SCI 230: Exam 3

To become specialized into particular types of cells

Stem cells that are able to differentiate into any type of cell

Stem cells that give rise to a limited number of different cell types

Cells in the early animal embryo that can differentiate into all the different types of cells

• Undifferentiated cells
• Tend to survive over many generations
• Kept alive by growing nutrients (cultured)

• Undifferentiated cells found in tissues or organs that can give rise to a limited number of cells
• Brain, bone marrow, blood, skin, liver cells, etc.

• Some stem cells extracted from the placenta
• Retain the ability to form any type of cell
• Artificial heart valves, working tracheas

Stimulating 1 cell to replicated and differentiate into a whole multicellular organism, identical to the organism

• Normal and necessary genes that regulate cell divisions and cell growth
• "On Switches" - Switches on and off (good and necessary)

• Proto-oncogenes that have had a mutation in their DNA causing them to always be turned on
• Stimulating the cell to keep dividing (NOT good)

• These are regulatory genes that normally turn "off" (suppress) cell division
• Mutations can make them code for non-functional proteins

• Agents that cause cancer
• Mutagen
• X-Rays, UV radiation, chemicals, tobacco

• Advantages - Cells tend to live for many generations
• Problems - Sometimes produce cancer-like tumors
• Controversial - These cells could grow into a human being, but are prevented from doing so

• Advantages - Few or no ethical issues and the person's body will not tend to reject new tissue if the original tissue came into his or her body
• Problems - They are more difficult to obtain and they don't tend to survive as long as embryonic stem cells

• Advantages - Since teh placenta is commonly discarded after birth, they could be an easy source of non-controversial stem cells, few ethical concerns, and pluripotent
• Problems - May not be as potent as Embryonic Stem Cells

• Genetic disease because it results from changes in the DNA
• These changes are caused by mutations such as base substitutions and deletions

These changes occur only in genes that regulate cell division and cell growth

Cells in their normal environment recognize their borders, but when they are dividing rapidly, they can pass their border and don't recognize the new borders, so they keep spreading

The scientific study of the interactions between organisms and their environment

All the living (community) and non-community living (abiotic) factors in an area

All the individuals of a single species in an area

The factors that influence a population's size, growth rate, and density

• Unrestricted growth under ideal conditions
• J curve model
• Enough food, water, etc. need for growth and reproduction of a species

• Growth levels off because of population-limiting factors
• Called the S curve model

The number of members of a species that the environment can support ("carry") at a particular tme

For non-human species - carry capacity is determined in terms of the resources needed for survival

• Solar energy
• Water
• Temperature
• Wind
• Soil
• Periodic disturbances

• Amount of food
• Waste buildup
• Disease
• Predation
• Availability of nesting sites
• Breeding territories
• Availability of shelters
• Weather

• Exponential growth
• Yes it can, but it can be limited by starvation, disease, and wars over resources

• 1) We can bring in resources from outside the local environment
• 2) We can use technology to exploit resources otherwise unavailable
• 3) For non-human species - carrying capacity is determined in terms of the resources needed for survival

• More equal economic growth - better distribution of wealth because the better off people are, the few children they tend to have later in life
• Education - The more educated the person is - have fewer children and later in life (education of women is a major factor in reducing population)

• A way to estimate the carrying capacity for humans on Earth by looking at how much land is needed per person to produce all the resources we consume and absorb the waste we generate
• US ecological footprint > Other countries by double

All the populations in an area, living close enough together for potential interactions

The study of the interactions between populations (species)

• Measure of the variety of organisms
• Richness: Total number of different species
• Abundance: Number of species

The feeding relationships among the various species

Show how energy moves in a system (up the food chain)

• Photosynthetic - Use energy from the Sun to store energy in the chemical bonds of organic molecules
• Plants, phytoplankton

Obtain their energy from the food they eat

Herbivores and Zooplankton

Eat plants - leaves, seeds, nectar

Carnivores and omnivores

Eat other animals

Eat both plants and animals

• More complex than food chain
• Shows the complexity of how energy moves up food chains in a real life situation

Eat dead material from both terrestrial and aquatic

• Species' role in its community, or the sum total of its use of the living and non-living resources of its habitat
• What it feeds upon, what feeds upon it, what it uses from the habitat (food, water) and what it adds to the habitat (waste, food)

Where a species lives

• 2 species that are so similar that they compete for the same resources CANNOT exist in the same place
• Competitive edge will drive the other out to extinction

• The organic material in an ecosystem
• Plant matter, animal bodies, etc.

In general, only about 10% of the energy taken in by an organism is stored in its biomass (body) and can be used by the next level up for energy

Interspecies interactions where 1 species lives in or on another

Both partners benefit

1 benefits at the expense of the other

• A force that alters the biological community and usually removes organisms from it
• Fires, floods, volcanoes, glaciers, human intervention

• A community that arises from a virtually lifeless area with no soil
• After a glacier or volcano

• When a community has been destroyed, but the soil is left intact
• After a fire, drought, or hurricane

The evaporation of water from plants (stomata open)

Underground rivers and lakes

• Energy flows because energy from the Sun can be stored in chemical bonds - photosynthesis
• Chemicals cycle because they can be recycled and used over again

About 10% because live sustaining activities use up as much as 75% of the energy we take in as food

• When we eat plants directly, we are primary consumers
• When we eat meat, we are secondary consumers

Predators have evolved mechanisms to help them catch prey such as claws, teeth, stingers, poisons, sharpened eyesight, smell, and hearing

• Spines, thorns, and sap
• Defense compounds: Poisons (cyanide, strychnine) and alkaloids (morphine, cocaine, cannabis, caffeine)

Fleeing, freezing, potent scents, camouflage, alarm calls, mobbing, quills, toxins, and mimicry

• 1) Lichens begin to establish soil
• 2) Mosses
• 3) Herbs and weeds overgrow the lichens and mosses
• 4) Grasses overgrow the weeds and herbs
• 5) Bushes and shrubs overgrow the grasses
• 6) Small trees eventually become established
• 7) Larger trees will eventually take over

Return nutrients back to the soil

• C and N are important ingredients in all organic molecules (C) and in nucleic acids and proteins (N)
• Weren't then we would have excess and it would affect plants and humans with greenhouse gases
• Fungi and bacteria

• Solar energy
• Dry air is moved towards the equator where air is warmed and absorbs moisture (deserts) and as air moves away from equator, the air is cooled and loses moisture (tropics)

• When air is warmed, it rises and absorbs moisture
• When air is cooled, it falls and loses moisture

The Earth's tilt (23.5 degrees) on its axis in relation to the Sun

• Tropical Rainforest - Sunlight (abundant), rain (abundant), temp (warm), biodiversity (very high)
• Savannas - Sunlight (abundant), rain (40-69 in/yr), temp (warm to hot), biodiversity (moderate)
• Deserts - Sunlight (abundant), rain (less than 10 in/yr), temp (hot days, cold nights), biodiversity (low)
• Temperate Grasslands - Sunlight (moderate), rain (seasonal), temp (seasonal), biodiversity (moderate)
• Temperate Deciduous Forests - Sunlight (moderate), rain (moderate), temp (seasonal), biodiversity (moderate)
• Coniferous Forests - Sunlight (moderate), rain (moderate), temp (cold winters), biodiversity (low to moderate)
• Tundra - Sunlight (low), rain (low, snow), temp (warm to very cold), biodiversity (low)

• The region into which sunlight penetrates
• Where photosynthesis occurs

• The region beneath the photic zone
• Not enough sunlight for photosynthesis

The sea or lake bottom or floor

• Phytoplankton - Do photosynthesis (release oxygen) and producers (bottom of the aquatic/marine food
• Zooplankton - Feed on phytoplankton and are in turn eaten by fish and other animals

• Calcium carbonate
• They are fragile because they are living organisms

The conversion of arid or semi-arid regions to desert by drought, overgrazing, over cultivating deforestation, or poor irrigation practices

• Species that humans have moved from 1 ecosystem to another
• Also known as exotic species

• Species that humans have moved from 1 ecosystem to another and they compete with native species
• No natural predators to control population

• Over-harvesting a species both on land and sea
• Harvesting a species faster than it can reproduce

Some chemicals, including some pesticides, accumulate in the biomass of organisms and increase in concentration as they move up the food web

Has a pH between 4.5 - 5.5

Humans destroy habitats through agriculture, housing, logging, mining, and environmental pollution.

• Habitat Destruction
• Introduced Species
• Overexploitation
• Chemical Use

Goes from a forest ecosystem to a grassland ecosystem (animals and plants that lived in forest would have to adapt to live in grassland) and rainforest destruction

Filter pollutants out of water and help prevent flooding by slowing down runoff into streams and rivers

• Humans - Monocultures - Plant just corn in the field
• Nature - Polycultures - Grows all kinds of weeds at once

Some species (Kudzu) tend to be so overbearing on already existing species (trees) that they kill them

• Intentional - Kudzu, Bush Honeysuckle, and European Starlings
• Unintentional - Zebra Mussels, Emerald Ash Borer, and Asian Longhorned Beetle