Biology Midterm 2 L15-L19

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Plants vs fungi vs animals

Plants - cell walls, autotrophy (carbon source), phototrophy (energy source)

Fungi - cell walls, heterotrophy, chemotrophy, absorption

Animals - mobile cells, heterotrophy, chemotrophy, ingestion

Fungi

Yeasts, molds, mushrooms

Cell walls made of chitin

Opisthokont: "posterior flagellum" - most current specieis lack flagella

Make hyphae: single-cell thick tubes

Extend into environment --> secrete digestive enzymes --> absorb nutrients

Mycelium: dense network of hyphae

Spores --> colonize new environments

Asexual reproduction

Dominated by haploid gametophyte

Heterokaryote

When 2 mycelia fuse

2 separate genomes sharing an organism

Not diploid

--> genetic diversity

Fungi reproduction

Lichens

Link fungi and plants --> mutalism

Sheet that grows hyphae around algae cells

Photosynthetic

Embryophyta

Plants

Shared ancestral characteristics: photosynthetic, cell walls

Plant zygotes form dependent embryos

Alternation of generations: multicellular diploids and multicellular haploids

Plant phylogeny

Bryophytes

Nonvascular

Independent gametophyte (1n) --> main macroscopic plant

Dependent sporophyte (2n) --> smaller organism dependent on haploid

Tracheophytes

Vascular

Gymno and angiosperms: dependent gametophyte, independent sporophyte

Lyco and monilophytes:

independent gametophyte; independent sporophyte

Sporangium

Diploid structure where meiosis occurs

Makes haploid spores

Plant life cycle general

Bryophytes life cycle

Tracheophytes seeds life cycle

Tracheophytes seedless life cycle

Tracheophytes vasculature

Xylem - dead, lignified vessels pull water

Phloem - live cells move sugars

Angiosperms monocot

Rice, corn, oil palm, sugarcane, wheat

Embryos --> 1 cotyledon

Leaf venation is parallel

Stems --> vascular tissue scattered

Angiosperm eudicot

Potatoes, cassava, soybean, sweet potatoes

Embryos --> 2 cotyledon

Leaf venation is netlike

Stems --> vascular tissue arranged in ring

Ovule

Gymnosperms exposed seeds

Climate is influenced by

Temperature, precipitation, sunlight, wind

Seasons result from

Earth's permanent tilt on its axis

Equinox

Length of night = length of day

Solar radiation varies with

Latitude

Global air circulation and precipitation

Tropics experience LEAST seasonal variation + GREATEST annual input in solar radiation

Closer to equator --> more moist

Closer to poles --> more dry

Air circulation = rising/sinking air precipiation + dry air and wind patterns

Coriolis effect

The Earth's rotation deflects the surface flow of air

Land near equator is moving faster than poles

Cooling trade winds flow

From east to west

Westerlies flow

From west to east

ITCZ

Where northeasterly and southeasterly trade winds meet

Not stationary; migrates toward region with warmest surface temperature

High amount of precipitation

Hadley cells

Circulation cells that surround equator

Ocean currents are created by

Winds, planet rotation, unequal heat of surface waters, locations and shapes of continents

Gyres

Formed as warm water moves away from the equator

Each ocean dominated by 2 gyres

Water moves clockwise in northern hemisphere

Water moves counter-clockwise in southern hemisphere

Ocean currents influence coastal climate

Specific heat is lower on land

Day --> land warms faster than ocean --> warm air rises and moves to the sea

Night --> land cools quicker --> warm air from sea comes in --> offshore breeze

Topography

Influences rainfall

Orographic lifting --> warm, moist encounters windward side of mountain --> air flows upward --> releases precipitation

Leeward side: dryer air descends --> warms --> rain shadow

How vegetation influences coastal climates

Forests absorb solar energy

Offset by transpiration

Lots of veg: low temp, high precipitation

Little veg: high temp, low precipitation

Tropical forest

High precipitation

High temp

Along equator

Drip tips on leaves allows water run off without damaging trees

Nutrient poor soil

Desert

Dry

High temp fluctuation

Low precipitation

Fat sacks i.e. humps on camels

Cacti survive on low water

Savanna

Warm year round

Low precipitation

Few trees, small and thorny leaves - minimize water loss, adapted to forest fires

Chaparral

Hot and dry summer

Cold and wet winter

Shrubs and small trees

Reptiles

Temperate grassland

Wet summer

Dry winter

Fertile soil

Field of grass

Northern coniferous forest

Stable temperatures

Dominant cone trees

Needles on trees prevent water loss

Lower temperatures than tropic forest

Broadleaf forest

Large trees

Low light penetration

Humid summers

Vertical layering

Tundra

Cold all the time

Layer of permafrost

Permafrost prevents roots of plants from reaching down or up

Small, low growing, clustered shrubs

Short roots, small leaves

Seasonal turnover

Plankton carried downward, nutrients carried upward

Phytoplankton have access to both nutrients and light

Eutrophication

Nutrient enrichment

Oligotrophic lakes

Low nutrient levels

Low algal growth

Good light penetration

High dissolved oxygen

Deep waters

Eutrophic lakes

High nutrient levels

High algal growth

Poor light penetration

Low dissolved oxygen

Shallow waters

Lake threats

Eutrophication --> algal bloom --> algae dies in lifecycle --> aerobic decomposers consume all oxygen

Excess fertilization runoff

Streams and rivers

Go downstream --> warmer, more sunlight, more turbid, suspended sediments, slower moving, more salt and nutrient dense, finer particles

Wetlands

Earth's kidneys

Take up pollution - N and P

Same threats

Brackish biomes

Estuaries connect rivers and oceans

High salinity

Plants are adapted to high salinity i.e. mangrove

Salt marsh plants

Adapted to high salinity and low oxygen

Intertidal zones

Where tide comes in

Tide comes in --> more nutrients

Pelagic zone

No turnover

Benthic zone

Hydrothermal vents

Chemoautotrophs

Hydrogen cyanide

High pressure prevents water from boiling

Mark recap equation

N = sn/x

s = number of individuals in first sample/marked

n = number of individuals in second sample

x = marked individuals recaptured

Mark recap assumptions

Marked and unmarked individuals have same probability of being captured or sampled

Marked organisms mix completely into population

No individuals are born, die, immigrate, or emigrate during resampling interval

Clumped

Most common

Presence of one individual increases probability of others being there too

Results from:

Clumped resource or favorable condition distribution

Mating or social behavior

Uniform

Presence of one individual decreases probability of other individuals being there

Results from:

Interactions between individuals of a population

E.g., plants release chemicals that inhibit nearby growth, animals have territorial behavior

Random

Rare

Equal probability of individual occupying any point

Type 1 survivorship curve

Mortality at end of max life span

Ex. humans

K-selected

Type 2

Constant mortality rate from birth to death

Ex. rodents

Mix of r and K selected

Type 3

Extensive mortality rate after birth; high rate of survival if live

Ex. marine invertebrates, insects

r selected

Exponential growth

dN/dt = rN

r = intrinsic/instantaneous rate of change

Logistic growth

dN/dt = rN*((K-N)/N))

((K-N)/N)) --> places a constraint

N = 0.5K --> population grows the fastest

K = carrying capacity

Life history traits

Affects organism's schedule of reproduction and survival

Factors:

Age of first reproduction, frequency of reproduction, number of offspring, amount of parental care

Semelparity

Die after first reproduction

More offspring in a single brood

Iteroparity

Breed repeatedly

Devote resources to survival to breed more

Produce fewer offspring in single reproductive event

K-selection

Life history strategy

Selection for traits that are sensitive to population density; favored at high density

Ex. large mammals, long-lived mature trees, old growth forests

r-selection

Life history strategy

Selection for traits that maximize reproductive success in uncrowded environments

Ex. rabbits, weedy species in abandoned fields

r vs K traits graph

Population regulation factors

Density-independent: birth/death rate don't change with population density

Density-dependent: birth/death rate change with population density

Density-dependent regulation mechanisms

Competition resources, territoriality, disease, intrinsic factors, toxic wastes

Population cycles

Plant-herbivore cycle that influences predator-prey interaction

Metapopulations

Groups of local populations linked by immigration and emigration

Habitat fragmentation

Habitat is destroyed --> leaves behind smaller unconnected areas

Corridors

Man-made plant bridges

Promotes dispersal, migration, gene flow

Reduces inbreeding

Can be harmful

Island biogeography theory

Latitude

Species richness and diversity generally declines along an equatorial-polar gradient

Shannon diversity index

Foundation species

Dominant in terms of abundance or size

Tend to be strongest competitors --> exert control over occurrence and distribution of other species

Usually occupy low trophic levels

Provide habitat or food

Keystone species

Not usually abundant or big in size

Occupy niche that hold rest of community in place

Ecosystem engineers

Create or alter environment

Ex. beaver

Intermediate disturbance hypothesis

Moderate levels of disturbances foster greater species diversity than extremes

High disturbance --> too much stress, species can't tolerate

Low disturbance --> allow competitively dominant species to exclude less competitive species

Primary succession

Occurs after disturbance has left land devoid of nearly all life

Ex. volcanic eruption, moraine left by retreating glacier

Secondary succession

Primary succession but there was more life left

Facilitation

Early successional species modify environment to be more suitable for successive species to invade and grow

Inhibition

Early colonists make the site less suitable for both early and late successional species

Tolerance

Species neither inhibited nor facilitated by species of earlier stages