Biology 182
Biological Evolution
is inheritable genetic changes in population organisms overtime.
Explain the meaning of each of the following terms in the logistic model of population growth: a. Rmax b. K-Nc. (K-N)/K
rmax: the exponential model for exponential population growth K-N: is carrying capacity minus population size (K-N)/K: Carrying capacity minus population size divided by carrying capacity
Explain the factors responsible for the "dead zone" where the Mississippi r meets the Gulf of Mexico. Make sure to tell me what the "dead zone" actually is.
"Dead zone" is a more common term for hypoxia, which refers to a reduced level of oxygen in the water. The factors responsible for the dead zone are enrichments such as nitrogen and phosphorus.
Describe the term 'trophic efficiency' and provide an example of it in a food chain.
% of production transferred from 1 trophic level to the next typically only about 10% between energy levels. Ex: a cow eating grass receiving 10% of the energy the grass had.
Identify the four major tissue types in animals, and give an example of each where you relate their structure to their function.
-Epithelia tissue, layers of tightly packed cells that line surfaces the body, its function is to protect and cover underlying tissues -Connective tissue binds and supports other tissues. It relates to its function because it connects bones to one another. - Muscle tissue, long fibrous cells which contract in response to nerve signals, three types of vertebrates - Skeletal muscle, responsible for voluntary movement -Smooth muscle, responsible for involuntary body activates -Cardiac muscle, responsible for contraction of the heart -Nervous tissue senses stimuli and transmits signals throughout the animal rapidly, its function related to its function include processing and transferring information.
How are radiometric dating and magnetic reversals used to determine the absolute age of rock Strata?
A "parent" isotope decays to a "daughter" isotope at a constant rate. Each isotope has a known half-life, the time required for half the parent isotope to decay. The magnetism of rocks also provides dating information, Reversals of the magnetic poles (geomagnetic reversals) leave their record on rocks throughout the world.
Describe the derived characters of humans that distinguish them from other apes. Even though the genomes of humans and chimpanzees are 99% identical, in what way does recent evidence suggest they are remarkably different genetically?
A number of characters distinguish humans from other apes, upright posture, bipedal locomotion, larger brains, language capabilities, symbolic thought,manufacture and use of complex tools, shorten jaw as well as shorter digestive tract.
What is a "protocell"? How did they likely form, and what could they do?
A protocell produces molecules surrounded by a membrane or membrane-like structure. They could've formed spontaneously from those abiotically produced organic compounds and what they can do is form other molecules.
What is a species, according to the biological species concept?
A species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring but do not produce viable, fertile offspring with members of other such groups.
Explain how the existence of homologous structures can be explained by Darwin's theory of natural selection.
A: Homologous structure means resemblances from organisms that were inherited by a common ancestor. Darwin proposed that an individual's ancestral species gave rise to a number of similar but distinct species. He looked at the Galapagos Island's bird and noticed that their beaks were shaped different but still seemed to have something in common. When he took Galapagos Island's bird specimens the results were in fact in many different species of birds. Darwin hypothesized that birds had been colonized by organisms that had stayed in South America and then diversified, giving rise to new species in different lands.
Describe the major differences between annual, biennial, and perennial plants.
Annual- complete their life cycle (germination to death) in one year Biennials - have a vegetative year, and then a flowering year Perennials- may live hundreds or even thousands of years
Explain how sexual recombination (what is a more common name for this?) generates phenotypic variation.
Another word for sexual recombination that could be considered is a chromosomal crossover, meaning that half of a parents offspring was combined while the other half of the other parent's genes are in the offspring, resulting in a gene combination that didn't exist before. Sexual recombination and mutations increase the amount of variation within a group. It constantly generates new variations in populations if it weren't for this, all offspring would be identical to their parents and the only way for diversity to develop would be through mutations.
Explain this statement: "In contrast to most animals, which have a stage of embryonic growth, plants have regions of embryonic growth."
Basically plant have growing regions known as meristems, which are capable of growing new plant parts for as long as the plant lives. They don't have any rules they have to abide or any shape they must be.
What are 'bottom-up' and 'top-down' controls in communities?
Bottom-up, control suggests a unidirectional influence from lower to higher trophic levels. Presence or absence of mineral nutrients determine community structure. Top down, suggest a unidirectional influence from higher to lower trophic levels. Predators control herbivores, which control the primary producers.
Explain why most bryophytes grow close to the ground.
Bryophytes grow closer to the ground because they lack conducting tissue to distribute water and organic compounds.
Explain how an ecological footprint can be calculated for an individual or country.
By adding up all ecologically productive land on the planet divide by the population. (1 person per 2.47 acres).as well as use energy.
Explain how crassulacean acid metabolism (CAM) is an important adaptation to reduce transpiration (water loss) in arid environments.
Cam is an important adaptation to reduce transpiration because it allows for CO2 to take place at night which allows for the stromata to remain closed during the day and not lose any water.
Describe how a countercurrent heat exchanger may function to retain heat within an animal body.
Circulatory adaptations that allow heat to be transferred from blood vessels containing warmer blood to those containing cooler blood.
Describe key components of the carbon cycle.
Complex molecules are made up of carbon bonded with other elements, especially oxygen, hydrogen, and nitrogen. Carbon is abundant on Earth.
Given examples and then explain directional, disruptive, and stabilizing selection.
Directional selection: Environmental favor pressure favor on one phenotype more than the other. An example of this would be lighter mice easily seen by predators due to the dark rocks that they live in, making it harder for them to hide from predators. Disruptive selection: Occurs when conditions favor individuals at both extremes of phenotypic range over individuals with an intermediate phenotype. An example of this would be light mice and dark mice living in an environment that is favored for both. Stabilizing selection: Favor individuals who have higher chances of reproducing than individuals who are less successful. An example would be, babies ranging from 3-4 kg and 6.6-8.8pounds, the smaller babies would've higher risk of mortality due to them being smaller.
Discuss the importance of gene duplication in chordate evolution. Why are duplications of "Hox" genes of particular importance?
Duplications allow for more morphological complexity because new genes can be allocated to new purposes.
Describe, in broad terms, how the energy budgets of ectotherms and endotherms of similar size differ.
Ectotherms like fishes and amphibians gain heat from external sources whereas endotherms such as birds and mammals generate their heat by metabolism.
Write the 2 Hardy-Weinberg equations. Use the equation to calculate the percentage of carriers of cystic fibrosis (a recessive disease, you must have two recessive alleles to have the disease) ina population if the frequency of cystic fibrosis births in that population is 81 in 1000.
Equations (p + q = 1) , (p^2+ 2pq+q^2=1) 81/1000= 0.081 q= 0.081 to find p 0.081-1=.919 p=.919 2*0.081*.919=0.148878 Frequency is = 0.148878 to find percentage multiply frequency by 100
Compare the exponential model of population growth with the logistic model.
Exponential grow very quickly and have not limit. Exponential grows slowly when its small but when the population gets bigger they tend to grow faster. Logistic growth does have a growth limit, they will reach their capacity.
Relate variations in length of the digestive tract to the diets of herbivores, carnivores, and omnivores.
HERBIVORES: -Don't need sharp teeth -Scissor like incisors to cut up plant matter -Big flat molars and premolars to grind down plant material CARNIVORES: -Long pointy canine for biting and killing prey -Sharp pre-molars to cut/rip flesh
Explain the importance of the Haber-Bosch process in a) feeding the world's population and b) polluting aquatic ecosystems.
Haber-Bosch process has helped feed the world's population conserving more than four times the expected amount of land mass and allowing for the world's population to grow from 1.6 to 7 billion in just over a hundred years. However, the efficiency of nitrogen use is less than 50% and farm runoff from heavy use disrupts biological habitats, especially aquatic systems.
What is heterozygote advantage? Give an example.
Heterozygote advantage is when something that is considered to be bad ends up being good for an organism. An example that could be considered is a sickle cell trait, it protects against malaria in heterozygotes, but is a deadly disease for homozygotes.
Explain the general function of homeotic genes (a class of developmental genes). Describe how changes homeotic genes, or how those genes are expressed, can lead to major differences between species, citing an example.
Homeotic genes determine such basic features as where a pair of wings and legs will develop on a bird or how a plant's flower parts are arranged. When homeotic genes are overactivated or inactivated by mutations, body structures may develop in the wrong place. Most animal homeotic genes encode transcription factor proteins that contain a region called the homeodomain and are called Hox genes. Hox genes are found in many animals, including fruit flies, mice, and humans. Mutations in human Hox genes can cause genetic disorders.
Of the many hominin species that preceded present-day humans, which one does current evidence indicate were the first to migrate out of Africa? How long ago did that occur?
Homo erectus and homo ergaster they had larger brains and were the first hominin to leave africa. It occurred 2 million years ago.
Define the difference between homologous and analogous traits. Try to explain how bird wings and bat wings are homologous as forelimbs but are analogous as wings.
Homologous is the characters in different organisms that are similar because they were inherited from a common ancestor. Whereas analogous traits are similar because of convergent evolution, not because of common ancestry. bird and bat wings are analogous as wings, as forelimbs they are homologous. Birds and bats did not inherit wings from a common ancestor with wings, but they did inherit forelimbs from a common ancestor with forelimbs.
How does the size of a population size effect genetic drift?
How does the size of a population size effect genetic drift?
Define hybrid breakdown and explain how hybrid breakdown maintains separate species even though fertilization has occurred.
Hybrid breakdown, some first generations hybrids are viable and fertile, but when they mate with other species the offspring of the next generation are feeble or sterile. This occurs because of the different chromosomes from each parent, meiosis in the hybrid fails to produce offspring when mating causing gene flow to no be able to flow freely between species.
Define allopatric speciation and then compare it to sympatric speciation.
In allopatric speciation, a population forms new species while geographically isolated from its parent population. The difference is that in allopatric speciation the population is separated by a physical barrier whereas in sympatric speciation occurs without a physical barrier.
Compare the age structures of Italy, Afghanistan, and the United States. Describe the possible consequences for each country.
In the U.S. people pass away at 85 years old, the same goes for Italy but, in Afghanistan people start dying at a younger age so only a few people make it to 85 years old.
Describe how the sporophyte and gametophyte stages of a plant life cycle differ.
In the gametophyte stage haploid gametes are produced by mitosis, In the sporophyte stage haploid spores are produced by meiosis.
Explain the role of vasoconstriction and vasodilation in modifying the transfer of body heat with the environment.
In vasoconstriction the blood flow in skin decrease lowering heat loss meaning smaller decrease in flow. In vasodilation the blood flow in the skin increases facilizing heat loss which is helpful because it helps cool you off.
Describe three new evolutionary adaptations that occurred with the origin of gnathostomes.
Increased complexity, enhanced smell and vision and lateral line system (sensitive to vibration).
Explain, in detail, why one individual organism cannot evolve, but a population can evolve.
Individual organisms do not evolve because they retain the same genes throughout their whole life. In fact, it's the population that evolves due to the different genetic types changing frequently. Meaning, Individual organism within a population do not change only the pollution gene does.
How was the amniotic egg a key evolutionary innovation for terrestrial life?
It prohibits external fertilization, facilitating the evolutionary innovation of internal fertilization. It increases the likelihood of survival of the eggs in a terrestrial environment and it enabled eggs to float in an aquatic medium.
How did Jean Baptiste Lamarck explain evolution, and why has the evidence not supported his explanation?
Lamarck explained evolution by using two principles, the first one was use and disuse, the idea that parts of the body that are used extensively become larger and stronger, while other body parts not being used became smaller. The second principle, inheritance acquired characteristics basically stating that organisms could pass down certain characteristics to their offsprings. Lamarck's theory was proven wrong because he believed acquired characteristics were passed down and inherited by future generations, which is false because acquired characteristics do not have genetic bases.
Distinguish between microevolution and macroevolution and explain how they are connected to each other.
Microevolution deals with changes in the gene pool of a single population and Macroevolution considers the broad pattern of evolutionary change over long periods of time and includes the origin of new groups. Both microevolution and macroevolution are connected by mutation.
Explain, with a specific example, how a mountain range can affect regional climatic conditions.
Mountain affects regional climate conditions because it decides how much sunlight can reach an area as well as the local temperature and the amount of rainfall they have. A good example would be the ocean in San Diego, the air flow Rises and air releases moisture on the windward side of a peak and creates a "rain shadow" as it absorbs moisture on the leewards side. The mountain decides whether the climate will be hot cold or if they will have rain.
List the characteristics and the hypothesized sequence of events in the origin of animals from single-celled eukaryotes (see the lecture slides).
Multicellular eukaryotes, animals ingest their food while fungi digest food with enzymes on their exterior and plants make their own food. They are cells without cell walls, specialize tissue for cell production, diploid body cells and haploid gametes.
Describe how, in general, natural selection on individuals in populations is an "editing" process.
Natural selection is an editing process because it favors individuals that are already in the environment. For example, if one sprays pesticide to kill some insects, some would be resistant to the pesticide which would result in the surging and reproduction of more offsprings resistant to the pesticide.
Explain the difference between primary growth and secondary growth in plants primary growth
Occurs in both roots and shoots Roots extend through soil Shoots extend to maximize sunlight and CO2 exposure Secondary growth - Adds thickness to roots and shoots - Early wood formed in spring, has thin cell walls to max water delivery. - Late wood formed in late summer, has thick-walled cells & contribute more to stem support
Explain the differences between oligotrophic and eutrophic lakes.
Oligotrophic lakes are nutrient-poor and generally oxygen-rich and Eutrophic lakes are nutrient-rich and often depleted of oxygen if ice covered in winter
How did atmospheric O2 accumulate over time?
Once the O2 dissolved in lakes and seas it began to "gas out" of the water and entered the atmosphere. The O2 accumulated overtime because of tiny organisms known as cyanobacteria, or blue-green algae. These microbes conducted photosynthesis using sunshine, water and carbon dioxide to produce carbohydrates and oxygen.
Explain why pollen grains were an important adaptation for successful reproduction.
Pollen grains are important because they give rise to a pollen tube that discharges sperm into the female gametophyte within the ovule.
define the terms population species, and gene pool.
Population is a group of individuals interbreeding and producing fertile offspring Gene pool is the total number of every individual in an interbreeding population Species refers to a group of individuals that are similar who potentially interbreed and produce fertile offspring.
Distinguish between positive and negative feedback mechanisms. Which type of mechanism contributes to homeostasis?
Positive feedback occurs in animals but does not contribute to homeostasis, negative feedback contributes to animals by returning a variable to a normal range or set point.
Define and describe an example of 1) a prezygotic barrier and 2) a postzygotic barrier.
Prezygotic barriers block fertilization from occurring. An example would be preventing an attempted mating from being completed successfully. Postzygotic barrier may contribute to reproductive isolations after hybrid zygote is formed. An example, would be a mule.
Compare the developmental differences between protostomes and deuterostomes, including pattern of cleavage, coelom development, and cell determination. Why can it be said that deuterostomes develop 'butt-first'?
Protostome development, there is spiral radial and indeterminate cleavage. The blastopore becomes the mouth and the coelom forms from the mesoderm. Deuterostome development, radial and indeterminate cleavage take place. The blastopore is the new anus and the coelom forms from budding off the wall of the archenteron
Explain how interspecific competition may lead to resource partitioning, providing an example
Resource partitioning is a differentiation of ecological niches, enabling similar species to coexist in a community. An example would be, distichous perches on fence posts and other sunny surface and A. insolitus perches on shady branches.
Explain why seedless vascular plants are commonly found in damp habitats.
Seedless vascular plants have flagellated sperm, so they are usually restricted to moist environments.
Describe, in broad terms, how the energy budgets of small and large endotherms differ.
Small endotherms have faster metabolisms, and larger organism have slower metabolisms, the reason their metabolism is slow is because they derive warmth externally. while small organisms gain heat from external sources.
Explain the benefits and costs of the broad external surface area of many leaves.
Taller plants with broad lat appendages have the advantage of absorbing more light. The cost of having an increase in surface area would simply mean more evaporation as well, as water is needed.
Are snakes tetrapods? Explain your answer.
Tetrapods usually have 4 legs, although snakes do not have limbs they are still considered tetrapods because they evolved from animals with four limbs.
What is the 'Cambrian Explosion,' when did it occur, and why is it significant?
The Cambrian explosion is the sudden appearance of fossils resembling modern phyla in the Cambrian period which was, 535-525 million years ago. It is very significant because it is the time when most of the major groups of animals first appeared in the fossil record.
Describe the "whole-lake" experiment conducted at the Experimental Lakes Area in Canada which demonstrated that phosphorus (P) was the nutrient most limiting algal productivity in lakes.
The Ela is a collection of 58 lakes in Canada that were preserved and set aside to study the effects of pollutants like mercury, nitrogen, and phosphorus. Ela lake was the site of a study conducted with pollutants to test algal bloom. Half o the lake had carbon and nitrogen and phosphorus added to it. In 8 years time, the side without phosphorus had no algal bloom, whereas the side with it saw eutrophic algal blooms. This experiment demonstrated that phosphorus is a key ingredient to the growth of algal bloom.
Summarize two hypotheses that explain why food chains are relatively short.
The Energetic Hypothesis: Length of food chain is limited by inefficient energy transfer (More support) The Dynamic Stability Hypothesis: Long food chains are less stable than short ones
Explain why deserts are most commonly found on the earth near 30°N and 30°S Latitudes.
The Hot air from the equator rises, then cools, moisture is lost, and the dry air comes down at 30 degrees north and south.
Explain the bottleneck effect and its impact on the genetic diversity in a population.
The bottleneck effect usually occurs when a big disaster reduces the size of the population. Its impact on genetic diversity is that the previous generations wouldn't be able to pass on their genes.
Explain the endosymbiotic theory for the evolution of the eukaryotic cell, and describe the evidence that supports this theory.
The endosymbiotic theory posits that mitochondria and plastids (includes chloroplasts) were formerly small prokaryotes that began living in larger cells. Evidence for endosymbiosis is that it shares organelles traits with prokaryotes. The Inner membranes of both organelles also have homologous enzymes & transport systems to those in plasma membranes of prokaryotes.
Explain the factors responsible for the 4 different annual 'seasons' we experience on the planet.
The factor that is responsible for the 4 different seasons is the entire world is tilted at a 23.5 angle. The seasons changing is a result of the sunlight striking the Earth's surface at different angles as the Earth revolves around the sun.
What were the first mineralized (bony) structures in vertebrates? What sort of functional changes did the mineralization of those structures allow?
The first bony structure in vertebrates was the mouth, their jaws enabled them to grab prey and bite chunks of flesh
Explain why the following statement is not exactly accurate: "Antibiotics like methicillin have created drug resistance in MRSA (methicillin-resistant Staphylococcus aureus).
The following statement is incorrect because a drug does not create resistance, but rather it selects traits that are already present in the population.
Explain the possible causes of lynx/hare fluctuations in the Hudson Bay Trading Company data, and why one cannot draw a definitive conclusion from the data.
The hare population densities could have been controlled by lynx predation, or by food availability. Maybe the cycling was more tied to fashion trends in Paris, than to biological reasons. (When hare furs are popular, the trappers catch more hare because they are worth more.) We can't draw an exact conclusion because maybe the trends are caused by a third unknown factor and we don't have enough background information to make a conclusion.
Explain how molecular clocks are used to determine the approximate time of key evolutionary events.
The molecular clock measured the absolute time of evolutionary changes based on the observation that some genes and other regions of genomes appear to evolve at constant rates. By comparing the number of genetic differences against the evolutionary dates that are known from the fossil record.
Explain this statement: "In plants, the upward movement of xylem sap (water and nutrients) is ultimately solar powered."
The movement of xylem sap against gravity happens by transpiration- cohesion transpiration (water evaporation via stomata) generates negative pressure (vacuum) that pulls water up through the xylem, so there is no energy cost to flow of xylem sap
Explain the principle of maximum parsimony (often called 'Occam's razor') as it applies to phylogenetic trees.
The principle of maximum likelihood states that, given certain rules about how DNA changes over time a tree can be found that reflects the most likely sequence of evolutionary events
Explain what the term "amphibian" says about their habitat, and about the evolution of this group of organisms.
The term amphibian means both ways of life, referring to the life stages of many frog species that live first in water and then on land.
explain what Tiktaalik suggests about the origin of tetrapods.
The tiktaalik helped discover how fins became progressively limb-like over time. As well as suggesting that key tetrapods traits such as wris,ribs, and a neck were ancestral to tetrapod lineage.
Describe, and explain, how global climate change is predicted to impact the range of the American Beech tree.
The trees are probably going to spread out to Northern Ontario and Quebec because of the huge effect global climate has done.
.Define the following characteristics of lakes: thermal stratification, thermocline, seasonal turnover.
Thermal structure - change in temperature at different depths in the lake and also the change in water's density with temperature(cold water is denser than hot water)Thermocline - a boundary that separates the warm upper layer from the colder deeper water Seasonal turnover - semiannual mixing of the waters, mixes oxygenated water from the surface with nutrient-rich water from the bottom
Explain why toxic compounds usually have the greatest effect on top-level carnivores.
Toxins are ingested by organisms and accumulate in the fatty tissues these toxins become more concentrated in successive trophic levels of a food web- biological magnification. Magnification occurs because the biomass at any given trophic level is produced from a much larger biomass ingested from the level below. Thus top-level carnivores tend to be the organisms most severely affected by a toxic compound.
Explain why, at the equator (0° latitude), the climate is most often a) very hot, and b) extremely wet (lots of rainfall).
Trade winds of the two hemispheres meet by the equator, so when the equator is at 0° latitude the air to rises. As it raises the air began to cool, thus the clouds and rain begin to develop. When trade air blows away from the 30* latitude, air slowly moves to replace the air that blows and the moisture evaporate from the heat.
Define a zoonotic pathogen. Explain how zoonotic pathogens might be controlled.
Zoonotic pathogen, refers to pathogens naturally transmitted between animals and humans.Zoonotic pathogens may be controlled by controlling the vectors that spread them.
Explain character displacement, and provide an example.
character displacement is a tendency for characteristics to be more divergent in (overlapping) populations of two species than in (non- overlapping) populations of the same two species. An example of this would be, beak variation between two species of Galapagos finches.
Explain how climate changes with the formation of the supercontinent Pangaea favored the spread of gymnosperms.
climate change turning from dry to warm, favored the spread of gymnosperms greatly due to the fact that gymnosperms could adapt easily to any climate.
What is the relationship between body size and metabolic rate per unit body mass in endotherms? What might explain this relationship?
the smaller the organism, the more rapid the metabolic rate is.
Explain how an environment's carrying capacity affects the rate of increase of a Population.
when a carrying capacity reaches the maximum population size the env can no longer support so many people so the population starts to decrease.