Biology Exam Review 2
Explain steps of how plants coevolved with insects
1) existing variation (UV or none) 2) plants with UV have inc number of pollinators 3) pollination is an inc in reproductive success 4) next generation of plants have greater proportion of alleles for UV coloring
2-38 What is the difference between a pollen grain and a sperm nucleus? Distinguish between pollination and fertilization.
A pollen grain is a gametophyte (multicellular haploid; n) that is the product of mitosis from microspores produced by the meiosis process in anthers A sperm nucleus is the product of mitosis of the generative cell from a single pollen grain (made up of generative cell and tube cell). Pollination is the transfer of pollen grain to the top of the carpel (specifically stigma), and the pollen tube grows toward the embryo sac (not the fusion of the egg and sperm). Fertilization is the fusing of the sperm and egg (2n); Fertilization is also the fusing of the 2nd sperm and 2 polar nuclei (resulting in 3n; the endosperm)
A biologist is studying phylogenetic relationships among these species, C-L. In order to best determine which traits are ancestral vs. derived she should use which of these as the outgroup? A. A B. B C. C D. any species within her study group C-L
B
3 domains of life
Bacteria, Archaea, Eukarya
2-42 What are some examples of flower adaptations to attract specific pollinators? What's the adaptive advantage of having a specific cue to attract specific pollinators and not just any pollinator?
Bees are attracted to bright colors, primarily yellow and blue; red appears dull; bees can see UV radiation; so dandelion have UV markings to guides the bees to the nectaries Pollination by moths and butterflies: they detect odors, so the flowers they pollinate are often sweetly fragrant; moths perceive white or yellow better Advantage: strengthens reproductive success since the pollinator will continue to pollinate within the same species; cross pollination with the same type of plants; doesn't waste the gametes by pollinating other species
According to this phylogeny (front page of homework quiz), species H shares more derived traits with which of these groups? A. F & G B. I & J C. K & L D. I, J, K, L E. Equally with F-L
D
Which group shares the most derived traits with angiosperms (flowering plant - rose, daisy)? A. ferns B. green algae C. moss D. pine tree (gymnosperms)
D
Which on of the following best describes plant meristems? A. continuous growth by cell elongation B. growth mainly in embryo plant C. determine growth in stem elongation in middle of the plant D. continuous mitosis, specialized cells E. continuous mitosis, undifferentiated cells
E
Number these in order, put X if not in process A. starch is digested into sugars B. hormone signal binds to receptor C. target cells secrete enzymes D. embyro grows E. Seed takes in water (imbibition) F. embryo secretes GA giberellins G. embryo secretes ABA abscissic acid
E F B C A D G NOT exist
2-18 Name the three 'germ cell layers' in animal embryos and tell one structure that develops from each.`
Endoderm - internal lining of body; lining of gastrointestinal tract; digestive system Mesoderm - organs; heart, muscle system, connective tissue Ectoderm - outer linings; epidermis, central nervous system
2-43 In the history of evolution of biodiversity on earth, flowering plants evolved a great diversity about the same time that insects evolved great diversity. Explain the coincidence.
Flowers evolved to attract pollinators to them so that the pollinators could help with reproduction by shuttling pollen between plants, thus fertilizing them
2-46 Give two examples of asexual (vegetative) reproduction in plants. Review: Compare the evolutionary advantages of sexual and asexual reproduction.
Fragmentation: type of vegetative propagation, separation of parent part that develop into whole plants Budding: cactus, potato Aspen tree- (connecting of the roots), create new trees, clones can also reproduce sexually Advantages of Sexual & Asexual: more genetic variability clones, faster, less energy, no need for pollinator
2-23 What are the major evolutionary innovations (new derived traits) in the Vertebrate phylogenetic tree?
Hinged jaws (effective predators and chewing not sucking) Tetrapod (4 legs, amphibians, then lungs) Amniotic egg: (reptiles, mammals, birds) keeps water in, gas exchange (CO2 & O2)
2-19 What are hox genes? Give an example of how hox gene expression controls development.
Hox genes all encode for transcription factors that bind to enhancers and promoters and turn on genes for body formation Ex) Chicken and Mouse vertebrae: both have the same hox gene but are expressed in different location ex) The sequence in which parts develop (i.e the head first or rectum first) is controlled by hox genes
Difference between Hox genes and organ identity genes
Hox: (animals) Activate in early development OIG: (plants) turned on at anytime produces any parts of a plant (petals, stamen)
2-37 What is the male gametophyte (a multicellular haploid structure) in a flower?
Male gametophyte: Pollen grain NOT the sperm Female gametophyte- embryo sac The male gametophyte consists of generative cell (makes the 2 sperm nuclei) and tube cell (makes the tube) Produces a pollen tube that delivers sperm to ovary
2-26 Animal mating behavior can be under genetic control, through hormones and neural pathways, and thus can evolve by natural selection. Name an example of a male-specific behavior, and tell how individuals with this behavior have greater reproductive fitness than males without it.
Male insects (butterflies) create mating plug in females so they cannot receive anymore sperm (Increases reproductive fitness of those who create plugs since it ensures the passing of their genes only.) New dominant male lion kills all the young cubs (Increases his own reproductive fitness, he passes his own genes only now. Lioness will want to reproduce after losing offspring, putting them in a reproductive state)
2-41 When a pollen grain nucleus fertilizes an egg nucleus from the same individual plant (self-pollination and self-fertilization), is that the same as asexual reproduction? Why or why not?
No, this is still considered sexual reproduction. Meiosis and fertilization (egg and sperm) are still occurring.
2-44 The fruit develops from what flower part? What is the function of fruit? Does it nourish the embryo?
Ovary Fruits help plants spread seeds out, because animals transport and discard seeds when they eat fruits and to protect the seeds No, only endosperm
2-36 Identify each of the following and tell its function: flower, petal, sepal, carpel (ovary at base), anther (on tip of stamen)
Petal: to attract pollinators Sepal: protect the budding flower Carpel aka pistil: [meiosis] serves as the female part of the plant which produces megaspore: (Consists of stigma, style, and ovary pistil; area where pollination and fertilization occur) Anther: [meiosis] serves as the male part of the plant which produces microspores (pollen); terminal end of stamen Ovary at base: site of egg fertilization and embryo sac Flower: reproductive shoots of angiosperm sporophytes
2-39 What is involved in double fertilization, and what are the two products of double fertilization?
Pollen grain → lands on stigma → absorbs water and germinates by producing pollen tube → grows toward the ovary → nucleus of generative cell divides by mitosis and forms TWO sperms → discharged from the tube → 1 sperm fertilizes the egg and form the zygote and the other sperm combines with the 2 polar nuclei to form a triploid (endosperm)
2-5 Advantage of using traits of an "outgroup" to construct a cladogram
Using an outgroup can help to determine which traits are ancestral and which traits are derived An outgroup can also be used as a standard of comparison All the members of target group are more closely related to each other than they are to the outgroup; outgroups has least similarities to other species
human evolution characteristics
bigger brain upright posture smaller jaws genomic comparison to neanderthals
what's wrong with "all members of the dinosaur mono-phyletic group are extinct."?
birds are descendants of dinosaurs
Multicellular components
cell-cell communications (gap-animals, plasmodesmata-plants)
sporophyte is
diploid ovary (female) anther (male)
2-40 Tell whether each is haploid, diploid, or triploid: petal, pollen, embryo sac, endosperm, ovary Petal Pollen Embryo sac Endosperm Ovary
diploid haploid haploid triploid diploid
2-45 What are some adaptations for seed dispersal? What adaptations might prevent seed predation?
fruit, so animals will eat and poop out the seed burs on seeds so it catches on animal furs and hitches a ride 'parachutes' on dandelion seeds so they can blow away in the wind some fruits have laxatives which encourages quicker digestion. protective seed coat strength/material chemical toxins (cyanide)/laxatives/tannins. example: Cashews have a section of nutritious fruit but also have a toxic seed on the top of the fruit to prevent animals from eating the seed.
gametophyte is
haploid pollen grain (male) embryo sac (female)
growth of roots occur at and by
meristem by cell division, elongation, and maturation
2-9 Name the (a) opportunities (b) challenges that early plants faced with life on land.
opportunity: space (new resources), more sunlight, less competition challenge: sunlight it too harsh, drying out (waxy cuticle), stomata to allow CO2 and O2 exchange, vascular tissue for firmer structure
Oogenesis
production of female gametes (eggs) via meiosis polar body (n) + n = fertilization --> Meiosis 2 ---> n in animals meiosis 2 occurs after fertilization
spermatogenesis
production of sperm (gametes) via meiosis 4 haploid in animals
reproductive isolating mechanisms of plants
shape, color, size, odors of petals flowers give rewards to the pollinators pollen attract specific pollinators
microspore
small haploid spore formed by some plants that develop into a male gametophyte by meiosis 4 ovaries (1/4 survive)
megaspore
the large spore germinates into a female gametophyte, which produces egg cells. by meiosis 4/4 survive
3-35 Write out a general, simple life cycle (diploid-meiosis-haploid-fertilization-diploid). In what organs do meiosis & fertilization occur in a flowering plant?
zygote(2n) - *mitosis* - diploid sporophyte(2n) - *meiosis* -unicellular spore(n) - *mitosis* - multicellular gametophyte (n) Meiosis: Anther & Ovary Carpel (embryo sac)
2-34 Explain the "acid-growth" hypothesis for the bending of a shoot towards the light. List the steps by which cells elongate in response to auxin. How is this an example of signal transduction?
1) Auxin accumulates on side away from light (dark side) , Auxin causes cell elongation 2) Increased auxin begins signal transduction by binding to receptors on plant cell 3) Proton pump activity increased 4) Protons pumped out of cell towards cell wall increases acidity 5) Cleaving protein (expansins) are activated due to acidity change which then breaks polysaccharide bonds in cell wall - "expands cell wall" 6) Loosening of threads allows for more water to come in and solutes. Water follows solutes, increasing the turgor pressure The sliding of the cellulose microfibrils allow the cell to elongate
2-31 Explain the process of seed germination (beginning with imbibition, up to mobilization of sugars for seedling growth).
1) Imbibition (seed takes in water; ABA is diluted) **water uptake is ALWAYS required** 2) embryo secretes GA (gibberellin; because of tissue activation through H2O) 3) hormone signal binds to receptor in target cell 4) target cells secrete amylase (hydrolytic enzymes) 5) Starch is broken down by amylase into glucose' glucose is taken in by embryo. Endosperm broken (Starch is digested into sugars). 6) Embryo grows
List 2 resulting changed in the cell membrane or cell wall which ultimately allow water to enter the cell and the cell to elongate (cellulose linkages and expansins - loosen the cellulose linkages)
1) auxin activates proton pump, creating more hydrogens on the gradient, more acidity, so constraints of cell wall are removed 2) more solutes are entering the cell so more water is entering the cell
name two traits that arose during the evolution of the plant kingdom and, for each, indicate what challenge/problem they solved for the plants that adapted them better to life on land.
1) waxy cuticle (prevention of water loss) 2) stomata (prevent gas exchange) 3) roots 4) height 5) pollen, Not swimming sperm
If a seed is dormant, it likely contains a high concentration of which/ A. abscisic acid B. auxin C. cytokinin D. gibberellin
A
In a phylogenetic analysis we must be careful to look for the presence or absence of traits that are homologous to each other in different groups. What are homologous traits? A. traits derived from the same ancestral trait B. traits that are for the same function C. traits that have similar shape D. traits that are easy to measure
A
In a phylogenetic tree of species the term "sister taxa" refers to any two species A. with the most shared, derived traits B. that evolved from the most ancient common ancestor C. that belong to the same monophyletic group D. that have the same function in the ecosystem E. that currently live in the same geographic region
A
high ABA and low GA - name the overall process in the seed and name one specific change in the seed
ABA promotes water loss and slows down (turn off) metabolism seed dormancy
Animal hox genes and plant origin-identity genes are similar in what ways (share which of these traits)? A. hox genes and organ-identity genes evolved from the same ancestral gene B. they both are expressed only early in development of the individual C. they both control development of body parts D. two of these are similarities E. all three of these are similarities
C
What is the original evolved, adaptive function of the attractive, nutritious tissue of a fruit such as peach or cherry? (A) nutrition for the embryo plant (B) protection of the embryo plant (C) nutrition for animals that disperse the seeds (D) Attract animals to consume the seeds (E) for humans to make pies.
C
Which if the following is a good match of a challenge of living on land with a new plant? A. genetic variability advantageous ---> meiosis B. genetic variability advantageous ---> mitosis C. reproduction out of water ---> pollen
C
Which is the best statement of a null hypothesis about phototropism? A. in phototropism the shoot tip does not grow to light B. in phototropism the shoot tip does not group C. there is no relationship between light and shoot tip growth
C
Which of the following correctly displays the sequence of developmental milestones in animal embryos? A. blastula ---> gastrula ---> cleavage B. cleavage ---> gastrula ---> blastula C. cleavage ---> blastula ---> gastrula D. gastrula ---> blastula ---> cleavage
C
Which of the following is a good match of an aspect of living on land with a new plant adaptation to solve a challenge? A. absorb light ---> roots to absorb water B. too much water loss ---> stem for transport C. waxy layer to save water ---> leaf pores for CO2 intake
C
Which of these best describes phototropism? A. is a turning movement by a plant shoot in response to light B. is a growth response by a plant shoot caused by uneven mitosis C. is a growth response by a plant shoot caused by uneven auxin D. involved plant shoot bending because of uneven apoptosis
C
Which of these events occurs first in the process of seed germination? A. cell division occurs in the embryo and growth starts B. Mitochondria multiply and provide energy for growth processes C. water is taken up by the seed D. oxygen is produced and proteins are synthesized
C
Which of these is a challenge of multicellular life that single-celled organisms do not face? A. solute-water balance B. regulation of cell division C. cell-cell communication
C
Which of these marine conditions was associated with the great burst of animal speciation and diversity over 500 million years ago? A. increased oxygen levels B. increased dissolved calcium levels C. both of these D. neither of these
C
Which one or more of these are characteristic only of the organisms we call Animals? A. Use O2 for cellular respiration B. have multicellular organs C. have gap junctions, tight junctions D. have embryonic germ cell layers E. are heterotrophs, no photosynthesis
C D
2-10 What are some distinguishing characteristics of Fungi?
Chitin in cell walls Asexually and sexually reproduce made of long threads of hyphae (make collective mass of mycelium), provides greater surface area to absorb nutrients as food
name two traits shared between plants and green algae (not red algae or other photosynthetic protists)
Chlorophyll A & B Cellulose Starch
2-12 Give examples of major changes in the earth's seas that provided 'opportunity' for large-scale adaptive radiation of groups of animals.
Inc. calcium in ocean to develop skeletons O2 levels inc (O2 for muscle and nerves, aerobic respiration, circulatory system) Inc in genetic # & morphological structures
2-11 What are some distinguishing characteristics of Animals?
Multicellular reproductive organs (also in plants) cell adhesion & gap junctions embryonic cell layers (2 or 3 germ layers) 4 tissue types: muscle, connective, epithelial, nervous contractile muscle movement (not flagella or cilia)
What wrong with "Snakes are slimy"?
Snakes are reptiles and slimy comes from amphibians
Design an experiment to test a factor that affects percent seed germination (not water) a. state a specific hypothesis b. state the null hypothesis c. what is the independent variable d. two control variables will be the species of seeds and the treatment with water. Name control variable (specific to your experiment)
a. sunlight and percent of seed germination have a relationship b. sunlight has no relationship to the percent of seed germination c. sunlight d. type of soil and temperature dependent: percent seed germination
2-20 Hox genes represent a multi-gene family. Tell why one can thus build a phylogeny with them.
because they are derived from ancestral hox genes. As hox evolution occurs, further diversity arises. Thus with more hox genes = more complex organisms arise
2-13 How do cell adhesion, cell-cell communication, and cell specialization help an animal be "multicellular"?
cell adhesion allows for cell to be anchored and organized in a way that allow them to serve a collective function, provide structure or movement cell communication allows cell to be met by others through sending and receiving signals cell specialization increases efficiency by allowing cells to focus on a single function instead of one cell doing everything to live a reproduce
name two distinctive traits of all plants that are not shared with their green algae ancestors
multicellular reproductive organs Apical meristem multicellular embryos
three major classes of vertebrates that have the amniotic egg
reptiles birds mammals
2-8 Origin of Plants: What is the evidence that land plants evolved from green algae ancestors?
same pigments in chloroplast, cellulose in cell walls, starch as storage
Since animals have nerve and muscle tissue and plants do not, which of the following events in earth's history would be associated with adaptive radiation of many groups of animals, and NOT particularly that of plants? A. increase in atmospheric O2 B. great increase in land mass area C. changes in global ocean temperatures D. meteorite impacts and volcanic eruptions E. earthquake activity causing increased barrier formation
A
The similarity of manatee and dolphin body form is because they are A. analogous B. homologous C. ancestral D. derived
A
Which if the shaded groupings above are clades (monophyletic groups)? A. 1 B. 2 C. 3 D. two of these E. all three of these
A
Which of the following is the set of taxa (vertebrate classes) that have amniotic eggs? A. birds, mammals, and reptiles B. amphibia, bony fish, and reptiles C. birds and reptiles D. amphibia, birds, mammals, and reptiles E. all classes of vertebrates
A
Which of these groups has the most recent common ancestor with the Animal Kingdom? A. Fungi B. plants C. ciliates (Protists) D. water molds (protists)
A
Which of these is/are reasons why a period of seed dormancy is advantageous? A. allow time for seeds to be dispersed away from B. allow time for pollination and fertilization to occur C. allow time for food to accumulate inside the seed D. allow time for water to be taken into the seed E. two of these are advantageous reasons
A
Which one or more of the following describes the evolution of hox genes? A. multiple hox genes evolved from a single ancestral hox gene B. the number of hox genes in an animal is related to complexity of the animal's structure C. hox genes have evolved to be expressed throughout lifetime of an animal D. two of these are true E. all three of these are true
A B
__________ is in charge of promoting seed dormancy __________ is in charge of ending seed dormancy A. parent plant B. seed (embryo plant)
A B
Which is/are the best statements of a testable hypothesis about phototropism? A. phototropism is a response to light B. phototropism is a response to fairy dust C. phototropism is a response to water D. two of these
A (best but needs to be more specific)
2-28 What is meristem? Where can apical meristem be found in plants?
A region of continuous mitosis of undifferentiated cells Apical meristem at tips of roots and shoots.
2-7 What are some advantages and benefits of multi-cellularity in organisms? What are some adaptations that must have evolved in order for multicellular organisms to be successful?
Advantages: bigger (complex structure), better for competition, leads to diversity less energy per cell used intercellular communication Adaptations: cell-cell communication cell adhesion vascular tissue
how do auxin's effects on cells cause phototropism in a plant shoot?
Auxin will accumulate on the side away from sunlight and elongates the cells on that side
In addition to having specific membrane transport proteins, animal cells can communicate directly with each other though A. plasmodesmata B. gap junctions C. desmosomes D. tight junctions E. two of these
B
In an animal that switched between sexual and asexual reproduction, when is sexual reproduction more likely to offer a selective advantage? A. when conditions for survival are favorable B. when conditions for survival are unfavorable C. when males and females find each other D. when conditions favor sexual over asexual remains a complete mystery
B
Many plants produce fruit that attracts animals and seeds that contain distasteful toxins that animals avoid. What messages is the plant giving? A. Eat my fruit and chew up my seeds B. Eat my fruit and scatter my seeds. C. Eat my fruit and disperse my pollen. D. Don't touch anything! E. Come and get everything!
B
Through what phylogenetic evidence do evolutionary biologists agree that the endosymbiosis of mitochondria evolved before the endosymbiosis of chloroplasts? A. because all organisms use O2 in respiration B. because all Eukarya have the derived trait of 'mitochondria present' C. because all Eukarya have the derived trait of 'chloroplasts present' D. because plants have chloroplasts and not mitochondria
B
What is the reason for using an "outgroup" in a phylogenetic tree? A. to be sure there is a sufficient number of taxa (species) B. to decide which form or a trait is ancestral or derived C. to decide which taxon (species) is the most derived D. because it is easier to find fossil data for an outgroup E. because every group needs something that doesn't belong!
B
Which of the following best describes the function of a hox gene? A. all transcription factors are encoded by hox genes B. hox genes all encode transcription factors that turn on genes for body form C. hox genes all encode proteins that are present in specific body structure (eyes, antenna)
B
Which of the following is a good match of a challenge of living on land with a plant adaptation to solve that challenge? A. absorb light ---> roots to absorb water B. too much water loss ---> waxy cuticle C. competition for light ---> new type of chlorophyll
B
Which of the following is an evolutionary advantage of seed dormancy in a plant species? A. maternal plant can build up more nutrients for the embryo B. seed can germinate in more favorable season C. dormant seeds are more difficult to disperse D. dormant seeds are less attractive to seed predators
B
Which of the following sets of species (in the phylogeny) consists of a clade (a monophyletic group)? A. A-E B. B-L C. C-G D. H & I E. H-J
B
Which of the following would you expect to see highly developed and more common in multicellular organisms and not so in single-celled organisms? A. sexual reproduction B. specialized cells C. well-developed cell wall
B
Which of these are properties of the amniotic egg, not present in aquatic vertebrates, that contributed significantly to the evolutionary success of vertebrates living on land? A. free exchange of water into and out of the egg B. free exchange of O2 and CO2 into and out of the egg C. provides food supply for the embryo D. hard or leathery shell protects the embryo E. two of these are helpful features of the amniotic egg
B
2-27 What is the structure of a plant embryo, and how does it grow?
Compact meristem with cotyledon (seed leaves) Monocot - (one seed leaf) Patterns of 3, 6, 9 Dicot - (two seed leaves) Patterns of 4, 5, varies Embryophyta = multicellular embryos stay on the parent plant Grows by the process of germination (started by water intake/imbibition) Seed: Seed coat, endosperm (stored nutrients, source of energy), embryo plant Endosperm is 3n (triploid) from double fertilization
2-24 How do we approach the study of human evolution?
Comparison of homologous structures (build phylogeny based on shared, derived traits) in fossils and DNA sequences Study using bones and fossils
2-32 Name a plant hormone that stimulates cell division and one that controls cell elongation.
Cytokinin - stimulates cell division (budding, branch formation) Auxin - controls cell elongation (in phototropism)
Asexual reproduction results in greater reproductive success than does sexual reproduction when ______? A. disease-causing microbes are rapidly diversifying B. there is some potential for rapid overpopulation C. a species is expanding into diverse geographic settings D. a species is in a stable and favorable environment
D
If relatively high levels of both auxin and cytokinin are added. A. both root tips and leafy branches will grow B. root tips will grow C. leafy branches will grow D. neither root tips nor leafy branches will grow
D
The backbone of a chicken has more neck vertebrae and fewer thoracic vertebrae than the backbone of a mouse (vertebrae form from embryonic mesoderm). This difference is likely due to which of the following? A. chicken and mouse embryos differ in the quantity of mesoderm they produce B. chicken and mouse embryos differ in the types of tissue that arise from mesoderm C. chicken and mouse embryos differ in the number of hox genes affecting the vertebrae D. chicken and mouse embryos have the same hox genes but differ in where they are expressed.
D
This cladogram indicates that manatees ("sea cows") are most closely related to which? A. dolphins B. killer whales C. walrus D. elephant
D
When a pollen grain nucleus fertilizes an egg nucleus from the same individual plant (self-pollination), isn't that the same as asexual reproduction, yes or no? A. yes, but I'm not sure why B. yes, because there's just one parent C. yes, because its not random fertilization D. no, because meiosis has been involved E. no, but I'm not sure why not
D
Which of the five marks in the tree above corresponds to the most recent common ancestor of a mushroom and a sponge? A. a B. b C. c D. d E. e
D
Which of the following was an advantage for plants to live on land? A. extra UV radiation available B. easier to support body weight of plant c. easier to reproduce, with swimming sperm D. easier for chlorophyll to absorb light energy
D
Which of the following was probably the LEAST important factor in bringing about the Cambrian explosion of animal diversity? A. the presence of new predators B. an increase in the concentration of atmospheric oxygen C. the availability of calcium and phosphates in sea water D. the movement of animals onto land E. the diversity of hox and other genes
D
Which of these is NOT a characteristic of organisms in the Kingdom Fungi? A. both sexual and asexual reproduction present B. chitin in cell walls C. feed by absorbing nutrients D. nearly all are parasites
D
during fertilization, the acrosomal contents released from the tip of the sperm function how? A. block polyspermy B. help propel more sperm toward the egg C. trigger the completion of meiosis by the sperm D. digest the protective jelly coat on the surface of the egg
D
Of the following, which of the following systems provides the LEAST genetic variability? A. fertilization within single flower on same plant; B. fertilization between two flowers on same plant; C. fertilization between flowers on different plants in same species D. asexual (vegetative) reproduction E. two or more of these are the same with respect to lowest genetic variability
D Asexual is mitosis
Two environmental changes that are associated with the burst of animal diversity known as the Cambrian explosion are: A. higher oxygen levels B. cooler global temperatures C. higher dissolved minerals in sea water D. two of these E. all three of these
D higher oxygen levels and higher dissolved minerals in sea water
Which describes the sexual life cycle of plants? A. alternation of multicellular and unicellular generations B. alternation of diploid and haploid generations C. alternation of spore-forming and gamete-forming generations D. two of these are correct E. all three of these are correct
D B & C
What are distinctive characteristics of multicellular life (not in most single-cell organisms)? A. cell specialization B. inter-cellular communication C. cell-cell adhesion D. two of these E. all three of these
E
Which of the following is a distinguishing trait of all true animals? A. circulatory system B. a head or cranium C. segments and appendages D. a body cavity E. embryonic cell layers
E
2-22 Give some examples of asexual reproduction in animals. What is hermaphroditism?
Fragmentation - organism breaks in two that develops new organism (starfish and coral) Budding - growth on an organism which eventually detaches; new individual arises from outgrowth of an existing one (hydra and jellyfish) Parthenogenesis - growth and development of embryo without fertilization (Male drone bees) Hermaphroditism (not asexual reproduction) - an animal has both female and male organs (individual has both ovary and testes) Sequential hermaphrodite- occurs when an organism changes their sex at some point in their life (ex. Clown fish male to female; other type of fish when the male dies, the dominant female becomes male) Simultaneous hermaphrodite- adult organism that has both male and female sexual organs at the same time
high gibberellins (GA) and low abscisic acid (ABA) - name the overall process in the seed and name one specific change in the seed (b/c of hormones)
GA will bind to target cells which secrete amylase with sugar as a biproduct seed germination
2-30 How do relative concentrations of abscisic acid (ABA) and gibberellins (GA) control the extent of seed dormancy? What are some environmental triggers to break dormancy?
High ABA (provided by parent plant) and low GA - seed dormancy Promotes water loss and slows metabolism ; closes pores Low ABA and high GA - seed germination Parent Plant promotes seed dormancy / See (Embryo Plant) ends seed dormancy Dormancy is broken by an environmental cue such as temperature change, day-length, flooding (depends on the species). Ex. fireweed - fire Weather conditions/cue would cause dormancy to break Rain, snow, fire, smoke, etc. In all cases, there must be water uptake to end seed dormancy. Seeds may not germinate until favorable conditions are met in order to increase chance of survival Water uptake DILUTES the ABA (ABA never disappears)
2-17 Differential gene expression in cells causes embryo shape changes & morphogenesis - how?
Hox genes are expressed in different areas TIMING: heterochrony (difference in timing/duration of developmental processes)
2-25 Describe the changes that occur when fertilization occurs in animals.
Sperm from male reaches Zona Pellucida (the outer layer of the egg), Releases acrosomal contents (hydrolytic enzymes) to break down the membrane Protein in sperm attaches to the specialized receptors. Prevent other species' sperm from fertilizing-Reproductive isolating mechanism Receptors are on the inner membrane Sperm attaches to inner egg cell membrane, both membranes fuse, and sperm is pulled inside Membrane becomes polarized when sperm fuses (block to polyspermy) egg releases chemicals which repel sperm away or trap sperm. On the outside- the Zona Pellucida hardens and no other sperm can enter and the previous sperm that entered are now trapped inside. Increase Ca 2+ (NEEDED) → cortical granules release content → hardens the vitelline layer, the resulting fertilization envelope blocks polyspermy Packed genetic material of sperm nuclei spreads out into 23 chromosomes Meiosis II finishes in egg AFTER the entrance of sperm nuclei -- results in 3 polar bodies and one egg Male and female genetic material fuse to form a nucleus Microtubules pull both sets of chromosomes together (a cell with 23 chromosomes from the mother and 23 chromosomes from the father) and a zygote is formed completing fertilization.
2-29 What unspecialized tissue types in animals are functionally like plant meristems?
Stem cells (bone marrow) Make different types of blood cells and undergo mitosis Potential to develop into many different types of cells in the body
2-21 "Evo-devo" (relationship of animal development & evolutionary history) is a hot research area. State two examples where study of embryos has answered questions about animal evolution.
Tails in embryonic development of humans and other organisms show a common ancestry, but the tail gene in humans as adults is turned off. HUMAN MANIPULATION of genes in order to observe a change -- take hox genes thought to control certain part of development and pasting it somewhere else which creates a second organ or body part (hox genes expressed wrongly) Mutant flies (ex. 1 gene off → no eye) Transgenic animals
2-15 Distinguish the functions of: tight junctions, gap junctions, and desmosomes ("anchoring junctions")
Tight junction: restricts movement of interstitial fluid or ions between cells. Watertight seal b/w 2 adjacent animal cells Gap junctions: allows for cell-cell communication/signaling. Like plasmodesmata in plant cells Channels b/t neighboring cells that allow for transport of ions, water, and others. Cell communication Desmosomes: links cells together allowing for anchoring Spot welds b/w adjacent animal cells. Cadherins that anchor. For cells in organs and tissues that stretch like skin and cardiac muscle so that they stay connected
2-33 Define "tropism", and give some specific examples of tropisms. Design an experiment (identifying independent, dependent and control variables) to test one aspect of phototropism.
Tropism - growth response causes it to turn away or towards a stimuli examples: phototropism (light), gravitropism (direction of gravity), thigmotropism (touch) Experiment: Independent: type of tip (opaque vs. translucent) covering the shoot whether we're cutting or covering the tip Dependent: measure how much the plant shoot bends, degree or % at which they turn/bend Control: Keep the soil type and water amount constant throughout the plants
2-16 Describe the changes in animal embryo form that occur in blastula formation and gastrulation.
Zygote divides 3 times (cleavage; mitosis) → 8 Cell Stage More cleavage → blastula (ball of many cells with fluid filled center called blastocoel) Blastula is the stage where body symmetry would be determined Gastrulation (one end of embryo folds inwards) → gastrula Gastrula: Stage at which germ layers are distinguished Endoderm is the inner layer that becomes the lining of the digestive tract and organs Mesoderm - all bilaterals have this; the space b/w endo and ecto Organs, heart, muscle system, connective tissue Ectoderm is the surface layer that gives rise to outer covering Blastopore is the opening
Petal pollen embryo sac endosperm ovary haploid n diploid 2n triploid 3n
diploid haploid haploid triploid diploid
