Changes in Living Systems

Science 20

Extinct Species in Canada• According to the Species at Risk Act, the following animals are

extinct:• Mammals• Dawson Caribou, 1984 • Sea Mink,1894 • Newfoundland Wolf, 1911 • Banks Island Wolf, 1920 • Cascade Mountains Wolf, 1940 • Birds• Passenger Pigeon • Fish• Benthic Hadley Lake Stickleback • Deepwater Cisco, 1952 • Lake Ontario Kiyi, 1964 • Limnetic Hadley Lake Stickleback • Blue Walleye • Arthropods• Rocky Mountain locust, 1902 • Mollusks• Eelgrass limpet

Extinct Species Worldwide

Quagga, extinct c. 1883, South Africa Thylacine or Tasmanian tiger, extinct c. 1933 Tasmania

Warrah or Antarctic wolf, extinct c. 1876 Falkland Islands

Warrah or Antarctic wolf, extinct c. 1876 Falkland Islands

Changes in Species

• Approximately 74 species are becoming extinct in the world every day. Living things depend on the biotic and abiotic factors in their environment to survive.

• What does biotic and abiotic really mean?

Biotic vs. Abiotic• A biologist might say that your fishing success

depends upon your knowledge of both biotic and abiotic factors in the environment of the fish. In other words, if you want to catch fish, you need to have some understanding of the local ecosystem.

biotic factor: a living organism in the environment

abiotic factor: a physical, non-living part of the environment

ecosystem: all the organisms in an area as well as the abiotic factors with which they interact

Native Species to Bolivia

Native Species to Bolivia

• Left: "Flame Crown", Rebutia fiebrigii, It’s a Bolivian mountain cactus, found at 3600m altitude, and therefore very hardy. It forms a cylinder about 6cm diameter and 10cm tall with few offsets and it produces striking, flame-red flowers over a long season.

• Right: In Bolivia, these pink (often grey and sometimes albino) dolphins can be found in the Madeira, Mamoré and Iténez Rivers. Their brain capacity is 40% greater than that of humans! (Photo: Rainforest Alliance). Guess what! A new species of river dolphin, native to Bolivia, was recently confirmed.

New Species

• Santa Cruz de la Sierra, Bolivia, April 23rd, 2008. The Bolivian river dolphin (Inia boliviensis) lives in the Beni Ecosystem.

• The Bolivian species is smaller and a lighter grey in colour than the other species and has more teeth. It lives only in the Bolivian Amazon and is isolated from the other Amazon River dolphins, separated by a series of 18 rapids between Bolivia and Brazil.

Local Ecosystem

• Think of an ecosystem in Bolivia. What are some biotic and abiotic factors unique to this ecosystem?

Let’s Practice

1. Before fishing in a newly discovered mountain stream, an avid angler uses a butterfly net to collect samples of the local airborne insects that are likely to find their way to the stream’s surface. The angler then examines these insects and selects the flies to be used for that particular stream. Determine if the angler is assessing the biotic or the abiotic factors of the ecosystem containing the stream when collecting the local insects.

Let’s Practice

2. Many streams are shaded by trees that grow close to the water’s edge. Branches extend over the stream.

a. Determine if the trees are a biotic factor or an abiotic factor in the stream’s ecosystem.

b. One effect of the shade cast by trees is to reduce the amount of water being heated by direct sunlight. Determine if the water temperature is a biotic factor or an abiotic factor in the stream ecosystem.

c. Is it possible for an organism to change abiotic factors within an ecosystem?

Water is an Abiotic Factor

• Perhaps the most important abiotic factor in the mountain stream’s environment is the water itself.

• The water is not just found in the stream—it is an essential component of every life form in the ecosystem.

• Water comprises 70% to 95% of all cells. Why is water so important?

• Many ionic components are dissolved in water and are transported between living cells in fluids, such as blood and tree sap. As you learn about other abiotic factors, keep in mind that there are usually connections between these factors and water.

Habitat

• “River dolphins are seriously threatened and in danger of extinction in other continents, such as Asia. Nonetheless, South America, and particularly Bolivia, still have river dolphin populations in relatively good conservation status”, ensured Mr. Fernando Trujillo, scientific director of Fundación Omacha, and leader of the first South American river dolphin census.

Habitat

• Obviously, all the biotic and abiotic factors present within Bolivia are suited towards the river dolphins since they are surviving.

• We say that all the biotic and abiotic factors present in an area that encourage the reproduction and survival of a particular organism are called a habitat.

• Any good habitat for organisms must have lots of nutrients to help it survive.

• nutrient: any element or compound that an organism needs for metabolism, growth, or other functioning

Is there such a thing as too much nutrients?• The Bolivian river

dolphin, is considered an important indicator regarding the quality of the freshwater ecosystems where it lives.

• For scientific study purposes this is fundamental because it allows measuring and evaluating threats, such as those presented by pollution from hydrocarbons, mercury, and algal blooms.

What are algal blooms?• Decomposers break

down decaying organic matter, naturally adding nutrients to the soil. As is the case with gardeners and their potted plants, farmers often supply additional nutrients to soil by using fertilizers.

• Adding fertilizers containing nitrogen and phosphates can double the yield of wheat and barley grown in nutrient-depleted soil.

But…

• If excess fertilizer is carried away from the soil by run-off into local streams and lakes, nutrients from the fertilizer can stimulate the growth of algae, leading to a population explosion. The individual alga, which are normally invisible to the naked eye, now form huge colonies and appear as mats of thick, green ooze. When this situation begins to have negative effects on other organisms, it is called a harmful algal bloom.

algae: microscopic, photosynthetic organisms that play a vital role in marine and freshwater ecosystems

harmful algal bloom: a rapid growth of algae that can deplete the oxygen dissolved in the water and block the sunlight required by other organisms in the aquatic ecosystem

How should we utilize water?