Lab Exam 1 Flashcards
How long ago did life first appear on Earth?
3.8 billion years ago
How long did Darwin wait after returning from his journey to publish his findings (On the Origin of Species?
23 years
One of the things that Darwin noticed about the natural world was that
organisms often produce an overabundance of offspring
What percentage best represents the amount of time that Homo sapiens have been present on Earth?
0.004%
Archaeopteryx was found within a limestone quarry in Bavaria as rectangles of limestone were split apart to make roofing tiles. Archaeopteryx is significant because it shows an evolutionary link between 2 groups of animals. What are the two groups?
Birds / Reptiles
how long ago did the earth form?
4.6 billion years
what percentage of species has become extinct?
99.9%
1 out of 1000 species survives
When did the first eukaryotic cells originate?
1.8 billion years ago
when did the Cambrian radiation occur? what era?
540 million years ago (paleozoic)
When did the dinosaurs appear? what era?
240 million years ago (Mesozoic)
when did the dinosaurs become extinct? what era?
65 million years ago (cenozoic)
when did homo sapiens evolve?
200,000 years ago
what percentage of time has life existed on Earth?
3.8 / 4.6 = 83%
For what percentage of time have eukaryotic cells existed on Earth?
1.8 / 4.6 bya = 39%
For about how many years of geological time have mammals existed on Earth?
220 mya / 4.6 bya = 5%
What type of animals did the Creodont skull that Dr. Gingrich discovered resemble?
wolf, walnut size bump at back of the skull was unusual
The Cambrian Explosion is thought to have occurred around 500 mya. What best describes the Cambrian Explosion?
a sudden appearance in the fossil record of many unique animal species
how was the fruit fly’s DNA mutated?
poison and radiation
how did humans differ from chimpanzees?
spinal column / pelvis / position of knees
the base of skull pointing downward
shorter pelvis
knees closer together
If the world’s history were compressed into one hour, what kind of life appeared during the first 50 minutes?
Last 10 minutes?
Last 0.01 seconds?
single celled organisms
animals
humans
What is whale valley and how would whale skeletons be found there?
Whale Valley is now the Sahara desert and it used to be the sea. Therefore whales once lived there.
what vestigial structure did basiolosaurus have that modern whales do not?
complete set of leg bones / 4 legged animal
how does the way that a fish swims differ from water mammals?
fish - spine side to side
mammals - spine up and down
what is a tetrapod?
4 limbed vertebrate
What advantage did the first limbs with digits provide?
ability to leave water without attracting predators
how does segmentation relate to DNA?
organization of genes in DNA that are responsible for a common trait amongst most animals (segmentation)
When the mouse “eyeless” gene was implanted into fruit flies, what happened?
Fruit fly did have eyes
how do chimpanzees walk in comparison to humans?
on knuckles / humans are bipedal
3 physical traits mammals have in common that relate to living on land?
reproducing live offspring
warm blooded / fur
breathing air
what is a transitional form?
intermediate states between ancestral forms and descendants
how did wolves evolve into whales?
sinonyx lived and hunted around the sea, those that could swim survived, legs adapted to fins
What caused the number of birds on Daphne Major (a Galapagos Island) to change (decrease then increase) over the time that the Grants have been studying them?
drought / changes in rainfall
Human ancestors left the trees and started to live life on the ground. This change had a significant impact on the evolutionary trajectory of hominids. Other than walking upright, what change occurred?
The homonids were able to use their hands for other things than holding on to limbs.
what is sickle cell anemia?
a genetic disease that is traced to a mutation in DNA that codes for hemoglobin
HbA (normal)
HbS (mutated)
how does sickle cell anemia help fight malaria?
Being heterozygous (HbA/HbS) allows the body to recognize and dispose of affected sickled cells.
how are malaria, precipitation, and HbS allele related?
greater precipitation = greater malaria prevalence = greater HbS frequency
Why is heterozygosity an advantage in areas of increased malaria prevalence?
heterozygotes are carriers for sickle cell, therefore they do not have it, and are immune to malaria.
what is genetic drift?
random events that affect the frequency of alleles in a population
small populations vs large
frequency is more likely to become fixed, either disappearing or dominating the gene pool
large = relatively stable over time
p + q = 1
p - frequency of dominant allele
q - frequency of recessive allele
p2 + 2pq + q2 = 1
p2 - frequency of homo dominant
2pq - frequency of heterozygotes
q2 - frequency of homo recessive
Were anoles on the same island (e.g., Puerto Rico) more closely related to one another or were anoles of the same ecomorph (e.g., grass-bush) more closely related?
same island
what trait or information was ultimately used to construct the phylogenetic tree that showed the evolutionary relationships of the anoles?
DNA analysis
Why did you determine relative hindlimb length in anoles?
it allowed you to directly compare the hindlimbs from anoles of different body sizes
The anoles that we studied have dewlaps. What is a dewlap used for?
visual communication
attract mates
lizards who belong to the same ecomorph type are similar due to similar environmental selection pressures (e.g., the need to not fall off of twigs). What evolutionary term is associated with this?
convergent evolution
What are Porifera?
sponges
Characteristics of Porifera
aquatic
radial/asymmetrical
no definitive tissues
cell specialization at the organizational level
examples of porifera
Scypha/ Grantia
Leucosolenia
Characteristics of Cnidaria?
aquatic
radial symmetry
diploblastic (endo / ectoderm)
tissue
polyp or medusa body structure
class of cnidaria
hydrozoa
Scyphozoa (jellyfish)
anthozoa (coral / sea anemones)
Platyhelminthes charachterisitcs
bilateral symmetry
cephalization
acoelomates
triploblastic
tissue specialization (organ, nervous, and excretory systems)
hermaphroditic
muscles for body support
classes of Platyhelminthes
turbellaria - planarians
Trematoda - flukes
cestoda - tapeworms
Rotifera Characteristics
bilateral symmetry
pseudocoelomates
head / complete gut
triploblastic
hydrostatic body
dioecious / sexual repro
rotifers
Nematoda characteristics
bilateral symmetry
psuedocoelomates
triploblastic
sexual repro
hydrostatic body
The oldest (i.e., first to have evolved) animal phylum is
Porifera
Hydra belong to which phylum?
cnidaria
Sponges possess nervous tissue, which allows them to respond to environmental stimuli.
false
What type of symmetry, if any, is exhibited by planaria, tapeworms, and flukes?
BILATERAL
The roundworm Ascaris shows sexual dimorphism. Name a characteristic that demonstrates sexual dimorphism in Ascaris.
females are larger than males
males have a hooked posterior end
Characteristics of Mollusca
coelomates (triploblastic)
nervous system with brain
excretory system w/ nephridia
open circulatory system
respiratory system
classes of mollusca
bivalves - clams / oysters
gastropods - snails / slugs
cephalopods - squid / octopus
Characteristics of Annelids
bilateral symmetry
segmented body
closed circulatory system
hydrostatic body
hermaphrodites
arthropod characteristics
bilateral
coelomates
segmentation in body
nervous system w brain, excretory, respiratory
open circulatory
exoskeleton of chitin
sexual repro