Final Flashcards
(15 cards)
What evidence is used to support the theory of evolution
- Direct observation–Ex- we observe bacteria changing over time (antibiotic resistance). Ex- introduced species
- Homology (common ancestry)–Refers to structures, organs, AAs, proteins, DNA.
- Vestigeal structures- leftovers, remnants. Ex- wisdom teeth
- comparative embryology- reveals anatomical homologous xtures not visible in adults. ex- all vert embryos have a post-anal tail and pharyngeal arches. - Fossil records– Some things leave better fossils than others because of body composition (hard body parts better). Also must be buried quickly- if left out on the surface will be degraded before it can make a good fossil. Also if you’re large or there’s a lot of you on the planet. However, the fossil record is bias and incomplete.
-Bio-geography– Study of geographic distribution of species. Incl the theory of plate tectonics. Can predict where fossils of different groups may be found.
Explain the concept of natural selection and give specific ex. Do the same for artificial selection
Natural selection– survival of the fittest. ex- an animals evolve to run faster due to an increase in predators, the animals that have the slower running genes get eaten thereby increasing the faster genes because they are left on the planet and reproduce with each other.
Artificial selection– humans have modified other species by selecting and breeding individuals with desired traits. Ex- breeding dogs with specific phenotypes for dog competitions.
List and explain the 5 causes of microevolution
(changes over time in allele frequency)
-Natural selection- Indivs with certain inherited traits tend to survive and reproduce at higher rates than other indivs bc of those traits.
- Genetic drift- Happens in small pops, usually suddenly–> endangered species bc can eliminate alleles from a pop. This is random and unpredictable. (genes are drifting away from a pop)
- Bottleneck- through humans or nature, the population is dramatically reduced.
- Founder effect- when a few indivs are isolated from a large pop, the smaller group establishes a new population with diff gene pool. Ex- Amish get unique genetic disorders. Royal family has hemophilia. - Gene flow– the transfer of alleles bw populations tends to reduce genetic differences bw populations over time. Has to do with migration, indivs coming and going– mixes up the gene pool, become more homogeneous
- Non Random mating (sexual selection) (type of natural selection)- not every indiv has an equal chance to reproduce. In plants the causes of this are where its places as well as issues with pollinators
- mutation: are changes in DNA. Can be caused by exposure to UV, carcinogens & mutagens, errors in transcription and translation. Mutations aren’t always a bad thing– there’s good, bad & silent mutations which have no effect on the product.
What are the ways that speciation can occur
-Allopatric speciation- Population forms new species while geographically isolated from its parent pop. Once geographic separation has occurred, the separated gene pools may diverge, reproductive isolation occurs over time. (including natural selection, mutation, genetic drift. Since they are so reproductively isolated, genetic isolation occurs.
Ex- mosquitofish- they colonized a series of ponds that later became isolated from one another. Little or no gene flow occurs bw the ponds, and the environment of the ponds is very similar except some contain predatory fish while others do not. In the high predation ponds, natural selection has favored a body shape which enables high speed, in low predation tank the mosquito fish have a different body shape which enables long steady swimming.
-Sympatric speciation–No geographic isolation. First there’s reproductive isolation, then that’s followed by genetic isolation. A subset of the population forms a new species without being geographically isolated. Less common than allopatric. So how to reproductive barriers form bw sympatric populations if the species remain in contact with each other?-Occurs if gene flow is reduced by such factors of: polyploidy, sexual selection, and habitat differentiation.
What are the source of new alleles/ genes in a population
Mutations are the only COMPLETE source of new alleles in a population. However, alleles can be changed and mixed by sexual reproduction. There are 3 variations in sexual reproduction: crossing over, independent assortment, random fertilization. Genetic mutation is the number one cause of new alleles.
What is the evolutionary advantage of sexual reproduction
Increases genetic diversity → thereby facilitating the evolutionary process. Two genetically different individuals can come together and created a third genetically different individual, now we have 3 genetically different individuals. A more diverse gene pool yields a greater number of unique alleles which may aid certain populations in natural selection.
What types of proks are there. What xtures, functions, etc. do they possess that make them well adapted for life on Earth?
Two types of proks are bacteria and archaea.
- Reproduction: simplier and faster reproduction than in euks, mostly via binary fission in stable environments. However, in unstable environments, variation is increased via conjugation, transformation, transduction, and horizontal gene transfer.
- Nutritionally and metabolically diverse: heterotrophs (require organic materials for energy), mixotrophs (have 2 or more of the above), phototrophs (derive energy from the sun), chemotrophs (derive energy from chemicals)
- They are unicellular and are able to form filaments, colonies and spheres.
- They have different relationships with oxygen: obligate anaerobes (can survive in oxygen low environments.) Obligate aerobes (need oxygen in order to survive). Faculative anaerobes (able to survive with or without oxygen)
- Diverse symbiotic relationships: commensalists, mutualists, parasites
- other traits include: forming metabolically inactive endospores to remain viable in harsh conditions (ex-anthrax), containing capsules as an extra protein layer for protection. Most archaea are able to live in harsh environments (thermophiles, methanogens, halophiles)
Pick 4 types of protists and compare and contrast them
1-diatoms- unicellular, look like glass– have 2 glass-like silica walls interlocking, Diatoms make up phytoplankton that make up diatomaceous Earth (fossil remnants of diatoms)
2-Brown Algae- all multicellular, marine, they are not plants but have some things analogous to plants.Have alternation of generations
both brown algae and diatoms are stramenophines- have hairy flagellum paired with smooth flagellum, incl some of the most impt photosynthetic organisms on Earth
3- Dinoflagellates- these are alveolates. Have 2 flagella, all aquatic (mostly marine but some fresh). They bloom in warm waters –> causes red tides– shellfish can eat these and we can eat the shellfish and get PSP
4-Radiolarans- in the rhizarians- marine, delicate symmetrical internal skeletons made of silica (so also glass-like). use pseudopodia radiate from the central body
All are in the SAR clade- very diverse and most contraversal supergroup
What are the 4 period of plant evolution? For each, describe the divisions of plans and some of the adaptations they have compared to the other groups
- Land- The plants here are non-vascular plants (bryophytes)- liverworts, mosses, hornworts. Contain rhizoids. Evolved from green algae. Contain cuticles to help with drying out and stomata to help with gas exchange. Gametophyte dominant life cycle. Have mycorrhizae– symbiotic relationship bw fungi and land plants– helped plants without true roots obtain nutrients. The plants get more SA for absorption, an the fungi get food and protection (mutualistic). Don’t have true roots- have rhizoids to help stabilize in soil. Can inhabit many diff envies but must be moist.
- Vascular tissue- FERNS tissue called xylem- transports water and minerals, and phloem- transports nutrients like sugars and AAs. The plants here are ferns which are seedless vascular plants. These were the first plants to grow tall. Sporophyte dominant lifecycle. The vascular tissues makes them more successful on land than the bryophytes
- Seeds- Reproduction was tied to water until now. The plants here are gymnosperms and angiosperms. change the course of evol for everything to follow. Advantage is they have their own food supply and can be dormant from days to years. Can also be transported long distances by wind
- Flowers- is a specialized xture for reproduction. These are angiosperms. Seed enclosed in a fruit (ovary) where gymnosperms have naked seeds. Most successful plant species. With flowers we can make sure cross-pollination happens which is important for genetic diversity. By evolving bright colors and scents, can attract animals which can carry pollen to the next flower for reproduction quite efficiently therefore they can produce less pollen
What characteristics do fungi share?
- heterotrophs
- feed by absorbing nutrients (decomposers)
- produce hydrolytic enzymes and secrete them and break their food into simpler components and the fungi absorbs them
- live off dead things (sapros) and living things (parasites), some are also mutualists
- single celled fungi are yeasts, multicelled fungi grow as filaments called hyphae
What are the 9 animal phyla we studied and what characteristics separate them?
1-porifera- lack true tissues, have choanocytes
2-cnidaria- nematocyts (unique stinging xtures) in cnidocytes (specialized cells). diploblastic, radially symmetrical, gastrovascular cavity (digestive compartment with a single opening)
3-platyhelminths- (flat worms) acoelomates, gastrovascular cavity
4-mollusca- Coelomates with 3 main body parts (muscular foot, visceral mass, mantle), hard shell made of CaCO3
5-annelida-Coelamates w segmental body
6-Nematoda- Roundworm, pseudocoelomates, they shed/molt, no CV system
7-Arthropoda- Coelomates w segmented body, jointed appendages, and exoskeleton made of protein and chitin.
8-Echinodermata- Coelomates w bilaterally symmetrical larvae, and 5 part body as adults (radial symmetry), unique water-vascular system
9-Chordata- Coelomates w notocord, dorsal hollow nerve card, pharyngeal slits, post-anal tail.
Choose 4 invert phyla and compare/ contrast them
Sponges- Basal animals that lack true tissues (metazoans- only animals that are not in the clade eumetazoans). filter feeders (have specialized choanocytes that do the filtering– how they get their nutrition). Have amoebocytes attached to the choanocytes to help transport material around. No symmetry. Some have antibiotic properties and promote wound-healing.
Cnidarians- Incl jellies, hydras, sea anenoemies, corals. have true tissues (eumetazoans). Diploblastic (2 tissue layers), radial symmetry, 1 opening in the GI tract, have a gastrovascular cavity (no stomach). Have cnidocytes on the tentacles– unique cells functioning in defense and capture of prey. Have nematocysts in the cnidocytes that eject a stinging thread.
Platyhelminths–flatworm, eumetazoans, acoelamates (no true body cavity). triploblastic, also 1 opening in gastrovascular cavity (also no stomach). 1-2 cell layers thick (they are very flat)– so helps to maximize SA for gas exchange. incl free-living flat worms like planaria, and parasitic flatworms like tapeworms and trematoads.
Molluscs– incl snails, slugs, oysters, clams, mussels, octopus, squids. Mostly marine, but some fresh and some moist subterrestrial. collimates, billet, 3 main parts to their basic body plans: muscular foot, visceral mass, mantle. Many have water-filled mantle cavity and feed using a rasplike radula.
Explain how extinction has played a role in evolution and biodiversity
The sudden loss of plants and animals that occupied specific habitats creates new opportunities for the surviving species. These species may now take over ecological roles that other organisms might have had because of natural selection. They may have evolved new specializations to take in the newly freed resources. In this way, extinction can increase biodiversity. Extinction reduces the competition for resources and leaves behind vacant niches which surviving populations can evolve into.
What are the main vert groups and what characteristics set them apart?
- Gnathostomes- hinged jaws. Have a lateral line system- actual line that is sensitive to vibration
- Osteichthyans- bony skeletons. Aquatic osteichthyans are the verts we call fish
- Lobe-fins- muscular fins or limbs
- Tetrapods- 4 limbs, neck, fused pelvic girdle, lungs all needed to move onto land
- Amniotes- terrestrially adapted amniotic egg- key adaptation for life on land because they don’t have to lay eggs in water. The extra amniotic membranes are the amnion, chorion and yolk sac.
In what ways have “humans” evolved
- Primates include lemurs, tarsiers and anthropoids (monkeys and apes)-US. 6 mya there was a split in primate evolution. Split to “human-like” (hominids) and other.
- Hominids can be distinguished by: walking upright, bipedal, larger brains, shorter GI tract, smaller jawbone and muscles. The trend is to a longer, lighter skeleton, less sexual dimorphism (males and females start to look like each other size-wise), increase in complex thought, incr in use of tools, artistic expression
