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17 Jul 2019

Please explain your answer if you can. Thank You!

What is the difference between planktons and nektons?

A. planktons are algae and cyanobacteria, nektons are larger plants

B. planktons are autotrophic, nektons are heterotrophic

C. planktons are mostly microscopic, nektons are macroscopic

D. planktons are in both freshwater and seawater, nektons are only in freshwater

The distribution of life in aquatic ecosystems are determined by;

A. all these factors determine the distribution of life

B. quality and quantity of light available at different depths

C. temperature changes at different depths

D. oxygen availability at different depths of water

Which of these would you find in the benthic zone of a freshwater lake?

A. large fish

B. submerged flowering plants

C. bacteria

D. green algae

The littoral zone of the ocean is characterized by;

A. the constantly high salinity in water

B. the presence of kelp forests

C. the presence of large marine animals

D. the presence of higher plants

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19 Jul 2019

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I am having trouble with these. Can you please explain correct answer for each? Thank you so much!

Which of these would you find in the benthic zone of a freshwater lake?

A. large fish

B. submerged flowering plants

C. bacteria

D. green algae

Bogs are areas with acidic soils in which carnivorous plants can often be found preying on insects. If insects are a good source of nitrogen, why don ?t more plants in all other ecosystems adopt carnivorous habits?

A. plants in other habitats obtain nitrogen from bacteria in their root nodules.

B. insects in other habitats do not contain as much nitrogen.

C. insects are more mobile and hard to catch in non-swampy areas.

D. it is more energy efficient to absorb nitrogen from soils that are not deficient of nitrogen

Millions of acres of spruce trees have been killed due an explosive increase in spruce bark beetles in recent years, and scientists suggest global warming as the underlining cause. How could this be related to global warming?

A. longer, warmer seasons have resulted in increased beetle populations.

B. spruce is more susceptible to beetles at high temperatures.

C. global warming is the cause of acid rain, and the trees are being weakened.

D. spruce bark beetles did not attack spruce trees until the Industrial Revolution.

In sustainable farming practices involving crop rotation, should the land be covered at all times with plant material?

A. No, the decaying foliage harbors disease.
B. No, it should be tilled under to add nutrients to the soil.
C. yes, because this minimizes the breeding of pests in soil
D. yes, this lessens erosion of topsoil.

7) According to the Red Queen hypothesis,

A) the population density of a predator depends on thepopulation density of its prey.

B) natural selection should favor the most efficientforagers.

C) prey must continually evolve means of avoiding capture toavoid extinction.

D) most predators consume a varied diet in order to meet theirnutritional requirements.

8) Which of the following is an example of crypticcoloration?

A) a brown bird that nests on the ground

B) a deer with a large, white tail

C) skunks with black and white stripes

D) snakes with black, yellow, and red bands

9) Which of the following is not a class of plant secondarycompounds?

A) terpenoids

B) phenolics

C) nitrogen-based compounds

D) alkanes

15) When an ecologist compares the diversity of differentcommunities by counting the number of species within eachcommunity, the measure of diversity being used is called

A) species evenness.

B) species diversity.

C) species richness.

D) relative abundance.

16) In a rank-abundance curve comparing two communities, thecommunity with the greater species richness is characterized bya

A) lesser length of the curve and a more gradual slope.

B) lesser length of the curve and a steeper slope.

C) greater length of the curve and a more gradual slope.

D) greater length of the curve and a steeper slope

19) The layer of a forest in which decomposition takes place andmineral nutrients are released for reuse by plants is calledthe

A) canopy.

B) understory.

C) herb layer.

D) forest floor.

20) Zonation within a community is typically the result ofdifferences in the

A) patterns of predation among species within a community.

B) rates of reproduction among species within a community.

C) patterns of competition among species within a community.

D) physical characteristics of the environment across a spatialgradient.

21) Food webs are typically arranged into trophic levelswith

A) primary producers at the bottom, herbivores in the middle,and carnivores at the top.

B) herbivores at the bottom, carnivores in the middle, andprimary producers at the top.

C) carnivores at the bottom, herbivores in the middle, andprimary producers at the top.

D) primary producers at the bottom, carnivores in the middle,and herbivores at the top.

22) When top-down control occurs within an intertidal zone alongthe rocky coastline of the Pacific Ocean, which of the followingspecies controls the abundance of other species?

A) kelp

B) mussels

C) barnacles

D) starfish

23) In coastal aquatic environments, the three majorenvironmental gradients of water that directly influence thedistribution and dynamics of communities include

A) temperature, depth, and top down regulation.

B) depth, aposematic coloring, and salinity.

C) pressure, temperature, and depth.

D) tidal action, salinity, and oxygen content.

28) The number of species within a community is usually greatestwhen

A) no disturbance occurs.

B) a low frequency of disturbance occurs.

C) an intermediate frequency of disturbance occurs.

D) a high rate of disturbance occurs

29) Succession in a community involves

A) only autotrophic species.

B) only heterotrophic species.

C) both autotrophic and heterotrophic species.

D) only detritivorous species.

32) The highest diversity of plant and animal life occurs in

A) tropical savannas.

B) tropical rain forests.

C) temperate deciduous forests.

D) boreal forests.

33) Plants that root and grow on other plants in the tropicalrain forest are called

A) phreatophytes.

B) succulents.

C) epiphytes.

D) halophytes.

34) Tropical Savannas typically occur in

A) cold areas with little rainfall in polar regions.

B) cold areas with little rainfall at high altitudes in thetropics.

C) very dry areas in the rain shadow of mountains of bothtemperate and tropical latitudes.

D) warm areas with seasonal rainfall in the tropics.

37) The vegetation of tundra is dominated by

A) broadleaf deciduous trees.

B) short ground covering plants such as sedges and heaths.

C) needle-leaf evergreen trees.

D) sclerophyllous broadleaf evergreen shrubs.

38) The part of a rocky shore in which barnacles, oysters,mussels, limpets, and brown algae are most common is called the

A) littoral or intertidal zone.

B) infralittoral or subtidal zone.

C) supralittoral or supratidal zone.

D) superlittoral or supertidal zone.

39) In comparison to rocky coasts, intertidal organisms livingon sandy or muddy beaches

A) experience greater variability in salinity.

B) experience greater variability in temperature.

C) are more likely to be attached to the substrate.

D) are more likely live burrowed and emerge with the incomingtide.

40) In salt marshes, predatory fish move in when

A) the tide is high.

B) migratory fishes are spawning.

C) the sun goes down.

D) salinity is low.

41) Intertidal mud flats in tropical regions are typicallycomposed of

A) salt marshes.

B) peatlands.

C) mangrove forests or mangals.

D) oysterbeds.

42) Mangrove swamps

A) are formed by a single species of tree adapted to variablesalinities.

B) have relatively anoxic soils.

C) occur mostly in temperate latitudes.

D) typically occur along rocky coastlines subjected to heavywave action.

43) Freshwater wetlands dominated by woody vegetation arereferred to as

A) swamps.

B) marshes.

C) mangrove forests or mangals.

D) prairie potholes.

44) The number of species of living organisms on the planet isprobably closest to

A) 100,000.

B) 1,000,000.

C) 10,000,000.

D) 100,000,000.

45) The end of the Permian period was characterized by a massextinction of

A) shallow-water marine invertebrates.

B) dinosaurs and other large reptiles.

C) small mammals.

D) large mammals.

46) The dinosaurs and many other animals became extinct at theend of the

A) Cambrian period.

B) Permian period.

C) Cretaceous period.

D) Pleistocene epoch.

47) Species richness of terrestrial plants and animals increaseswith

A) latitude.

B) the structural diversity of plant communities.

C) elevation.

D) flatter terrain.

48) In marine environments,

A) both species richness and productivity increase withlatitude.

B) species richness increases and productivity decreases withlatitude.

C) species richness decreases and productivity increases withlatitude.

D) both species richness and productivity decrease withlatitude.

49) As temperatures decreases with latitude in marineenvironments,

A) both species richness and species dominance increase.

B) species richness increases and species dominancedecreases.

C) species richness decreases but productivity increases.

D) both species richness and species dominance decrease.

50) All species eventually become extinct

A) True

B) False

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