Biol212 Exam 4

What does a landscape ecologist study?

Connections in a heterogenous landscape consisting of multiple interacting ecosystems.

What type of population growth is the human population currently experiencing?

Exponential population growth.

The greatest proportion of which two biomes have been converted to agriculture?

Temperate deciduous forest and temperate grassland

Which aquatic and terrestrial ecosystems have the greatest primary productivity?

Tropical rain forests have the highest productivity, next is wetlands, the least productive terrestrial are tundra and desert. Most productive aquatic are algal beds, coral reefs, and estuaries.

The ability to meet humanity's current needs without compromising the ability of future generations to meet their needs is

environmental sustainability.

Sea Grass Plains

flowering plants that have adapted to submersion in temperate, subtropical and tropical waters. Live in shallow water to depths of 10m, where they receive enough light to photosynthesize. Roots and rhizomes stabilize the sediments, reducing surface erosion. Important source for shelter and food

A population that is divided into several local populations among which individuals occasionally disperse (emigrate and immigrate) is known as a:

metapopulation

The Earth's carrying capacity is:

unknown

1. Arrange the following stages of oogenesis in sequential order. 1- Secondary oocyte 2- Oogonium 3- Ovum 4- Primary oocyte

2 > 4 > 1 > 3

What is a typical feature of K-selected organisms?

A low reproductive rate

What is the endangered species act?

Act passed in 1973 to provide legal protection to listed species and requires the US fish and wildlife service to select critical habitats and design a recovery plan for each species.

Which of the following is a characteristic of desert plants?

Adaptions that conserve water

What environment is characterized by high nutrient inputs and by relatively great fluctuations in salinity and temperature?

An estuary

What major roles does the atmosphere play?

Atmosphere performs essential ecological functions: supplies organisms with oxygen and CO2, protects Earth's surface from most of the sun's UV and X-rays and cosmic rays from space, also interacts with solar energy to create weather and climate.

The ____ realm has long been separated from other land masses and is the area in which marsupials are particularly common

Australian

What is biodiversity? What are genetic diversity, species richness and ecosystem diversity?

Biodiversity is the variation among organisms - includes Species richness is number of species. Genetic diversity is the genetic variation within a species Ecosystem diversity is the variety of ecosystems on earth

______ is an index of the variety of living organisms in an ecosystem.

Biological diversity

Approximately how much energy and matter goes "up" the pyramid of energy and biomass to the next level?

Biomass is reduced by an average of 90% at each trophic level. So only 10% goes up to the next level. Only about 40% of energy goes up to the next level.

Stratospheric ozone is important because it

Blocks solar UV radiation

In the carbon cycle, what are the major reservoirs on earth? How is carbon moved from on reservoir to another?

Carbon cycle is the global movement of carbon between the abiotic environment and organisms. Carbon is in all organic molecules essential to life. The main reservoirs of carbon are wood, fossil fuels, and marine sediments. Also found in atmosphere as CO2, in water as carbonate and bicarbonate, and in rocks as limestone. Carbon is moved through photosynthesis, production of shells by marine organisms.

The major components of Earth's atmosphere, from the lowest concentration to the greatest concentration, are

Carbon dioxide < oxygen < nitrogen

What is the difference (and similarities) between a food chain and web?

Chain: Energy flow occurs in food chains, in which energy from food passes from one organism to the next Web: energy flows through a complex of interconnected food chains, once an organism loses energy as heat, it can't be passed to another organism.

What is a consumer compared to a producer?

Consumer: extract energy from organic molecules produced by other organisms Producers: use sunlight directly for energy and produce the organic compounds to be consumed.

The world human population has increased dramatically during the past few centuries due to:

Decreased death rates

What is deforestation? How much forest are we losing each year?

Destruction of forests for agricultural and commercial uses. We are losing 22.2 million acres of forest each year.

Today, the major danger to species is

Destruction of habitats

What human activities contribute to endangering and threatening species?

Destruction or modification of habitats Pollution, including gases that cause climate change Introduction of invasive species Overexploitation, such as overfishing/hunting

How does the latitude of the earth influence how much energy it receives from the sun?

Earth's spherical shape and tilted axis allows for variation in exposure to sunlight. Rays strike almost vertically near the equator and obliquely near the poles (meaning this is reflected and spread out more

A(n) ____ is the transition zone where two ecosystems meet and intergrade.

Ecotone

What is an ecotone? What is biogeography?

Ecotone is the transition zone where two communities or biomes meet/intergrade Biogeography is the study of the geographic distribution of plants and animals.

What is a habitat corridor?

Effort to connect isolated habitat patches with strips of habitat to allow wildlife to move about so they can feed, mate, and recolonize after local extinctions. This will retain more native plant species than isolated fragments.

A species' numbers are so severely reduced that it is in imminent danger of extinction throughout all or a significant part of its range. This species would be considered

Endangered

What characteristics make a species vulnerable to extinction?

Endangered species are more vulnerable to extinction if they have an extremely small range, need a large territory, live on islands, have low reproductive success, need specialized breeding areas, or have specialized feeding habits.

What is the difference between an endangered and threatened species?

Endangered species is a species in imminent danger of extinction throughout all or a significant part of its range; unless humans intervene, the species will go extinct Threatened species is a species likely to become endangered in the foreseeable future, throughout all or a significant part of its range.

In an ecosystem, does energy flow or cycle? What about matter?

Energy passes through an ecosystem in a one way direction, it flows. It enters as sunlight, used, and dissipated as heat. Matter is also a flow, it is consumed by consumers, and then excreted to be used by producers.

What is eutrophication? What causes it?

Excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen It is caused by human development that uses nitrate and phosphate fertilizers, these get into the water through runoff and alter the nutrient availability.

Sexual reproduction involves which of the following processes?

Fertilization

Describe the endocrine regulation of reproduction in the human male. Be sure to recognize the roles of the following molecules: testosterone, GnRH, FSH, LH, ABP, and inhibin

GnH from the anterior pituitary stimulates LH and FSH which stimulates Sertoli cells and interstitial cells to produce testosterone. Testosterone then goes back and acts as negative feedback to stop GnRH.

What is climate change? What are some factors that have been proposed to drive climate change?

Gradual warming of atmosphere. CO2 emission causing a greenhouse effect

Building roads, parking lots, buildings and bridges all contribute to

Habitat destruction

Which of the following is NOT a shared characteristic that makes threatened and endangered species vulnerable to extinction?

Having a broad range

What is the difference between an herbivore, carnivore, omnivore and decomposer?

Herbivores are consumers that eat plants Carnivores eat herbivores or other animals Omnivores eat a variety of organisms, both plant and animal Detritovores eat detritus, decomposers break down organic remains and release simple inorganic molecules used by producers.

The tropical rain forest biome is characterized by:

High density of plants, and nutrient poor soil.

____ includes the establishment of parks and reserves, concentrates on preserving biological diversity in nature.

In situ conservation

What is in-situ vs Ex-situ conservation?

In-situ conservation preserves biological diversity in nature, includes establishment of parks and preserves Ex-situ conservation conserves individual species in human-controlled settings like zoos.

The Southern Hemisphere has no equivalent of the boreal forest of the north. Why?

It has very little land in the corresponding latitudes

Be prepared to describe the development of an ovum from oogonia through to a secondary oocyte.

Lots of oogonia are I the ovaries of a female embryo, during prenatal development, oogonia become primary oocytes which enter a resting phase before birth. During puberty, the primary oocyte completes meiosis I, producing two haploid cells of different sizes. The smaller is a polar body that will disintegrate. The larger enters meiosis II but remains in metaphase II until fertilized. This second division gives rise to a single ovum and another polar body.

Which of the following hormones stimulates ovulation?

Luteinizing hormone

Describe the endocrine regulation of reproduction in the human female and be able to identify key events in the menstrual cycle. Be sure to recognize the roles of the following molecules: estrogen, progestrerone, GnRH, FSH, LH, ABP, and inhibin.

Menstrual cycle has preovulatory phase the first two weeks, ovulation on 14th day, weeks 3 and 4 are postovulatory phase. LH and FSH are low through 1 and 2, peak on ovulation day, steady for 3 and 4. Estrogen steadily increases through 1 and 2 to peak right before ovulation day, it then decreases and peaks again in the middle of the postovulatory phase with progesterone. GnRH stimulates LH and FSH which stimulates inhibin estrogen that inhibits GnRH

Some animals are facing extinction as a direct result of deliberate efforts to exterminate them because of their perceived harm to economically useful species. Examples of these include

Mountain lions and wolves

In the nitrogen cycle, what are the main reservoirs? How is nitrogen converted from one form to another?

N essential part of proteins and nucleic acids. Main reservoir is the atmosphere, 78% N2, which doesn't react with other compounds. Nitrogen is converted from N2 to NH3 by nitrogen fixation by bacteria. NH3 is converted to NO3 by nitrifying bacteria and it is assimilated into plants and animals by consumption/absorption. This is converted back into NH3/NH4 for release back into the environment, NO3 is reduced back into gaseous nitrogen.

Which process is not involved in the hydrologic cycle?

Nitrification

What are the two major elements in the earth's atmosphere? What percentage do they make up?

Nitrogen makes up 78% and Oxygen makes up 21%.

Nitrogen is a critical requirement for living organisms because it is a component of

Nucleic acids and proteins

Biotic pollution (invasive species) has been particularly harmful to native species

On islands

The effect of DDT on birds is a result of which three characteristics of DDT?

Persistence, bioaccumulation, and biological magnification

Fixation of carbon is accomplished by

Photosynthetic organisms

Which of the following series correctly represents the hierarchical organization within ecology?

Population < community < ecosystem < biosphere

Natural selection acts most directly on:

Populations

In large measure, differences in ____ that are due to variations in the amount of _____ at different locations on Earth drive the circulation of the atmosphere.

Rainfall, solar energy

What is restoration ecology, and one example of it working well? (think Costa Rica)

Restoration ecology is scientists trying to return a degraded environment to one that is functional and sustainable. Restoration of prairies in 1930s.

What are the factors that influence aquatic ecosystems?

Salinity (salt concentration), dissolved oxygen, light penetration for photosynthesis, essential minerals, water depth, temperature, pH, presence/absence of waves and currents.

What is the difference between shallow continental seas, the euphotic zone, bathyl and abyssal zones?

Shallow continental seas: continental shelf, photosynthesis, Turtles, jellyfish, seahorses, coral, seaweed The euphotic zone: 0-200 m, photosynthesis, whales, fish, sharks, plankton, turtles Bathyl zones: 200-1,500 m, twilight, shrimp, giant squid, octopi, fish Abyssal zone: 1,500-10,000 m, darkness, angler fish.

The logistic equation:

Takes into account the carrying capacity of the environment

What are the two major components of climate?

Temperature and precipitation.

What two abiotic factors are considered to most affect organisms?

Temperature and water

Which trophic level would contain the lowest quantity of energy (kcal per m2)?

Tertiary consumer

Net primary productivity represents

The amount of biomass in excess of that needed to support plant cell respiration

What is an ecosystem?

The basic units of ecology, made up of individual communities and their abiotic environments.

What is extinction? How much has extinction rates increased during our lifetimes?

The death of a species when the last individual member has died. Extinction rate is 1000 times greater with human activities than the normal background extinction rate.

What is carrying capacity?

The largest population that can be maintained for an indefinite period by a particular environment, assuming no changes in environment.

What is minimum viable population?

The smallest population with a high change of continuing into the future

What is the ultimate source of energy for all life on earth?

The sun

What causes seasons, in terms of the earth's orientation compared to the sun?

The tilt also allows for changes in seasons as the axis tilts toward and away from the sun. Near the equator it is more close to the sun at both times so it stays warm.

Which statement reflects a key concept about ecosystems?

There is a one-way flow of energy through the food webs of ecosystem

What are biodiversity hotspots?

These are small areas of land that contain a large number of species.

Which of the following characteristics applies to biomes?

They encompass interacting landscapes

What is accounting for human's exponential population growth, in terms of changes in the birth and death rate?

This is due to a decrease in death rate, but no increase in birth rate.

What type of curve is related to r and K species?

Type 3 for r, type 1 for K

Be prepared to describe the development of sperm from spermatogonia through to mature sperm.

Undifferentiated diploid cells in the walls of the tubules enlarge and become primary spermatocytes. Meiosis I produces haploid secondary spermatocytes, and meiosis II produces haploid spermatides. Four spermatids are produced from the original primary spermatocyte - each differentiates into a mature sperm.

In the water cycle, what are the major reservoirs of water on earth? How is water moved from one reservoir to another?

Water moves from ocean to atmosphere to land and back to ocean. Main reservoir is ocean. This evaporates into the atmosphere, it condenses as rain, and soaks through the land back into the ocean.

When r = -0.00057, the population size:

Will decrease

An Invasive Species

a foreign species being introduced into an area upsets the balance of organisms there, it causes environmental and economic harm, there is a lack of natural agents to control them, and they are usually introduced by humans.

What is the difference in an age structure chart for a growing, shrinking and non-changing population?

a. Age structure is the number and proportion of people at each age in a population. b. Growing: pyramid, most people are pre-reproductive age. c. Shrinking: upside down pyramid, most people are post-reproductive age. d. Stationary: equal number of people throughout the age groups.

What is birth rate and death rate? How do these compare to each other when the population is growing, shrinking and staying the same?

a. Birth rate is number of individuals born over time. Death is number who die over time. b. Population size depends on the death and birth rates over time. If there is a big birth rate and small death rate, population is increasing. If there is a low birth rate and high death rate, population is shrinking. If the birth and death rate are the same the population stays the same.

1What is the difference between clumped and uniform dispersion? What social tendencies and resource distributions lead to these two types of dispersion?

a. Clumped: individuals are concentrated in specific parts of the habitat. Results from patchy distribution of resources, presence of family groups and pairs, limited seed dispersal, social animals benefit from association (fish less likely to be eaten while in a school). b. Uniform: individuals are evenly spaced. Results from when competition among individuals is severe, plant roots or leaves produce toxic substances that inhibit growth of nearby plants, animals establish feeding or mating territories.

What are density dependent and density independent characters?

a. Density dependent factors are altered in the way they effect a population as that population changes in density. These act as negative feedback systems. b. Density independent factors affect the size of a population but aren't influences by changes in population density. These are typically abiotic like weather events.

What is Ecology? What are the population, community, ecosystem and biosphere levels of organization?

a. Ecology is the study of how organisms and the physical environment interact b. Population: members of the same species that live together in a specific area at the same time. c. Community: all organisms living in a particular area at the same time. d. Ecosystem: community and all the abiotic (environmental) factors they interact with e. Biosphere: where life can exist on the planet.

What is the difference between exponential growth and logistic growth?

a. Exponential growth occurs when optimal conditions allow for constant per capita growth, the larger the population the faster it grows, the results in a J shape curve b. Logistic growth is an S shape, when a population is regulated by environmental limits over long periods. There is an initial exponential increase, followed by a leveling out as carrying capacity is approached.

What is fertility rate? What is replacement rate?

a. Fertility rate is the number of children born per female of childbearing age b. Replacement rate is the number of children a couple must produce to replace themselves.

1. What are some differences between asexual reproduction vs. sexual reproduction? What are some advantages of each type and an example of each?

a. In asexual reproduction, a single parent gives rise to offspring that are genetically identical to the parent. Advantageous when the population density is low, and mates aren't available. Disadvantages is there isn't any genetic variability. Examples are sponges, flatworms, and bacteria. b. In sexual reproduction there is a fusion of two haploid gametes, a male parent provides sperm and a female parent provides the egg/ovum, these unite to form a zygote, the first diploid cell of the new individual. Advantageous as it promotes genetic variety, favored in an unstable environment. Disadvantageous as it is less efficient than asexual production, and not favored in a stable environment.

What are the lifestyle differences between r and K species?

a. Populations with traits that contribute to a high population rate are r species. These are small, mature quickly with a short lifespan, they have large broods with little parental care, these are opportunists in variable, temporary, or unpredictable environments. b. Populations with traits that maximize survival in an environment near the carrying capacity are K species. These produce few offspring, have long lifespans, late reproduction, and large body size. These tend to be found in relatively constant or stale environments where there is high competitive ability.

Briefly describe fertilization, pregnancy, and birth.

a. Sperm ejaculated into female reproductive tract, sperm encounters egg in oviduct, enzymes digest a path through protective lining, entry stimulates second oocyte to complete its second meiotic division. Egg and sperm fuse to produce diploid nucleus of zygote, development of embryo in oviduct begins. After a few days the embryo moves to the uterus. b. After 7 days it implants in the endometrium, estrogen stimulates uterine wall development. After 38-40 weeks high levels of estrogen are secreted to increase the receptors for oxytocin. Oxytocin produces strong contractions

What is a Type I, Type II, and Type III survivorship curve?

a. Survivorship: the probability that a given individual will survive to a particular age. b. Type I: decreases more rapidly with increasing age, mortality is greatest later in life (humans) c. Type II: doesn't change with age, age is equally likely across all age groups (rare) d. Type III: increases with increasing age, young are most likely to die (oysters)

In males, gonadotropin-releasing hormone stimulates the ____ to secrete ____.

anterior pituitary; FSH and LH

Marine snow is a major source of energy for the ____ region of the ocean.

aphotic

In the female, the____ serves as a temporary endocrine gland and secretes ____.

corpus luteum; progesterone and estrogen

Mangroves

cover up to 70% of tropical and subtropical coastal mudflats where tides and waves fluctuate. Roots stabilize sediments, preventing coastal erosion and providing a barrier against the ocean during storms. Roots are breeding grounds and nurseries for commercially important fish and shellfish. Branches are nesting site for many species of birds.

One primary spermatocyte ultimately produces

four mature sperm.

Habitat destruction:

fragmenting or degrading natural habitats resulting in decreased biological range and ability to survive.

Coral Reefs

most diverse of all marine environments, providing habitat for hundreds or thousands of species of fishes and invertebrates. Protect coastlines from shoreline erosion and provide humans with seafood, pharmaceuticals and income from tourism and recreation

Fertilization normally occurs in the ____.

oviduct

An example of a density-dependent factor that influences the size of a population is:

parasites

One function of the developing follicle is to

secrete estrogens.

Which of the following is NOT a condition that is likely to lead to clumped population dispersion?

severe competition among individuals

One advantage of sexual reproduction over asexual reproduction is that

sexual reproduction promotes genetic diversity.

An example of a primary sex characteristic in males is

spermatogenesis.

Salt Marshes

temperate estuaries with shallow wetlands in which salt tolerant grasses dominate, may are polluted by human dumping, many have been filled for development, lost many habitats, sediment and pollution trapping, groundwater supply, and storm buffering.

Near the poles, what is generally the overriding climate factor?

temperature

Kelp Forests

the largest brown algae, are common in cooler temperate marine waters. Primary food producers for the kelp forest ecosystem; provide habitats for many marine animals. Consumed mainly in the detritus food web.

Intertidal Zone

the productive shoreline area between low and high tide with high levels of light, oxygen, and nutrients. Shifty sandy shores: most animals have no notable adaptions to survive exposure. Rocky shores: organisms are adapted to wave action, drying, and temperature.

Conservation biology

the scientific study of how humans impact organisms and the development of ways to protect biological diversity.

Overharvesting

unregulated hunting and fishing, illegal commercial hunting, commercial harvesting of organisms endangers plants and animals.

Freshwater Wetlands

usually covered by shallow water, marshes, swamps. Wildlife habitat, holding areas for river flooding, groundwater recharging areas, cleanse and purify water by trapping and holding pollutants in flooded soil.