Semester 1: Unit 3 ECOLOGY

Transcription

1 Semester 1: Unit 3 ECOLOGY

2 Ecology- scientific study of interactions among & between organisms & their physical environment.

3 3.1- What is Ecology? Ecology studies levels of organization: *Specie- Individual organism *Population- group of the same type of individuals that live in the same area *Community- groups of different populations living together in a defined area *Ecosystem- all the organisms that live together in a place with their physical environment *Biome- a group of ecosystems that share similar climates & typical organisms *Biosphere- entire planet

4 3.1- What is Ecology? biotic factors- biological influences on organisms (living factors) Examples of biological influences on a bullfrog- algae it eats as a tadpole, herons that eat bullfrogs, & other species competing for food or space.

5 3.1- What is Ecology? Abiotic factors- physical components of an ecosystem (nonliving factors) a bullfrog could be affected by abiotic factors such as water availability, temperature, & humidity.

6 3.1- What is Ecology? abiotic & biotic factors- not always clear Ex: pond muck contains nonliving particles, mold, & decomposing plant material that is food for bacteria & fungi

7 4.1- Climate Weather - day-to-day conditions of Earth s atmosphere Climate- year-after-year patterns of temperature & precipitation. main force in climate= solar energy from sun Some energy absorbed & converted into heat Some heat is trapped in the biosphere & determines average temperature

8 4.1- Climate

9 4.1- Climate Earth s temp controlled by 3 atmospheric gases- CO 2, methane, & water vapor greenhouse gases - allow light to enter but trap heat- the greenhouse effect Greenhouse gas concentrations rise, more heat trapped= Earth warms. Without greenhouse effect, Earth would be 30 C cooler than it is today.

10 4.1- Climate

11 4.2- Niches & Community Interactions Each species has its own tolerance- ability to survive & reproduce under a range of environmental circumstances. Cannot survive past upper & lower limits

12 4.2- Niches & Community Interactions Habitat- place an organism lives. (address) Niche- conditions in which a species lives & how it obtains what it needs to survive & reproduce. (job) resource - necessity of life- water, nutrients, light, food, mates, space Competition- organisms try to use the same limited resource in same place at same time competitive exclusion principle- no 2 species can occupy exactly the same niche in the same habitat at the same time

13 4.2- Niches & Community Interactions Showing different species in different niches in same habitat Competition: winner? Loser?

14 4.2- Niches & Community Interactions Predation- one animal (predator) captures & feeds on another (prey) symbiosis- relationship in which 2 species live closely together 3 types of symbiotic relationships: mutualism- both species benefit parasitism- 1 organism lives in/on another & harms it commensalism- 1 organism benefits & other is not helped or harmed

15 4.3- Succession Ecological succession- series of predictable changes that occurs in a community over time 1-primary succession- begins in areas with no soil or life (ex- volcanic explosion) pioneer species- 1 st to colonize barren areas

16 4.3- Succession 2-secondary succession- begins where soil remains rebuilds faster than primary ex-wildfire, hurricane, natural disturbance, or human activities- logging & farming.

17 4.4- Biomes Biomes- consist of abiotic & biotic factors seasonal patterns of temp & precipitation in a- climate diagram Temp- line graph Precipitation- bar graph

18 5.1- How Populations Grow Exponential Growth: Ideal conditions & unlimited resources, population grows exponentially the larger a population, faster it grows on a graph over time, a J-shaped curve

19 5.1- How Populations Grow Logistic Growth: a population s growth slows & then stops, following exponential growth. Natural populations do not grow long exponentially; something stops growth On a graph, curve has an S-shape

20 5.1- How Populations Grow Carrying capacity- maximum # of individuals that a particular environment can support. Where dotted line intersects the y-axis = carrying capacity.

21 5.2- Limits to Growth limiting factor- factor that controls the growth of a population 1. Density-dependent limiting factors -operate strongly when population density is large. D-D L F: competition, predation, herbivory, parasitism, disease, stress from overcrowding Competition: populations become crowded, individuals competefood, water, space, sunlight, etc. lower birthrates, increased death rates

22 5.2- Limits to Growth Predation: predator population affects prey population & viceversa Herbivore Effects: To plants, herbivores are predators

23 5.2- Limits to Growth Parasitism and Disease: Parasites & disease-causing organisms feed & harm hosts- weaken, cause disease, or death more dense host population, easier to spread Stress From Overcrowding: species fight if overcrowded; increase stress & weaken body s ability to resist disease Females neglect, kill, or eat own offspring decrease births, increase deaths, & increase emigration

24 5.2- Limits to Growth 2- Density-Independent limiting factors- affect all populations regardless of size & density D-I L F include: Unusual weather- hurricanes, droughts, floods, & natural disasters- wildfires

25 6.1- A Changing Landscape Sustainable development- provides for human needs & preserves ecosystems that produce natural resources. Goods- items that can be bought & sold Services- processes or actions that produce goods. ecosystem goods & services- produced by ecosystems that benefit human economy. Healthy ecosystems provide goods & services naturally & free of charge: air, water

26 6.2 Using Resources Wisely Biological magnification- a pollutant is picked up by an organism & is not broken down or eliminated from its body. pollutant collects tissues & build as it moves up trophic levels in body

27 6.3 Biodiversity Biodiversity- total of all the genetically based variation in all organisms in biosphere. Ecosystem diversity- variety of habitats, communities, & ecological processes in the biosphere species diversity- number of different species in the biosphere or particular area Genetic diversity- sum total of all different forms of genetic information carried by a particular species, or all organisms on Earth.

28 6.3 Biodiversity Humans reduce biodiversity by: *altering natural habitats *hunting *introducing invasive/exotic species *releasing pollution into food webs *contributing to climate change To conserve biodiversity, we must protect species, preserve habitats & ecosystems ecological hot spot- place where large numbers of species & habitats are in immediate danger of extinction.

29 6.3 Biodiversity Development splits ecosystems into pieces- habitat fragmentation- leaving habitat islands - patch of habitat surrounded by a different habitat. 6.4 Meeting Ecological Challenges ecological footprint- total area of functioning land & water ecosystems needed to provide the resources an individual or population uses & to absorb the wastes that it generates.

30 6.4 Meeting Ecological Challenges Ecology can guide humans toward a sustainable future & have a positive impact on the global environment by: (1) recognizing a problem in the environment (2) researching the problem to determine its cause (3) using scientific understanding to change our behavior