Term
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Definition
| Taxonomic group reflecting true evolutionary lineage. Group is monophyletic, meaning it came from single ancestor. |
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Term
| What are the five traits of animals? |
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Definition
| 1. multicellularity 2. different cell types 3. heterotrophy 4. potential for reproduction via gametes 5. bastula stage |
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Term
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Definition
| Choanocytes (also known as "collar cells") are cells that line the sponge's interior. Believed to have developed from choanoflagelletes. |
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Term
| What is radioactive dating? |
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Definition
| - Certain isotopes decay at constant rate “radioactive dating”. Atoms that are unstable will decay to become different elements. - Ratio of parent to daughter isotopes is what allows us to date the material |
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Term
| Cnidarians have true tissue. What is true tissue? |
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Definition
| cells separated by membranes and carries out a coordinated function. |
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Term
| Explain the molecular clock. |
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Definition
The molecular clock is a System for counting how different diverging lines are.
o It takes this long for change to occur
o There’s this many changes
o Species are therefore this many yrs apart |
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Term
| What feature connects all superphyla lophotrochozoa? |
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Definition
| - While molecularly similar, there are two physical characteristics that all have: 1. lophophore –ciliated tentacles 2. Trochaphore larvae: ciliated larvae |
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Term
| Recognize key traits of flatworms: |
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Definition
o 12,000 species
o Mainly aquatic
o Bilateral symmetry
o Triploblastic: Endoderm, mesoderm, ectoderm
o Tissues and organs. An organ is a greater level of organization of cells – it’s a combo of multiple tissue layers integrated to carry out a function
o Still no separate mouth and anus |
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Term
Class: Turbellaria
Phlya?
Traits? |
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Definition
Flatworm phlyum
non-parasitic
Diffusion circulation |
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Term
Class: Trenatroda
Common name?
Phylum
traits |
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Definition
Flukes - phylum flatworms
parasites
most organs are for reproduction
Life stages: 1. ciliated larva stage, 2. snail host, 3. human host |
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Term
Class: Cestoda
common name
traits
phyla |
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Definition
Phylum: flatworms - tapeworms
parasites
complex lifestyle
can reduce mosquito population |
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Term
| How do you recognize rotifera? |
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Definition
- Not very diverse: 2,000 species
- Cilia brush food into mouth where it’s grounded
- Fresh water
- Complex organs
- Complete digestive track
- Filter feeders
- Foot has toes
- Only have females |
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Term
| How to recognize mollusks? |
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Definition
Very diverse
Unifying traits: radula (scrapes food), mantle( flap of outer body wall that secretes protective layer), shell, foot |
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Term
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Definition
| Mollusk phyla - The chitons – feed on algae in marine habitats, intertidal |
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Term
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Definition
| Mollusks phyla - o Class: Gastropods: adaptive radiation, lots of different environments |
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Term
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Definition
| Bivalves are mollusks - mostly filter feeders, adduction muscle holds shell together, most are sessile, siphon evolved from foot – it’s a muscular tube for drawing water in and out |
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Term
Cephalopod class?
traits
phyum? |
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Definition
| mollusk phylum - Class Cephalopoda: Very different from other mollusks, (octopus, squid), marine, predators that stalk prey, have good sensory system – well developed eyes that can focus light, jaws, siphon allows movement, large brains |
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Term
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Definition
| Annelid phylum- polychaeta: many setae, active marine predators, tube dwellers/feather dusters – use tentacles lined by cilia to draw in particles |
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Term
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Definition
| Annelids - § Oligochaeta – few setae, earthworms, most are scavengers, terrestrial or freshwater, decomposers, circular and longitudinal muscles allow movement, setae are used for anchoring |
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Term
Class vestimentifera
phylum
traits |
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Definition
| Annelids - vestimentifera: deep water tube dwellers, 1,000 meters deep near hot water vents, no digestive system, use mutualistic bacteria for digestion, live in colonies |
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Term
| Traits of superphyum Ecdysozoa |
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Definition
- Ecdyses implies molting
- Hardened exoskeleton = cuticle gets secreted
- Nematodes and anthropods |
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Term
Phylum nematodes?
Traits?
common name? |
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Definition
-Roundworms
-12,000 species
-Abundant in all habitats
-Traits: cuticle, pseudo coelom – not completely lined by mesoderm but still used as hydrostatic skeleton
-Longitudinal muscles only give thrashing motion
-Complete digestive track
-Consume soil matter = food chain food source
-Model species for human genetics
Endoparasites – swallowed by organisms that eat soil developed parasitic behavior |
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Term
| Traits of phylum arthropods? |
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Definition
- Very abundant, diverse (60% of all species)
- Success due to joints, cuticle
- Many aquatic, most terrestrial
- Fossils show up around Cambrian explosion (550 mya)
- Cuticle (exoskeleton)
- No cilia |
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Term
Arthropod subphyla: trilobita
traits?
Body plan? |
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Definition
Subphyla: tilobita: marine environments w/sedimentation give us good fossils (500-250 mya),
- Body plan: repeating segments –many jointed legs, antennae, very simple
-Hump in middle creates 3 division body (thus tri) |
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Term
Subphyla: Chelicerata
phylum
examples
traits |
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Definition
Phylum: arthropods
-spiders
-Chelicerae: fangs for paralyzing prey
-lack antenae
-Humans: insect control, disease |
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Term
Subphylum uniramia
phylum
traits |
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Definition
Arthropod phylum - includes insecta, millipedes, centipedes
characterized by one pair of antennae and two pairs of mouthparts |
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Term
Class insecta
phylum
subphylum
traits
Orders? |
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Definition
Arthropods - uniramia - most successful class
-Key traits: 3 division body (head, thorax, abdomin), 6 legs, wings (evolved from exoskeleton – used to be scales)
-Ancestral traits: 2 sets of wings, 1st set is the elytra which function for protection
Orders:
1. Beetles -Coleoptera
2. Diptera - Flies
3. Hymenoptera: Bees, wasps, ants –diverse feeding modes, many are social and have sterile castes |
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Term
| Deuterstome Echinodermeta phylum: Traits, 4 classes |
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Definition
Echinodermeta: spiny skin o No head, radial symmetry as adults, calcified endoskeleton, water vasucles system (movement, physical support), tube feet, marine habitats ONLY, filter feeders o Class 1: Asteroidia: sea stars o Class 2: Holothuroidea = sea cucumbers o Class 3: Crinoidia – sea lilies o Class 4: Ophuroidia: Brittle stars |
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Term
Tape worms
phylum and class |
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Definition
| Phylum Platyhelminthes; Class Cestoda |
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Term
| Flukes: phylum and class? |
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Definition
| Phylum Platyhelminthes; Class Trematoda |
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Term
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Definition
| Linnaeus - Taxonomy allows us to see how close species are related and provides communication among scientists. |
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Term
| What early group of organism is closely related to the sponge? |
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Definition
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Term
| What are orthologous genes? |
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Definition
have same function but maybe have a change in amino acid sequence. These are often neutral changes (no gain, no loss)
- These genes can help estimate divergence times. We see there’s been “x” number of changes based on how different the genes are and estimate how long it took for these changes to occur. |
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Term
| Compare feeding of porifera vs. Cnidaria. |
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Definition
Porifera wave flagella to create a water current that flows through their pores and out thru a large hole (the osculum).
Cindaria: They use cells called cnidocytes to poison prey and collect it. |
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Term
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Definition
| a protein that is resilient – it’s how sponge’s retain shape after being squeezed. |
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Term
| What is the difference between microevolution and macroevolution? |
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Definition
| Micro is within populations, macro is at higher taxonomic levels. |
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Term
Subphylum crustaceans?
phylum?
examples?
Traits? |
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Definition
Arthropod phylum
crab, lobster
a. All major habitats, mostly marine
b. Branching appendages allow claw motion
c. 2 sets of antennae
d. varying numbers of legs
e. Humans: food, food chain, |
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Term
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Definition
| cells of cnidarians that inject posoin, “a venomous harpoon” |
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Term
| What is the phenetics approach? |
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Definition
It takes all traits into account and places species based on trait differences.
-Types of traights: morphological, behavior, molecular, physiological |
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Term
Class: Hirundinea/leeches
phylum? traits? |
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Definition
| § Hirundinea/leeches: fresh water, mostly ectoparasites, some are predators, more flattened annelid, dorsoventally flattened, latch on to exteriors and use suckers, lack setae, have jaw to create wound on host, anticoagulant limits clotting, degenerate, no digestive enzymes – mutualistic bacteria in gut instead, can be used as fish bait |
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Term
| What are choanoflagelletes? |
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Definition
| A choanoflagellete is a protista: A eukaryotic one-celled living organisms distinct from multicellular plants and animals: protozoa, slime molds, |
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Term
| How can evolution occur without natural selection? (3 things) |
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Definition
| 1. Mutations 2. Gene flow from other pops. 3. Genetic drift: random factors (i.e. natural disasters) |
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Term
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Definition
| cells that collect food from choanocytes and distribute nutrients. |
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Term
| What are the three points of evolution via natural selection? |
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Definition
| 1. Individuals w/in pop vary 2. Variation is heritable. 3. Fit individuals have more offspring. |
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Term
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Definition
| hierarchical classification of species based on evolutionary ancestry. Hypothesis about relationships between organisms – uses derived characters. |
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Term
| What is the Cambrian explosion? |
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Definition
| Sponges appeared a little before this time. This was an era in which huge animal diversity evolved. It occurred about 530 mya. |
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Term
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Definition
| The sequence of events involved in the evolutionary development of a species or taxonomic group of organisms |
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Term
|
Definition
| Used to measure the rate of radioactive decay of disintegration. The time lapse during which a radioactive mass loses one half of its radioactivity. |
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Term
| Name the five steps of the evolutionary timeline. |
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Definition
| 1. Formation of Earth, 2. Prokaryotes 3. O2 accumulates, 4. Eukaryotes 5. Mulitceullar life |
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Term
| How to recognize annelid phyum? |
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Definition
| Phylum: Annelids – 12,000 species, common in all 3 major environments, leeches can be used to withdraw fluid after surgery, Key traits: segmentation, complexity – full digestive system, setae for locomotion, lack gills or lungs – skin is used to take in O2 |
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Term
| Difference between protostomes and deuterstomes? |
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Definition
Protostome means 1st mouth, deuterstome means 2nd mouth.
The 1st opening is the blastopore. In protostomes, this is the mouth.
In deuterstomes, blastopore becomes the anus. |
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Term
| 1. Briefly describe two traits of Phylum Cnidaria that are unique among animals (i.e. found in no other phylum). |
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Definition
| Cnidaria is the only phylum that exhibits the cnidocyte, a specialized cell type that houses an organelle capable of lauching a venomized harpoon at large prey, which the cnidarians then consumes. Cnidaria alone also are diploblastic; that is, they exhibit ectoderm and endoderm during development, but not mesoderm. |
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Term
| 2. Name two characters of sponges that make them look like possible ancestors of all animals. Name two characters that make them look too specialized to be THE ancestor of all animals |
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Definition
| Sponges exhibit choanocytes, cells that closely resemble choanoflagellates, the colonial protist group from which animals evolved. Porifera also possess a very simple level of organization, lacking tissue, which all other animal phyla have. Spicules and spongin are specialized traits that sponges alone possess and which make the phylum look like an evolutionary offshoot, rather than a mere ancestor of all other animals. |
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Term
| 3. Name and briefly describe two traits among animals that are plastic and two that are conservative. Give examples for each of these 4 traits to support them. |
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Definition
| Foraging mode is a plastic trait. Molluscs, for example, include filter feeders, predators and rock-scraping herbivores -- which shows that foraging mode can change quickly over evolutionary time. Body size also evolves rapidly within different groups. Again, mollusks vary from tiny snails and bivalves to the giant clam and giant squid. Number of legs is a trait that tends to be conserved over time, as chelicerates have 8 legs and insects 6. Also, derived traits within a phylum or class that tend not to change over time. An example is the cnidocyte, possessed by all cnidarians. |
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Term
| 4. Explain what the molecular clock system is and how it is helpful to biologists. |
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Definition
| The molecular clock is a system that allows a biologist to determine how long ago two different organisms diverged based upon differences in sequences of base pairs in orthologous genes within their DNA. (Orthologous genes are genes in two different species that their common ancestor possessed and passed on to both species, like the cytochrome C gene, which is crucial to cellular respiration in all organisms.) The use of molecular sequence data as a clock is based on the observation that orthologous genes accumulate mutations at a fixed rate. This being the case, we can look at how different the DNA sequences are in between two related organisms and determine how long they have been evolving separately. For example, a DNA sequence for an orthologous gene in SPECIES 1 might have a sequence of CGGACTAGCGTT, while the same gene in SPECIES 2 might have a sequence of CGGACAAGCGCT (different in 2 bases from SPECIES 1). SPECIES 3 might have a sequence of GGTACAAACGTA (different in 5 bases from the other two), reflecting the fact that it branched off evolutionarily from the other two species much longer ago than they did from each other. But the crucial value of the molecular clock is that it is quantitative. That is, by knowing how long it takes for DNA bases to mutate we can estimate absolute dates of divergence. If we knew that DNA bases within a certain gene tended to mutate at a rate of once every 100 million years, then we could estimate that SPECIES 1 and 2 had a common ancestor 200 million years ago and SPECIES 3 had a common ancestor with 1 and 2 500 million years ago. It is the ability to produce estimates of absolute dates without fossils that makes molecular clock uniquely valuable to biologists. (Use of the molecular clock does, however, depend critically upon calculating rates of mutation in each orthologous gene, which requires us to have radiometrically dated fossils from some group of organisms that possess the gene in question.) |
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Term
| 5. Cite two examples of convergence. For each, explain what environmental factor led to the convergence. |
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Definition
| Fusiform shape evolved in many aquatic groups – such as fishes and plesiosaurs – and permitted these groups to move through water without using too much energy. Camera-like eyes evolved separately in cephalopods and vertebrates to facilitate their active lifestyles and rapid, efficient movement through their environments. |
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Term
| 6. Name two clear ways in which leeches differ from others in their phylum. |
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Definition
| Leeches lack setae (bristles) that other annelids use to grasp onto the substrate and anchor themselves as they move about. Leeches are also mainly ectoparasites – living on the exterior surfaces of other animals – unlike oligochaetes and polychaetes. |
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Term
| 7. Explain how convergence is a problem with an analysis of taxonomy by phenetics. |
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Definition
| Through convergence, two distinct animal groups possess traits (like fusiform shape) that make them APPEAR similar in a way that might suggest that they are evolutionarily related. In fact, convergent traits come about not because of common phylogeny, but because the animals face similar environments. By using all traits, a pheneticist is lumping convergent traits -- which are misleading -- with shared, derived traits, which reveal true evolutionary patterns. Thus, phenetics analyses fail to remove the “noise” from the system. |
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Term
| 8. Is radial symmetry a primitive trait? Explain. |
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Definition
| Primitive (or “ancestral”) traits are those that evolved long ago within an evolutionary lineage. Radial symmetry could not be labelled a primitive trait in animals, because it is absent in the most ancestral group of animals (Porifera) and evolved in Cnidaria and in Echinoderms. So radial symmetry evolved convergently in these two groups well after Kingdom Animalia evolved. |
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Term
| 9. A budding young scientist collects a soil sample and searches systematically within it for animals. Name 3 phyla that she is likely to encounter and briefly explain your reasoning. |
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Definition
| Of the phyla we have studied, the most numerous in terrestrial regions are arthropods, nematodes and annelids. (I would probably give you credit for mollusks, possibly even flatworms.) |
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Term
| 10. Why is the taxonomic level “species” different from every other level? |
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Definition
| Species has a single, objective definition that is employed across all living things. It is defined as a group of organisms that can mate with each other and produce fertile offspring. Other taxa (genera, orders, families) may be distinguished in ways that vary with the taxonomic group. For example, two beetles might be placed in separate genera because their wings are a different color or because of the different shape of their antennae. Two chitons might be placed in separate genera because of sharpness of their shells. Hence, there are infinite different ways that genera (and all other taxa except for species) could be defined. |
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Term
| 11. Pick two groups we have studied this semester and explain why they might have been so successful. Make sure to explain what is meant by “successful”. |
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Definition
| Successful means that a group contains many species and is very diverse in appearance, lifestyle, etc. Molluscs are very successful, perhaps because their shells have allowed them to invade many different habitats. Insects are hugely successful, and their success is likely attributable to their possessing wings, which permit rapid movement from one microhabitat to another to collect resources. |
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Term
| 12. What is the purpose of an outgroup in a cladistic analysis? Explain what would happen to a cladistic analysis that lacked an outgroup. |
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Definition
| An outgroup is a taxonomic group outside of a focal group that is being analyzed (termed the “ingroup”) but closely related to it. Comparison of species within an ingroup to an outgroup tells us if each trait of the ingroup is derived or ancestral. It is only identification of derived traits that permits cladistic analysis; therefore, the lack of an outgroup would make cladistic analysis – which aims to determine evolutionary patterns -- impossible. |
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Term
| 13. Explain why the taxonomic scheme we use today is a “hybrid” between the phenetics and cladistics approaches. Pick an organism and give an example of one taxon it belongs to that was named by pheneticists and another that was named by cladists. |
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Definition
| Historically, all taxonomy was done by phenetics, the approach that uses all possible traits of an organism to place it in the proper group. In recent decades, we have realized that cladistic analysis – placement of organisms in groups according to evolutionary history – is far more informative than phenetics, because evolution is the process that produced the organisms. However, phenetic names are in wide use by many scientists and in many publications, so it is difficult to switch quickly to cladistic groupings. Hence, scientists tend to retain phenetics names and supplement them with cladistic groupings, where it can clarify evolutionary patterns to do so. A nematode is both within phylum Nematoda (a phenetic group) and the clade Ecdysozoa (a clade). |
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Term
| 14. Are new classes of organisms still being discovered? Explain. |
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Definition
| Yes. Class Vestimentifera is an annelid group recently discovered when biologists explored deep-sea thermal vents. |
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Term
| An ambitious taxonomist travels to the Amazonian rainforest in an attempt to describe new species of animals before they perish from the earth. After two weeks of tireless sampling of soil, plants, streams and ponds, he returns home to his lab. Eight months of study reveal that he collected 107 species previously unknown to science. His sample consists of nothing but protostomes of which 93 are from one phylum, 11 are from a second phylum, 2 are from a 3rd phylum, and 1 is from a 4th phylum. Based on what you have learned, explain which 4 phyla are likely represented in this sample, in order from most to least abundant. |
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Definition
| Most protostomes in terrestrial/freshwater habitats are arthropods, so they must be the phylum from which 93 species were described. Molluscs are also rather abundant in these habitats, so likely the 11 species are from this phylum. One cannot be certain from which phyla the 2 and 1 species come, but annelids and nematodes are possible. (Rotifers and flatworms also good candidates.) |
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Term
| 16. From what group did animals probably evolve? Explain why biologists think this. |
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Definition
| Choanoflagellates, which are colonial protists, closely resemble certain simple sponges in terms of appearance and feeding mode. Indeed, sponges are little more than choanoflagellates that have become multicellular and evolved some specialized new cell types to extract food particles from the water column. Because of this striking resemblance, scientists are fairly confident that animals evolved from colonial protists into a simple sponge-like form. |
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Term
| 17. Make the case that the molluscan foot was the most important trait leading to the group’s evolutionary success. Be complete and convincing. |
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Definition
| The molluscan foot serves as a locomotory structure. The evolutionary plasticity of the foot has permitted molluscs to evolve a vast array of different ways of moving about and feeding. For example, in cephalopods the foot has evolved into tentacles that allow animals to creep about and grasp living animal prey; chitons and many gastropods use the foot to cling to rocks and move slowly about their surfaces, scraping off algae; bivalves use the foot for digging. By permitting many different functions, the foot has led to great diversification of species. |
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Term
| 18. Describe one clear way in which non-human animals can be important to humans. Next, list and briefly explain how two animal groups are important in this way. Repeat the process so that you end up with two distinct ways that animals can be important to humans and 4 groups listed (2 for each type of importance). |
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Definition
| Many animals are important to humans as parasites of our own species and other animals we depend upon for food. Flukes (Phylum Platyhelminthes; Class Trematoda) live in the liver and other tissues of humans and domesticated mammals. Tapeworms (Phylum Platyhelminthes; Class Cestoda) reside in the gut of these groups. Both classes kill or reduce the quality of life of the host. Other animals serve as important sources of food for humans. Molluscs (Phylum Mollusca) and crustaceans (P. Arthropoda; subphylum Crustacea) both fall into this category. |
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Term
| 19. What can you conclude from the changes in feeding mode that have occurred within Kingdom Animalia? Are there types of feeding that seem “advanced” or “primitive”? Explain. |
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Definition
| It is difficult to point to a feeding mode and conclude that it is either “advanced” or “primitive”. Instead, most modes of foraging -- like predation, scavenging, filter feeding have evolved many times in different animal groups and do not appear only in more primitive or advanced groups. Predators can be found in phyla like Cnidaria, Platyhelminthes, Mollusca and Arthropoda; yet the last 3 groups also contain scavengers and herbivores. Filter feeding too is widespread, as it is seen in Porifera, but also in P. Annelida (feather dusters) and crustaceans (barnacles). So filter feeding cannot be termed a primitive feeding mode. |
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