BIS 2B Midterm 1

What is the smallest possible unit of life?

Cell

Ecology

The study of how organisms interact with each other and with the environment in which they live

Biotic Interactions

The way in which living organisms interact with each other in an ecosystem

Abiotic Interactions

The ways that non-living components of an ecosystem influence the organisms that live there. Ex: sunlight affecting plant growth

Evolution

The study of changes in heritable characteristics ofbiological populations over successive generations

biodiversity

All the variety of living things AND all the ways they are connected

How does the study of ecology relates to evolution?

Study of ecology reveals the forces shaping survival and reproduction (and therefore, evolution)

How does the study of evolution relate to ecology?

Study of evolution offers insight and predictions about ecology ofpopulations

The Biosphere

All life that we know lives within 10 km (up or down) from the surface of the Earth

Latitude

described in degrees north or southof the equator, horizontal lines

What does each degree north or south of latitude correspond to?

around 69 miles of distance

At which latitude is sunlight most intense at?

latitude that is directly facing the sun

Hadley cells

patterns of atmospheric circulation, with air rising near the equator (and raining), then descending as dry air at 30°N and 30°S

How do Hadley cells explain the patterns we see where it is very wet near the equator and dry on average at 30°N and 30°S?

Air rising near equator, makes it very wet, and then descending as dry air to the drier parts at 30°N and 30°S

Clouds

moisture/rain

Does the hottest latitude change by season?

Yes

What's the difference between the Northern and Southern hemispheres?

Dates are the same everywhere, but seasons are different in Northern and Southern Hemisphere

What occurs when the southern hemisphere is tilted toward the sun?

It is summer there and winter in the northern hemisphere

What occurs when the northern hemisphere is tilted toward the sun?

It is summer there and winter in the southern hemisphere

Intertropical Convergence Zone

Thermal Equator

What is the thermal equator (Intertropical Convergence Zone)?

The band of clouds/moisture/rain that shifts up and down periodically through the seasons and the area with highest solar intensity

Where does the wind pick up moisture from?

the ocean

What is a rain shadow?

a dry area of land that occurs on the leeward side of a mountain range, where precipitation is significantly reduced

Is the earth spinning and orbiting the sun?

yes

Earth's axis tilt

23.5 degrees, tilt is responsible for seasons

Does sunlight carry energy?

yes, when it hits things, they heat up

When does water condense more?

when air cools down

Weather

current, short-term atmospheric conditions, ex: temperature, rain ,wind

Climate

average atmospheric conditions/patterns/cycles over many years/millennia

Weather or climate? A big winter storm

Weather

Weather or climate? Typicalpatterns of flooding in a region

Climate

What is the atmosphere composed of?

78% Nitrogen, 21% oxygen, and 1% (CO2, Ne, He, H2)

Earth's radiation budget

describes the overall balance between the incoming energy from the sun and the outgoing thermal (longwave) and reflected (shortwave) energy from the earth

What radiation is emitted by our bodies (anything slightly warm)?

infrared radiation

What light is emitted by hot metal?

visible light

What does the sun emit?

visible and UV radiation

greenhouse effect

a natural process that warms the Earth's surface and atmosphere by trapping heat from the sun with greenhouse gases

Chlorofluorocarbons (CFC's)

nontoxic, nonflammable chemicals containing atoms of carbon, chlorine, and fluorine, known for depleting the ozone layer

How can we find out the CO2 concentration years before present day?

ice cores

Hottest place on earth?

Death valley

Of the 20 largest fires in California's history (since1932), how many have occurred since 2000?

19

The cryosphere

frozen water on Earth's surface

Whats the typical annual pattern of sea ice?

increase and decrease, but extent of sea ice has been declining

What percent reduction in glaciers since 1960?

40%

What occurs as a result of sea ice and glaciers melting, as well as thermal expansion?

Increased sea level

How does the ocean slowly changes in temperature?

absorbs heat

What happens when the ocean absorbs CO2?

acidifies, CO2 reacts with water molecules to form carbonic acid, which breaks down into hydrogen ions (H+), causing pH levels to decrease and ocean becoming more acidic

Representative Concentration Pathways (RCP)

trajectories for greenhouse gas concentrations, there are 4 possible climate futures

What is the RCP for "business as usual"

RCP 8.5

Genetic or trait diversity

different genes ortraits within the same species

Species diversity

different speciesoccupying same habitat at same time

What might the genetic diversity in a species affect?

the viability of the species (ability to survive)

What might the viability of a species affect in relation to a community?

Species diversity in a community, influences the diversity of communities at a larger scale

Diversity Index (D)

Species richness + Species evenness

Species richness

total # species in habitat

Species evenness

relative abundance of each species

What happens when the D value (diversity index) is perfectly even?

D = species richness

What does a higher diversity index (D) mean?

A higher D means a more diverse environment

what's the range for the diversity index

1 to n

What does it mean when the diversity index (D) is close to 1?

D close to 1 means you will usually encounter just one type

What can be used to sample the diversity of types of species in an area?

transects and quadrats

Rarefaction curves

diversity as a function of the # individuals sampled, y= # of species and x= # of individuals

Vicariance

The geographic separation of a species into separate populationsthrough some sort of physical barrier

Wallace's Line

an imaginary boundary running through the Indonesian islands that separates the animal species of Asia from those of Australia, meaning that the animals found on either side of the line are distinct from each other due to their different evolutionary histories

Diversity index equation

𝐷 = (𝑝1−𝑝1)(𝑝2−𝑝2) (𝑝3−𝑝3)...(𝑝𝑛−𝑝𝑛)

What is the D value equal to when it is perfectly even? when species evenness is equal to D value

D = species richness

Principle of allocation

Each organism has a limited amount of energy that can be used for all life processes:

• Obtaining food

• Escaping predators/pathogens

• Reproduction

• Growth and metabolic functions

Can the energy used for one function of the principle of allocation be used for another?

No, there are tradeoffs in how an organism can use energy

What percent of water are living things comprised of?

70%

Photosynthesis

the process by which plants change the energy in sunlight to kinds of energy that can be stored for later use

What's the primary photosynthetic pigmenst in most plants?

Chlorophyll a and b

Why are many plants green?

They reflect green and yellow light

C3 photosynthesis

All mesophyll cells take up CO2 and build sugar, Light reactions and carbon-fixation takeplace at the same place and same time

What percent of plants do C3 photosynthesis?

Most common pathway, 85% of all plants

What are two problems with C3 photosynthesis?

Water loss and Photorespiration

stomata

tiny openings present on the epidermis of leaves

How does water loss occur in C3 photosynthesis?

H2O escapes from stomata that are open to allow CO2 to enter and carbon fixation occurs during the daytime, resulting in water loss

carbon fixation

CO2 gets converted in an organic compound

Photorespiration

begins when rubisco acts on oxygen instead of carbon dioxide (O2 instead of CO2)

Rubisco

the key enzyme for carbon fixation

What does photorespiration do to carbon?

depletes carbon rather than fixing it

Do light reactions in C3 plants happen in the same place as the calvin cycle?

yes, exposes rubisco to O2

C4 photosynthesis

Initial carbon fixation and sugar-building are spatially separated

What happens during C4 photosynthesis?

Mesophyll cells take up CO2 and Bundle sheath cells build sugar, not much O2 near the rubisco

How many extra atp per sugar molecule does C4 photosynthesis require?

2 extra

What percent of plants do C4 photosynthesis?

3%

What percent of plants do CAM photosynthesis?

7%

CAM photosynthesis

CO2 uptake and sugar-building are separated in time

What is the process of CAM photosynthesis?

Open stomata at night, store CO2 as acid invacuole, Close stomata during day, convert acid back toCO2 to build sugar

Where does CAM usually occur?

very dry environments, very water efficient

Fix nitrogen

convert nitrogen gas into ammonia

What allows legumes (pea family) to thrive in soils with limited available nitrogen?

bacteria in the genus Rhizobium, live in plant nodules in the roots and fix nitrogen

Do many plants have a mutualistic relationship with mycorrhizal fungi?

yes, access to additional water and nutrients

Liebig's law of the minimum

Plant growth is not determined by the total amount of all resources available, but by the amount of the resource that is most scarce compared to how much the plant needs

Autotrophs

at the base of all food chains, ex algae, fungi

Heterotrophs

consume autotrophs or each other, ex humans, lions, earthworms

Animals

most move to go find their food, this means time management is often key

Fungi

most grow to go find their food

Do carnivores feed less or more frequently?

less

Do herbivores feed less or more frequently?

more, need a diverse diet to find nutrients