Biogeography Flashcards, test questions and answers

P1/P2//P3/P4

A four-way cross. Used if pollen production in the male parent is also decreased by inbreeding depression. Hybrids have low uniformity and vigour. Has the worst vigour, uniformity, and cost of production of all the hybrids. This type of cross was used in 1930s, when inbred lines had economically low yields.

Hybrid vigour

Increased vigour from heterozygosity. Expression of recessive traits is less likely. Some crosses produce better vigour than others. Probably caused by a mixture of all theories: dominance, overdominance, and model epistasis. First demonstrated in corn by crossing different open-pollinated populations; even this produces some amount of heterosis.

Pure line

A fixed genetic entity. If self-pollinated it does not change. A valuable inbred line has alleles which contribute to vigour in crosses with other lines, and not necessarily vigour in itself. Recurrent selection is used to produce superior inbreds. May have severely low yields, thus producing uneconomical amounts of hybird seed. Development:

1. Formation of a segregating population

2. Inbreed the population with selection. There is no advantage to the inbred line if there is no selection. Selection is similar to the methods used for self-pollinated crops, often using pedigree method, but single-seed descent and bulk methods may be used.

3. Evaluate line performance for general and/or specific combining ability. The number of reciprocal hybrid crosses possible in a populatoin of n inbreds is (n(n - 1))/2. A test-cross is performed.

4. Evaluate lines for potential hybrids.

P1/P1'//P2

A type of hybrid. Used if the female parent has insufficient seed production. P1 and P1' are different but related inbred lines, derived from the same population or cross. Some of the vigour is restored to the female parent, to enhance seed production, but minimizes segregation. Hybrids made this way are not quite as vigorous as hybrids from a single cross. Has the second best vigour, uniformity, and cost of produciton, after single-cross hybrids.

mm = female

Mm = male

MM = supermale

P1/P2

A type of hybrid. Result from crossing two inbred lines. Has the best vigour, uniformity, and cost of production of all hybrid types. Became popular in the 1950s when the yield of inbred lines had improved to an economic threshold.

MM asparagus plants

Produced using tissue culture, or from rare male perfect flowers. When crossed with female asparagus plants, they produce all-male hybrids. By the 1980s, this was common practice.

P1/P2//P3

A type of hybrid. Used if the female parent has severely insufficient seed production. Commonly used in carrots. Results in segregation. Hybrids are less uniform than single-cross or modified single-cross, and have less vigour, since alleles are diluted. Has the thrid best vigour, uniformity, and cost of production, after single-cross and modified single-cross hybrids.

Charles Darwin

plants/animals adapt to changes in the enviroment (will die if they don't)

"Biomes are classified by predominant vegetation which is characterized by adaptations of organisms to the particulat enviorment." [Campbell]

;

biomes have changed/moved many times

;

• formed 10,000 years ago
• northern fringes of Canada/Russia/Finland; southern Greenland; 55 degrees N to 70 degrees N
• -70 degrees F (-56 degrees C)
• 48 species of land mammals --> shrews, rodents, hares, foxes, wolves, deer, bears
• adaptation: thick fur

• Canada/Russia (below tundra)
• half of the year = below freezing; range = -65 to 30 degrees F (-54 to -1 degrees C); long winters, short summers
• Plants: coniferous (keep leaves year round?) trees with needle-like leaves
• Animals: many predators --> lynx, wolverines, bobcats, red deer
• Adaption: hibernation, fly south

• Eastern North America, Mid Europe, Eastern Asia (China)
• 30 - 60 in./year
• 50 degrees F (avg.); has 4 seasons
• Adaptatation: hibernate in winter (shorter); camaflouge; eat fruits, fish, and roots; trees have big wide leaves to get rid of water because there is so much
• There are more HUMANS (predators)

• Covers 6% of land (was once 20%); 50% of plants and animals; 40% of oxygen of world
• Mid South America, Mid Africa, Indonesia/Indo Pacific, equator?
• 50 - 260 in./year
• year-round warmth
• tall trees, rough underbrush; colorful birds, butterflies, plants; many monkeys (species unique to each rainforest)

• Africa, north Australia, India, EQUATOR
• can get as high as 50 degrees (F or C?)
• grasses/trees --> more variety than in a dry savanna
• LARGEST = Australian Tropical Savanna
  • seperated from rest of world for 35 million years
  • contains endemic species --> only place with marsupials
  • saltwater dominator = crocodiles

• Covers 20% of land surface
• formed because of not much precipitation (because of ocean currents and winds)

HOT DESERTS

• Located between Tropic of Cancer and Tropic of Capricorn
• 43 - 49 degrees C
• nocturnal carnivores (it's cool at night); borrowers, mourning wheatears, horned vipers
• Camaflouge

COLD DESERTS

• Located in the Arctic and Antarctic
• antelope, ground squirrels, kangaroo rats (?), rabbits
• (Camaflouge)

• 1% of water is fresh
• Variety of fish, plankton; species can't live in high salt concentrations; has fish that require less oxygen; fish can live in rivers/streams
• Fertilizer and industrial waste kill plants/animals and people will eat the organisms that DON'T die

• 75% of surface covered with oceans, coral reefs, estuaries
• many invertibrates, fishes, worms, clams, predatory crestaceans, crabs, shore birds
  • Estuaries --> diverse fauna (?), variety of worms

UV hits earth directly:

• causes algae (protective shield of coral reefs) to die
  • UV will bleach corals
• Skin cancer

the one and only crop that is grown in a field; also, monoculture is the practice of growing only one crop in a field

1. light,
2. temperature,
3. precipitation,
4. and wind.

1. altitude
2. aspect
3. slope angle

1. effects of plants (for example, the measures a plant takes because of competition or parasitism)
2. effects of animals (the balance between different consumers)
3. effects of fire (forest fires)

Charles Darwin

plants/animals adapt to changes in the enviroment (will die if they don't)

"Biomes are classified by predominant vegetation which is characterized by adaptations of organisms to the particulat enviorment." [Campbell]

;

biomes have changed/moved many times

;

• formed 10,000 years ago
• northern fringes of Canada/Russia/Finland; southern Greenland; 55 degrees N to 70 degrees N
• -70 degrees F (-56 degrees C)
• 48 species of land mammals --> shrews, rodents, hares, foxes, wolves, deer, bears
• adaptation: thick fur

• Canada/Russia (below tundra)
• half of the year = below freezing; range = -65 to 30 degrees F (-54 to -1 degrees C); long winters, short summers
• Plants: coniferous (keep leaves year round?) trees with needle-like leaves
• Animals: many predators --> lynx, wolverines, bobcats, red deer
• Adaption: hibernation, fly south

• Eastern North America, Mid Europe, Eastern Asia (China)
• 30 - 60 in./year
• 50 degrees F (avg.); has 4 seasons
• Adaptatation: hibernate in winter (shorter); camaflouge; eat fruits, fish, and roots; trees have big wide leaves to get rid of water because there is so much
• There are more HUMANS (predators)

• Covers 6% of land (was once 20%); 50% of plants and animals; 40% of oxygen of world
• Mid South America, Mid Africa, Indonesia/Indo Pacific, equator?
• 50 - 260 in./year
• year-round warmth
• tall trees, rough underbrush; colorful birds, butterflies, plants; many monkeys (species unique to each rainforest)