BIO 001 - Ecology & Evolution

ecology

the scientific study of interactions among organisms between organisms and their environments

fundamental question: what factors determine the distribution and abundance of organisms?

population

an interacting group of conspecific (same species) species individuals

individual

individual traits determine respond to environmental factors

species

a group of organisms of the same type often defined by ability of group members to interbreed with one another, but not with members of other species

community

a set of co-occurring interacting (different) species

ecosystem

interacting systems of specific and their abiotic factors

- energy flows

- biogeochemical cycles

abiotic environmental factors

the non-living physical and chemical elements of an ecosystem that shape environments and influence living organisms such as,

temperature, sunlight, elevation, percipitation (water), soil

biotic environmental factors

the living components of an ecosystem tha shape their environment and interact with abiotic factors to sustain ecosystems.

biotic factors affect one another through processes such as predation (one organism eats another), competition (organisms compete for resources), and symbiosis (organisms living together)

physical constraints on organisms

gravity, fluid dynamics, diffusion, surface/ volume scaling, freezing and boiling points of water

evolution

changes in heritable characteristics in populations over successive generations

*individuals don’t evolve, only populations do

micro-evolution

small scale genetic changes

macro-evolution

accumulation of small scale genetic changes leading to new species

adaptaion (adoptive evolution - process)

the process of evolution by nayural selection, resulting in organisms that are well-suited to their environment

adaptation (adaptive trait - trait)

a trait that has eveolved to enhance an organisms survival/ reproduction in its environment

phylogeny

represents the evolutionary history of a group of organisms through time

*modern DNA evidence allows us to trace ancestry to infer evolutionary relationship

ecology and evolution link

1. ecology - the interactions between organisms and their environment create adaptations via natural selection

2. evolution - natural selection and evolution mold ecological interactions

rapid evolution

evolutionary and ecological processes may occur on similar time scales leading to feedbacks that can be observed directly

gravity - physical constraints

influencing organisms’ structure, size, and metabolism. requires structual supports such as skeletons in animals and lignin in plants, to counter weight

fluid dynamics - physical constraints

managing viscosity, pressure, and nutrient uptake, setting bounds for their maximum size, speed, and morphology, affecting how organisms occupy space and interact.

diffusion - physical constraints

refers to the movement of organisms, nutrients, or signals. governed by physical constraints, such as time, spatial scale, which limit the rate of movement, metabolic capacity, and the size of organisms.

surface/ volume scaling - physical constraints

as an organism increases in size, its volume grows faster than its surface area. it creaed physical limits on metabolic raes, resource acquisition, and body size

freezing and boiling points - physical constraints

it determines habitat suitability, species distribution, and ecosystem stability.

species richness

the total number of species present

species evenness

the extent to which individuals are distributed equally among species within a community *relative abunsances are similar

causes of contemporary patterns of biodiversity

1. a legacy of geological and evolutionary events

2. present-day interactions with other species and the environment

wallace’s line

when looking at Bali and Lombok, the flora (plants) and fauna (animals) are drastically different despite being so close

climate

average and annual variation in temperature and precipitation in a region over the long-term

weather

conditions in the atmosphere over a short period of time such as current conditions or individual events

the rain shadow effect

as moist air rises over mountains, it cools and drops rain, leaving the air dry as it descends and warms on the other side, often creating deserts

plasticity

phenotype variations in same genotypes

genetic

genetic variation in a species

functional groups

organizing groups by how they function

habitat

variety of different ecosystems

levels of biological diversity

plasticity, genetic, species, functional groups, habitat

classification of life

placed into hierarchial categories based on similarities based on similarities in morphology and genetics

diversity

depicted as a brancing tree based on genetic similarity

how many species are there?

approximately 2.15 million described eukaryotic species

influence of ancient events on pattern of diversity

very similar fossils are found in the land masses that were once joined in the supercontinent Pangaea

what determines climate?

1. incidient solar radiation

2. air circulation

incident solar radiation

unequal heating of Earth's surface more intensely at the equator than the poles creating a temperature gradient

air circulation

driven by this unequal heating from incidient solar redistribution, redistributes heat from the tropics to the poles through convective cells (Hadley, Ferrel, Polar), establishing global wind belts, rainfall patterns, and climate zones

biomes

world’s major communities, classified according to the predominant vegetation and characterized by adaptations of organisms to a particular climate

seasonal variation in climate

caused by Earth’s 23.5-degree axial tilt as it orbits the Sun, dictating the intensity and duration of sunlight received across different latitudes

Earth’s radiation budget

the balance between incoming energy from the Sun (mostly visible light) and outgoing energy radiated back into space (infrared and reflected light)

tundra climate

coldest of all biomes, with mean annual temperatures below freezing (-12° to -6°C) and very low precipitation (150-250 mm/ yr).

boreal forest (taiga) climate

the boreal forest experience long, severely cold winters (-20° to -5°C). annual precipitation is low to moderate (300-500 mm), largely as snow.

mountains (alpine/ montane) climate

defined by strong altitudinal gradients rather than latitude alone, compressing multiple climate and vegetation zones over short vertical distances. temperature decreases ~6°C per 1,000m gain in elevation, and precipitation patterns vary greatly with aspect and local topography

temperature deciduous forest climate

mean annual temperature range from 6°-20°C and precipitation is moderate and relatively evenly distributed throughout the year (750-1,500 mm/ yr).

temperature evergreen forest climate

occur in coastal and inladn regions where mild, moist conditions prevail year-yound. temperatures are moderate (5°-15°C anually) and precipitation is high (1,000-3,000 mm/ yr), ofen augmented by fog

temperate shrubland and woodland (mediterranean) climate

the biome is characterized by a distinctive climate of warm, dry summers (often 20°-35°C) and mild, wet winters (300-700 mm/ yr)

tropical seasonal forest/ savanna climate

tropical seasonal forests (also called tropical dry forests) occur where mean annual temperatures and high (20° - 30°C) but precipitation is strongly seasonal with a pronounced dry season of 4-6 months and total annual rainfall of 500-1,500 mm. at lower rainfall levels (roughly 300-900 mm/ yr), tropical seasonal forest frades into savanna

tropical rain forest climate

occuer within approximately 10°C of the equator where temperatures are consistently high (25° - 30°C year-round) and rainfall is abundant and relatively aseasonal (>2,00 mm/ yr, often 2,500 - 4,000 mm)

temperatate grassland climate

temperature grasslands occupy regions where precipitation (250 - 750 mm/ yr) is sufficient to support grasses but insufficient (or too seasonally variable) to support closed-canopy forests.they experience cold winters and warm to hot summers

desert climate

defined by extreme aridity, typically receiving less than 200 mm of precipitation per year, often highly unpredictable in timing and intensity. temperatures vary widely, hot deserts such as the Sahara and Sonoran average well above 30°C in summer with intense solar radiationw hile cold deserts such as the Gobi and Great Basin expereince pronounced seasonal temperature swings.

tundra vegetation

the growing season lasts only 6-10 weeks. permanenetly frozen subsoil (permafrost) prevents deep root prenetration and waterlogging created boggy surface conditions in summer. vegetation is low-growing and wind-resistant, dominated by mosses, liches, sedges, dwarf shrubs, and scattered grasses

boreal forest (taiga) vegetation

conifers dominate—particularly spruce, fir, and pine— whose needle-like leaves and conicla shape reduce desiccation and snow loading. acidic, nutrient-poor soils and slow decomposition rates mean that organic matter accumulates as a thick litter layer

mountains (alpine/ montane) vegetation

above the treeline, alpine vegetation resembles tundra: low-growing cushion plants, sedfes, and grasses adapted to thin soils, intense UC radiaion, and frequen freeze—haw cycles. below the treeline, montane forests typically grade from broadleaf species at lower elevations through mixed and then coniferous forest at higher elevations

temperate deciduous forest vegetation

the defining feature is pronounced seasonality: broad-leaved trees such as maples, beeches, and hickories shed heir leaves each autumn in response to decreasing daylength and temperature. soils are relatively fertile enriched by annual leaf litter decomposition. a well-developed vertical structure—canopy, subcanopy, shrub, herb, and ground layers—support high species diversity

temperate evergreen forest vegetation

dominant trees are large-stature confiers—coast redwood, Douglas fir, Sitka spruce—or, in the Southern Hemisphere, broad0leaves evergreens such as souther beech, these forests store extraordinary amounts of carbon in both living biomass and slowly decomposing organic matter

temperate shrubland and woodland (mediterranean) vegetation

vegetation consists of dense, drought-adapted shrubs with hard, waxy leaves—such as manzanita and chamise—as well as low-stature woodlands of drought-tolerant oaks or pines. fire is a natural and integral disturbance process; many plant species have fire-adaped traits such as thick bark, serotinuous cones, or root cwosn capable of resprouting after burning

tropical seasonal forest/ savanna vegetation

many rees are drought deciduous, shedding leaves during the dry season to reduce water loss—the opposite phenological cue from temperature deciduous species. savanna is a fire-maintained landscape with a continuous grass layer and scaers, widely spaced drought-tolerant trees such as Acacia and Baobab. unlike seasonal fores, the savanna canopy cannot close; fire and grazing by large herbivores are integral processes that keep woodly cover in check.

tropical rain forest vegetation

these biomes harbor extraordinary biodiversity—more than half of all terrestrial specoes—supported by high solar energy input and constant warmth and moisture. vegetation is structured in multiple canopy lauers. despite their lush appearance, tropical rain forest soils are ancient and highly weathered, with most nutrients locked in living biomass and rapidly recycled through decomposition

temperate grassland vegetation

dominant grasses such as big bluestem and buffalo grass in North America prairies, and feather grases (Stipa) across the Eurasian steppes. trees are largely absent except along water courses. fire and grazing by large herbivores are key processes that maintian grassland structure, and temperate grassland soils are among the most fertile on Earth, making these regions globally important for agriculture

desert vegetation

soils are thin, rocky or sandy, low in ogranic matter, and oftena ccumulate salts. desert begetation is sparse and high adapted to water scarciy; succulents (cacti, agaves) store water in tissues; many shrubs (e.g creosote bush) have deeo taproots or waxy leaves; and ephemeral annuals complete their entire life cycle rapidly following rare rain events