Biology 201 Exam 2- Evolution and Ecology

CAM photosynthesis

CAM - CrassulaceanAcid Metabolism CAM plants separate the light-dependent and light-independent parts of the photosynthetic reaction in time Open stomates at night, taking up CO2 , converting it to malic acid During the day, stomates are closed, malic acid converts back to CO2 and carbon is fixed

Moisture holding capacity

Different soils have different capacities to hold water and there are some terms that are important in understanding this concept: MHC is largely controlled by soil texture A saturated soil is at field capacity: water occupies all of the pores spaces in the soil and is held there by capillary forces Water evaporates from soil and plants extract it - when soil moisture is no longer extractable by plants it has reached its wilting point The amount of soil water between field capacity and the wilting point is the available water capacity of the soil

Small populations are susceptible to extinction

Genetic drift Inbreeding In plants, small populations have reduced visitations by pollinators = reduced seed set (if flower not abundant bee programmed not to like it as much) In animals, social structure in leks (communal mating grounds) can be disrupted Allee effect: when population density becomes low enough that otherwise healthy males and females can't find one another (spread over wide area)

C4 photosynthesis

PEP carboxylase catalyzes the reaction that fixes CO2 PEP does not interact with O2 , so it is more efficient

Temperature and photosynthesis

Plants vary in their tolerance of temperature During hot July and August days the C3 trees in NC will close their stomates to keep from losing water C4 plants can photosynthesize at higher temperatures but they don't sequester much carbon

Why don't populations always grow exponentially?

Population dynamics represent the combined outcome of many individual probabilities, including: ◦ Variations in bx and sx which we call demographic stochasticity- loss of heterozygosity, genetic drift ◦ Variations in environmental conditions, we call environmental stochasticity- environment good for 1 b and s may be bad for another

Carrying capacity

Populations can't grow exponentially forever because of various forms of stochasticity All populations have a maximum sustainable population size, which we call carrying capacity (K) ◦ For a population whose size is stabilized at K, births will equal deaths (r = 0) Carrying capacity imposes constraints on population growth K can be used to modify the exponential growth model ◦ dN/dt = rN (K-N/K) The resulting curve is S-shaped

Demographic transition

The Demographic Transition Model suggests that a regional human population can exist in one of 2 configurations ◦ Zero population growth = high birth rates - high death rates ◦ Zero population growth = low birth rates - low death rates The movement from the first toward the second state is called the demographic transition

C3 photosynthesis

The enzyme rubisco catalyzes the reaction that fixes CO2 Rubisco is inefficient because it also captures O2 This eventually results in the loss of CO2

Features of populations

Unitary vs. modular growth habits of individuals Distribution: geographic range Abundance: density of individuals per unit area Populations can be sampled Age structures Sex ratios Individuals move (disperse) within the range of the population Populations change in time and space all discussed below

G. Evelyn Hutchinson and N-dimensional hypervolume

"N" is the number of biotic/abiotic factors that influence the survivorship and reproductive success of the species An organism requires an infinite number of factors or "dimensions" in order to thrive

Endosymbiosis

"internal" symbiosis — one organism taking up permanent residence inside another and eventually evolving into a single organism -Separate prokaryotic cells joined together in a symbiotic union (endosymbiosis) -a free-living bacterium was engulfed by another cell, perhaps as a meal, and ended up staying as a sort of permanent houseguest - the mitochondria and chloroplasts are a product of this (mitochondria from alpha proteobacteria and chloroplasts from cyanobacteria) -the host cell profited from the chemical energy the mitochondrion produced, and the mitochondrion benefited from the protected, nutrient-rich environment surrounding it.

Important dates to know:

4.6 billion years ago- origin of earth 3.5 billion years ago- oldest fossils of cells (prokaryotes) 65.5 million years ago- extinction of dinosaurs 542 million years ago- cambrian explosion *ALSO NEED TO KNOW ORDER OF DIFF EVENTS**

Cambrian explosion (542 million years ago)

A burst of evolutionary origins when most of the major body plans of animals appeared in a relatively brief time in geologic history; (before this there was gradual, slow change) - "sudden" appearance of fossils resembling modern phyla in the Cambrian period (535 to 525 mya) --some extant phyla already existed (sponges, molluscs, cnidarians) --Animals evolving in this period, known from the Burgess Shale (fossil-bearing deposit exposed in the Canadian Rockies), are mostly bilaterally symmetric --Earlier animals, known as the *Ediacaran fauna*, were simpler and mostly radially symmetric This era provides the first evidence of predator-prey interactions: e.g. the appearance of features for capturing prey (claws), and avoiding becoming prey (body armor, spines)

Niche theory

A niche is the range of some number of environmental conditions to which an organism is adapted *Joseph Grinnell* said it was the place an organism lives *Charles Elton* said it was the "role the organism plays" *Prof says he will open a restaurant called "grinnell's place" and serve "elton rolls"* Really its both G. Evelyn Hutchinson defined a niche as an N-dimensional hypervolume

Cohorts (age classes)

All individuals in a particular age group represent a *cohort* -for long-lived animals in a particular age group, the cohort can be a 5 or year age class or generation (we are generation Y) *These age classes are denoted by x*

Genetic diversity among apes

All modern humans are very closely related to eachother - However, there is more diversity in groups within africa than those outside africa -this supports the idea that the differences have arisen rather recently Modern humans are less genetically diverse than any other group of apes

Population growth

All populations have the potential to grow exponentially - As we have seen, population growth is a function of the difference between birth and death rates - To develop an exponential growth model we can say that b - d = r As long as r is positive (more births than deaths) the population can grow exponentially - Then the change in population size over time (dN/dt) = rN

Character displacement

An evolutionary shift in behavior or physiology/morphology that results in niche partitioning e.g. Dar baby's fave Finches When each finch species existed on separate islands (allopatry) their range beak sizes was very similar - the ranges overlap When both exist on the same island (sympatry) their beak depth ranges diverge --> one species selects for large beaks while the other selects for small beak so they don't have to compete for food Two modes of speciation: -allopatric: geographic separation of populations restricts gene flow -sympatric: two or more species evolve within geographically overlapping populations

Lynn Margulis

An evolutionist who created the endosymbiotic theory -married to Carl Sagan -wrote "Microcosmos" along with her daughter

Obligate anaerobe

An organism that can only survive in the absence of oxygen (anaerobic metabolism); oxygen is toxic to obligate anaerobes.

Autotroph

An organism that is able to form nutritional organic substances from simple inorganic substances such as carbon dioxide.

Facultative anaerobe

An organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation or anaerobic respiration if oxygen is absent

Obligate aerobe

An organism that requires oxygen to survive (aerobic metabolism only)

*Bergmann's rule and allen's rule*

Animals in colder climates have a large body mass and shorter limbs to produce heat (less SA) vs. *Allen's rule*- In a hot climate you want more surface area to less mass e.g. imagine a 1 by 1 cube - the surface area is 6 feet squared -the volume is 1 foot cubed now imagine a 2 by 2 cube -the surface area is now 24 feet squared -the volume is now 8 feet cubed Increasing body size will always result in a greater increase in volume (8x the volume here) than in surface area because volume is cubed -explains why cold climate animals are bigger

Donald Johanson - "Lucy"

Anthropologist who found bones that were 3 million years old and named his find Lucy; she was small and had walked on 2 legs and erect but was small brained Example of mosaic evolution

Hominoids

Any of a superfamily (Hominoidea) of primates including recent hominids, gibbons, and pongids together with extinct ancestral and related forms (as of the genera Proconsul and Dryopithecus) which term is not to be confused with hominids, the family of great apes; or with the hominins, the tribe of humans also known as the human clade; or with other very similar terms of primate taxa the gibbons, or lesser apes; and the hominids, or great apes.

apes vs. monkeys (CLEARING THIS UP BECAUSE I AM WAYY OVERTHINKING THIS)

Apes and monkeys are two kinds of animals under the classification of primate humans are apes! Humans are part of the category "Great Apes". The Great Apes have characteristics that set them apart from other apes and primates: The Great Apes are able to use tools, and use language. Their social lives are complex and they are able to solve problems Who? The great apes include orangutans, chimpanzees, orangutans, gorillas, humans and bonobos (shown below in order) - These great apes are included under the family Hominidae. WE ARE APES CHIMPS ARE APES

Environmental constraints in aquatic environments

Aquatic environments generally: -Can be oxygen poor -have sharp vertical stratification of light -Far less variation in temperature -Gravity not an issue (buoyancy) but water imposes drag on organisms -Organisms don't rely on soil/benthos Marine -Plenty of water, isotonic to cell solute concentrations -same concentration of solutes outside the cell as inside the cell -External fertilization: much gamete "flinging" Freshwater -Plenty of water; too much - hypotonic relative to cell --lower concentration of solutes outside the cell than inside the cell -Directional movement of water calls for internal fertilization or coordination during mating

Intertidal zones

Area between low and high tide Can be rocky or sandy Animals have adaptations to prevent drying out *Joseph Connell*- chthalamus vs. banalus *Robert Paine* - pisaster

Biodiversity (TEST QUESTION)

Biodiversity refers to the variety of species found in a particular area TEST QUESTION; what are the two components of biodiversity according to ecologists? ◦ *Species richness*: the # of species -# species per unit area eg. # species in a tropical rainforest ◦ *Evenness* - the proportion/distribution of each species within the community - evenness and dominance are inversely related The shannon index is used to measure diversity

Aquatic biomes

Biomes of water with similar depths e.g. in open ocean or near shore Marine biomes- -salt concentration of about 30% -approximately 75% of earth's surface Freshwater biomes- - salt concentration<1% - closely linked to the soils and biotic components of the terrestrial biomes through which they pass -- if terrestrial systems are healthy, water should be clean (humans have big impact) List of aquatic biomes: -lakes -rivers -estuaries -intertidal zones -coral reefs -oceanic pelagic -abyssal zones (below oceanic pelagic) *COME BACK TO FLASHINESS OF CREEKS pg 4*

Bilateral symmetry

Body plan in which a single imaginary line can divide the body into left and right sides that are mirror images of one another

Radial symmetry

Body plan in which any number of imaginary planes drawn through the center of the body could divide it into equal halves

Boreal forest

Boreal forest biomes are found on high mountains because of the cooling effect with increased elevation: adiabatic lapse rate High elevation areas in S appalachians are a boreal forest biome -Smoky mountains in W. N. Carolina and E. Tennessee

epicormic bud

Bud that lies under the bark of stem or root of a plant, that are able to sprout and grow after damage to the plant, eg. outer fire.

4 main elements

C, H, O, N make up 95-96% of living things

GF Gause and competitive exclusion

Gause came up with this principle Connell-boy just used it GF Gause was a Russian ecologist -he proposed that when the niches of two species overlapped they would not coexist - one would competitively exclude the other -This is *interspecific competition*- competition between species Gause used two Paramecium species (P. aurelia and P. caudata) to test his hypothesis If this is so, then why are there so many species in any one place? WELL.. Limiting similarity, resource partitioning, and character displacement allow them to coexist Do read on...

Geographic ranges of Generalists vs. specialists

Generalists will have larger ranges than specialists Specialists are often endemic -have small geographic ranges with relatively little variation in environmental conditions -distributions look like little islands

Stratification of soil

Generalized soil profile: The O horizon is primarily decomposing organic material The A horizon is a mixture of organic materials leached from above and inorganic minerals The B horizon is principally inorganic minerals The C horizon contains lumps of unweathered rock

Photosynthesis and global warming

Given what you know about photosynthetic mechanisms, which plants would likely benefit from a warmer, more CO2 rich atmosphere? C4 and CAM plants are grasses, some shrubs, and desert plants - they don't sequester lots of carbon C3 plants are most shrubs and trees - Because the inefficiency of rubisco has to do with the concentration of CO2 in the atmosphere these plants should grow better in a warmer, more CO2 -rich atmosphere But do they?

Global climate patterns

Global climate is driven by differences in the intensity of the sun as it strikes the earth- this causes differences in heating at different latitudes (NC is 35 degrees N of the equator) What does warm air do? RISES Which holds more water? Warm or cold air? WARM AIR *Greenhouse effect* is responsible for warming *Seasonal temperature changes* are due to the tilt of the earth as it orbits the sun *The coriolis effect* is responsible for air circulation patterns

Invasive plant species

If they are capable of establishing themselves outside of cultivation (TLC), we consider them "invasive"

Tropical forests

Lots of rainfall, great variety of plants and animals Has complex vertical stratification resulting in variation of sunlight and moisture. -all forests have this - most biomass and biodiversity is in the canopy because that is where the sunlight is - in tropical forests we would recognize the importance of lianas or vines which are part of the herb layer Nutrient poor soils (*slash and burn agriculture*) -Rapid decomposition and *tight nutrient cycling* Little variation in temperature or precipitation

Marhes vs. Swamps

Marshes- are wetlands dominated by herbaceous vegetation - no woody trees Swamps- are forested wetlands -area that is covered by water is predominantly inhabited by woody trees

Movement within populations

Migration/gene flow - Emigrants move out of a population - Immigrants move into a population -The movement of individuals within or between populations is called dispersal e.g. The dispersing unit of a plant is called a "propagule

Monoecious vs. Diecious plants

Monoecious plants- have both male and female flowers on the same plant -can pollinate itself Diecious plants - plant is either male or female and only has one set of sex organs e.g. american holly- only females have berries e.g. ginko trees- females have stinky fruits!

Steven J. Gould- Mosaic evolution

Mosaic evolution- A pattern of evolution in which the rate of evolution in one functional system varies from that in other systems - the emergence of characteristics at different times - e.g. our pedigree has ancestors who walked upright but had brains much developed than ours (LUCY) Term is coined by Steven J Gould who also coined *punctuated equilibrium*

Regional climate patterns

Mountains and large water bodies create weather patterns Mountains: -Windward side of mountains- air rises and cools releasing moisture and snow -Leeward side of mountains- air descends and warms and picks up moisture which results in little rainfall -creates a rain shadow

Temperate deciduous forests

NC is deciduous forest! Dense stands of trees Cold winters and hot summers Deciduousness -shedding foliage at the end of the growing season -an adaptation to seasonally low resources -top layer of soil freezes during the winter Most diversity on forest floor -wintergreen plants!- green all winter long (perrenial) -no canopy cover during winter :) -->all leaves get sunlight -more dormant during winter weather -flower in late july e.g. crane-fly orchids! Good, productive soils -not as good as prairies -layer of decaying leaves and twigs on topsoil -takes 1500 years to replace topsoil with more decaying leaves and twigs

Spencer wells

National geographic genographic project Spencer wells is PI of project -takes cheek swabs and looks for SNIPS unique to particular groups -follows a migration Genetic odyssey, pandora's seed 23 and me is similar company

El Nino

Normal trade winds move from east to west El nino happens when these trade winds are weak -warmer waters in the pacific -America gets wetter winters -dryer in autralia and asia -economic repurcussions

Modern Human genetic bottleneck

Occurred between 50,000-100,000 ya -before modern humans left africa -genetic evidence points to 70,000 ya Human population was reduced to around 3,000-10,000 individuals Reason that human populations so genetically similar

Eutrification of lakes

Over time, lakes get filled by sediment Lakes that were once deep and nutrient poor become shallow and nutrient rich --> Oligotrophic becomes Eutrophic ---> Eutrification!!!!!!

RNA world hypothesis

Primordial life was an RNA based system -RNA was the first genetic material (simpler molecule, 1-stranded) -theory by *Carl Woese* Evidence: -RNA is autocatalytic -RNA is involved in replication and metabolism -RNA constitutes the frame of ribosomes - the oldest and most highly conserved information-processing machinery in the cell -Ribonucleside triphosphates (ATP and GTP) are involved in almost all cell processes Picture: Phylogeny of all living things based on the nucleotide sequences of small subunit rRNAs -work is by *Carl Woese* -told us we had 3 domains: bacteria, eukarya and archaea (indroduced archaea- more closely related to eukarya than bacteria) -came up with RNA world hypothesis

Transformation

Process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria (by the uptake and incorporation of exogenous DNA) e.g. non-pathogenic pneumonia becomes pathogenic in the presence of a pathogenic gene

*Protobionts* - Formation of a proto-cell, protecting polymers from the environment (3)

Protobionts are groups of abiotically produced molecules surrounded by a membrane or membrane-like structure -exhibit simple reproduction and metabolism -maintain an internal chemical environment Experiments demonstrate that protobionts could have formed spontaneously from abiotically produced organic compounds -e.g. small membrane-bounded droplets called liposomes can form when lipids or other organic molecules are added to water --Liposomes are capable of simple reproduction and, if certain enzymes (phosphatase and amylase) are added, simple metabolic reactions. A protobiont with *ribozymes* could grow, split, and pass RNA to its daughters *Craig venter* - took prokaryote and put synthetic genome in it; it worked, first artificial prokaryote kind of

Ribozymes (Self-Replicating RNA) - Cells and polymers must be self-replicating (4)

RNA molecules that can catalyze many different reactions; *self-replicating RNA* --Ribozymes can make complementary copies of short stretches of their own sequence or other short pieces of RNA --A protobiont with ribozymes could grow, split, and pass RNA to its daughters In 2009 Canadian researchers found that ribosomes could self-assemble via basic chemical principles

Reid's paradox of rapid plant migration

Reid was confused by the fact that plants with large seeds were able to travel far distances rather quickly -he knew they weren't able to be carried by the wind so how did they travel? -he assumed that birds carried them

Robert Paine- pisaster ocraceous

Sea stars (pisaster) are predators -in areas where sea stars were excluded tehre was a huge reduction in the diversity of the prey -Counter-intuitive...why?? dominant prey species out-competed all other prey species -predator keeps the dominant prey from "winning"

Temperate grasslands

Seasonal drought- dry and wet periods Rich soils- -prairies -mideast is temperate grassland -productive agricultural areas Too dry for trees, too wet to be desert Fire is important!

Serotiny

Seeds have to burn in order to germinate e.g. NC pinecones have serotinous cones

Excurrent tree form

Shaped like a christmas tree :) -limber branches can handle the weight of snow

Decurrent tree form

Shaped like a round blob -good for where there isn't a lot of snow -most of the trees on campus

Chaparral

Shrublands characterized by mild wet winters and dry hot summers - Mediterranean climate -LA is a chaparral ! Dense spiny, evergreen shrubs (schlerophylly) Periodic fire: adaptations to fire include serotiny (fire enhances germination) - its supposed to burn every 5-10 years -historically by lightning strikes -leaves have waxy coverings so when they burn it burns really really hot and is hard to put out -bad for S. california :(

Synthesis of biological polymers (2)

Small organic molecules polymerize spontaneously when they are concentrated on hot sand, clay, or rock -this is the energy required for the polymerization reaction -if Zinc is present, it enhances polymerization! (longer chains) -These polymers could then have acted as catalysts for other biological reactions

Microclimate

Small-scale climates in which organisms live Small scale variations in light, heat, moisture, and air circulation can be due to things like aspect (the compass direction a slope faces) and exposure

Soil texture

Soil texture is the proportion of different sized particles in the soil, specifically the relative amounts of sand, silt and clay You can have soil texture analyzed in a lab these days but the old-timers used to just grab some soil, spit into it, and rub it between their fingers

Ecosystem service

Something that a healthy ecosystem provides that is beneficial to humans e.g. aquifers

Niche space

Species do not always occupy their entire niche why not? -competition -no easy way for them to get there (dispersal limitation) -etc

Specialist species

Species that need specific requirements and occur in habitats with a relatively narrow range of environmental conditions -have a narrow niche -endemic species are specialists

Generalist species

Species that seem to occur in many different habitats under a wide range of environmental conditions -have a broad niche (wide ecological amplitude) e.g. humans, cockroaches

Joseph Connell - Chthalamus vs. Banalus

Studied interactions between 2 barnacle species Chthalamus vs. banalus- AN EPIC BARNACLE BATTLE -both lived on the rocks... but banalus hated being dry so he wanted to live on the lower wetter parts of the rock #locationlocationlocation -Banalus was a BIG BADDASS BULLY BARNACLE and took all the prime real estate for himself -Chthalamus was a HUGE PUSSY and allowed himself to be competitively excluded to the top drier parts of the rock ugh even though he could live on the lower rocks is he wasn't such a weak bitch Therefore, Banalus's realized niche is equal to its fundamental niche- it does grow everywhere it can grow BUT Cthalamus's realized niche is smaller than its fundamental niche because it's only allowed to grow where it isn't competitively excluded by Balanus

Carbon dioxide and photosynthesis

Studies show that C4 plants have small (and nonsignificant) changes in productivity Loblolly pines (Pinus taeda), C3 plants, such as those at the Duke Forest FACE site (see right), had increased productivity...for a while What happened?

Conjugation

The direct transfer of DNA between two cells that are temporarily joined via a cytoplasmic bridge

Soil orders result from soil forming processes

The dominant soil forming process in NC is laterization: occurs in humid, rainy regions where water movement through the soil leaches nutrients that are not taken up by plants These are old, weathered soils This produces ultisols, our dominant soil order in the Piedmont of NC To the right is a soil profile of an ultisol There are 13 soil orders in the U.S

Human population growth

The human population has been growing exponentially for three centuries The human population increased slowly until about 1650 when the Plague took 34 million lives (originally thought to be due to swamp vapors) ◦ Ever since, human numbers have increased rapidly Graph is from 2000 was 6 bill people now 7.5 bill -9 bill in 2050

Dispersal

The movement of individuals within or between populations e.g. The dispersing unit of a plant is called a "propagule Animals are motile, but how do plants disperse? - Wind, water, animals all carry plant propagules -Some animal dispersal is passive but sometimes plants "manipulate" animals Eliaosomes: fleshy fat-and protein-rich structures on seeds ▪ "Designed" for ant dispersal Humans are excellent dispersers -"The botany of desire" by Michael Pollan? --Non-indigenous species are those that humans have either intentionally or accidentally dispersed to new habitats -If they are capable of establishing themselves outside of cultivation, we consider them "invasive"

Sex ratios

The on-going success of any population of sexually reproductive organisms is most heavily dependent on the number of reproductive females -Sex ratios at birth can change throughout the lifetime of the individuals in any cohort Males usually die out quicker

Transduction

The process of transferring genetic material from one cell to another by a plasmid or bacteriophage -viral mediator

Adiabatic lapse rate

The rate at which air cools as it rises (it DOES always cool as it rises)

Reproductive rates

The reproductive output of females by females -A more accurate way of determining birth rate is to estimate births of female offspring per female, specifically those who have reached reproductive age

Paleoanthropology

The study of human origins and evolution -Paleoanthropologists have found fossils of 20 species of extinct hominoids that are more closely related to humans than to chimpanzees ◦ These species are known as hominins ("hominid" is an older term that means the same thing)

African Replacement model

Theory argues for the African origins of modern humans, who left Africa in waves of migration which populated the world, replacing older human species - all MODERN humans evolved in africa - Replaced earlier humans in Asia and Europe as they left Africa approx. 50,000 ya - some even returned to africa -Human migration was not linear - our ancestors left africa in multiple different rounds -one batch would leave and migrate elsewhere, then another to a different lands--> leading to the various migration patterns we have -*Africa has the greatest genetic diversity on Earth* -different groups in different migration patterns evolved different characteristics at different times and then some migrated elsewhere but some stayed in Africa -those who migrated elsewhere were small groups at first that were all genetically similar--> greater genetic similarities now -a lot of different groups stayed in africa--> more diverse genetic differences

Limiting similarity

There is a maximum level of niche overlap between 2 species that allows them to coexist In any situation in which resources are too available, species will increase their niche space in order to utilize those resources - expand to their fundamental niche If resources are limiting then competition will force those species back to their realized niche or the parts of the niche where they're most competitive

Origin of Modern Humans

There is still much debate about which fossil species is the direct ancestor of the modern Humans - Homo erectus and Homo Ergaster left Africa around 2 mya and became neantherthals in Europe and the peking man/java man in Asia Most anthropologists agree that the Homo Sapiens evolved in Africa from Homo erectus/ergaster ancestors about 160,000 ya

Distribution of an invasive plant at multiple scales

This is the distribution of Japanese stilt grass (Microstegium vimineum) in the United States (top) and in Battle Park (bottom) -Like a number of noxious invasive plants, Japanese stilt grass is a successful and aggressive invader in specific types of habitats -In Battle Park it is possible to find places where it and two other invasive plants - Japanese honeysuckle (Lonicera japonica) and Chinese privet (Ligustrum sinense) - are almost completely dominant -very invasive and hard to control - does better in moist areas

Tundra

Tundra: low growing plants Adaptations for cold, very short growing season, little precipitation -very thin layer of soil, ice melts to water in short summer months -permafrost- permanently frozen soil with lots of organic material preserved; as it melts it will decay and produce CO2 and methane increasing the speed of climate change Two types of tundra: Arctic: found in very high latitude polar areas (primarily in the north) Alpine: found on very high mountaintops above the tree line -Adiabatic lapse rate again!

Uniform (or regular) distribution

Uniform distributions are usually the result of some repulsion amongst individuals within the population Reasons for this: -Competition -territoriality- animals have territories -parasite loads- Black cherry trees are evenly spaced because parasites attack their seedlings when they start to grow

Abyssal zone communities

Very deep communities lie here greater than 2000 m deep -organisms are adapted to continuous cold and perpetual dark and high pressure -deep sea hydrothermal vents are found here -have elemental nutrients coming out of them

Biomes

Very large areas that are defined by similarities in their vegetation Temperature and precipitation determine the distribution of biomes -aka the locations of biomes are caused by global and regional-scale climate patterns

The shannon index

WIll have to calculate on test -most commonly used measure of diversity -other indices exist but they tend to only measure dominance/evenness -the shannon index is great because it takes abundances into account -unitless, good for comparison equation: H= the negative sum of psubi x ln (psubi) psubi is always less than 1 ln of anything less than 1 is negative --> must multiply by -1 to make it positive!! DON'T FORGET TO MAKE IT POSITIVE HOW TO CALCULATE -set up a chart listing each species and total at the bottom -in column N write the number of each species -find psubi by taking the # of each species and dividing it by the total number -multiply psubi by ln psubi -->add all of the results together -MULTIPLY BY -1 TO MAKE POSITIVE!!!!

Resource partitioning

aka niche partitioning aka niche shift Competing species utilize parts of the habitat in which they are most competitive e.g. lizards that have long legs and tails for jumping would be able to live up in the trees successfully and jump around -short squat lizards are more competitive on the ground

Wetlands

areas that are covered with water (shallowish) -e.g. swamps, marshes, estuaries, lakes, lagoons, ponds, coral reefs Freshwater wetlands (marshes, swamps) Provides *ecosystem services* -purification effect, pollutants sink to bottom -great place for aquifer recharge- water sinks under the ground to aquifer -->subterranean lakes that provide good drinking water for humans -->pump from a well have to filter for sediments -no need to clean for because soil microorganisms consume all other pollutants

Law of the minimum- *Liebig*

growth controlled not by total # of resources but by the scarcest resource

Distributions of populations

the distribution of a population is the area over which it occurs or its *Geographical range* The most important factors influencing the geographic ranges of an organism are usually abiotic, temperature and precipitation e.g. american chestnut trees used to have a range all over the NE but was affected by a blight (asian fungus) -wiped out all of the trees in this area (4 bill trees!!) -all american chestnuts are functionally extinct now :( Organisms will not be found everywhere within their range -Local and microclimate effects and interactions with other species will influence distribution at various scales

Biogeochemistry

the science of element cycles through living (bio) and non-living (geo) systems through space and time -biology and geology influence each other during earth's long history e.g. acids produced by living things leak through soil and break up bedrock--> releases nutrietnts -chemistry is the thread through which these fields interact

What is an individual? Unitary vs. modular growth

unitary organisms - 1 individual per genotype -growth is determinate - grow to a certain size than stop (trees can be an exception to this) Modular organisms- can produce numerous individuals with the same genotype -usually plants -plants can reproduce asexually creating clones - methods of reproduction are layering, sprouting, fragmentation

What is the carrying capacity of Earth for humans? (given particular quality of life)

◦ Wide range of estimates for carrying capacity ◦ Estimates are usually based on food, but human agriculture limits assumptions on available amounts Ecological footprint ◦ Humans have multiple constraints besides food ◦ The concept an of ecological footprint uses the idea of multiple constraints 2 billion people is the max amount the earth can handle wo environmental problems

Quantifying generalist and specialist species

*Fridley et al. 2007 (Journal of Ecology)* used species cooccurrences rather than direct measurements of environmental conditions to measure generalist/specialist tendencies of trees in NC, SC, and GA Logic: species that co-occur with more other species do so because they can live in a variety of habitats and are therefore generalists ---> generalists have higher co-occurrence values than specialists -american holly is a very generalist species, not a lot of it but there's like 1 everywhere! Conversely, species that live in few habitats will co-occur with few other species and are therefore specialists

Marine zonation (ocean!)

*Intertidal zone*- land meets water; area between high and low tide *Neritic zone*- shallow regions over continental shelf *Oceanic zone*- area past the continental shelf (akin to limnetic zone) *Pelagic zone*- open water *Abyssal zone*- very deep deep ocean communities - near hydrothermal vents

Zonation in freshwater biomes (ponds and lakes)

*Littoral zone*- shallow, close to shore -aquatic plants *Limnetic zone*- open surface water *Profundal zone (aphotic zone)*- deep aphotic regions -between the photic zone and the benthic zone (bottom)

Synthesis of organic molecules (1)

*Oparin and Haldane hypothesis* -Early Earth had a reducing atmosphere with water vapor and chemicals released by volcanic eruptions (N, H, CO2, methane, ammonia, hydrogen sulfide) -"reducing" means non-oxidizing, there was no O2 to oxidize/pull apart energy rich monomers *Miller and Urey experiments* -Took the Oparin-Haldane hypothesis and added an energy source (electricity) to their version of early atmosphere and found that it was possible to make amino acids -Other researchers have duplicated this experiment and also manufactured nucleotides and sugars Also possible that a meteorite (a.k.a. carbonaceous chondrite) could've brought the first amino acids to earth

Environmental constraints in terrestrial environments

- Plenty of oxygen - Adaptations to deal with gravity - Less sharp vertical stratification of light - Leaf-area index (LAI) and sunflecks - Big issue is resistance to desiccation (maintain water balance) - Internal respiratory organs - Internal fertilization - Integument that maintains internal environment - All terrestrial life depends on soil

Uniquely human synapomorphies(traits)

-Bipedal locomotion -very large brains -manufacture and use of complex tools (many animals can use tools but not manipulate) -use of language

Soil forming factors

-Climate influences both mechanical and chemical weathering - Organisms release acids that are involved in chemical breakup of bedrock, roots can mechanically fracture rock - Relief affects the rate of water runoff - Parent material can be igneous, metamorphic, or sedimentary - All of this happens over varying lengths of time

Synapomorphies (shared dervived traits) of hominoids (apes)

-Large brains -Absence of a tail (almost always!) -More erect posture - Greater flexibility of the hips, ankles, wrist, thumb, and shoulder -Certain molecular homologies

What characterizes a living thing?

-Made of cells -has ability to reproduce -has ability to grow -has ability to evolve -must take in energy, use it and convert it -all living things possess a genotype and a phenotype

Populations change in time and space (they are dynamic)

-Migration and environmental change can alter population abundance and density -The primary factors driving changes in populations are demographic processes

Synapomorphies

-derived characteristics shared by all members of the clade -common homologous features -an evolutionary novelty unique to a particular clade

Hominins (aka Hominids)

-species of extinct hominoids that are more closely related to humans than to chimpanzees -directly within human ancestry -These species are known as hominins ("hominid" is an older term that means the same thing) Another hominin was identified: Homo Floreneses -short - 3 ft. -hobbit poeple- died 12000 ya - Neanderthal can not mate properly w modern human women bc of molecular setbacks

Steps in the formation of the first living thing (KNOW THESE FOR TEST)

1) Abiotic synthesis (not synthesized by living things) of small, organic, information-containing molecules e.g. amino acids, nucleotides 2) Organic molecules form biological polymers -amino acids--> proteins 3) Formation of a proto-cell, protecting polymers from the environment -the inside of the cell must be different than the outside 4) Cells and polymers must be self-replicating

Sources of Confusion about human evolution

1) our ancestors were NOT chimpanzees or other MODERN apes - chimps and humans represent 2 divergent branches of the hominoid tree that evolved from a common ancestor that was neither a chimp or a human 2) Human evolution did NOT occur as a series of steps leading directly from an ancestral hominid - many splinter groups went extinct and several different human species coexisted with diversity increasing rapidly 2-4 mya - human phylogeny is a multi-branched bush with our species as the tip of the only surviving twig 3) the various human characteristics such as upright posture and enlarged brain did NOT evolve in unison - Different features evolved at different times at different rates called *mosaic evolution* (coined by Steven J. Gould) - e.g. our pedigree has ancestors who walked upright but had brains much developed than ours 4) humans are NOT more evolved than current chimps/apes -we just evolved differently

The coriolis effect

A phenomenon that causes fluids like water and air to curve as they travel across/above earth's surface -Earth is constantly spinning on its axis from west to east -but earth is a sphere and wider in the middle, so points around the equator are spinning faster than points near the poles *Air is always deflected to the right in the Northern hemisphere and to the left in the southern* e.g. throw a paper airplane north from texas to nebraska but texas moving around axis faster than nebraska because closer to equator -so paper airplane moving faster too -SO paper airplane would appear to have a curved path to the right (and vice versa; In southern hemisphere, object travels from eq. to south would be deflected to the left) It is the reasons that storms spin (counter-clockwise in the Northern hemisphere and Clockwise in the southern hemisphere) WHY? At the center of a storm is an area of low pressure (eye) -high pressure air surrounding it rushes toward the low center but keeps getting deflected toward the right (Northern hemisphere) - causes the storm to spin toward the right --> counter-clockwise motion

Lateral gene transfer

A process in which organisms that reproduce asexually pass genes from one individual to another, or even from individuals of one species to another -Microbes exchange genetic material much more freely than do "higher" organisms -They do this via formation of symbioses (endosymbiosis and secondary endosymbiosis) -Bacteria also share genes across species via: transformation, transduction ◦ And within species via conjugation

Life tables LEARN THE SIGNIFICANCE OF ALL PARTS OF THE LIFE TABLE *QS ON TEST*

A schedule of age specific mortality and survivorship for individuals in a population *X*- denotes each age class *Nx* - represents the number of individuals alive at the beginning of that time period *Ix* - the probability of surviving to any age - found by dividing the number alive at Nx by N0 *Dx*- the number of individuals who died during that time period - found by subtracting the number of individuals alive from one time period from the time period before it *Qx*- the age specific mortality rate -Qx= Dx/Nx *Lx*- the average number of individuals alive at any age interval x -Lx = (nx + nx+1)/2 *Tx*- the total future years lived by all individuals of age class x in a population -sum of all Lx column below a certain age class *Ex* - life expectancy; of the number of future years lived by each age class divided by the number of individuals living at the beginning of that age class -so if you make it to age 1, you add Ex value (1.7) to 1, so you would live 2.7 years

Population abundance

Abundance refers to the number of individuals within a population

Age structures in populations

Age structures provide information on the number of proportion of individuals in different age classes -These classes are often best defined by reproductive status: -pre-reproductive -reproductive -post-reproductive Age structure requires the ability to estimate age: -In animals adults (reproductive members of the population) often have different features than juveniles (pre-reproductive) -In trees, diameter can be used as a proxy for age -Or, trees can be cored using an increment borer and their rings can be counted. As seen in picture, the age structures can determine how much the population is growing Kenya is undergoing rapid growth while the US is growing slowly and Italy isn't growing at all Why did they growth slow? female education -economics counts on population growth to keep the system going...

Coriolis effect on wind patterns

Air wants to move from high to lower pressure systems HOTTER AIR IS LOWER PRESSURE (expands and becomes less dense) COLDER AIR IS HIGHER PRESSURE -since earth is rotation, the path of the air will curve to the right as it moves instead of moving straight from high to low (NORTHERN HEM) -curve happens as if you are facing from the perspective/direction that the wind is facing/blowing Sets up certain patterns of wind (wind belts) on the earth -equator is lower pressure area, so wind between 30 degrees N of equator and equator will curve toward the right TOWARDS equator (from NE to SW) -30 degrees is higher pressure system so wind will move away from it towards the right in the N hemisphere (FROM SW TO NE)

Convergence and divergence

Convergence and divergence roughly determine where air will be sinking or rising AIR RISES NEAR THE EQUATOR AND SINKS NEAR 30 DEGREES LATITUDE!! IT ALL MAKES SENSE!!!!!!! -Rising air is associated with clouds and precipitation (EQUATOR) Low pressure systems have a counterclockwise rotation in the Northern Hemisphere, with the wind turning slightly inward towards the lowest pressure -This causes air to converge, or come together, at the center of the rotating system near the ground -Since the converging air has nowhere else to go, it rises. As the air rises, the water vapor within cools and eventually condenses into cloud droplets and raindrops. Sinking air is associated with clear, calm conditions and good weather. -Surface high pressure systems in the Northern Hemisphere have a clockwise rotation with wind turning slightly outward away from the highest pressure -This causes air to diverge, or move away, from the center of the high pressure near the ground -Air has to come from above to fill in the void left by the diverging air at the surface - This leads to sinking motion in the center of a high pressure system and generally clear air -Convergent zone (inter-tropical convergent zone)

Tight nutrient cycling

Dead tree decomposes quickly, nutrients released by the decomposing tree are absorbed by organisms around it -very little nutrients are lost Vs. Leaky nutrient cycling -nutrients are lost to the system after decomposition -to flowing water, air, etc.

Stochastity

Density dependent "Demographic stochasticity" Negative feedback between the size of the population and the strength of environmental resistance Competition, territoriality, predation, dispersal, disease, waste accumulation, breakdown in social structure Density independent "Environmental stochasticity" Natural disasters - "disturbances" limit population size - but they don't occur because of the density of individuals in the population - no feedback Fire, flood, drought, severe weather events

Population density

Density refers to the number of individuals per unit area (usually referred to as #/ha) ha= hectare; A hectare is about 2½ acres The spatial distribution of individuals within a population can tell us something about intraspecific interactions for that species Distributions can be: - Random, uniform, clumped

Deserts

Deserts: low rainfall - can be hot or cold -30 degrees north and south latitiude -can be a rainshadow dessert on leeward side of mountains -Vegetation is sparse, includes cacti and succulents and euphorbs (less sharp) -CAM photosynthesis- don't open stomata during day to preserve water Cacti and euphorbs are not closely related but grow together in some deserts -They have evolved similar features in response to a common environmental factor: convergent evolution Adaptations to sparse water and high heat -Many animals are nocturnal (behavioral adaptation) -many animals are corpuscular- active at dawn and dusk Can you think of a morphological adaptation? - Large ears! - the ear has a lot of surface area and not much mass so its a great way to lose heat -small body size- ideal to create more surface area and less mass --> *Allen's rule*

Vertical stratification of all aquatic biomes

Divided into zones based on variations in light (some wavelengths penetrate deeper) and temperature *Photic zone* -light penetrates and photosynthesis can occur *Aphotic Zone*- little light can penetrate *Thermocline*- A narrow stratum of rapid temperature change -warm on top then gets cold very quickly *Benthic zone*- bottom of any aquatic biome, contains detritus

Dynamic/cohort life tables vs. time-specific life tables

Dynamic or cohort life tables- -require ecologists to follow all the individuals of a single cohort (age group) in a population from birth to death. Time-specific life tables- -consist of data on individuals of all ages in a population from a single point in time Make assumptions: -

Hadley Cell

Encompasses latitudes from the equator to about 30° -Hadley cells release dry air making deserts

How prokaryotes evolved into eukaryotes

Environment at the time of the oldest prokaryotes was reducing, there was not a lot of oxygen -The prokaryotes metabolic processes created oxygen in the atmosphere ---> this led to selective pressure for prokaryotes that could use Oxygen for metabolic processes (facultative anaerobes) --->separate prokaryotic cells joined together in a symbiotic union (endosymbiosis) ---> eventually evolved into mitochondria and chloroplasts of eukaryotic cells

Division of geologic record (greatest -> smallest)

Eons -> Eras (major events) -> Periods -> Epochs

Homogenocene era

Era in which human interaction with the environment has lead to the homogenizing of biological species -biodiversity is declining -"weedy" organisms are thriving and unique organisms are dying out

Fundamental Niche

Everywhere an organism COULD live in the absence of interspecific competitors (competition between diff species)

Realized Niche

Everywhere that an organism DOES live as a consequence of competitive outcomes with other species

Fecundity tables

Fecundity tables take into account age specific birth rates (bx) and survivorship (lx) The sum of the lxbx values is the net reproductive rate R0

Forest stratification

Forests often have complex vertical stratification resulting in variation of sunlight and moisture From top to bottom: -emergent - above canopy -canopy- most biomass and biodiversity is in the canopy because that is where the sunlight is -intermediate -suppressed -shrub -herb Sideways growing trees limit self shading! some trees grow in fibonacci sequences! cool!

Human evolution

Humans are descended from African Great Apes - great apes includes gorillas, chimpanzees and bonobos *Jared diamond's the third chimpanzee* characterize chimps as: 1- bonobos 2- regular chimps 3- hairless human chimps - Humans and chimps diverged from gorillas about 6.4 mya - humans diverged from chimps about 5.4 mya

Savannas

Grasslands with scattered trees -not many trees because there isnt enough rain for them -Generally warm with wet and dry seasons -Many types of plants and animals Fire is an important abiotic factor -comes from lightning -fire is an important facter in almost every ecosystem except tropical rainforests

Hans Jenny and soil formation

Hans Jenny defined soil formation in this way: S = f(Cl, O, R, P, T) That's right, it's "clorpt"! - CL = climate, soils age through weathering - O = organisms, the biota - R = relief, topography - P = parent material - the weathered rock that formed the soil - T = time

Coniferous forests

Have evergreen trees (perrenial!) Largest terrestrial biome -boreal forest is a type of coniferous forest???? - e.g. SW colorado Long cold winters and short wet summers Adapted for cold and snow: tree form and hibernation *Excurrent tree form* (like a christmas tree)

Flowing water ecosystems

Have two distinct habitats that interact: Turbulent riffles- - sites of primary production by sites of primary production by periphyton: diatoms, cyanobacteria, algae -sites of producers, grazers, and predators -organisms obtain energy through shredding, grazing, gouging, and filtering Quiet pools- -sites of decomposition of dead organic material from riffle -Decomposition restores bicarbonate to the water -recycling! w/o decomposition life as we know it is not possible Flowing water selects for bilateral symmetry -cephalization - head and tail (e.g. fish)

What is soil?

Healthy soil is a three-dimensional living thing that provides important ecosystem services: - Breaks down dead material (decomposition) - Regulates water cycle - mitigates flooding - Key part of most element cycles - sequesters carbon - Is the medium and provides nutrients for plant growth and shelters seeds

Neanderthals

Homo sapiens neanderthalensis, a European variant of Homo sapiens that died out about 25,000 ya. -Said to have very much culture -have the FOX B2 gene for language -said to have red hair

Evolution of Language use (uniquely human synapomorphies)

In 2002 geneticists found that the FOXP2 gene (gene essential for human language) experienced intense natural selection after the ancestors of humans and chimps diverged -comparisons of flanking regions of this gene suggest that most changes took place within the past 200,000 years -evolution of the FOXP2 gene may be the first genetic clue about how our own species came to be -Neanderthals also had the gene (communication)

Coral reefs

In the neritic zone -dominated by coral -highest biodiversity on earth -coral is colorful because of mutualism with dinoflagellate

Steven J. Gould (and Eldredge)- Punctuated equilibrium

In the punctuated equilibrium model, the rate of speciation is not constant -Species undergo rapid modification when they first diverge -Once established as separate species, they change little Gould and Eldredge based their theory in part on the observed "rapid" diversification in animals about 540 mya -this diversification took about 30-40 mya and is called the *cambrian explosion* -resulted in adaptive radiation

The 6th Mass extinction

It is estimated that the current rate of extinction is 100 to 1,000 times the background rate -More than 1000 species have become extinct in the last 400 years, most of these were found on islands (endemic species) What groups of organisms do you think are likely to be going extinct? -The unique, specialized species; groups that live only in a small area that humans want to develop (endemic species) -"weedy" species are becoming more prominent --->we are losing organisms that are specialized and unique and gaining more of things that are common everywhere How many species can we lose before the quality of human life is affected? -OH NO e.g. bananas; the cavandish banana is the current banana sold in stores -gross-michelle banana was the banana of the early 1900's but a fungal disease wiped it out -the Cavandish banana was resistant to the fungal disease but it isn't anymore -WE MAY LOSE BANANAS!!!!!!!! Some ecologists suggest that the current epoch should be called the "homogenocene" or "anthropocene"

The greenhouse affect

Light from the sun strikes the earth and warms it -the earth then emits radiation back towards space, some of which escapes and some of which is trapped by gases in the atmosphere -Gases such as CO2, water vapor and methane trap this radiant energy near Earth's surface -*Methane is a much more powerful gas than CO2* -Clouds also trap heat- reason why a clear night would be colder than a cloudy night

Population projection table

Like fecundity tables, these tables focus on the reproductive output of females The population size N(t) of any year is a function of the survivorship (sx) of females in each age class plus the product of the age-specific birth rates (bx) of females in each age class -as long as sx and bx are stable a population can grow exponentially Using sx and bx from the earlier table, the change in population size N(t) can be estimated The percent change in N(t) from period to period is the finite multiplication rate (lambda) -Lambda = N(t+1)/N(t) After year 5, this Population Projection Table shows squirrels them increasing at a constant rate of 20% per year It remains constant because the squirrel population has reached a stable age distribution Population growth (lambda) is a function of the age-specific survival (sx) and birth (bx) rates The constant rate of increase of the population from year to year and the stable age distribution are because of the constant survival and birth rates through time *AS LONG AS LAMBDA IS GREATER THAN 1 THE POP WILL GROW*

Oligotrophic vs. Eutrophic lakes

Oligotrophic lakes- deep and nutrient poor Eutrophic lakes- shallow and have more nutrients and plant life (EATrophic... more plants to EAT) -lots of algae can cause problems for anumals living there -can create toxins -can create oxygen starvation ---> algae need tons of oxygen and there won't be enough for the fish!

The pelagic biome

Open ocean water -the north pacific gyre aka the great pacific garbage patch -microplastic trash- plastic that looks like fish eggs, gets eaten by animals -hydrophobic toxins stick to plastic

Clumped distribution

Organisms within a population that are attacted to one another will have a clumped distribution Reasons for this: -Facilitation -protection- prey animals, e.g. schools of fish and herds of elk -patchy resources -asexual reproduction -social groups

Tool use (uniquely human synapomorphies)

Other animals use tools but only humans can make and use/manipulate complex tools -other animals use tools found on site that will do a job but they usually don't "manufacture them" -e.g. jungle book :) Stone tools date to 2.5 mya -at this point humans were bipedal but had relatively small brains -mosaic evolution!! growth in brain size did not occur at the same rate as evolution of bipedalism

Seasonal temperature changes

The angle of earth's axis (23.5 degrees) relative to the sun is responsible for seasonal variation of temperature - winter when N. Hemisphere is tilted away, etc. etc. duh

Slash and burn agriculture

People would burn trees creating ash which gives the soil enough nutrients to support crops -have to give the trees enough time to regrow before doing it again or it won't work

Photosyntesis

Photosynthesis is the capture of light energy and its conversion into chemical energy Sunlight + 6CO2 + 12H2O C6H12O6 6O2 + 6H2O It has two stages: Light-dependent: Water is split by sunlight Oxygen is released NADPH and ATP are made Light-independent Energy from NADPH and ATP are used to reduce CO2 to carbohydrate Three photosynthetic mechanisms -C3, C4, and CAM

Modular growth in plants

Plants can reproduce asexually creating clones - methods of reproduction are layering, sprouting, fragmentation 2 parts of modular plants: Genet- genetic individual (the entire group of clones) ramet- the modular individual/clone e.g. in aspen (and beech) groves there are many trees (ramets) but potentially only one genet -the lifespan of the genet is not limited to the lifespan of any one ramet Pando, a clonal colony of aspen trees is the biggest single organism on earth

Survivorship Curve

Plots Ix against age *Ix* - the probability of surviving to any age - found by dividing the number alive at Nx by N0 3 different models shown in picture blue- huge dip early on but if you make it to adulthood there is a high likelihood of reaching maximum age (red crabs) black- relatively constant mortality rate (squirrels) red- high likelihood of making it to old age but sharp dip at old age

Populations at small scales - subpopulations

Populations that range over wide geographic areas may have smaller, local subpopulations These subpopulations may or may not interact with one another directly -should try to facilitate interaction for the conservation of the species! Metapopulations are subpopulations linked by migration -a metapopulation is a large population that is not contiguous

Random distribution

Populations with random distribution patterns the location of 1 individual has no influence on any other individual -They neither attract nor repulse one another e.g. white oak tree in a forest

Primary vs. secondary endosymbiosis

Primary endosymbiosis involves the engulfment of a bacterium by another free living organism -An organism may then use that organism to its advantage -e.g. The creation of the mitochondria- an alpha proteobacteria was engulfed by another living cell *if the larger cell dies the smaller cell can survive and leave its host* Secondary endosymbiosis occurs when the product of primary endosymbiosis is itself engulfed and retained by another free living eukaryote e.g. a eukaryote will engulf an alga and use the products of its photosynthesis (become an autotrophic organism), but once the prey item dies (or is lost) the host returns to a free living state *after the cell is engulfed it becomes dependent on the larger cell. It cannot leave and return to its original state*

Survival rates

Survival rates (sx) represent the proportion of individuals that survive to the next age class sx = 1 - qx (mortality rate) Using this data, a population projection table can be constructed

ECOLOGY! Rule #1

THE ENVIRONMENT ALWAYS CHANGES -does so across space and through time e.g. climate varies geographically because of global, regional and micro-scale reasons

The Cretaceous-Tertiary mass extinction (the K-T extinction)

THE EXTINCTION OF THE DINOS! The cause of this is often attributed to an enormous asteroid striking Earth -The impact changed atmospheric and oceanic chemistry via the production of intense acid rain -Triggered massive earthquakes and set off volcanoes leading to global cooling and extensive darkness reducing primary productivity on earth -Caused an enormous tidal wave There is a theory that the dinosaurs were already suffering from intercellular parasites at this time so their numbers were already reduced when the asteroid hit. Estimated 60-80% of all species went extinct -Most large terrestrial animals were lost (dinos :( ) -Forest communities were dramatically affected -Crocodiles, alligators, turtles, and mammals were little affected

Terrestrial biomes

Terrestrial biomes are based on regional variations in climate! List of terrestrial biomes -tropical forest -savannah -desert polar and high mountain ice -chaparral - temperate grassland - temperate deciduous forest - coniferous forest - tundra (arctic and alpine)

Rachel Carson "silent spring"

We may never know Earth's carrying capacity for humans, but we have the responsibility to decide our fate and the fate of the rest of the biosphere ◦ Rachel Carson proposed using the "precautionary principle" in her book Silent Spring Look before you leap

Estuaries

Wetlands formed where rivers meet the sea - salination varies greatly (as tides flow in and out) -lots of biodiversity e.g. chesapeake bay

Climate

What is climate? Climate is a long-term description of the weather at any location, or over larger geographic areas Climate controls where and how organisms live -Organisms represent climate extremes more than they do climate averages -biomes are dependent on temperature and participation Vs. weather-short term changes; what we experience everyday as we walk outside climate varies geographically because of global, regional and micro-scale reasons! *Merchants of doubt- book by Naomi Oreskes and Erik M. Conway* -about the science behind climate change and why we shouldn't ignore it

Bipedalism (uniquely human synapomorphies)

Why did hominids become bipedal? -our anthropoid ancestors of 30-35 mya were arboreal (lived in trees) (arthropoids are humanlike primates that include monkeys and hominoids) 20 mya forests changed to savannas as the climate became drier -for decades paleontologist sthought that bipedalism was an adaptation to life on the savannah- WRONG -BUT all early hominids show indications of bipedalism but they lived in the forests and open woodlands (wet environments), not the savanna -Only 1.9 mya did hominids living in dry environments begin walking long distances on 2 legs The energetic cost of moving long distances is less for 2 legs than that of 4 legs Humans sweat to establish homeostasis (evolutionary advantage)

Circulation cells

Wind circulates in each hemisphere in three distinct cells which help transport energy and heat from the equator to the poles. The winds are driven by the energy from the sun at the surface as warm air rises and colder air sinks e.g. Hadley cell