BILL. Explain how parasitism differs from mutualism with reference to named organisms.

Transcription

1 BILL Explain how parasitism differs from mutualism with reference to named organisms.

2 BILL define parasitism / one benefits one suffers; define mutualism / both benefit (neither suffer); example of parasite and host (eg tapeworm and human); what the parasite gains from host specific to example given (eg obtains digested food); what the host suffers specific to example given (eg cysticercosis / weight loss); example of two organisms in mutualistic interaction (eg sea anemone and hermit crab); what one gains (eg protection and camouflage); what the other gains (eg mobility);

3 ECOLOGICAL SUCCESSION

4 Ecological Succession Changes that occur in a community over time is called ecological succession Older inhabitants gradually die out and new organisms move in, causing further changes in the community Can be caused by natural and human disturbances

5 Primary Succession Occurs on surfaces where no soil exists First species that appear are called pioneer species Pioneer species add organic material to help form soil in which plants can grow

6

7 Secondary Succession Occurs after wildfires burn woodlands and when land cleared for farming is abandoned When the disturbance is over community interactions tend to restore the ecosystem to its original condition

8

9 Marine Succession

10 HOW POPULATIONS GROW

11 Important Characteristics of Populations Geographic Distribution (range), or the area inhabited by the population Density, or the number of individuals per unit area Growth rate, how fast, slow, or steady a population is in terms of numbers of individuals

12 Growth Rate Three factors affect growth rate: Number of births Number of deaths Number of individuals that enter or leave the population (immigrate/emigrate)

13 Types of Growth Exponential Growth When a population have abundant space and food, and is protected from predators and disease, they will multiply rapidly A population will reproduce at a constant rate

14 Types con t. Eventually resources become less available and the growth of a population slows or stops, called LOGISTIC GROWTH The population will reach their carrying capacity the largest number of individuals an environment can hold

15 LIMITS ON GROWTH

16 Limiting Factors A limiting factor is a factor that causes population growth to decrease Two types of limiting factors Density-dependent Density-independent

17 Density-Dependent Limiting Factors Factors that are limiting only when the population density reaches a certain level Includes competition, predation, parasitism, and disease Ex. Predator Prey Relationships

18 Lynx and Hare

19 Density-Independent Limiting Factors Unusual weather, natural disasters, seasonal cycles, and certain human activities such as damming rivers and clear cutting forests are all examples of limiting factors

20 Human Population Growth

21 Population Growth What influences population growth? Birthrates, death rates, and the age structure of a population help predict population growth Age Structure diagrams can be used to determine the growth rate of a given area

22 Age Structure Diagrams

23 HUMAN IMPACT ON THE BIOSPHERE

24 Progression of Man Early man were mostly hunters and gathers Thousands of years later man developed agriculture

25 Progression con t. Then man came into the industrial revolution Development of factories, cities, and mass burning of fossil fuels

26 Types of Resources Renewable resources can be replenished by natural processes Example trees, fresh water Nonrenewable resources cannot be replenished Fossils fuels such as coal, oil, and natural gas The idea that humans can use these resources without depleting them or harming the environment is called sustainable development

27 Land Resources Soil allows for water to be absorbed and nutrients to be retained for plant growth Removal of plant roots by plowing increases soil erosion Desertification, turning once productive areas into desert, can happen through farming, overgrazing, and drought

28 Forest Resources Forests produce excess oxygen, store nutrients, provide habitat and food to numerous organisms, and limit soil erosion Deforestation, or loss of forest, can lead to severe erosion that can wash away nutrients

29 Fishery Resources Provides people with a wealth of food Overfishing, or the harvesting of fish faster than they can be replaced by reproduction, drastically lowers the available fish to be caught

30 Air Resources Humans need air to breathe The condition of air affects a person s health Cities are a large producer of smog, or a pollutant, due to automobile exhaust Burning of fossil fuels can produces acids in the atmosphere, or acid rain

31

32 Freshwater Resources Humans use fresh water for drinking, washing, and making products We use billions of water daily! Chemicals, bacteria, and sewage can leak into our supplies and be harmful Wetlands are also beneficial because they purify water

33 GENETIC AND BIODIVERSITY

34 Variety is Diversity Biodiversity is the sum total of the genetically based variety of all organisms in the biosphere Genetic diversity refers to the sum total of all the different forms of genetic information carried by all organisms living on Earth today Biodiversity has supplied us with foods, industrial products, and medicines

35 Threats to Biodiversity Extinction Habitat alteration Fragmentation Pollution Biological magnification

36 Threats con t. Invasive Species Species that are introduced into new habitats Survive because there are no predators to limit their numbers and they often reduce the number of available resources to the native species

37 Conserving Biodiversity Conservation describes the management of natural resources, including the preservation of habitats and resources Focus has been on protecting entire ecosystems as well as single species

38

39 HUMAN ACTIVITIES ON THE BIOSPHERE

40 Ozone Depletion Ozone layer lays about km above the Earth and consists of ozone gas It absorbs UV rays and serves as a global sunscreen Since the 1970 s the ozone has been depleting Gap, or hole, in the ozone was found over Antarctica

41

42 Ozone con t. Cause CFC s found in aerosol cans, coolants in refrigerators, freezers, and air conditioners By banning CFC s, the amount in the atmosphere will decrease and within 50 years the ozone holes should shrink and disappear

43 Global Warming Global warming is the increase in the average temperature of the biosphere Human activities that add greenhouse gases and carbon dioxide into the atmosphere could have caused this Greenhouse effect carbon dioxide, methane, water vapor, and other gases trap heat energy Carbon dioxide has been increasing in the atmosphere for 200 years, causing the Earth to retain more heat

44 Effects of Global Warming Global surface temperatures will increase by 1 to 2 degrees Celsius by 2050 Sea levels may rise causing flooding More droughts New organisms may begin to live in areas where they previously couldn t and some species will become extinct

45