Intro to Evolution

Question 1

Mycorrhizae

Answer 1

The critical relationship between plans and fungi-symbiosis. Fungus-facilitates absorption of nutrients and water from soil for the plant. Plant-supplies fungus with sugars.

Question 2

Shared Derived Characters of Kingdom Animalia

Answer 2

No cell wall, multicellular, tissue level of organization, gap, tight, and adhesion junctions. Heterotrophs with extracellular digestion, mobile in at least one stage of life cycle. Requires muscle and nervous tissue (most, not all).

Question 3

Ancestral Animal Sister Group

Answer 3

Choanoflagellates-colonial flagellated protists have lower level similarities. Evidence suggests that original ancestral animal lived 1 billion years ago.

Question 4

Demands made on Animals

Answer 4

Must be mobile, requires muscles and skeleton. Obtain enough oxygen to support an active lifestyle, which requires an exchange surface. Be able to transport digested nutrients to where they are needed, and get rid of wastes. (transport systems).

Question 5

Animal Cell Demands

Answer 5

Must be able to get rid of wastes and import nutrients and oxygen. All ways of getting material in and out of cells only work at a very short range. All depend on surface area of plasma membrane.

Question 6

Animal Anatomy

Answer 6

Folding very large membrane surface within a compact volume.

Question 7

Radial Symmetry

Answer 7

Body has no anterior-posterior axis, can be cut on more than 1 plane to produce mirror image segments. ex) starfish

Question 8

Oral and Aboral ends

Answer 8

Bag-in-a-bag body plan. (radially symmetric organisms)

Question 9

Sessile

Answer 9

Don’t do well with rapid movement in one direction or the other. (radial symmetric organisms)

Question 10

Bilateral Symmetry

Answer 10

Body has anterior-posterior axis, can be cut on one plane to produce two mirror image segments. Tube within a tube body plan.

Question 11

Cephalisation

Answer 11

Bilaterions tend to have heads with sense organs. Dorsal and ventral sides, tend to be active.

Question 12

Animal Phylogeny-Phylum

Answer 12

Major systematic grouping of Animalia, distinguishable by unique combo of very basic shared derived characters.

Question 13

Charles Darwin

Answer 13

Wasn’t the first to come up with the idea that evolution happened-but first to come up with proposed mechanism for evolution. Incremental actions of everyday processes-“descent with modification.” Sparked by observations made on his trip around the world on the Beagle.

Question 14

Charles Darwin’s theory

Answer 14

Developed through extensive research over next 20 years- Used data from comparative anatomy, fossil record, artificial selection, biogeography. Able to correlate relationships among modern species and their geographic distributions in the Galapagos.

Question 15

Alfred Russel Wallace

Answer 15

Forced Darwin to publish his work when he threatened to scoop him.

Question 16

Artificial Selection

Answer 16

Domestic plants and animals had changed greatly from their ancestors under domestification.

Question 17

Fossil Records

Answer 17

Nature of the fossils in sedimentary rocks and the order in which they are laid down are evidence that living things have been evolving as far back as the fossil record goes-fossil distribution is NOT arbitrary.

Question 18

Transitional Forms

Answer 18

Transitions from one form to another in fossil record-dinosaurs to birds, mesonychids to whales, lobe-finned fish to tetrapods… etc.

Question 19

Biogeography

Answer 19

Distribution of many modem and fossil taxa can be correlated with known geographical history. Ex) Ratites lived in Gondwanaland- still live in continents derived from break up of Gondwanaland.

Question 20

Comparative Anatomy

Answer 20

Homologous organs exemplify descent with modification. Way in which homologous structures differ in related species indicates action of evolution.

Question 21

Convergent Evolution

Answer 21

Produces similar independently derived analogous structures-not present in common ancestor. Analogous structures have similar functions but different origins.

Question 22

Embryology

Answer 22

Animals share patterns of development. Ex) vertabrates all pass through an embryonic stage with pharyngeal pouches. Common embryonic structure reflects common evolutionary history.

Question 23

Phylogenies

Answer 23

Family trees of species (shared derived features enables us to derive phylogenies). Are hypotheses concerning relationship and descent.

Question 24

Postulates

Answer 24

Individuals in a population vary in some behavioural or physical characters. Variation is heritable, correlation between nature of heritable variation and reproductive success.

Question 25

Attributes of natural selection theory

Answer 25

Organisms don’t evolve-populations do. Natural selection only works with available variation-does not produce new alleles. Has no foresight-selects adaptations to immediate conditions. Aren’t necessarily universally useful for more than one generation ahead.

Question 26

Pesticide Resistance

Answer 26

Small proportion of wild insect population likely to have some resistance to any given pesticide-quite possibly due to single allele of a single gene.

Question 27

Adaptation

Answer 27

Is a result of selection-character produced by action of natural selection, enabling an organism to survive and reproduce in a particular environment more successfully than it would otherwise. Sufficient-not perfect. Trade-offs-not perfected by selection.

Question 28

Variation

Answer 28

Is random and may not be sufficient.

Question 29

Organisms

Answer 29

Produced by history and constrained by its effects. Organs frequently have more than 1 function. Biological materials may not allow perfection. Accident plays a large role in evolution.

Question 30

Early Earth

Answer 30

First 200 million years it was very hostile to life. Even after things settled, conditions were still inhospitable-high UV and vulcanism. Very little oxygen which allowed for existence of very complex organic molecules which would not survive today.

Question 31

Theoretical Steps of Abiogenesis

Answer 31

1-Abiotic Synthesis of small organic molecules-amino acids, fatty acids, monosaccharides, nucleotides.

2. Polymerization of these monomers
3. Protobionts- Membrane bound vesicles maintaining an internal environment different from external.
4. Incorporation of self-replicating molecules into protobionts, allowing inheritance and selection.
5. Energy extraction from environment.

Question 32

Millers Experiment

Answer 32

Exposed mix of gasses (H20, H2, NH3, CH4), thought to correspond to early Earths atmosphere to repeated electrical discharges, repeated cycle of evaporation and concentration. Began finding amino acids in mix.

Question 33

What is the atmosphere made up of?

Answer 33

Largely CO2 and N2. May have taken place in more restricted locale (deep sea vents).

Question 34

Polymers

Answer 34

Lengthened by dehydration. Monomers shown to spontanously polymerize abiotically with concentration through evaporation on hot solid surfaces.

Question 35

Protobionts

Answer 35

Precurser of cell, membrane (lipid) bound vesicle, selectively permeable bilayer, allow concentration of other biomolecules

Question 36

RNA World

Answer 36

Short lengths of RNA can self-assemble-polymerase not required. Can also act as a template for self-assembly of complementary strand.

Question 37

Ribozymes

Answer 37

RNA lengths which carry out enzyme -like functions. Protobionts could have served as reservoirs within which RNA “genes” could replicate generation to generation.

Question 38

What did early prokaryotes produce?

Answer 38

Stromatolites

Question 39

Early Prokaryotes

Answer 39

Very diverse biochemically-most forms were anaerobic chemoautotrophs. Tend to exist now where there is no O2.

Question 40

How did oxygen come into play?

Answer 40

Producing photosynthesizers began leaking oxygen into atmosphere by 2.7 billion years ago. By 2.2 Billion years ago, rising oxygen levels probably caused first mass extinction.

Question 41

First Eukaryotes

Answer 41

First fossils-2.1 billion years ago. Condition not acheived in single step-incorporation of mitochondria came first.

Question 42

Multicellular Eukaryotes

Answer 42

First fossils more complex multicellular eukaryote “animals.” Ecliacaran Fauna-600 million years ago. Nobody is quite sure what these were.

Question 43

Cambrian Explosion

Answer 43

Appearance in rapid diversification of “true” animals-535-525 million years ago.

Question 44

Colonization of the land

Answer 44

Originally by prokaryotes (bacterial films) 1 Billion years ago. By multicellular eukaryotes- 500 million years ago. First by plants and fungi-symbiotic relationship of animals, anthropods and tetrapods. Vertebrates were the most successful.

Question 45

Radiometric Dating

Answer 45

Radioactive elements (radioisotopes) decay into other elements at predictable rates. Half life-half a given quantity of radioactive elements will turn into its decay product within a specific time frame.

Question 46

Radioactive Clock

Answer 46

Age of volcanic rock can be determined by ratio of decay product to remaining radioisotope.

Question 47

Geological Record

Answer 47

Chronology for much of history of earth-divided into Eons, Eras, Periods. History of life is not directive but consecutive-change through time is not haphazard. Also shows mass extinction.