UCD BIS 2B - MIDTERM 1

What is Ecology?

the scientific study of interactions among organisms & their environments

What are abiotic environment factors?

Non-living condition that affects an organism or ecosystem

Name some abiotic factors

Altitude, Water, Erosion, Sunlight, Wind

What are some physical laws that affect organisms?

Gravity, Fluid dynamics, Diffusion, Surface/Volume Scaling

What is a biotic environmental factor?

Any living component that affects the population of another organism or the environment

Name some biotic factors

Interspecies competition, predators, mutualistic relationships

Name the hierarchy of levels of organization, from smallest to largest (5 terms)

individuals, population, species, community, ecosystem

How is a species defined?

A group of organisms of the same type that can interbreed

Why does ecology matter?

It affects health, food supply, and the health of the ecosystem.

What is evolution?

The change in the genetic composition of a population over time

What is natural selection?

The differential survival or reproduction of individuals with different trait values within a population

What is adaptive evolution?

The process of evolution by natural selection of favorable traits

What is an adaptation?

A trait that has evolved to enhance an organism's survival/reproduction in its environment

What is descent with modification?

The passing of traits to from parents to offspring

What does a phylogenetic tree represent?

The evolutionary history of a group of organisms through time

What is a theory?

A far-reaching explanation of observed facts that is supported by such a wide body of evidence, with no significant contradictory evidence, that it is scientifically accepted as a factual framework

Why does evolution matter?

Health, food security, and climate change

What are the three types of scientific methods?

Observational, Experimental Manipulations, and Mathematical Models/Computer Simulations

What is biodiversity?

Variation among genes, causing variety of life in an ecosystem

What are the levels of diversity? (most to least)

Habitat/Ecosystem, Higher Taxa, Species, Genetic, Plasticity

What is "True Diversity"

A measure of both species richness and species evenness

What is species richness?

The # of species in a specific area

What is species evenness?

The degree to which species are equally abundant

What are some threats to biodiversity? (There are 4)

Habitat alteration and destruction, harvesting/fishing, climate change, introduced species

What does it mean when a species is Endemic to a region?

It occurs nowhere else

What are some things we need biodiversity for?

Food & Clothing, Aesthetics, Medicine, Antibiotics, and Diverse communities

What is a climate?

A measure of the average pattern of variation in temperature, precipitation, and other meteorological variables in a given region over long periods of time

What is a biome?

A major community, classified according to the predominant vegetation and characterized by adaptation of organisms to that particular climate

What is a Chaparral biome?

Temperate shrubland and woodland; hot, dry summer; cool, moist winter; dense vegetation, vulnerable summer fires

What is a Tundra biome?

A treeless biome occurring in areas with cold climates and a short growing season. Subsoil is PERMAFROST

What is a Boreal Coniferous forest biome? (Taiga)

Defined mainly by the trees, also has permafrost. Long winters, short summers. (Essentially a Tundra with trees)

What is a Temperate Deciduous Forest biome?

Forests dominated by species-rich mixtures of trees; occurs in relatively moist, temperate climates. The foliage is seasonally deciduous, because it can get cold during the winters. (Leaves shed during autumn, regrow during spring)

What is a Temperate Rainforest biome?

Characterized by mild winters and an abundance of precipitation. Too moist to support wildfires, so they develop into old-growth forests.

What biome is Davis?

Chaparral

What determines climate? (2 things)

Solar radiation that varies with season and latitude, and air circulation driven by the sun and Earth's rotation

What are the three air cells?

Polar cell, Ferrel cell, and Hadley cell

In what direction do the cells spin?

Polar and Hadley counterclockwise, Ferrel clockwise

What is the Coriolis effect?

Push something away from the equator and it will appear to pick up speed and move east. Push something towards the equator and it will appear to lose speed and move west.

Which way does the air appear to move between 0 and 30 degrees latitude?

West

Which way does the air appear to move between 30 and 60 degrees latitude?

East

Which way does the air appear to move between 60 and 90 degrees latitude?

West

What is air moving to the east called?

Westerlies

What is air moving to the west called?

Easterlies

What happens when air hits a mountain range?

The air is pushed upwards, cooling it and leading to precipitation

What is a rain shadow?

Windward side gets rain and leeward side is dry

Earth's inclination causes seasonal changes where?

In the latitude where solar input is the most intense

What is the ICTZ?

The Inter-Tropical Convergence Zone - the area of intense rainfall in hadley cell circulation

What is the difference between temperate and tropical deciduous forests?

Temperate drop their leaves in the cold season (winter), while tropical drop their leaves in the dry season (summer)

What is considered a "stressful" condition?

Those outside the normal "optimum" zone

What are the 3 ways organisms deal with stress?

Behaviorally, metaphorically, and physiologically

What is adaptation?

Evolutionary change in genotype that increases performance. Result of evolution

What is acclimation?

Change in phenotype within an individual's lifetime to increase performance (often reversible)

What is thermal stress?

When an organism is outside of it's optimal temperature zone

When does maximum reaction rate occur?

At optimal temperature

What is an ectotherm?

Body temperature is determined primarily by external conditions

What is an endotherm

Body temperature is determined primarily by internal, metabolic energy

How do ectotherms regulate their temperature so well?

They absorb sunlight &

How do desert plants regulate heat?

Open growth form, leaves reflective, leaves parallel to the sun, and leaves up off the ground

Do plants sweat?

Yes - water inside the plant leaves the stomata to keep the leaves from overheating

What adaptations do plants have to reduce heat stress

Waxy leaves, small leaves, low surface area : volume ratio, wilting

What is a tradeoff in biology?

Losing one quality, trait, or advantage in order to gain another

What is gas exchange in plants?

Water lost for CO2 gain - water diffuses out of the leaf while CO2 diffuses in

What type of plants are most plants? (C3 or C4)

C3

What happens in C3 plants?

CO2 and RUBISCO mix for the Calvin Cycle normally

What makes C4 plants different?

C4 plants have spatially segregated the process of capturing CO2; they pump concentrated CO2 near RUBISCO for the calvin cycle.

Which plants photosynthesize more at low light levels? High light levels?

At low light levels, C3 plants photosynthesize at a higher rate, but C4 plants photosynthesize faster in high amounts of light because they are not limited by CO2 intake like C3 plants are.

Which type of plant has a lower optimal temperature? (C3 vs C4)

C3 plants have a lower optimal temperature for photosynthesis.

Where do we find more C4 plants? Where do we find more C3 plants?

We find more C4 plants near the equator, where light levels and temperature are highest. As we move away from the equator, the percentage density of C4 plants vs C3 plants decreases.

What plants would be affected more

in increasing CO2 concentration in the atmosphere?

C3 plants, they are limited by their carbon intake. C4 plants are limited by the amount of sunlight they receive, rather than the amount of CO2 in the atmosphere

What is a fundamental niche?

A set of environmental conditions in which individuals perform optimally

What is the equation for the probability of being eaten?

P(Detection) x P(Capture) x P(Consumption). Reducing any of these terms will reduce predation

How have animals adapted to avoid consumption?

Easily caught animals have chemical or mechanical defenses - slime, to make them harder to catch; armor, to strengthen the outside of their bodies; venom, to hurt their attackers; thorns, to hurt their attackers

How have animals adapted to avoid capture?

Groups - schooling, masting, or herding. Reduces probability of a specific individual being captured, however increases chances of detection and increases competition between individuals

How do we estimate population size?

Sampling - quadrat or transect methods

What is population density?

The number of individuals per unit area in a sample

What are some issues of sampling?

Some animals may cross the path twice - so they are counted twice; some animals may also be afraid of the person counting the area and will run away

What are the three steps of the mark-recapture method?

1. Capture, mark, and release M individuals.

2. Recapture another set of n individuals later.

3. Count how many of n were previously marked, and call them m.

N/M = n/m (N=pop size)

What are the 2 main factors of population growth, and the 2 main factors of population decline?

Growth - Births and immigration ; Decline - Deaths and Emigration rate

What is a closed population?

Immigration and Emigration are negligible, so changes in population are dominated by births and deaths.

What is an open population?

Immigration and Emigration must be taken into account when determining changes in population size.

What is the KISS principle?

Keep it simple, stupid;

The best answers often come from the simplest equations

What is the simple model of growth?

dN/dT = bN - dN (b = births d = deaths)

What can dN/dT be simplified as?

r = dN/dT, when r>0 there is growth, when r<0 the population is declining, when r=0 the population stays the same

What are examples of density independent population control?

Fires, hurricanes, etc

What are examples of density dependent population control?

Fecundity, mortality, growth, sickness, resource limitation, cannibalism, spatial crowding

What is fecundity?

The ability to produce offspring. AKA fertility

r(1-N/K) when growth rate decreases with density linearly

When N is less than the carrying capacity, K, the population increases. When N is greater than K, the population decreases.

What is the logistic population growth model?

dN/dT = r(1-N/K)N

What does logistic growth look like?

Begins as exponential, but then levels off as N approaches the carrying capacity

How far do living organisms range in size?

10^22 kg, 10^16 for animals.

S=6L^2 ~ L^2

V=L^3 ~ L^3

M=V ~ L^3

.

Doubling the linear dimensions in all directions increases volume by a factor of 8 and surface area by a factor of 4

Halving the linear dimensions in all directions decreases volume by a factor of 8 and surface area by a factor of 4

What is the danger index?

The amount of water you're carrying in relation to your mass

The mass of H20 divided by M

L^2 / L^3 aka 1/L

The smaller you get, the more dangerous it is to get dipped in water

Gravity

Proportional to L^3 (volume)

Air Resistance

Proportional to L^2 and V^2

Terminal Velocity

L^3 ~ L^2 x V^2

rtL ~ V

What is strength proportional to?

Size (cross sectional surface area) (L^2 ~ M^2/3)

What is the 2/3rd law?

Describes strength of olympic weighlifters - they can lift 3/2 their body weight

What is Isometric scaling?

All dimensions increase the same amount as the size of an organism changes

What is Allometric scaling?

Disproportionate growth of a part or parts of an organism as the size of the organism changes