up topics and finding connections between them

elaboration

finding additional layers of meaning to new material: relating material to what you already know, explaining it to someone else in your own words

generation

attempting to answer a question or solve a problem before seeing the solution

reflection

reviewing what you learned in class and asking yourself questions

calibration

the act of aligning your judgments of what you know and don’t with objective feedback

mnemonic devices

handy ways to store information