Leader: Kirsten Karkow
Course: Biol 211 - Wilsey
Date: 3/5/2012
Worksheet 18 – Review for Exam 3
Supplemental Instruction
Iowa State University
Characteristics of Chordates
Notochord
Dorsal, hollow nerve chord
Pharyngeal slits
Postanal tail
Additional Characteristics of Vertebrates
Pronounced cephalization
Vertebral column
Closed circulatory system
Separate males and females
Which of the following gives the correct order of development of vertebrates?
a.
b.
c.
d.
Vertebrates, gnathostomes, lungfish, reptiles, eutherians, monotremes
Craniates, vertebrates, chondrichthyes, lobe fins, amniotes, mammals
Vertebrates, gnathostomes, amniotes, amphibians, mammals, humans
Craniates, vertebrates, lobe fins, bony fishes, reptiles, monotremes
Match each group with an appropriate organism from the right column.
Craniate
Vertebrate
Chondrichthyan
Amphibian
Reptile
Monotreme
Marsupial
Eutherian
Platypus
Lamprey
Monkey
Ray
Bird
Hagfish
Caecilian
Opossum
First organisms to have jaws? Sharks
First organisms to live on land? Amphibians
Cephalochordata
Urochordata
“Tunicates”/“Sea Squirts”
Lose chordate characteristics
“Lancelets”
Keep chordate characteristics
Ray-finned Fish
Ray fins (bones)
Monotremes
Lay eggs
Coelocanths
Lobed fins (bone + muscle)
Lungfish
Lobed fins + lungs (+ gills)
Marsupials
Develop young in marsupium
Eutherians
Placental animals
Humans are most closely related to apes.
They share 99% of their DNA.
Supplemental Instruction
1060 Hixson-Lied Student Success Center  294-6624  www.si.iastate.edu
Define:
Genome – all of the DNA within a cell
Chromatin – loose DNA.
Chromatid – condensed DNA molecule.
Chromosome – individual condensed mass of DNA. 1 or 2 chromatids.
Somatic Cells – asexual cells. Diploid.
Gametes – sexual cells. Haploid.
Centromere – attachment point of sister chromatids.
Kinetochore – attachment point for mitotic spindle.
G1 Checkpoint
During G1
Size? Big enough?
Favorable environment?
G2 Checkpoint
During G2
Synthesis went okay?
Favorable environment?
M Checkpoint
During (any) metaphase
All lined up/connected?
What organisms perform binary fission? Prokaryotes
What organisms perform mitosis? When/why? Eukaryotes – growth, cloning, etc.
Benign Tumor
Mass of cancer cells that hasn’t spread.
Malignant Tumor
Tumor that has metastasized ⇛ cancer.
Define:
Gene – hereditary unit. Codes for a protein.
Allele – specific version of a gene.
Locus – location of the gene on the chromosome.
Synapsis – close association of homologous chromosomes. PROPHASE 1!
Crossing Over – gene trading between homologous chromosomes. PROPHASE 1!
Chiasmata – location of crossing over on homologs. Stay attached until anaphase 1.
Euploidy
2n
Aneuploidy
2n ± 1/few
Polyploidy
2n + n
When do homologous chromosomes separate? Anaphase I
When do sister chromatids separate? Anaphase II and Anaphase (of mitosis)
What processes contribute to genetic variability? Crossing over. Independent assortment.
Random fertilization.
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