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Biology > Bisc 102 Midterm > Flashcards

Bisc 102 Midterm Flashcards

1
Q

Adaptation

A

Any TRAIT that helps an organism survive and reproduce. Can be structural, behavioural, or physiological

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2
Q

Structural adaptation

A

ex. crab spiders that mimic the petals of a flower; clam that has a mantle that looks like a fish for dispersion of parasitic larvae; the neck of a giraffe to reduce competition for food or attracting mates; angular fish- light attracts food; peacocks attract mates

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3
Q

Behavioural adaptation

A

ex. archer fish shoots insects on branches with a jet of water, correcting for angle; bowerbird decorates nest to attract a mate with objects the colour of its eyes; migration tracks good foraging areas throughout the year

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4
Q

Physiological adaptation

A

desert animals; camels have efficient storage mechanisms; bombardier beetle shoots a hot chemical reaction for defense; human sperm- through number and protective coat

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5
Q

Jean Baptiste Lamarck

A

(1744-1829) First suggested that species are not fixed, but change over time. His ideas were –Use and disuse; Inheritance of acquired characteristics (ie. cutting a tail off a mouse)
These processes have been refuted

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6
Q

Charles Darwin

A

(1809-1882) Traveled around the world as a naturalist on “The Beatle” Studied finches, tortoises at the Galapacos Islands. Wrote The Origin of Species (1959)

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7
Q

Alfred Russel Wallace

A

(1823-1913) Realized the same thing as Darwin around the same time, the two corresponded

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8
Q

Natural selection

A

A PROCESS by which the individuals in a population that have the characteristics best suited to the environment survive and reproduce better than other individuals

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9
Q

The five steps of evolution by natural selection

A

Observations: competition, variation among individuals, heritable variations
Inference: Selection, Adaptation

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10
Q

Evolution: Step 1- Competition

A

In theory, populations are exponential while in reality they are fairly stable because resources are limited

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11
Q

Evolution: Step 2- Variation among individuals

A

Some individuals are better at competing for resources than others

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12
Q

Evolution: Step 3- Heritable variation

A

At least some of the differences in ability to compete for limited resources are heritable
(= genetically based)

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13
Q

Evolution: Step 4- Natural selection

A

Those individuals with traits that allow better survival and/or reproduction have higher fitness (ex. large rabbits eat the most, reproduce the most whereas small rabbits die off from lack of food

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14
Q

Evolutionary fitness

A

The number of progeny (offspring) produced

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15
Q

Evolution: Step 5- Adaptation (evolution)

A

The CHANGE in a population over time (ie. Large body is an adaptation for competing for limited carrots)

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16
Q

Three conditions necessary and sufficient for evolution by natural selection

A
  1. There must be variation in the trait 2. Variation is heritable 3. Variation has fitness consequences
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17
Q

Adaptation does not mean perfection because…

A
  1. Organisms are adapted to the current environment

2. Natural selection is often constrained

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18
Q

Constraints to natural selection

A

Adaptations are often compromises (consdering all pressures on an organism); Natural selection is constrained by history (there are no 6 limbed vertebrates); Natural selection acts on existing variation (acts more on a population with a large variety)

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19
Q

Protocells

A

Abiotically produced collection of molecules, fluid-filled vesicles bounded by a membrane-like structure

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20
Q

Define life

A

1) Metabolism (nutrient uptake, processing, waste elimination) 2) Generative process (growth and reproduction/replication 3) Responsive processes (immediate responses to environment, individual adaptation, population adaptation) 4) Control processes (coordination, regulation) 5) Structural organisation (cellular level, organismal level)

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21
Q

Proposition by Aristotle

A

(4th century BP) First idea of the origin of life:
Spontaneous generation- ‘Living organisms arise spontaneously from non-living matter’
Evidence: Maggots from dead meat, Mice from wheat seeds, Lice from sweat, Frogs from damp mud

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22
Q

Proposition by Louis Pasteur

A

Biogenesis: ‘Life can only originate from pre-existing life’. His experiment used sterilized soup broth in a bottle that bacteria couldn’t enter, and he did not find growth

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23
Q

The recipe for life

A

Energy source, raw materials, suitable environment

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24
Q

Conditions on the early Earth

A

Extremely high temperatures; Different, Reducing atmosphere (Water vapour, Nitrogen, Carbon dioxide, Methane, Ammonia, Hydrogen, Hydrogen sulfide); No liquid water; Little oxygen; As Earth cooled, water vapour condensed and hydrogen escaped

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25
Q

Energy sources

A

Sun (light, UV); Volcanic eruptions; Lightning

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26
Q

Raw materials

A

Elements present on Earth (CHNOPS); Extraterrestrial sources

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27
Q

Extraterrestrial sources

A

Initially proposed by Arrhenius in early 1900s; Support from a meteorite containing amino acids and one with things that may be fossilized martian bacteria?

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28
Q

Origin of life on Earth by chemical evolution

A

With the right chemical and physical conditions, life could have began in four stages. 1) Abiotic synthesis of monomers 2) Formation of polymers 3) Packaging of polymers into protocells 4) Self-replication

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29
Q

Origin of life Stage 1: Spontaneous formation of monomers

A

Oparin’s hypothesis- a reducing atmosphere, a suitable environment, and energy will cause simple molecules to combine into organic compounds. Problem: The Earth’s atmosphere may not have been reducing, though there are alternative “suitable environments” (deep sea vents, volcanoes)

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30
Q

Testing Oparin’s hypothesis

A

Miller -Urey experiments- combining water vapour, methane, ammonia, hydrogen with electricity synthesized sugars, pyrimidine and purine bases, amino acids, ATP.

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31
Q

Origin of life Stage 2: Polymer formation

A

Monomers could have combined to form organic polymers; using the same energy source as stage 1; Clay as substratum for polymerization? Experimental evidence: Dripping solution of amino acids on hot clay results in spontaneous formation of polymers

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32
Q

Origin of life Stage 3: Protocells

A

Polymers aggregated into complex, organized, cell-like structures called protocells; Form spontaneously in the lab such as coacervate droplets, liposomes, and proteinoid microspheres

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33
Q

protocells

A

Polymers aggregated into complex, organized, cell-like structures; add some living qualities: Structural organisation, Simple homeostasis and metabolism, Simple reproduction

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34
Q

Origin of life Step 4: Self-replication (Which came first, genetic material or the enzymes required to catalyze it?)

A

RNA, Single-stranded genetic material that can form enzymes (ribozymes)
Could have facilitated both replication and reaction catalysis on early Earth

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35
Q

Natural selection in an RNA world

A

Variation among RNA strands due to copying errors+Replication+Some strands better at competing for nucleotides and replicating
->Natural selection for shape, stability, replication accuracy & speed most suited to environment

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36
Q

RNA world -> DNA world

A

RNA served as template for assembly of DNA nucleotides, which occured because DNA is a more stable genetic molecule

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37
Q

Which protocells would have been the most successful?

A

Protocells able to take up RNA with superior replication and catalytic abilities would have been more successful than those with inferior or no RNA

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38
Q

Prokaryotes

A

The most ancient organisms; Unicellular; Lived alone on Earth for nearly 2 billion years; Greatest diversity of lifestyles and habitats; They have created the Earth we know

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39
Q

Prokaryote domains

A

Bacteria and Archaea (Only 4,500 species described so far)

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40
Q

Pro vs Eu

A

Prokaryotic cells are Smaller; Single membrane system; Nucleoid (no nucleus); No walled organelles; No cytoskeleton

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41
Q

Bacteria

A

Includes most known prokaryotes; Hugely diverse in metabolism and structure

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42
Q

Examples of Bacteria

A

Photosynthetic cyanobacteria; Organisms important in decomposition and nutrient cycles; Some disease organisms (salmonella, chlamydia); 500-1,000 spp of bacteria in your gut!

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43
Q

Archaea

A

Key differences from bacteria: Cell wall composition and Details of protein synthesis; They live in harsh and extreme environments, Extremophiles
(‘extreme-lovers’) include Methanogens (methane-makers), Halophiles (salt lovers) and Thermophiles (heat-lovers)

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44
Q

Why is studying modern prokaryotes important?

A

Some modern prokaryotes live in environments similar to those in the early Earth; The metabolism of these groups may be similar to the metabolism of ancient groups

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45
Q

Nutritional diversity in modern prokaryotes

A

Photo-autotroph (Light + CO2)
Chemo-heterotroph (Organic compounds)
The two below are only in prokaryotes:
Chemo-autotroph (Inorganic chemicals + CO2)
Photo-heterotroph (Light + Organic compounds)

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46
Q

Respiratory diversity in modern prokaryotes

A 
Obligate anaeroby (Fermentation/anaerobic respiration)
Facultative anaeroby (O2 if present, or fermentation)
Obligate aeroby (Always O2)
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47
Q

The first organisms- chemoheterotrophs?

A

Could have ‘eaten’ ATP,With depletion of ATP in environment, selection for ability to make ATP; The Evolution of glycolysis occured early, which is further evidence

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48
Q

The first organisms- hemoautotrophs?

A

May have oxidised H2S and reduced forms of iron found at Deep-sea vents that were more abundant on early Earth

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49
Q

The evolution of photosynthesis

A

Chemotrophy -> Phototrophy
Likely scenario:
Non-oxygen-producing
photosynthesis->Oxygen-producing photosynthesis

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50
Q

Non-oxygenic photosynthesis

A

Occurs in green and purple sulfur bacteria from anoxic swamps;
H2S and light, gives S2??, ATP, NADH

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51
Q

Oxygenic photosynthesis

A

Occurs in cyanobacteria;

H2O and light, gives )2, ATP, NADPH

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52
Q

Proof oxygenic photosynthesis arose early

A

2.7 by-old banded iron formations indicate increased atmospheric O2; 3.5 by-old stromatolites = photosynthetic cyanobacteria

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53
Q

Stromatolites

A

Cyanobacteria trap sediment, form calcium carbonate mounds; Added oxygen to Precambrian atmosphere (ex Shark Bay)

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54
Q

The danger of oxygen

A

Oxygen can produce highly reactive, short-lived ‘free radicals’; Free radicals inhibit enzymes and damage cells; Probably drove many prokaryotes extinct

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55
Q

Adaptations from the appearance of oxygen– free radicals

A

Natural selection favoured forms capable of detoxifying oxygen free radicals– Evolution of protective enzymes and molecules (Vitamins A, C, E, Peroxidases, Carotenoids in plant chloroplasts)

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56
Q

Adaptations from the appearance of oxygen– oxidizing power

A

Natural selection favoured forms capable of harnessing the oxidizing power of oxygen– Evolution of aerobic respiration (Evidence: Living purple non-sulfur bacteria use the same ETC for photosynthesis and aerobic respiration)

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57
Q

The Evolution of metabolism by natural selection

A
  1. Variation in metabolic pathways
  2. Variation heritable (As the environment changes, selection pressures change, modifying existing metabolic pathways in a step-by-step fashion)
  3. Some pathway modifications increased the fitness of the organism displaying them
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58
Q

Fossil record

A

Includes:

partial or complete remains (e.g., bones, shells); traces (e.g., footprints, ‘shadows’)

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59
Q

Why is fossil preservation biased?

A

hard vs soft parts; abundant vs rare species; long-lived vs short-lived species; size of geographical range

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60
Q

When did Multicellularity arise?

A

~ 2 bya – Unicellular eukaryotic organisms;
1.2 bya – Oldest known fossils of multicellular organisms (small algae that already showed some adaptations including different sexes)

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61
Q

How did multicellularity begin? Symbiosis

A

Two different species- how to incorporate the genomes of two species into one

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62
Q

How did multicellularity begin? Cellularisation

A

ie. incorporating mitochondria/chloroplasts in a cell

no known example

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63
Q

How did multicellularity begin? Coloniality

A

All of the same species. Ex. Many colonial protists, some with cell specialisation such as slime molds

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64
Q

What is an animal?

A
  1. Multicellular
  2. Heterotrophic
  3. Eukaryotic
  4. Structural proteins (e.g. collagen), nerve and muscle cells
  5. Unique sequence of development, regulated by Hox genes
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65
Q

Ediacaran fauna

~544 mya!

A

Earliest known complex multicellular organisms; Can be fond-like, disk-like, or segmented; Lived 610-542 mya; ‘Discovered’ in 1947 in Ediacara Hills; Occur around the world

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66
Q

Ediacaran fauna legacy

A

What happened to them? DId they die out by predation, competition, change in environment? Did they die without descendants or are they ancestral to modern animal phyla? Were they really animals?

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67
Q

The Cambrian explosion 535-525 mya

A

Modern animal phyla appear in the fossil record suddenly, dramatically, simultaneously; All major body plans; Hard body parts; All 35 living phyla
(+ a few more)

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68
Q

Burgess Shale – 520-515 mya

A

Animals include: Gorgonians, sponges
Marella, Ottia, trilobite, Anomalocaris (1m long!), Pikaia (ancestor of vertebrates?)
Wiwaxia (snitch like creature)

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69
Q

Why did animal life appear so suddenly?

A

Threshold oxygen levels crossed; Nutrient levels may have risen, increasing primary productivity and therefore consumer productivity (O2 would have allowed higher metabolism, so larger bodies.)

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70
Q

Why did animals diversify so quickly? Ecological causes

A

New niches arose with evolution of animals; Predation led to selection for increased size

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71
Q

Why did animals diversify so quickly? Geological causes

A

Active metabolism possible with oxygen availability opened new ways of life; Supportive collagen can only be formed in presence of oxygen

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72
Q

Why did animals diversify so quickly? Genetic causes

A

Evolution of Hox complex led to variation in morphology; Early animal genomes were simple and thus easily modified

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73
Q

Why did animals diversify so quickly? Climatic causes

A

Series of freeze-thaw cycles preceded the Cambrian explosion = Snowball Earth hypothesis

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74
Q

Alternative: Cambrian animals did NOT diversify quickly

A

“The Cambrian explosion had a long fuse…”
Chengjian site – 10 my older than Burgess Shale, includes all major animal groups
Molecular clocks suggest most animal phyla diverged >600 mya
Perhaps animals diversified gradually before the Cambrian but were suddenly preserved in the fossil record during the Cambrian

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75
Q

What is a land plant?

A

Multicellular, eukaryotic, autotrophic (P/RBC Algae)
Cellulose in cell walls (P/BC Algae)
Chloroplasts with chlorophyll a b (P/G Algae)

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76
Q

Green algae

A

Chlorophytes- Mostly freshwater, some marine

Charophytes- All freshwater, Indicators of good water quality

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77
Q

Shared features of Charophytes & land plants

A

Cell wall composition; Cytokinesis; biochemistry; sperm ultrastructure
Suggests close relationship between the two groups

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78
Q

Land plant origins

A

DNA comparisons identify charophytes as closest relatives of land plants; The two groups diverged ~475 mya

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79
Q

Characteristics of land plants reflect:

A

Evolutionary origin of plants from ancestral algae (= ancestral traits); Adaptation of plants to a terrestrial environment (= derived traits)

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80
Q

What are the problems faced by land plants?

A

Desiccation; support; reproduction and development; coping with environmental fluctutations

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81
Q

Derived traits of all land plants

A

Alternation of generations and multicellular embryo develops within the mother plant; Walled spores (with sporopollenin) produced in multicellular sporangia; Gametes produced in multicellular gametangia; Growth of shoots and roots (apical meristems)

82
Q

Alternation of generations

A 
Gametophyte = multicellular adult with haploid cells that produce gametes by mitosis
Sporophyte = multicellular adult with diploid cells that produce spores by meiosis
83
Q

embryophytes

A

Land plants- refers to their shared derived trait of multicellular, dependent sporophyte embryos on gametophytes

84
Q

Other adaptations to life on land for some plants

A

Waterproof cuticle to prevent water loss; stomata (exchange of O2 and CO2, prevent moisture loss); Vascuar tissues (Xylem/ phloem); Secondary compounds to protect agaisnt herbivores, UV, pathogens

85
Q

Adaptations of Bryophytes ~475 mya

A

Include Liverworts, hornworts, and mosses;
Non-vascular plants;
Key adaptations: the 4 derived traits of plants; a waxy cuticle to reduce water loss; stomata to allow exchange of CO2 and O2 (Not present in liverworts)

86
Q

Constraints of Bryophytes

A

Height: No vascular system, no true roots, no true leaves, Water and nutrients transported by diffusion
Moist environments: Flagellated sperm must swim to egg through a film of water

87
Q

Seedless vascular plants ~420 mya

A

Ferns, club mosses, and horsetails;
Key adaptation: vascular tissue (xylem & phloem)- Allows for efficient transport of water, nutrients, and sugars, Provides structural support, Reduces height constraint
Also, dominant sporophyte

88
Q

What is the consequence of taller plants being better competitors (from evolution of seedless vascular plants)?

A

Increased vegetation, Increased photosynthetic activity caused a decrease in atmospheric CO2

89
Q

Constraint of seedless vascular plants

A

Periodically moist environments- Flagellated sperm must swim to egg through a film of water

90
Q

Gymnosperms ~360 mya

A

Conifers, ginkgos, cycads, and gnetophytes
Key adaptations: seed- New sporophyte embryo protected in a protective coating with nutrients; Allows for interruption of lifecycle (until conditions are good)
pollen– Male gametophyte protected by spore coat, Sperm travels in pollen, by wind: no need for water

91
Q

Angiosperms ~142 mya

A

Flowering plants
Key adaptation: flower- Vector pollination increases reproductive success, More economical, Effective even at low population density, Co-evolution of plants and pollinators
Fruit- dispersal of seeds by animal movement

92
Q

Fungus

A 
Multicellular, eukaryotic, heterotophic (=not a plant)
Absorptive nutrition (=not an animal, the distinguishing feature of fungi)
93
Q

Fungal origins

A

Oldest fungal spore fossils are 460 my old, right after land plants appeared ~ 475 mya.
This is not a coincidence! –Mycorrhizae

94
Q

Mycorrhizae (‘fungus-root’)

A

Mutualistic association between fungal hyphae and plant root; Fungal hyphae absorb water and minerals better than plant, so plant exchanges sugars for water and nutrients

95
Q

Taxonomy

A

The science of classification; Naming and organising species into related groups based on similarity of features

96
Q

Linnaean classification

A

Made life simple by giving binomial names: Genus species
species-Genus-Family-Order-Class-Phylum-Kingdom-Domain
But often reveals little about evolution

97
Q

Phylogenetics

A

The study of the evolutionary history of related groups of organisms; Organisms are grouped into taxa based on SHARED CHARACTERISTICS that result FROM COMMON ANCESTRY

98
Q

phylogenetic tree

A

represents a hypothesis about the evolutionary relationships among species or higher taxa
Uses the fossil record, and similarities of anatomy, development, proteins and DNA, when due to homology

99
Q

Sister taxa

A

Species that share an immediate common ancestor on a phylogenetic tree

100
Q

Node

A

Represents the common ANCESTOR of all the species branching from the node

101
Q

Rooted phylogenetic tree

A

has at its base the common ancestor of all taxa shown on that tree

102
Q

Derived character

A

Traits that are shared by a group of related organisms, but not found in their ancestors (have been modified from the ancestral form)

103
Q

Ancestral character

A

Traits that are shared by a group of related organisms and their ancestor (arose early in the evolutionary history of a taxon)

104
Q

Homologous

A

Similar traits resulting from shared ancestry

ex. the forelimbs of vertebrates

105
Q

Analogous

A

Similar traits resulting from convergent evolution and NOT from shared ancestry
ex. dolphin and Ichthyosaur

106
Q

Monophyletic group (clades)

A

a common ancestor + ALL of its descendents

ex. Superorder Cetartiodactyla (deer/whales/hippos/pigs/camels)

107
Q

Paraphyletic group

A

a common ancestor + some but not all of its descendents ex. Artiodactyls (deer/pigs/hippos/camels NOT whales)

108
Q

Polyphyletic group

A

all or some of the descendents of two or more ancestors ex. Suborder Suiformes (peccary/pigs/hippos which are more related to whales)

109
Q

Ecology (oikos = home, logos = to study)

A

The study of interactions between organisms and their environment; Major ecological questions:
•What limits species distribution?
•What determines species abundance?
•What controls species diversity?
•How does energy flow through the environment?

110
Q

The biotic and abiotic environment

A

Biotic: All the living things that an organism deals with, including members of its own & other species
Abiotic: The physical and chemical features of the environment (water, salt, sun, rocks and soil, temperature)

111
Q

The scope of Ecology

A

Earth, Ecosystems (Ecosystem ecology), Communities (Community ecology), Populations (Population ecology), Organisms (Organismal ecology)

112
Q

Organismal ecology

A 
Study of interactions of individual organisms with their abiotic environment
Study Structure (Evolutionary ecology),Physiology (Physiological ecology), Behaviour ( Behavioural ecology)
113
Q

Population ecology

A

Study of the factors that effect population size and composition

114
Q

Community ecology

A

Study of how the interactions among species affect community structure and organisation

115
Q

Ecosystem ecology

A

Study of the effect of abiotic factors on community structure

116
Q

Ecosystem

A

All communities in an area and their physical (abiotic) environment

117
Q

Landscape ecology

A

Study of interactions among ecosystems, the axchanges of energy, materials and organisms

118
Q

Why ecology is important?

A

It provides a scientific context for evaluating environmental issues
Know the difference between ecology vs environmentalism

119
Q

Conservation ecology

A

Managing harmful, invasive species

Finding the consequences of killing certain species in an ecosystem (ie. top predators)

120
Q

How do ecologists tackle questions about distribution?

A

Dispersal limits distribution? (Area inaccessible/insufficient time); Behaviour? (Habitat selection); Biotic factors? (Predation, parasitism, competition, disease) Abiotic factors? (Chemical: water, oxygen, salinity, pH, soil nutrients- or Physical: Temperature, light, soil structure, fire, moisture)

121
Q

Dispersal

A

Movement of individuals away from centres of high population density or from their area of origin

122
Q

Ecological methods

A

The role of an ecologist is to detect natural patterns, to explain processes that underlie them, and to generalize these explanations.
Observations, Experiments, Predictions

123
Q

What is a population?

A

A set of individuals of one species living in a given area, using common resources, coping with similar environmental factors, and interacting with one another and with their environment

124
Q

Characteristics of populations

A

Size & density; Sex ratio; Gene frequencies; Distribution

125
Q

Population dynamics

A

Changes in population size and density over space and time; Based on what individuals do; Need info on life history

126
Q

Life histories

A

Scheduled events in an organism’s life

Age of first reproduction; Number of young; Number of reproductive events; Life span; Mortality

127
Q

You can think of life histories coming in packages. Describe “Package A”- Die young

A

Breed young; Many small babies; Breed often;

Small body size); (Little parental care

128
Q

You can think of life histories coming in packages. Describe “Package B”- Die old

A

Breed late; Few large babies; Breed rarely;

Large body size); (Long parental care

129
Q

“Energy Pies” describe the facts that

A

An organism’s resources are finite, maintenance is a fixed so there is a trade-offs between growth and reproduction (large body, few young or small body and many young)

130
Q

What determines population size (N)?

A

Population gains = B and Population losses = D
Assuming immigration=emigration
Comparing births and deaths gives the change in N

131
Q

Per capita rate of increase

A

b-m, where b=births/individuals and m=deaths/individual

r greater than 0 means population grows

132
Q

If r is stable, greater than 0…

A

you get exponential growth, if at the maximum rate it is r-max

133
Q

Carrying capacity

A

k = Maximum number of individuals that a
particular environment can support
A good environment has high k, a poor environment has low k

134
Q

As N approaches K

A

r decreases, either from b decreasing, m increasing or both

135
Q

Proportion of the carrying capacity still available for population growth

A

Given by (K-N)/K
A small N is ~1
A large N near K is ~0
An intermediate N is ~0.5

136
Q

Logistic growth

A

Given by Nr-max(K-N)/K

this is the absolute # of individuals added. The number will be small for extreme N, quite large for intermediate N

137
Q

Graph of logistic growth

A

population vs. time

Includes establishment phase, boom phase, stabilisation phase

138
Q

Factors affecting r

A

Limitations on available space; Increased predation; Increased disease; Decreased food availability; Changes in behaviour: Reduced reproduction or Increased emigration

139
Q

Community

A

Assemblage of populations of various species inhabiting a common environment and interacting with one another

140
Q

Name the 7 interspecific interactions

A

Competition, predation, herbivory, parasitsm, mutualism, commensalism, disease

141
Q

Competition (-/-)

A

Interaction between organisms using the same limiting resource (e.g. food, water, light, nesting sites)
Negative effects of competition: reduced growth, reduced reproduction, local exclusion

142
Q

Competitive exclusion principle

A

Two species competing for the same limiting resource cannot co-exist, restated as:
Two species cannot coexist in a community if they share an identical niche

143
Q

Niche

A

The ecological role played by a species in a community; The sum total of the organism’s use of biotic and abiotic resources in its environment
Includes: physical limits (temp), nature and amount of food sources, patterns and timing of activities, type of microhabitat

144
Q

Explain “Selection to be different”

A

Resource partitioning; Realised niche is narrower than fundamental niche
Example, warbler species live on different parts of a tree

145
Q

Predation & herbivory (+/-)

A

Eating of live prey. Effects: availability of prey is a major determinant of k of predators; Selective predation can alter population structure or life histories of prey; Non-consumptive effects: the ecology of fear

146
Q

The ecology of fear

A

ex. in yellowstone park, loss of wolves meant elk browsed unimpeded, decreased amounts of vegetation, beaver disappeared, wetlands disappeared. Reintroducing wolves scared elk back into woods, plants regrew, beavers returned, wetlands returned

147
Q

Predator-prey coevolution

A

Gave predators poison, claws, teeth. Prey developed camouflage, warning colours, spines, plants had poisons

148
Q

Mutualism (+/+)

A

Symbiotic interaction between two species that benefits both species; Effects on communities: Increase species diversity, Increase distribution range

149
Q

Commensalism (+/0)

A

Symbiotic interaction between species that benefits only one of the species; Unclear effects on communities. Often when studied, it is found the 0 organism is effected in some way

150
Q

Parasitism/disease (+/-)

A

Symbiotic interaction in which the parasite or pathogen benefit from living on or in a host that is harmed by the association; reduce host survival/reproduction/density. Major effect on r

151
Q

Parasites (vs. pathogens)

A 
Large, multicellular
Live on or in host
‘Steal’ nutrients from host
Usually non-lethal
ex. brown-headed cowbird
152
Q

Pathogens (vs. parasites)

A

Often unicellular
Live in host
Use host to reproduce
Often lethal

153
Q

Food chains

A

Primary producers, primary consumers, secondary consumers, tertiary consumers, quaternary consumers

154
Q

Food webs

A

Still a simplified version of real life, but good for asking:
What happens when you lose a species? What happens when you add a species?

155
Q

Not all species are equal: Dominant species

A

Most abundant species in a food web OR Species with highest biomass. expect extinction with loss of dominant species

156
Q

Keystone species

A

Species that has an influence on community structure that is out of proportion with its abundance; Disappearance can trigger ecological ‘meltdowns’ ex. otters-urchin-kelp relationship

157
Q

Foundation species

A

Species that exert significant physical change to their environment; Can act as facilitators for other species. Ex. coral, which creates the foundation of the ecosystem. Beavers is another

158
Q

What controls community structure?

A

May be a top-down processes (predation) or a bottom up processes (nutrient limitation, primary productivity). Experiments will show which is true for the individual community

159
Q

Biomediation

A

???

160
Q

Ecosystem

A

All organisms living in a community as well as all the abiotic factors with which they interact. An open system. Can be any size.

161
Q

Ecosystem ecologist’s view of the world

A

Biogeochemistry (nutrients); Energy (nutrients into life); Organisms (the result of
nutrient-energy interaction)

162
Q

Energy flows, nutrients cycle

A

energy from sun is lost at every point as heat, with little energy moving to the next
nutrients cycle through the entire thing, as they do not leave the atmosphere

163
Q

Energy flow: Primary production

A

Amount of light energy converted to chemical energy by autotrophs during a given time period; Primary producers create 150 billion metric tons of organic material each year, from ~ 1% of sun energy that reaches Earth

164
Q

Net primary production =

A

(Amount of light energy converted to chemical energy per unit time) subtracting (Amount of chemical energy used by autotrophs in respiration)
*** NEW biomass produced

165
Q

What is NPP measure in?

A

Joules/m2/year or grams/m2/year

166
Q

Which ecosystems are important for NPP

A

Open ocean- large % of Earth’s NPP because of the amount of open ocean
Tropical rain forest- high individual NPP and high %
Reefs- low %, but the highest individual NPP

167
Q

What controls primary production?

A

Light limitation; Nutrient limitation (nitrogen on land, phosphorus in lakes, iron in the sea)

168
Q

Energy flow: Secondary production

A

The amount of chemical energy in consumers’ food that is converted to new biomass during a given time period

169
Q

Production efficiency

A

Energy used for growth and reproduction (net secondary)/Total NRG taken in used for growth, reproduction & respiration(assimilation of primary ie. through respiration, energy is lost to the organism)

170
Q

Trophic efficiency

A

Proportion of production passing from one trophic level to the next
ie. 10% flower to deer, 10% deer to wolf, 1% flower to wolf

171
Q

Trophic (in)efficiency

A

Three hundred trout are needed to support one man for a year. The trout, in turn, must consume 90,000 frogs, that must consume 27 million grasshoppers that live off of 1,000 tons of grass.

172
Q

Ecological pyramids

A

Can be for production, biomass, or numbers- they all have similar shape. There is a limited amount of enery at the top, which constrains the possible number of levels (quaternary is the most!). Trophic inefficiency is what causes few large carnivores.

173
Q

Nutrient (re)cycling

A

By detrivores and decomposers- consumers that get their energy from detritus, nonliving organic matter

174
Q

Nutrient cycling- Biogeochemical cycles

A

Can be on a global scale (C, O2, S, N cycling) or a local scale (P, K, Ca normally stay within an ecosystem)

175
Q

Assimilation

A

N used to form proteins and nucleic acids

176
Q

Ammonification

A

N returned to soil

177
Q

Nitrification

A

Conversion of ammonium to nitrate (NH4 to NO2 to NO3)

178
Q

Denitrification

A

Return of N to atmosphere (under anaerobic conditions)

179
Q

Human impacts on nutrient cycles

A

Atmospheric nitrous oxide, acid rain, catalyze breakdown of O3, reduction in spp diversity, eutrophication, algal blooms, fish kills, drinking water contamination

180
Q

Endosymbiosis

A

Smaller prokaryotes began living in larger ceslls, eventually becoming a single organism– the first eukaryotes?

181
Q

Nitrogen fixation

A

Converting N2 to NH3

182
Q

Heterocytes

A

Specialized cells in a colony of cyanobacteria that do nitrogen fixation while the others in the colony perform photosynthesis

183
Q

Microphylls and Megaphylls

A

Branching in leaves of vascular plants (micro is one branch, mega is highly branched

184
Q

Polytomy

A

A branch point from which more than two descendant groups emerge

185
Q

Semelparity

A

a single reproductive opportunity in the life of an organism before it dies (ie. salmon)

186
Q

Iteroparity

A

repeated reproduction

187
Q

K-selection

A

ex. mature trees growing in an old-growth forest shows that life-history is sensitive to the population density

188
Q

r-selection

A

found in disturbed habitats, where r is maximized because N is well below K

189
Q

Competitive exclusion

A

A slight reproductive advantage will eventually lead to local elimination of the inferior competitor when the two are fighting for the same resource.

190
Q

Resource partitioning

A

the differentiation of niches that enables similar species to coexist in a community

191
Q

Character displacement

A

ie. the beaks of the finches
the tendancy for characteristics to diverge in sympatric populations of two species to be able to use different resources

192
Q

allopatric

A

geographically separate

193
Q

Sympatric

A

geographically overlapping

194
Q

Cryptic coloration

A

Camouflage

195
Q

Aposematic coloration

A

Warning coloration, that often use chemical or physical defenses

196
Q

Batesian mimicry

A

a harmless species mimics a harmful or unpalatable one

197
Q

Mullerian mimicry

A

two unpalatable species resemble each other

198
Q

The green world hypothesis

A

Terrestrial herbivores are held in check by a variety of factors, which accounts for the fact that less than one sixth of NPP is consumed

199
Q

Facilitation (+/+)

A

Having positive effects on the survival and reproduction of other species without living in direct or intimate contact

200
Q

Symbiosis

A

When individuals of two or more species live in direct and intimate contact with one another

Biology (3 decks)

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