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Biodiversity > Midterm 1 > Flashcards

Midterm 1 Flashcards

0
Q

How to measure biodiversity- molecular measures

A

Adv- DNA and RNA found in all living organisms, direct basis of comparison

Disadv- very incomplete, ignores phenotype

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1
Q

How to measure biodiversity- counting species

A

Adv- intuitive measure, relatively easy to quantify

Disadv- numbers don’t tell you about components/ what it’s made of, species identification can be hard

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2
Q

How to measure biodiversity- phylogenetic measures

A

Adv- incorporates historical info

Disadv- we don’t know the evolutionary relationships of most species yet

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3
Q

How to measure biodiversity- functional measures

A

Adv - captures ecological aspect of biodiversity,

Disadv- can be hard to measure, not clear how to compare between diff groups

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4
Q

Differences between land and seA

A

15% of described species live in the ocean

32 out of 33 phyla live in the ocean
12 out of 33 phyla live on land

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5
Q

Two types of characters

A

Primitive = plesiomorphic

Derived = apomorphic

A character may rn primitive at one level and derived at another

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6
Q

Monophyletic group

A

Group containing all descendants of a MRCA

AB
ABC
ABCD

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7
Q

Paraphyletic group

A

A group in which some but not all descendants of a single MRCA is present

CD

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8
Q

Poly phyletic group

A

A group that contains the descendants of more than one MRCA

ABCE

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9
Q

Sister group

A

Closest relatives of taxa under study

A and B
AB and C

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10
Q

Parsimony

A

Based on Occam’s razor

Minimizes the # of character changes- always picks the shortest possible tree

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11
Q

Neighbor joining

A

Builds a tree based on distances between all possible pairs of taxa

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12
Q

Maximum likelihood

A

Gives probability that the tree you have fits the model

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13
Q

3 types of evidence regarding early forms of life

A
  1. Preserved micro organisms (fossils)
  2. Microbially produced stromatolites
  3. Geochemical signatures-keragen, stable isotopes
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14
Q

Proterozoic era

A

of microfossil species increases rapidly, stromatolites abundant, eukaryotes present, many forms identical to modern Cyanobacteria

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15
Q

Phanerozoic era

A

Ediacaran biota appear- tribrachidium

Cambrian explosion, predator prey system, stromatolites decline rapidly, rise of metazoa and plants

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16
Q

Marina biota - Cambrian fauna

A

Trilobites, inarticulate Brachiopods, hyoliths

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17
Q

Marine biota- Paleozoic fauna

A

Articulate Brachiopods, Crinoidea, corals, Cephalopods, bryozoans

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18
Q

Marine biota- modern fauna

A

Bivalves, gastropods, marine vertebrates, bryozoans, crustaceans, echinoids

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19
Q

Big five mass extinctions

A 
Ordovician
Late Devonian
Permian
Triassic
Cretaceous
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20
Q

Ediacaran fauna

A

All soft bodied, no skeletons

some with tri radiate symmetry, which is not seen in the modern world like tribrachidium

Dickinsonia

Trace fossils present- show that someone lived on the bottom/ ground link footprints, don’t know what organism it is but tells you there are organisms able to move around

More similar to animals than fungi or algae

Likely to be a poly phyletic assemblage rather than a single class

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21
Q

Burgess Shale- who discovered it, what is it, what does it say, what animals were discovered

A

Charles Walcott discovered it

Bottom of a steep cliff that was constantly buried with sand, and had low o2 levels, which is perfect for making a fossil

Hallucigenia, pikaia, opabinia, wiwaxia

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22
Q

Cambrian explosion - what is it? What is it not? What was the environment like?

A

First appearance of a large number of skeletonized animal phyla in the fossil record within a short amount of time

It isn’t the origin of animals, or origin of animal body plans, or origin of adaptations that led to colonization of land or the evolution of flight

Increased tectonism and breakup of continents, large shift in strontium curve which increased continental erosion and change in ocean chemistry, two major ice ages

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23
Q

Molecular basis of animal development

A

This is something that is shared by all types of animals

Sequential activation of specific genes by regulatory switches – transcription – protein

The regulatory switches also set up the basic tissue types

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24
Q

Hox genes/ hox cluster

A

Many types of genes share a common DNA sequence called a homeobox

It’s clustered next to each other on a chromosome

It’s a sequence that specifies the development of diff parts of the body

Regulatory switches existed before the Cambrian explosion - and some evolved additionally, which could be specific to certain species. But basic elements are preserved throughout all species

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25
Q

Long evolutionary fuse vs potential environmental trigger

A

Long evolutionary fuse: lineage divergence, hox-gene duplications, evolution of novel morphologies began slowly over time and all came together at Cambrian explosion- more likely

Potential environmental trigger: regulatory systems were in place (you could make an animal already) but conditions didn’t meet quota - low oxygen levels to support life - suggests an environmental trigger

26
Q

Closest living relative of animals

A

Choanoflagellates
Free living, single cell and colony forming eukaryotes

Important predators of bacteria, important component of food webs

27
Q

Simplest and most basal group of animals

A

Placozoans (don’t know exactly where they fit in relative to animals)
Sponges
Ctenophores

(Sponges and Ctenophores are the sister group to cnidarians

28
Q

Placozoans

A

First found on glass walls of aquarium

In tropical and subtropical oceans

Not much known about biology and ecology

29
Q

Sponges

A

Simplest animals

A hollow tube of tissue with perforations on the sides (Ostia) and open top (osculum)

Water pumped thru Ostia and osculum and the sponge traps particles in the water

Lined with choanocytes that produce water flow

30
Q

Cnidaria

A

Basic body form is a sac - stomach with two layers of cells and an opening which is used as the mouth and butt

Colonial and solitary species

31
Q

Bilateria - major clades

A

Protostomia and deutorostomia

32
Q

Protostomia - clades

A

Ecdysozoa and lophotrochozoa

33
Q

EcdysozoA

A

Characterized by ecdysis/ molting

Nematodes and arthropods

34
Q

Lophotrochozoa

A

Lophophorata and trochozoa

Mollusk and annelids

35
Q

Lophophorata

A

All have a lophophore - a feeding organ

Phoronids, Brachiopods, bryozoans

Bryozoans - solitary animals but are interdependent for the function and survival of the colony

Brachiopods- sessile, attached to the substrate

36
Q

Two things needed for suspension feeding? Every suspension feeder needs ?

A
  1. Animal with a separator

Particles in suspension

  1. A filter

Mechanisms to move the medium past the filter
Stokes law

37
Q

Types of suspension feeders

A

Active

Passive

Facultatively passive - uses both

38
Q

Mechanisms of suspension feeding

A

Sieving- particles caught by mechanical trapping

Aerosol capture - particles caught on adhesive surface of filter

Scan and trap - a biologically active response

39
Q

Phylum mollusca

A

Aplacophora - worm like. No shells

Polyplacophora - chitons. Flattened elongated molluscs with a shell that has many plates

Monoplacophora- cap shaped shell. Closely related to chitons

Gastropoda- mollusks that exhibit extorsion

Bivalvia - bilaterally symmetrical

Cephalopoda- squids and octopus. Highly active predators, brain well developed. Active swimmers using jet propulsion

Scaphopoda- have a tusk shaped she’ll open at both ends

40
Q

Non marine molluscs

A

Land snails. High diversity on tropical islands

41
Q

Echinoderms

A

Benthic. Have pentaradial symmetry, but evolved from a bilaterally symmetrical ancestor

Echinoidea- sea urchins and sand dollars. Aristotles lantern, a structure with 5 hard teeth, used to grind food and scour hard rock

Asteroidea- star fishes. Most are scavengers or predators. Lay on top of food then secrete enzymes to digest it

Crinoidea- many species with stalks but some have lost it. Trap suspended particles with their arms

42
Q

Characteristics of reefs

A

Organic network

Wave resistance

Photic zone restriction

Raised relief

Tropical (warm water) distribution

43
Q

Relationships in modern coral reefs

A

Zooxanthallae (algae) provide corals with food and in turn receive nutrients and co2 for photosynthesis

44
Q

Catastrophes of coral reefs

A

Hurricane Allen- changes reef from stag horn coral dominated to non stag horn dominated

Hurricane Hugo - changed coral cover and also affected invertebrates

Acanthaster outbreak - a planci ate corals which caused over abundance of algae. And algae eating fish dominated. Could be cuz of loss of predators of a planci or eutrophication caused more phytoplankton which is more food for a planci larvae

Coral bleaching - could be cuz of increases in sea surface temperature or solar radiation and UVB. Reproductive and growth output are reduced and eventually the coral die

Diadema die off- sea urchins died off. They ate algae so there was an abundance of algae and seaweed

45
Q

Threats to coral reefs

A

Destructive fishing

Overfishing

Coral mining

Pollution

Ship groundings

Tourism

Disease

46
Q

Arthropods

A

Growth by ecdysis , ventral nervous system with dorsal brain

Two types of appendages - uniramous and biramous

Tardigrada - water bears that can survive everything

Onychophora- velvet worms that are brightly colored and are carnivorous

47
Q

Cheliceriformes

A

Body Divided into two - cephalothorax and abdomen

Book gills and book lungs

48
Q

Crustacea

A

Body has a 5 segmented head and trunk is divided into thorax and abdomen

Breathe by aqueous diffusion

49
Q

Insects

A

3 body parts - head, thorax , abdomen

Breathe thru trachea and spiracles

50
Q

Why are insects small

A

Exoskeletons must be small - they’re sensitive to damage from impact

Molting is not efficient for large size animals. It would be hard to maintain body shape during molt

Surface to volume ratio is maximized in small size. Tracheal density constrains body size

51
Q

Decline of invertebrate biodiversity

A

Agriculture and loss of habitat

Loss of wetlands

Introduced species

Climate change

Loss of host

52
Q

Benefits of insects

A

Pollination

Dung burial

Food source for wildlife and fish

Control of agrocultural pests

53
Q

Charophyceae/ charophytes

A

Land plants are most closely related to these

54
Q

Features of charophytes that are more expressed in land plants:

What do charophytes lack that land plants have?

A

Sporo-pollenin
Cutin
Phenolic compounds

Well developed sporophytes
Sexual organs of the land plants
Cuticle and airborne spores

55
Q

Wen did land plants originate ?

A

Ordovician era

Happened cuz of major radiation, which is kind of similar to the Cambrian explosion- involved the origin of most major body plans seen in living plants, increase in species richness relatively small compared to increase in phenotypes, development of impermeable surfaces, and the radiation happened at the same time co2 levels fell and 02 levels rose

56
Q

Consequences of evolution of land plants

A

Energy and nutrient fluxes

Evolution of well developed root systems – led to acidification of soils– led to decreasing ca-mg silicate minerals– led to decrease in co2 in atmosphere

57
Q

Non vascular plants

A

Mosses, liverworts, hornworts

Lack vascular tissue

No seeds, flowers, fruits

Small in size

58
Q

Higher plants

A

Have vascular tissue, a complex tissue consisting of multiple cell types

59
Q

Pteridophytes

A

Ferns and stuff

Dominant during Paleozoic but extinct now

60
Q

Gymnosperms

A

Diverse before angiosperms appeared

Cycads, ginkos

61
Q

Angiosperms

A

Evolved in Cretaceous, dominated since then

Monocots, but mostly eudicots

62
Q

Why are angiosperms so diverse?

A

Biotic pollination-pollen can be delivered efficiently even in small amounts. Insect pollination is unique to angiosperms. Birds and mammals carry the seeds to places the plants can’t reach

Plant-insect co evolutionary arms race-
Insects damaged gymnosperms

63
Q

Problems with the theory that biotic pollination helped angiosperms dominate

A

Wind pollination is also efficient

Wind pollinated species have similar rates of gene flow to insect pollinated ones

Living cycads/ gymnosperms insect pollinated and animal dispersed

Biodiversity (2 decks)

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