The species richness within a region.

G (Global)

The turnover of species from one habitat to the next.

B (between)

Cause some kind of change in the structure of ecological communities.

-Categorized by the intensity and frequency of event

-high intensity and high frequency are the most sever disturbances.

-Intermediate levels may actually promote higher species diversity

Biodiversity

Does it matter?

way of describing a particular community

-some people believe that the preservation of biodiversity is important for moral or aesthetic reasons

-provide us w/ food safety, new meds, and healthy ecosystems.

-matters to ecosystem productivity

-Can help protect communities from disturbance

Occuring when all life has been removed from an area, for example following volcanic activity or glaciation

-Occurs slowly, b/c species have to colonize from elsewhere and the process of soil formation takes along time.

occures after a disturbance that does not eliminate all life. (fire, clear cutting, storm damage)

-proceeds much more rapidly than primary succession, at least in part b/c soil function is not utterly lost

Believed that climax vegetation, the supposed equilibrium endpoint of succession, was the "best" possible outcome for the natural system

-predictable

Viewed as the result of individualistic responses

-species could either live in an area, or are unable to do so, based upon their physiology

-Favored view

-Changes in tilt of earths axis occur on a ~41,000 yr cycle

-Changes in wobble of the spin axis occur on a ~23000 yr cycle

-Shape of earth's orbit changes on a ~100,000 yr cycle

Characterized by high temperature and moderate to high levels of precipitation.

-There are "tropical dry forests" as well as "tropical rainforests"

-Tropical forests are not "aseasonal"

-Precipitation levels can vary among seasons

Overstory (emergent layer) includes trees that emerge above the thick, closed canopy

-pretty dark on the forest floor

-as you travel north or south from the equator the number of species in most taxonomic groups declines

-Known as latitudinal gradient in species diversity

-likely due to a combination of the greater age, high rainfall, and high solar inputs of tropical regions

-many woody plants have lifespans well over a century

-woody material if recalcitrant to decomposition

-end result is long-term carbon storage in both standing biomass and forest soils

-however, in trop. forests, not much carbon is stored in litter and soil

-agricultural system in which plots of land are cleared & farmed until soil lose fertility

-tropical areas used

-clear area of land, grow crops for 2-3 yrs

then let succession proceed.

move to another area

-creates a mosaic

-vegetation is cut & allowed to dry

-some timber products may be removed

-rates of dispersal among major biogeographical zones have historically been relatively low

-new rates of dispersal of organisms among major biogeographical zones occur as a direct result of human activities

-Humans have accidently and deliberately introduced exotic species into most of earths ecosystem

(naturalized)

-species that have escaped human cultivation and become established in the native community

Ballast water is often taken up in one ocean and flushed out in another

-in advertent vector for trans-global marine and freshwater biotic exchange

invasion is a mutivariate ecological and evolutionary problem

-sometimes seems as if every invasive species problem is unique and unrelated to any other problem

-release sperm and eggs directly into the water for external fertilization

-females can produce from 30,000+ eggs each year

-Fertilized eggs develop into pelagic larvae must feed on phyte plankton and grow 7-30 days prior to settlement

-dispersal is passive and dependent on water currents

-they greatly reduce phytoplankton biomass, alter foodwebs and change nutrient cycles

-exotic invasive plant species from eastern Europe

-spreading widely in U.S. and Canada

-Colonizes sites after disturbance

Fierce competitor b/c:

-long tap root sucks water faster than root system of neighbors

-produces lots of seeds

-Few herbivores are willing to eat it

-may poison other plants...

+/- : latechin is a phenolic compound

-said to be released from knapwood roots

-can be toxic to other plants

-exotic invasive plant species native to europe

-able to invade dark forest understory

-biennial plant, forming a rossette in the first year and flowering in the second year

-Secretes toxic chemical from roots that inhibits mycorrhizal fungi in soil

-Spread may be increased indirectly by deet

-deer dont eat it so they eat its competitors

-Frequency of contact

-efficiency w/ which the disease is transmitted

-infectious period, or length of time that an infectious to other individuals

-number of secondary cases of disease that result from a single infected individual entering a population of susceptible individuals

-Product of transmission efficiency and infectious period

-Diseases w/ high Ro are very hard to control

-Disease control and eradication are all about managing the Ro of a given disease

-improved nutrition

-improved access to housing

-access to clean water and safe food supply

-improved sanitation and hygiene

-Invention of antibiotics and immunizations

-bacterial infection

-kills between 2-3 million people each year

-encapsulated bacteria are difficult to kill

-requires long periods of antibiotic treatment

-can be asymptomatic

-bacterial infection caused by vibrio cholerae

-Infects the intestinal tract

-death by dehydration

-spread by water or food contaminated by human feces

-commonly emerges during periods of social disruption

- Emerging disease b/c of increasing stresses placed on supplies of freshwater, sanitation and healthcare

-caused by 4 strains of a flavivirus

-symptoms are sever headaches and muscle aches

-strictly infects humans

-transmitted by "tropical" mosquitoes

emerging infectious disease b/c: 

-humans are transporting the disease vectors all over the globe

-increasing global temp. appear to be facilitating range expansion of the "tropical" mosquito vectors

-flavivirus, disease in humans is a zoonosis

-natural viral hosts are birds

- EID b/c humans have transported it around the globe to areas w/ high densities of zoonotic hosts

-small habitat fragments tend to support only small populations of the species that they contain

-small populations are at particular risk of extinction b/c of what is known as the extinction vortex

-Mountain tops are islands of high elevation surrounded by "seas" of low elevation

-Woodlands are forests islands surrounded by a sea of agricultural land

-lakes are "islands of water" surrounded by a "sea of land"

-Nature reserves are often islands of natural habitat surrounded by a matrix of human development

-large areas may support higher rates of colonization and lower rates of extinction

-the number of species on an island is determined by the dynamic balance between colonization of new species and the extinction of species

-Number of species remains constant, not their indentity

-extinction rates increase w/ the number of resident species on an island

-Extinction rates are higher on small islands b/c population sizes are smaller

-Large islands exhibit higher colonizatin rates

-islands close to shore exhibit higher colonization rates than isolated islands

-Manipulated the size of small mangrove islands by cutting down trees

-Islands were composed of mangrove, so they had identical habitat diversity

-Species richness of arthropods on the mangrove islands declined when island size was reduced

-make sense to have large nature reserves instead of small ones- support more species

-Should not be isolated from potential sources of colonization

-single large or several small

-some species require large areas of contiguos habitat in order to persist. Single large reserves might be most suitable

-But several small reserves may actually cover a greater variety of habitats and support a greater total richness of species

-Several small reserves may also reduce the probability of extinction that results from catastrophic events or disease epidemics

-can reduce habitats to a size that is too small to support some species

-By creating islands of habitat in a sea of human dominated landscapes, fragmentation reduces the ability of individuals to disperse from one habitat to another.

-Creates large amount of "egde" habitat

-multicellular, photoautotrophic eukaryotes

-unique life cycle: alternation

-Phanerozoic era

-class of endothermic vertebrates w/ fur and lactation

-diverged early in the evolution of the amniotes from an extinct group of mammal-like reptiles that were around about 290 MYA

-First true mammals appear in fossil record in the Jurassic, about 195 MYA

-all mammals were likely small and nocturnal until after the extinction of the dinosaurs about 65 MYA

Placental mammals

-placenta develops from the charion and allentois

-Much larger and long-lasting structure, nourishing the growing fetus for many months to the point where it is often born (in some species) close to being fully functional

-eyes on the front of the face w/ binocular vision

-hands and nails that are efficient at grasping

-flattened nails instead of claus on the fingers and toes

-large brains

-complex social behavior

-extensive parental care of offspring

-two main groups, prosimians and Anthropoids

-Prosimians ("before monkeys") include the lemurs, tarsiers, pottos and lorises

-Anthropoids include 4 key groups:

New world monkeys, old world monkeys, gibbons, hominidae (great apes)

-composed of bipedal robust australopithecines and hypothesized to be an independent lineage during human evolution that become extinct

-Massive cheek teeth and jaws, very large cheek bones and a sagittal crest-flange of bone at the top of the skull

-Composed of the first humans

-Larger braincase, flatter face, smaller jaw and teeth

-possibility of toolmaking

-cro magnons and neanderthals

-Evidence both populations created art and buried their dead in an organized manner

-several lines of evidence support the hypothesis that increased tool and languages use triggered natural selection for the ability to reason and communicate, which resulted in humans w/ large brains

-gene flow between neanderthals and modern humans current answer no

-populations in africa have the highest levels of genetic variation whereas native americans share the lowest levels of genetic variation

-These data are consisten w/ genetic drift acting on human populations on different continents that were founded from small groups of settlers

-evidence of recent change in genotype frequencies in human populations resulting from natural selection acting after serial founder effects

-Biologists study human evoltion by looking at changes in allele frequencies, DNA sequence data from specific genes, and large areas of the human genome

-evolution can be traced through single nucleotide polymorphisms (snps), haplotypes, CNVs

-selection appears to have operated in response to:

changes indiet

changes in climate

emerging diseases

examples of recent human evolution include:

-changes in sucrose metabolism in east asians

-changes in pigmentation

-Gain in lactose tolerance in Europeans

-Changes in mannose metabolism in Africans

-Lactase, the enzyme that digests the principal sugar in mile, is usually switched off in human babies when they are weaned

-Lactose tolerance (enzyme remains "on") has evolved independently (convergent evolution) several times in human groups, including cattle-herding northern europeans about 5,000 years ago and kenyans 3000 yrs ago

-There is a significant nutritional advantage to using dairy products containing lactose if youre a cattle herding population

Ardipithecus: had most apelike features 5.5 Ma

Australopithecus: small brained, gracile hominins w/ fruits and vegetable diet 4 ma

Paranthropus: small brained, robust hominins w/ grassland vegie diet 3 ma

homo- large brained hominins w/ omnivorous diet 2ma

-scientists debate over how species related or which ones simply died out

-& how to identify and classify particular species of early humans and what influenced the evolution and extinction of each species

pollination of anguria and gurania vines by heliconius butterflies

-male flowers produced year round, even when female flowers are absent

-vines are "training" the long-lived butterflies to forage on them

-aganid (fig)wasps and fig plants

-usually one species of wasp per species of fig

-the fig is a false fruit containing the real fruits within it

-female wasps enter the fals fruit throgh a hole called the ostiole

-there are both short-stemmed and long-stemmed female flowers within the fig

-wasps pollinate the long-stemmed flowers and lay eggs in the short-stemmed flowers

- males emerge first, mate w/ females still in galls, and excavate an emergence hole in the fig

-mated females emerge, gather pollen from the male flowers, and depart to start the cycle again

-orchids trick insects into transferring their pollen from flower to flower w/ out providing a reward

-this is done by either mimicking flowers of nectar producing species or else mimicking the mating partner of the insect

-Many latter orchids also produce chemicals that resemble mating pheromones produced by the insects, so the deception occurs on multiple reinforcing levels

simple-develops from a single flower w/ one carpel or fused carpels

aggregate- develops from a single flower w/ many seperate carpels

multiple fruit- develops from many flowers w/ many carpels

bees: see yellow, blue and UV

butterflies: diurnal and good vision- weak sense of smell

moths: nocturnal, have good sense of smell

-white or pale flowers, strong sweet scent

-brain encased in protective skull

-head w/ complex sense organs: binocular eyes, 2 nostrils, 2 ears

-backbone

-jaws

-paired appendages

-only 5 species

-an extinct group gave rise to all tetrapods

-common in the fossil record

-their fleshy fins shar homologous bones and muscle w/ tetrapods

2 marine and 3 freshwater

-have gills and lungs

-can survive in anoxic water and can also survive the drying out of lakes rivers and ponds by burrowing in the mud and breath in air

-transition from fish to first tetrapods

-had fins w/ thin ray bones, scales, and gills like most fish; however, it also had the sturdy wrist bones, neck, shoulders and thick ribs of a four-legged vertebrate

Gravity: air is much less dense than water

less drag:viscosity of air is much lower than water

temperature is much less stable on land

oxygen is 20% in air

waterloss is a severe physiological prob in air

sound waves are slower in air

chemical communication is diffuse in air

vision is clearer in air

food and predators were originally rare in terrestrial environments

-strong vertebrae and limbs for locomotion

-protective skin to prevent waterloss

-body plan freed from drag contraints

-choanae(nasal cavity) and lungs for air breathing (in adults)

-loss of gills (in adults)

-acute smell, taste, vision and hearing for life in air

-amphibians retained aquatic food habits for many million years

-amphibians still retain aquatic reproduction and larvae

-have shells that minimize water loss as the embryo, bathed in liquid, develops inside

-contain a membrane bound supply of water in a protein rich solution called albunen

-embryois enveloped in a protective innermembrane, or annion

-yolk sac is a membranous pouch that contains nutrient for the growing embryo and the allantoisis is a membranous pouch that holds waste materials

-middle membrane, the charion, seperates the amnion, yolk sac, and allantois from the albumen and provides a surface where gas exchange between the embryo and the surrounding air can take place

-most diverse clade of metazoa in part b/c of their interactions w/ plants

-rely on insects for a wide variety of ecosystem services

-over 65% of angiosperms are insect pollinated

-20% of insects depend on flowers for food

-jellyfish, corals, sea anemones, hydroids, sea fans

-radial symmetry

-diploblasts

-digestion begins in the gastrovascular cavity and is completed inside food vacuoles in the gastrodermal cells

-one pore

-sponges

-only tissue type is epithelial

-2 main taxonomic groups

-calcarea and silicaria

-oldest animal phylum

-bilateral symmetry

-Triploblastic

-most have an internal fluid-filled body cavity: coelom

-split into protostomes and deuterostomes based on early developmental distinctions of cleavage, gastrulation and coelom formation

Ecdysozoa-molting organisms

-arthropoda, especially insects, dominate animal species level diversity

Lophotrochozoa- named for typical larval type

gut formation

Echinoderms- adults w/ secondary radial symmetry

Chodata- Possess the 4 structural trademarks of the phylum at some point during their development

-dorsal, hollow nerve cord

-notochord

-muscular, postanal tail

-pharyngeal slits or clefts

-multicellular

-photoautotrophic eukaryotes

-reproduce by alternation

-phanerozoic era

advantages: more sun light and carbon dioxide available in air than in water

-soil richer in mineral nutrients than water

-no predators and few pathogens on land

475 MYA

Challenges: avoid drying out

-reproducing in air vs. water

-dramatic temp. flux in air

-supporting body weight

-transporting nutrient and waste throughout body

-preventing waterloss from cells

-transporting water from tissues w/ access to water to tissues w/ out access

- green algae are strictly aquatic

waxy, watertight sealant that gives plants the ability to survive in dry environments

gas exchange is accomplished by stomata, which have a pore that opens and closes

-adaptation for preventing waterloss

evolved in a series of gradual steps that provided an increasing level of structural support, allowing plants to grow upright

-tissue involved in conducting water or solutes from one part of a plant to another

-mosses

specialized groups of cells that conduct water (xylem) or dissolved nutrients (phloem) from one part of the plant body to another

-nonvascular

-have vascular tissue, but do not make seeds

-horsetails, ferns, lycophytes, whisk ferns

have vascular tissue and make seed

Cycadophyta (cycads)

ginkgophyta (ginkgos)

gnetephyta (gnetophytes)

other conifers

anthophyta (angiosperms)

when evolved, land plants lost their dependence on water for fertilization

pollen grain: tough outercoat made of sporopollenin that contains male gametophyte which willgrow toward female ovary and release sperm cells

embryo along w/ food supply, packaged within a protective coat

-enable plants to better resist harsh environments. some species have seeds that can remain dormany for days, months and even decades

-have many adaptation to disperse their seeds

monocots: any plant that has a single cotyledon upon germination.

-grasses, palms and lilies

-monophyletic group

-flower petals in multiples of 3

-vascular tissue scattered throughout stem

Dicot: any plant that has 2 cotyledon upon germination

-flower petals in multiples of 4 or 5

-vascular tissue in circular arrangement

multicellular photoautrophs w/ vascular systems, pollen and seeds

-reproduce by means of flowers w/ male and female structures

-often produce fruit

-most diverse group of land plants

-phanerozoic era

-represents one of the great adaptive radiations in the history of life

stonewarts

-lineage of green algae most closesly related to plants

-sister group to land plants

-pollination is the transfer of pollen grains from an anther to a stigma

-insect pollination is an imp. adaptation b/c it makes flowering plant sexual reproduction much more efficient

-animal pollinated flowers are much more "showy" than wind pollinated flowers

-colonized land about 460 mya, shortly after the appearance of the first land plants (475 mya)

-some developed mutualisms w/ plant roots very early in the colonization of land and likely played a significant role in plant diversification

-absorb nutrition from other organisms- dead or alive

-capable of completely digesting both lignin and cellulose that make up wood.

-have a profound influence on productivity and biodiversity

-contribute to carbon and nutrient cycling

-some are pathogenic

-grow either single cells or as mycelia

-mycelia provide very large surface area to volume ratios which allow fungi to absorb nutrients from the environment around them

-prone to desiccation

-abundant in damp environments

Hyphae: individual filaments

-play important ecological roles in the environment

-important evolutionary interactions w/ other organisms

-master decomposers, mutualists,and miserable agents of disease

-critical to decomposition and nutrient cycling

-speed the carbon cycle land

-plant residues contain "recallitrant" compounds that are difficult to break down

-in terrestrial and freshwater ecosystems, fungi are primary decomposers of plant residues

influenced by abiotic conditions and the quality of the detritus as a nutrient source

decomposition of detritus limits the rate at which nutrients more through an ecosystem

-fungi release enzymes to break down organiz tissue

-digestion takes place outside their cells and digestion products are then absorbed by hyphae

-peptidases break bonds between amino acids and carbon compounds in dead tissue, releasing nitrogen

-during permian mass extinction, huge pulse in fungal spore fossils-b/c of all the dead organisms available for decomposition

fungi engage in mutualistic interactions w/ a wide variety of organisms

-mychorrhizae

-lichens

-leaf-cutter ants

-90% of plant species have fungi associated w/ their roots

-contributed to the success and diversity of land plants

-trade phosphorous, water and nitrogen w/ plants, gaining carbon in return

-some act to decompose plant residues then pass some of the nutrients onto plants in return for carbon

-usually benefit plant growth and fitness

-attine ants actively propagate, nuture and defend a basidiomycete fungal cultivar

-ants actively cultivate their fungus, feeding it and maintaining it free from pests and molds

-sensitive enough to adapt to fungis reaction to diff plant material

-some have become parasitic

-chytrid fungi are implicated in global amphibian declines

-live primarily in water or wet soils

-motile cells

-spores they produce during asexual reproduction have flagella

-make swimming gametes and spores

-haploid

-cells from the yolked hyphae fuse to form a spore-producing structure called a zygosporangium

-yolked hyphae reproductive structure unique to this group

club fungi

-inside these structures, specialized cells called basidia form at the ends of hyphae and produce spores

-common for multiple mating types to occue in these species

-monophyletic

sac fungi

-produce complex reproductive structures- largest often cup shaped

-tips of hyphae produce distinctive sac like cells called asci

-ascus is a spore producing structure found only in ascomycota

-monophyletic

-primary succession

-succession doesnt host the same things

-more than one way of recovery

2 marine, 3 freshwater

-extinct group that gave rise to tetrapods

-same bones in tetrapods

-bony projections in fins

-most diverse

craniata

not vertebrates

-theory of fluctuating resource availability

-developed experimental plots that varied in their fertility (eutrophication) and in their disturbance regime

-the plots with the combination of high fertility and high disturbance were the most susceptible to invasion

theory of fluctuating resource availability

- a community becomes more susceptible to invasion whenever there is an increase in the amount of unused resources

-theory allows that multiple ecological factors can promote invasion

a disease that affects only humans

ex: smallpox, malaria

a disease that has animal reservoirs

ex: lyme disease, ebola

-found in seed plants, made the evolution of pollen possible

-produce two types of spores

open to allow gas exchange and close to decrease water loss

-solves two problems that are imposed on land plants