ECO FINAL

ecology

- The scientific study of interactions between organisms and the environment

- Events in the natural world are interconnected

- Not even direct connections, they may just share environmental features

- God cares about relationships!

Environmental Science

Incorporates concepts from the natural sciences (including ecology) and the social sciences and focuses on how people affect the environment and how to address environmental problems

levels of organization

- Molecule

- Cell

- Tissue

- Organ System

- Individual

- Population

- Community/ecosystem

- Landscape

Biosphere

energy and nutrients

- Energy moves through in a single direction, not recyclable

- Nutrients are continuously recycled (nutrient cycle)

methods for answering ecological questions

- Observational studies in the field

- Controlled experiments in the Laboratory

- Experiments in the field

- Quantitative Models

Solar radiation

- Is more intense near the equator, and less intense near the poles

- Winds and currents are a result of the differences in solar radiation

- The greenhouse effect help makes earth livable and warmer

Weather and Climate

- Determines where organisms can live

- Weather: Current conditions (temperature, humidity, precipitation)

- Climate: Long term (averages over decades)

Uplift

- Warm air is less dense than cold air, and it rises! Due to heating of the earth's surface

- KNOW THE HADLEY CELL DIAGRAM

Subsidence

- Air sinks when it cools and forms high pressure cells ( at about 30 degrees North and South)

- This forms major deserts

Prevailing winds and Coriolis effect

- Prevailing winds come from areas of high/low pressure (the hadley cells)

- The coriolis effect (spinning)

- North winds go right (clockwise)

- South winds go left (Counter clockwise)

- Ocean currents are driven by the winds, and modified by the coriolis effect (ocean is 2-3% of wind speed)

Heat capacity of water

- Water has a high heat capacity

- Heat capacity: the ability to absorb/store Energy without a change in temperature

- Major oceans currents are driven by surface winds and modified by the coriolis effect

- Upwelling: deep ocean water comes to the surface

Rain shadow effect

- Air mass goes up, cools off, becomes dry

- Heavy rain on the west side of the mountain range, allowing for plants to grow well. The east side gets very little rain, and the clouds pull moisture in making it arid and dry

Albedo and Evapotranspiration

- Albedo: The capacity of a land surface to reflect solar radiation. This is influenced by vegetation, soil, and topography

- Evapotranspiration: the sum of water loss through transpiration by plants and evaporation from the soil

Lake seasonal stratification

- Stratified: Warm surface water on top of colder denser water results in layers that do not mix.

- Tis determines the movements of nutrients and oxygen (that's important for organisms)

- Turnover ( complete mixing) happens during the spring and fall when temperature and density become uniform with depth

Terrestrial biomes - how classified and basic characteristics of each

- classified by the dominant vegetation

- Biomes are communities shaped by the physical environment, particularly climate, such as average temperatures and average precipitation

Tropical Rainforest

Consistent rain and temperature

Multiple levels of trees

Broad leaves on lower level pants

Epiphytes cling to tree trunks

Tropical Seasonal Rainforests

More or less tropical, due to the tilt of the earth

Forests / savannas

Influenced by fire

Deserts

Limited precipitation and plant growth year round

Desertification: the loss of plant cover and soil erosion due to long term droughts or heavy grazing

Temperate Grasslands

Good precipitation, but it can get cold (nebraska/russia)

NEEDS fire, or trees will encroach and take over

Temperate shrublands + woodlands

Fire is present again, keeps forests at bay

Shrub growth depends on fire

Deciduous forests

HOME (we live here)

Solid precipitation and fertile soil

Why is that important? Because leaves regrow every year

Temperate evergreen forests

Acidic, low nutrient soil

Severe fires

Washington state / twilight saga

Boreal forests

Lots of blue (cold)

Permafrost: soil is permanently frozen

Only a short layer of soil is available for growth

Shallow root system

Canada

Tundra

Only a few months to grow, because of the extreme cold

Solid precipitation

Often called "cold deserts"

Permafrost is present here as well

Freshwater biological zones - rivers and lakes

Streams and lakes connect terrestrial to the marine ecosystems

They transport and process chemicals along the way to the oceans

Lakes have been formed by the glacial process

Lotic

flowing water

(lazy river tube)

Lentic

nonflowing water

Riffles

fast moving water

Pools

deeper water, slower flow

Lake Food Chain

Piscivores: fish eating fish

Planktivores: fish eating plankton

Zooplankton: nonphotosynthetic tiny animals that eat algae

Phytoplankton: photosynthetic organisms restricted to the upper layer (photic zone.

Marine zones - general definition

71% of the earth

Categories by location to shoreline and ocean bottoms

Estuaries

Rivers moving to the ocean

Salinity variation (fresh to salt, salt to fresh)

Good for young fish and plants

Salt marshes

Shallow coastal wetlands

Grasses and rushes emerge from the water

Mangrove Forests

Salt-tolerant plants

Evergreen trees and shrubs

Rocky intertidal zone

Zone between the tides

Creatures Alternate between between being terrestrial and aquatic ( starfish, barnacles, etc)

Coral Reef

Warm shallow water

Kelp beds

Diverse community (lobsters, urchins, sea otters)

Pelagic zone (open Ocean)

Photic zone: Clearer, about 200m deep

Detritus falls from the photic zone for creature in the depths (angler fish)

Acclimatization

Adjusting to stress through behavior or physiology (short term, reversible)

ie different breathing rates at different elevations

Adaptation

Natural selection due to environmental stress.

The new traits enable ways to cope with stress, and are favorable among the them

the desirable traits become more frequent overtime

Temperature and plants

*

Temperature in an organism is determined by exchanges in energy with the external environment

Environmental temperature varies greatly through the biosphere

Some areas vary little, some areas vary greatly

The balance of inputs and outputs of energy determines the temperature of an organism, and whether it will increase or decrease

Enzymes function

Enzymes catalyst metabolic reactions

only stable within a certain temperature range

Denatured at high temperatures

Ectotherms and Endotherms

Ectotherm: body temp is regulated through exchanges with the environment

Endotherm: Internal heat generation

Water availability and plants

Plant cell walls allow Turgor Pressure: Water moves into a cell , the expanding cell presses against the cell wall

Waterlogged soils inhibit aerobic respiration in roots

Too much water can wilt plants

DRAW IT

Hadley Cell

Water Cycle

Rain Shadow Effect

Uplift / Subsidence

Logistic / Exponential Growth

Water availability and animals (ex/ Kangaroo rat)

Most animals are mobile and can seek out water

Kangaroo rat uses adaptations to cope with arid environment

Water is obtained from dry seeds

Eat food with high water content, like succulents

Minimize water loss by being active at night, having fewer sweat glands

Autotrophs and Heterotrophs

Autotrophs: Energy comes from sunlight (photosynthesis) or from inorganic compounds (chemosynthesis)

Heterotrophs: Energy comes from consuming organic compounds or other organisms

Photosynthesis and Chemosynthesis

Photosynthesis: sunlight provides energy to take up CO2 and synthesize organic compounds

Chemosynthesis: Energy from inorganic compounds is used to produce carbohydrates

Photosynthesis equation

6CO2 + 6H2O ------> C6H12O6 + 6O2

C3, C4, and CAM photosynthetic pathways

Plants that lack specialized biochemistry use the C3 photosynthetic pathway

C3 is the most inefficient bc it allows photorespiration (water is lost)

C4 pathway reduces photorespiration and evolved independently many times (corn, sugarcane)

CAM minimizes water loss; Stomata are open during night and closed during day (succulents, good houseplants!)

- CO2 uptake and Calvin Cycle are separated temporally

Natural selection

individuals with certain heritable traits survive and reproduce more successfully than others

Mutation

Change in DNA over long periods of time

Directional Selection

Individuals favored at one extreme

- Drought favored large beak size in medium finches

Stabilizing selection

Individuals with as intermediate phenotype are favored

- Parasitic wasps select for small gall size; while birds select large gall size

Disruptive Selection

Individuals at both phenotypic extremes are favored

- African seed crackers have two food sources, hard seeds that require big beaks, soft seeds which require small beaks

Genetic Drift (short answer)

When chance events determine which alleles are passed to the next gen.

EX: Moose and flowers

Mass extinctions and Adaptive Radiation

Following each mass extinction and increases diversity of surviving groups

Clownfish

Hierarchy system (largest fish is female, next largest in breeding male)

They are completely dependent on protection by the sea anemone.

They are easy prey outside the anemone.

Conflicts result in expulsion and death, probably without having reproduced

Hierarchy is needed to survive

Life history

A record of events relating to its growth, development, reproduction, and survival.*

Characteristics:

Age and size at sexual maturity

Amount of reproduction

Timing and reproduction

Survival and mortality rates

R-selected vs K-selected (R Selected)

R-K spectrum: spectrum of population growth, form fast to slow

R-selected end: Short life spans, rapid development, early maturation, low parental investment, high rates of reproduction

Examples are insects, invertebrates, mice, and weedy plant species

R-selected vs K-selected (K Selected)

Long-lived, develop slowly, delayed maturation, invest heavily in each offspring, and low rates of reproduction

Examples: mammals, reptiles (tortoises and crocodiles), long lived trees (oaks and maples)

Trade-offs

Organisms allocate limited energy or resources to one function at the expense of another

Examples:

More eggs, more offspring, less energy,

Big eggs, more energy, less offspring

By allocating resources to reproduction instead of growth, an individual will reproduce at a smaller size

Small individuals often produce fewer offspring than large individuals,

suggesting that allocating resources to current reproduction might decrease an individual's potential for future reproduction.

Parental investment and dispersal

Trade Off

Provisioning eggs or embryos: yolk and protective coverings for eggs, nutrient-rich endosperm in plant seeds

Parental care: invest time and energy to feed and protect offspring

Dispersal

Small offspring are suited for this

reduce competition among close relatives

Allow colonization of new areas

Allows escape from areas of high predation or disease (sea turtles)

Dormancy

State of suspended growth and development in which an organism can survive unfavorable conditions.

Smalls seeds, spores, eggs, and embryos are suited for this, as well as some larger mammals too (bears)

Distribution controls -

Abiotic features

Moisture

Temperature

pH

Sunlight

Nutrients

Distribution Controls - Biotic

Herbivores

Predators

Competitors

Parasites

pathogens

Disturbance

Events that kill or damage individuals, creating opportunities for other individuals to grow and reproduce

Example: some species only exist where there are periodic fires

Quadrats

Sampling areas of specific size, such as 1 m2

Area Based Counts

individuals in a given area or volume are counted;

Mark-recapture

(Used for mobile organisms)

A subset of individuals is captured and marked or tagged, then released.

At a later date, individuals are captured again, and the ratio of marked to unmarked individuals is used to estimate population size

Killer whales to beach erosion - Connections

Orcas eat otters (Prey Switching)

Otter population down

Otters eat urchins (now less otters)

Urchin population go up

Urchins eat kelp (now more urchins)

Kelp goes down

Kelp protects shoreline from erosion (less kelp)

Beach erosion goes up

Age structure

Proportion of the population in different age classes. Influences how fast a population will grow

Population is predicted by...

Calculate the number of individuals that survive to the next time period

Calculate the number of offspring those will produce into next time period

Density-independent factors

Effects on birth and death rates are independent of the number of individuals in the population

Weather conditions (temp and precipitation)

Catastrophes (floods hurricanes)

Density-dependent factors

Birth, death, and dispersal rates change as the density of the population changes

As density increases, birth rates often decrease

death rates increase, and dispersal (emigration) increases

all of which tend to decrease population size

Carrying capacity

Max population size that can be supported indefinitely by the environment

Logistic growth

population increases rapidly, then stabilizes at the carrying capacity

Ecological footprint

A measure of how much an individual consumes, expressed in area of land

Total area of productive ecosystem required to support a population.

Population equation

Nt+1= Nt + B +I - D - E

Nt =population size at t time

B= number of births

I = number of immigrants

D = number of deaths

E = number of emigrants

Delayed density dependence

Delays in the effect that density has on population size

Genetic drift (long definition)

Chance events influence which alleles get passed onto the next generation

Reduced genetic variation reduces ability of population to respond to environmental change

Harmful alleles can occur at high frequencies

High frequency of inbreeding

Inbreeding - mating between related individuals

Habitat fragmentation

Large tracts of habitat are converted to isolated patches, resulting in a metapopulation structure

Habitat corridors

Area of habitat connecting wildlife populations separated by human activities or structures

Resources

environmental features required for growth, survival, or reproduction that can be consumed to the point of depletion

ex. Food, water in terrestrial habitats, light, space, refuge places for mobile animals

Physical Factors (affect and define)

population growth rates but cannot be consumed or depleted

ex pH, salinity, temperature, water in marine ecosystems

Exploitation Competition

Species compete indirectly

Individuals reduce availability of a resource as it is used

This makes it less available for other

ex: Diatom experiment

Interference Competition

Species compete directly

Individuals antagonize the others

EX two predators fight over prey

EX voles aggressively exclude other voles from prime habitat locations

In sessile (immobile) species (plants), interference competition can occur through chemical warfare, growing shade over other plants, allelopathy

Resource partitioning

species using a limited resource in different ways

Competitive Reversal

Inferior competitor in a habitat becomes the superior competitor

Fires or storms scan kill one species but create opportunity for others → disturbance

EX the disease kills all elk making the deer top competitor

Character Displacement

Natural selection can influence morphology of a competing species

Phenotypes of competing species can become different over time

EX beak sizes changing from different islands on the galapagos

Lynx-Snowshoe hare cycles

As hares increases, lynx increase

Lynx increase, less hares

Less hares, less lynx

Less lynx, hares increase

Herbivore and Predator

Herbivore: eats tissues of living plants or algae.

Predator: kills and eats other organisms, referred to as prey.

Parasite

Lives in or on another organism (its host), feeding on parts of it. Usually does not kill the host. (Some parasites, like pathogens, cause disease)

Adaptations to avoid being eaten

Animals

Large size (elephants)

Rapid movement (gazelle)

Body armor (armadillo)

Warning coloration (poison dart frogs)

Crypsis: The prey is camouflaged, or resembles its background (octopus)

Mimicry: The prey resembles another organism that is toxic or very fierce (fake monarch)

Defensive circles ( oxen )

Keeping lookouts ( canadian geese)

Adaptations to avoid being eaten

Plants

Masting

(oak trees)

Compensation

Secondary compounds

Masting

produce huge numbers of seeds in some years and hardly any in other years

(oak trees)

Compensation

Removal of plant tissue stimulates new growth (Full compensation—no net loss of plant tissue)

Tough leaves

Spines

Thorns

Saw-like edges

Pernicious hairs that pierce skin

Secondary compounds

toxic chemicals to reduce herbivory

or compounds that attack attract predators

or parasitoids that will attack herbivores

Changing outcome of competition

If a predator or herbivore decreases performance of the top competitor, the inferior competitor may increase in abundance.

Example being Deer and Elk

Elk are top competitor but slower that deer

Wolves hunt elk

Absence of elk allow deer to become top competitors