SCI 230: Exam 3
Card Set Information
SCI 230: Exam 3
Chapters 11, 18-20
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
Embryonic Stem Cells
Cells in the early animal embryo that can differentiate into all the different types of cells
Tend to survive over many generations
Kept alive by growing nutrients (cultured)
Adult Stem Cells
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.
Amniotic Epithelial Cells
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)
Tumor Suppressor Genes
These are regulatory genes that normally turn "off" (suppress) cell division
Mutations can make them code for non-functional proteins
Agents that cause cancer
X-Rays, UV radiation, chemicals, tobacco
Advantages and Disadvantages of Embryonic Stem Cells
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 and Disadvantages of Adult Stem Cells
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 and Disadvantages of Amniotic Epithelial 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
Why do we say that cancer is a genetic disease? What role do mutations play in cancer?
Genetic disease because it results from changes in the DNA
These changes are caused by mutations such as base substitutions and deletions
Cancer is caused by genetic changes in what types of genes?
These changes occur only in genes that regulate cell division and cell growth
What is the progression that takes place as a cell goes from being a normal cell to a malignant cell?
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
Exponential Growth Model
Unrestricted growth under ideal conditions
J curve model
Enough food, water, etc. need for growth and reproduction of a species
Logistic Growth Model
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
Cultural Carrying Capacity
For non-human species - carry capacity is determined in terms of the resources needed for survival
What are the 6 abiotic factors in an ecosystem?
What are the 8 population-limiting factors?
Amount of food
Availability of nesting sites
Availability of shelters
What kind of growth is the human population currently experiences? Can that continue indefinitely?
Yes it can, but it can be limited by starvation, disease, and wars over resources
Why is it harder to determine the carrying capacity for humans than other species?
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
What are 2 ethical means that have been found to limit the human population? Why?
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)
What is an ecological footprint? What does it tell us about our use of resources? What does it tell us about how the US compares to other countries in use of resources?
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)
Biodiversity - Richness and Relative Abundance
Measure of the variety of organisms
: Total number of different species
: 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
Obtain their energy from the food they eat
Herbivores and Zooplankton
Eat plants - leaves, seeds, nectar
Secondary, Tertiary, and Quaternary Consumers
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
Competition Exclusion Principle
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.
Production or Energy Pyramid
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
Disturbances in Communities
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
Why do we say that energy flows and chemicals cycle?
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
How much energy is passed on as you move up a food chain? Why?
About 10% because live sustaining activities use up as much as 75% of the energy we take in as food
Why do we get energy more efficiently when we eat grains, fruits, and vegetables than when we eat meat?
When we eat plants directly, we are primary consumers
When we eat meat, we are secondary consumers
What are some predator adaptations in animals?
Predators have evolved mechanisms to help them catch prey such as claws, teeth, stingers, poisons, sharpened eyesight, smell, and hearing
What are the defense adaptations in plants? What are defense compounds?
Spines, thorns, and sap
: Poisons (cyanide, strychnine) and alkaloids (morphine, cocaine, cannabis, caffeine)
What are the defense adaptations in animals?
Fleeing, freezing, potent scents, camouflage, alarm calls, mobbing, quills, toxins, and mimicry
What are the 7 stages of primary succession?
1) Lichens begin to establish soil
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
What is the role of fire in many ecosystems?
Return nutrients back to the soil
Why is it important the chemicals like carbon and nitrogen are constantly being recycled? What would happen if they weren't? What 2 organisms are the primary decomposers?
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
What is the driving force that causes global climate patterns? Why does it rain so much in the tropics and so little in the deserts?
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)
How does the uneven heating of the Earth's surface effect rainfall and wind?
When air is warmed, it rises and absorbs moisture
When air is cooled, it falls and loses moisture
What causes seasons?
The Earth's tilt (23.5 degrees) on its axis in relation to the Sun
What are the 7 major terrestrial biomes? How does the amount of sunlight, rain, and temperature affect the biodiversity for each?
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
What are the roles of phytoplankton and zooplankton in aquatic and marine biomes?
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
What makes up coral reefs? Why are they so fragile?
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
Why is habitat destruction by humans the single greatest threat to ecosystems and biodiversity?
Humans destroy habitats through agriculture, housing, logging, mining, and environmental pollution.
What are 4 ways that humans alter habitats and effect ecosystems and biodiversity?
Why does cutting down a forest to make farmland effect the plants and animals that live there? Why are wetlands valuable?
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
Why are wetlands valuable?
Filter pollutants out of water and help prevent flooding by slowing down runoff into streams and rivers
What is meant by the phrase "Humans tend to simplify and nature tends to diversify"?
Humans - Monocultures - Plant just corn in the field
Nature - Polycultures - Grows all kinds of weeds at once
Why can introduced species be so destructive to ecosystems?
Some species (Kudzu) tend to be so overbearing on already existing species (trees) that they kill them
What are examples of intentional and unintentional invasive species?
Intentional - Kudzu, Bush Honeysuckle, and European Starlings
Unintentional - Zebra Mussels, Emerald Ash Borer, and Asian Longhorned Beetle