BIO TEST 1
The study of the process of evolution focuses on
all of the mechanisms that affect how living things have changed overtime (genetic variation, natural selection).
Define biodiversity
all organisms alive today or in the past
7. Based on DNA evidence, the ancestor of whales belonged to a group of land mammals called the _____________________, which includes hippos and camels
artiodactyls
Which two domains contain prokaryotes?
Bacteria and Archaea
Describe the Three Domain classification system. Describe the characteristics of the organisms in each Kingdom.
Bacteria: unicellular, prokaryotic Archaea: unicellular, prokaryotic, hostile environment Eukarya: multicellular with nuclei, complex organisms
What unexpected evidences of whale evolution did Gingerich discover when he found Basilosaurus fossils in the Valley of the Whales?
Basilosaurus had tiny hind legs with a mobile knee and several bones.
Why do evolutionary biologists use fossils?
Because it is exactly what extinct plants/animals looked like
Why did Alvarez's team choose to use iridium instead of beryllium-10 to determine how long it took to form the clay layer?
Beryllium-10 decays too quickly to be used to date rocks that are 65 million years old.
What evidence found in the KT boundary by Alvarez's team supported the supernova hypothesis?
High levels of iridium
What are the parts of a scientific name?
Two latin words, first is the Genus (capitalized), second is the unique species name
What kinds of structures have been used in classification?
Used to be external features like flowers, body plants and feathers. Now with technological advances, we can compare internal organs, embryos, behaviors, chemical composition and DNA
What assumption can be made about plants or animals that have similar embryos? Why is this assumption valid?
Vertebrates all look similar in the womb because they all inherited genes that control embryonic development from a common ancestor
A series of steps designed to help you solve problems and answer questions while reducing the influence of personal preconceived ideas
scientific method
All of the following are potential "culprits" that might have played a role in triggering the KT mass extinction except
heavy metal poisoning
Study of the process of evolution focuses on _______
how living things have changed overtime
In science, an educated guess is called a/an
hypothesis
How does a hypothesis differ from a scientific theory?
if a hypothesis is not rejected despite testing over a long period of time by hundreds of scientists, it is called a scientific theory.
In an experiment, the one variable that is changed is called the
independent variable
In all scientific studies, the major underlying assumption is that the ____ variable is causing some measurable change in the ___ variable
independent; dependent
Explain how the process of classification works
looking for similarities between organisms and putting the most similar things together in the same group
What skill is a scientist using when she listens to the sounds that whales make?
making observations
Describe the characteristics of FUNGI
multicellular eukaryotes that are absorptive heterotrophs (they cannot make their own food so they have to eat other organisms, dead or alive) - digestion occurs outside the body, and then the fungus absorbs the digested particles (absorptive). Ex = mushrooms, molds and yeasts
Describe the characteristics of PLANTS
multicellular eukaryotes that are autotrophs (make food by photosynthesis); ex = mosses, ferns, horsetails, conifers
Describe the characteristics of ANIMALS
multicellular eukaryotes that are ingestive heterotrophs - bring food into their bodies (ingestive), secrete chemicals internally to break down the food substances, and then absorb the particles into their body fluids; ex = crustaceans, insects, fishes, reptiles, birds, and mammals
A prokaryotic cell lacks a _____
nucleus; These cells are typically small with no internal organelles
The process of obtaining information by using the senses is called a/an
observation
Scientific processes CAN be used to study phenomena that can be ____ and ____. Scientific processes CANNOT be designed to study things that cannot be observed or measured objectively.
observed; measured
Define SCIENCE
process of objective problem solving methods to observe the natural world and arrive at reasonable explanations of how the world works
The earliest cells to evolve were ___
prokaryotes
The study of the HISTORY of evolution focuses on the ___
results
What would cause a scientist to reject a hypothesis?
*if a hypothesis is tested --
There are two lineages of modern whales, both descended from a common ancestor that lived about 35 million years ago. Name the two lineages and briefly discuss the differences between them.
- Toothed whale: has teeth, can produce high-pitched sounds with it's blowhole for communication and echolocation - Baleen whale: no teeth just baleen pleats that allow the whale to swallow massive amounts of water then push it back straining out the fish and shrimp left behind
What two conditions are necessary for individuals to belong to the same species?
1) they can interbreed in the wild 2) live healthy offspring can be produced which in turn can have offspring
Compare the development of the forelimbs of the four animal embryos seen in the video.
1. Pig: human like at first, limbs begin like buds, but take on distinct pig shape 2. Fish: No limbs, because they split from the other animals long ago 3. Human: limbs begin as buds, arms look similar to legs kinda look like tiny paddles. Human arm looks very similar to pig front leg. 4. Chicken: buds look similar to human or pig but develop into different things
Identify and discuss four differences between whales and fish
1. Whale tails go up and down while fish go side to side. Bc up and down is otters or beavers. 2. Whales don't have gills, they have blowholes on the tops of their heads. Evolution didn't go backwards and remake gills, it moved the nostrils up the face until they were above the eye sockets. 3. Whales give birth to live young like land mammals 4. Whales have tiny bones in their flesh where hipbones would be if they had legs
What is the correct order of steps in the scientific method?
1. ask question 2. make hypothesis 3. test hypothesis 4. analyze results 5. draw conclusions 6. communicate results
Define biogeography
A branch of science that attempts to explain the distribution of species on Earth, living and extinct. And studies why extinct animals no longer live in their former habitat.
What did Phil Gingerich discover in Pakistan? What was unusual about this fossil?
A fossil he hypothesized to be a wolflike creature, but had the ear of a whale. It was a link to whales on land ancestry. Named Pakicetus.
What was the supernova hypothesis?
A supernova caused the mass extinction at the KT boundary.
After rejecting the supernova hypothesis, what became the new hypothesis for the Alvarez team?
An asteroid impact caused the mass extinction at the KT boundary.
Which Domain is most closely related to Domain Eukarya?
Archaea
Explain how predictions are formulated from hypotheses using the "if...then..." process
DEDUCTIVE reasoning - "If (fill in a hypothesis) is correct, then when we do this test we should see these results; EX - "If the battery is dead, then the car lights won't work."
List the levels of taxonomic classification, from largest to smallest
Domain -> kingdom -> phylum -> class -> order -> family -> genus -> species
Describe the requirements for a controlled experiment
Each controlled experiment looks at the effect of just one variable (the independent variable) on some event or condition (the dependent variable)
What are protists?
Eukaryotes that aren't plants, animals or fungi. Ex: Ciliates, brown algae, and euglena
Define fossil
Evidence of past life, whether it be chemical remnants, body parts, or traces/impressions of animal/plant that has been preserved.
What were the two possible hypotheses about how long it took to form the clay layer?
Few years VS. few thousand years
Describe the origin of eukaryotic cells, including the origin of the nucleus, mitochondria, and chloroplasts.
From prokaryotes and endosymbiotic relationships. - Nuclei formed from an infolding of plasma membrane, dividing the cell's interior into separate compartments that allowed each function to proceed more efficiently. - Mitochondria formed form engulfed aerobic bacterium that produced chemical energy from food which it shared with the host cell. - Chloroplasts formed from engulfed cyanobacteria that produced food and oxygen by photosynthesis that it shared with host cell.
How do scientists decide if the results of their experiments are valid?
If a statistical analysis of the data reveals that there is a probability of 5% or less that the results of the test could have occurred by chance, then the results of the experiment support the hypothesis
Alvarez's team had two hypotheses about the amount of time it took to form the clay layer. What did they expect to see for each hypothesis?
If it took a few years to form the clay layer, there would be no detectable iridium. If it took a few thousand years, there would be small detectable amounts of iridium.
Why did Alvarez and his team reject the supernova hypothesis?
No plutonium-244 was found in the KT boundary.
When Thewissen and his team measured the ratio of light and heavy oxygen in fossil whale teeth, what did they discover about the lifestyles of Pakicetus and Ambulocetus?
Pakicetus: drank fresh water Ambulocetus: drank brackish water
What assumption can be made about plants or animals that have similar body structures? Why is this assumption valid?
Plants/animals that have similar body structures are assumed to be closely related, this is valid because these similar body structures were inherited by a common ancestor.
Explain the statement 'Natural selection does not have foresight'.
Populations of organisms adapt to current surroundings, what works at one time may not work at another.
Give an example of how evolution today affects all of us, not just biologists
Rapidly evolving bacteria and viruses exist that doctors are using evolution to better understand
Three billion years ago, what type of organisms were present on Earth?
Single-cell microbes
What is the key evidence that all living things descended from the same common ancestors?
That all living things are made of the same chemical elements and basic molecules.
What did the distribution of plants and animals he observed suggest to Darwin?
That in each part of the world they evolved gradually over many thousands of years and evolution didn't follow the same path in all parts of the world.
How could the impact of a large asteroid on Earth cause the dinosaurs to become extinct?
The asteroid impact caused tons of dust to float into earth's atmosphere, blocking out the sun. This slowed down photosynthesis and disrupted food webs. The lack of adequate sunlight and food killed many plants, leading to the death of the dinosaurs.
What is the "iridium anomaly"?
The clay layer at the KT boundary contains extremely high levels of iridium.
What did Alvarez notice about the marine fossils found in different rock layers marking the 65 million years old boundary between the Cretaceous and Tertiary periods?
The lower layer was sedimentary rock with abundant marine fossils. The middle layer was a thin clay layer with no fossils. The upper layer was sedimentary rock with very few marine fossils.
What is the relationship between the difference in the DNA of two species and the time of divergence of their evolutionary history (split from a common ancestor)?
The more similar the DNA is, the more recent the split from a common ancestor has occurred.
What is shown on phylogenetic trees?
The relationship between different species or other groups is represented by branching diagrams
How is the process of science applied to a group of phylogenetic trees showing different possible relationships among groups of organisms?
The trees are hypotheses, each is tested against factual evidence. A tree that contradicts current knowledge is eliminated or revised.
What assumption can be made about two different organisms that have the same type of cell or tissue in their bodies?
They have descended from a common ancestor at some point in our evolution.
Which of the following statements accurately describes the Alvarez's team conclusions after they measured the iridium levels in the clay layer?
They rejected both hypotheses
Why are cyanobacteria important in the history of the Earth?
They were the first bacteria to generate oxygen through photosynthesis. From that, oxygen filled the oceans and atmosphere allowing more complex organisms and cells to be formed.
What became Alvarez's new research question after the iridium anomaly was discovered?
Why are the iridium levels so high at the KT boundary?
An experiment that tests only one factor at a time by using a comparison of a control group and an experimental group is?
a controlled experiment
3 experiments are described in the video. In one Marion Petrie cut off the eyespots of some peacocks with "otherwise well-endowed tails, " then compared their mating success with males with unclipped tails. a) which group was the experimental group? b) which group was the control group? c) what was the independent variable? d) what was the dependent variable?
a) The peacocks with eyespots cut out of their tails. b) Those peacocks whose eyespots were left intact c) How many eyespots were on a peacock's tail d) How the amount of eyespots on the male's tail effected female peahens choice of mates.
Based on fossil evidence, what evolutionary changes evolved in whales with respect to a) front legs b) rear legs c) nostrils
a) flippers b) gone c) up, over eyes now blowhole
On a phylogenetic tree, what is represented by: a. the location of the branch points b. the positions of the species on the tree
a. the relative time of origin of different groups (branch point for gorillas is lower than that for humans and chimpanzees -- gorillas originated earlier than humans and chimpanzees) b. closeness of relationship
When the scientific community started paying attention to Alvarez's asteroid hypothesis, all of the following lines of evidence were explored except
reversal of magnetic fields
Define a species, using the biological species concept
collection of similar organisms that can interbreed under natural conditions to produce living and fertile offspring.
The purpose of controls is to be used as a basis for _____ with the experimental group
comparison; without a control we could never show that changes in the dependent variable are caused by the independent variable
In an experiment, the factor that we measure is called the
dependent variable
What has comparing whales to land mammals revealed about the method of swimming used by whales?
fish tails move side-to-side while whale tails move up and down, like land mammals who swim; ex: beavers or seals
What are the rules for writing out a scientific name by hand? In print?
hand = underlined; print = italicized
Explain why science can be called a process of elimination
scientists eliminate the explanations which they can show are not valid and keep the others open for further consideration; idea of eliminating all possible hypotheses
Disabled genes have been found in dolphins and baleen whales. If these genes still worked what structures would be formed?
teeth
In a controlled experiment, all variables are kept the same except the one that is being ____
tested
Define evolution
the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth
What is taxonomy?
the process of identifying and classifying species
Define phylogeny
the study of the evolutionary history of organisms
What is the value of a scientific theory?
they can be used to tie together facts in a coherent pattern or to identify the principles underlying complex natural patterns
What did Alvarez's team actually find when they measured the iridium in the clay layer?
they found very high levels of iridium
Explain why controls are necessary
they're a group that is exactly the same as the experimental group except they're NOT exposed to the experimental variable
Explain why humans use classification systems and the limitations of the systems we use.
to simplify and understand relationships between organisms; The limitation is that the system isn't real, we made it up so organisms don't really fit neatly in it.
When you decide whether or not the data supports the original hypothesis,
you are drawing a conclusion
