Exam 2

Question 1

Plants and their environment – what plants cue in on

Answer 1

which direction is up and which is down
when to germinate, when to remain dormant
when they are old enough to reproduce sexually
needs to know the right time of year for blooming, and the right time for producing fruit
needs to know when to open
if they are being attacked by animals, fungi, viruses, and so on, and then produce protective chemicals
Roots and shoots must coordinate with each other
Newly formed embryos need to inform the plant that they exist and need not only nutrients, but also the protection of a surrounding fruit or cone

Question 2

Flowers and pollination

Answer 2

Some flowers are pollinated by insects that land on them and then crawl inside; many such flowers orient themselves to be horizontal, aligned with the flight pattern of their pollinators

Question 3

Abscission zone

Answer 3

(where a piece of the plant falls off) needs to know when to remain dormant and when to be active so that healthy leaves and immature fruits are retained but old ones are allowed to fall off

Question 4

Environmental Stimuli: gravity, touch, temperature, light, chemical

Answer 4

Gravity indicates the direction of “up” and “down” for plants and their roots ◦ It also causes plants and organs to have weight. The heavier something is, the more strengthening tissues it needs
Touch can illicit a response in plants Examples: venus fly trap, mimosa plant, tendrils
Temperature is an important stimulus for plants in temperate environments that undergo freezing temperatures
Light not only is an important source of energy, but also carries information about the time of year shorter days in winter, longer days in summer ◦Help indicate for the plant which direction is “up” – towards the light!

Question 5

Phototropin

Answer 5

a pigment that perceives the direction of light and directs plants in that direction

Question 6

Phytochrome

Answer 6

A pigment called phytochrome detects light for measuring day length

Question 7

Vernalized

Answer 7

Biennial plants need to be exposed to cold/freezing temperature (to be vernalized) – to know that they are passing from their first year (vegetative state) to their second year (reproductive state)

Question 8

Transfer of information from plants: hormones

Answer 8

allow molecules to carry information from one area of a plant to another. All plant hormones are involved in numerous responses, none triggers just a single, specific response

Question 9

Auxins, gibberelins

Answer 9

Auxin helps activate dormant buds, stimulates growth, promotes development of embryos and fruits, and prevents leaves from senescing
Gibberellins are involved with stem elongation, seed germination, and several aspects of flowering

Question 10

Asexual vs sexual reproduction in plants

Answer 10

During asexual reproduction, a single parent produces progeny that are genetically identical to itself
During sexual reproduction the offspring (progeny) are genetically diverse • Each parent produces gametes which are sperm cells or egg cells, that each contain one complete set of genes of that species. • A sperm cell fuses with an egg cell, resulting in the beginning of a new individual, that will have genes that not only differ from its parents but also from its siblings

Question 11

Asexual Advantages:

Answer 11

Because the parent lived long enough to reproduce, it must be well-adapted to its environment therefore the offspring will be well-adapted too
Asexual reproduction only requires one parent, so plants that are growing in sparse populations and far away from other plants of its species, are still able to reproduce
Reproduction and rapid colonization is possible in isolation

Question 12

Asexual Disadvantages:

Answer 12

No genetic diversity (if new traits or alleles are needed to survive, they are at at risk of dying and not reproducing)
Not able to adapt to changing environments, and will not be able to reproduce or have their offspring reproduce if conditions change

Question 13

Sexual Advantages:

Answer 13

Progeny are genetically diverse
Offspring can therefore be even better adapted than the parent
Offspring could potentially colonize environments that one of the parents couldn’t
New conditions and habitat changes may not have such adverse affects than with asexual reproduction

Question 14

Sexual Disadvantages:

Answer 14

Even though some offspring might be more adapted to their environment, others might be less adapted
Cannot colonize a new site as rapidly because not all progeny are adapted for it
Changes in habitat could still adversely affect progeny
Isolated individuals cannot reproduce

Question 15

Mitosis vs meiosis

Answer 15

Mitosis creates duplicate copies of a cell’s genes (this is how most cells multiply as an individual grows from zygote/fertilized egg, to adult) ** All outcome cells are diploid, meaning, they have twice the necessary chromosomes
Meiosis is used to ‘shuffle’ the genes when sex cells are made and to ensure that each egg or sperm cell (called a gamete) receives one – and only one – complete set of genes ** Outcome cells are haploid, meaning, they have one set of necessary chromosomes

Question 16

Haploid vs diploid

Answer 16

Haploid nuclei have one chromosome of each pair

Diploid nuclei have pairs of homologous chromosomes

Question 17

Methods for asexual and sexual reproduction in plants

Answer 17

Common form of reproduction is fragmentation: • A wide spreading or vining plant grows several meters in length, then establishes its own root system and can survive if detached from the parent plant
Sexual reproduction in angiosperms involves flowers, which produce the necessary cells and structures
In animal life cycles, diploid adults have sex organs that produce haploid gametes, either sperm cells or egg cells, by meiosis
Once egg cells and sperm cells are brought together, the fertilized egg (now diploid) is called a zygote

Question 18

Sporophyte vs gametophyte stage (which is haploid vs diploid, asexual vs sexual)

Answer 18

Sporophyte stage – where the plant is diploid and produces spores (spore = a single cell that is a means of asexual reproduction)
Gametophyte stage – where the plant is haploid and produces gametes

Question 19

Pollen

Answer 19

sperm cells

Question 20

eggs

Answer 20

egg cells (both gametes)

Question 21

How plants avoid self-fertilization

Answer 21

In some plants with bisexual flowers, the stamens and carpels mature at different times or are structurally arranged in such a way that it is unlikely that an animal pollinator could transfer pollen from the anthers to the stigma of the same flower

Question 22

Fruit development

Answer 22

As the ovule develops into a seed, the ovary matures into a fruit. • The stigma and style usually wither away, as do sepals, petals, and stamens. • Fruits are adaptations that result in the protection and distribution of seeds.

Question 23

Daily changes on earth vs longer scale changes

Answer 23

Daily changes are familiar to us, and have a profound effect on the biology of all organisms
Every 24 hours, there are changes of light and darkness, warmth and coolness
There are seasonal changes of temperature, precipitation, flooding, drought
Changes such as wildfires, earthquakes, landslides, and volcanic eruptions do not occur on a regular cycle, but happen often enough to be familiar to us and impact all forms of life

Question 24

On longer and larger scales, there are changes that are major but less familiar to us

Answer 24

The continents move across the surface of the Earth, changing their shapes
This changes the shape of the ocean basins, and affects the patterns in which water and air circulate
Mountains build where none were before, and others erode away
Rivers change their courses
At times in the past, earth has been hotter, it has been almost completely frozen over
Earth has gone through eras of humid climate, and eras of dry climate
As these changes occurred, some plants, animals, fungi, and other forms of life were able to adapt
Some individuals had beneficial alleles and even though some of Earth’s changes caused many individuals to perish, those that were adapted to altered conditions survived

Question 25

Know what alleles are = traits in plants

Answer 25

one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

Question 26

Two major extinction periods

(know what likely caused them) MYA = million years ago

Answer 26

Cretaceous Period 65.5 Million Years Ago, a giant asteroid struck Earth and killed most of the living creatures, including the dinosaurs
The Permian-Triassic extinction event occurred 251 Million Years Ago and eliminated 94% of all marine species, and 70% of all land vertebrates

Question 27

Biogeography definition

Answer 27

the distribution of plants, animals, and other forms of life on Earth, and is heavily influenced by random events
Such events include changes in the size, shape, positions, topography, and climate of the land and water that life inhabits
Millions of years ago, there would have been no way to predict where the continents and oceans would be now, and no way to predict the types of animals and plants that would exist now

Question 28

3 things that influence biogeography

Answer 28

1. Earth’s rotation on a tilted axis – which causes seasons to change during a yearly cycle and which drives massive flows of air in the atmosphere and water in the oceans
2. The position of the Earth’s land masses, the continents – when they lie in warm moist areas they are covered with life, but when they drift to inhospitable regions (Antarctica at the South Pole), they become barren
3. Origin – The Earth is approximately 4.5 Billion years old. About 470 Million years ago, true plants originated and they diversified as the ground beneath them drifted, and the climate around them changed

Question 29

How plants on land influenced evolution of animals on land because

Answer 29

animals had to venture onto land to find plants

Question 30

What would happen if the earth wasn’t tilted?

Answer 30

The sun would rise exactly in the East, pass directly overhead, and set directly in the West ¡ We would have no change during the year, no seasons
Parts of the planet higher than 40 degrees latitude would never have the sun overhead
The equator would be really hot all the time and other regions would receive only oblique lighting

Question 31

Solstices and when days are longest

Answer 31

At summer solstice, June 21 or 22, the North Pole points directly toward the sun as possible
The days are their longest
By September 23, the autumnal equinox, Earth has made ¼ orbit and the sun is directly over the equator (12 hour light vs. dark at the equator)
Three months later, the winter solstice (December 21 or 22) the South Pole points as directly as possible toward the sun.
The days are their shortest in the Northern Hemisphere, and summer begins in the Southern Hemisphere

Question 32

Air and oceans distribute heat and moisture slides

Answer 32

Our atmosphere and oceans, being fluids, develop massive flows (currents) when heated in one area and cooled in another
They distribute heat from the tropics all the way to the poles

Question 33

Solar heat = fuels currents (whether water currents or air currents)

Answer 33

Throughout the year, the water and air receive solar heat, causing tremendous amounts of evaporation
As most air warms, it expands, and rises high into the atmosphere
Once high enough, the air cools, water vapor condenses into rain and calls in torrential storms, producing tropical rainforests in Central America, northern South America, central Africa, and Southeast Asia

Question 34

Trade winds vs westerly winds

Answer 34

Once back at Earth’s surface, part of the air spreads toward the equator and part flows toward the poles.
Earth’s rotation causes the air moving toward the equator to be deflected westward as a northeast trade wind in the Northern Hemisphere. Air spreading toward the poles from the latitudes is deflected eastward and blows west (called a westerly)

Question 35

Hurricane vs cyclone

Answer 35

A hurricane is in the Atlantic and Northeast Pacific

A cyclone is in the the South Pacific and Indian Ocean

Question 36

What causes Santa Ana winds?

Answer 36

The Santa Ana winds originate from high-pressure air masses over the Great Basin and upper Mojave Desert.
The air mass, flowing from high pressure in the Great Basin to a low pressure center off the coast, takes the path of least resistance by channeling through the mountain passes to the lower coastal elevations, as the low pressure area off the coast pulls the airmass offshore.

Question 37

What el Nino is

Answer 37

The climate phenomenon known as El Niño shows us that weather and climate patterns can be unstable
At irregular intervals between 3 and 7 years, warm water moves eastward along the equator and comes to rest in the eastern Pacific Ocean (near South America)
The warm water evaporates, moves north, providing extra rainfall across the southern United States
El Niño lasts a few months, then weather conditions return to normal

Question 38

How tectonic plates move and how this is connected to the term continental drift

Answer 38

The Earth’s surface is not static
Moten rock rises from inside the Earth and emerges through volcanoes and fissures
The solid parts of Earth’s crust are broken into giant pieces called tectonic plates
As molten rock rises between the plates, it pushes on them, causing them to slide across the molten rock
This movement is called continental drift

Question 39

Pangaea, Laurasia, Gondwana

Answer 39

Pangaea – large supercontinent
Laurasia - North America collided with Eurasia
Gondwana – South America, Africa, India, Australia, Antarctica

Question 40

ALL the biomes (no word bank will be included)

Answer 40

a major category of the world’s distinctive plant assemblages, e.g. the tundra biome, the tropical rainforest biome
Note: mountains are not biomes, but various biomes may be present on one mountain throughout its elevation gradient

Question 41

Difference between climate and weather

Answer 41

Weather refers to short-term changes in the atmosphere

Climate describes what the weather is like over a long period of time in a specific area

Question 42

Tropical rain forest

Answer 42

Abundance of resources throughout the year
Biodiversity “hotspots”
Very high species richness

Question 43

Savanna

Answer 43

Tropical grassland with scattered trees
Tree growth and forest development checked by:
Limited, seasonal moisture
Grazing
Fire

Question 44

Tundra

Answer 44

Permafrost: soil remains frozen throughout the year and is very rich in organic matter
Very low plant diversity:
100 species of vascular plants in High Artic
2 species of vascular plants Antartica

Question 45

Desert

Answer 45

Little and unpredictable rainfall
Low productivity
Low species diversity
Plant adaptations
Drought and frost tolerance
Chemical and physical anti-herbivory defenses

Question 46

Temperate grassland

Answer 46

Very productive biome, in which natural grasses have been mostly replaced by domesticated grasses
Most anthropogenically transformed biome

Question 47

Temperate forest

Answer 47

Moderate temperature and precipitation
Deciduous and evergreen trees
Soil rich in organic matter

Question 48

Boreal forest

Answer 48

Coniferous forest or taiga, the largest terrestrial biome in the world
Low diversity of tree flora: pines, firs, spruces
Pest outbreaks
Spruce budworm
Rocky mountain pine beetle
Emerald ash borer

Question 49

Mediterranean and chaparral

Answer 49

Mild/wet winters, hot/dry summers, and frequent wildfires