Topic_5_-_Ecology_Class_Presentation11.ppt

5.1 Communities and Ecosystems

5.1.1

Define: (1)

Ecology—the study of relationships between living organisms and between organisms and their environment.

Ecosystem—a community and its abiotic environment.

Population—a group of organisms of the same species who live in the same area at the same time.

Community—a group of populations living and interacting with each other in an area.

Species—a group of organisms which can interbreed and produce fertile offspring.

5.1 Communities and Ecosystems

5.1.2

autotroph (producer) – organisms that use an external energy source to produce organic matter from inorganic raw

materials

Examples: trees, plants, algae, blue-green bacteria

5.1 Communities and Ecosystems

heterotroph (consumer) – organisms that use the energy in organic matter,

obtained from other organisms

5.1 Communities and Ecosystems

1. consumers – feed on other living things 2. detritivore – feed on dead organic matter

by ingesting it

3. saprotroph (decomposer) – feed on dead organic material by secreting digestive

enzymes into it and absorbing the products

5.1 Communities and Ecosystems

5.1.4

Describe what is meant by a food chain

giving three examples, each with at least three linkages (four organisms). (2)

A food chain is a sequence of relationships between trophic levels where each

member feeds on the previous one.

5.1 Communities and Ecosystems

5.1.5

Describe what is meant by a food web. (2)

A food web is a a diagram that shows the

feeding relationships in a community. The arrows indicate the direction of energy

5.1 Communities and Ecosystems

5.1.6

Define trophic level. (1)

A trophic level is where an organism is positioned on a food web (it’s feeding relationship to other organisms).

Producer

Primary consumer

5.1 Communities

and Ecosystems

5.1.7

Deduce the trophic level of organisms in a food chain and a food web.

(3) Quaternary consumers Tertiary consumers Carnivore Carnivore Secondary consumers Carnivore Primary consumers Herbivore Primary producers Plant

5.1 Communities and Ecosystems

5.1.9

State that light is the initial energy source for almost all communities. (1)

5.1.10

Explain the energy flow in a food chain. (3) Microorganisms and other detritivores Tertiary consumers Secondary consumers

Detritus Primary consumers

5.1.11

State that energy transformations are 10–20% efficient. (1)

Growth (new biomass)

Cellular respiration Feces 100 J

33 J

67 J 200 J

5.1.12

Explain what is meant by a pyramid of energy and the reasons for its shape. (3)

5.1 Communities and Ecosystems

5.1.13

Explain that energy can enter and leave an

ecosystem, but that nutrients must be recycled. (3)

Energy enters as light and usually leaves as heat. Nutrients do not usually enter an ecosystem and

Assimilation

N₂ in atmosphere

Decomposers Nitrifying bacteria Nitrifying bacteria Nitrogen-fixing soil bacteria Denitrifying bacteria Nitrification Ammonification Nitrogen-fixing bacteria in root nodules of legumes

NO₃–

NO₂–

NH₄+

NH₃

G1 Community Ecology

• G.1.1 Outline the factors that affect the distribution of plant species, including

• G.1.2 Explain the factors that affect the distribution of animal species including temperature, water, breeding sites, food supply and territory.

Assignment Question

Think about what will effect how plants are distributed in an

G1 Community Ecology

G.1.5 Explain what is meant by the niche concept.

The total of a species’ use of biotic and abiotic resources is called the species’ ecological niche.

- Habitat

- Feeding relationships

G1 Community Ecology

G.1.7 Explain the principle of competitive exclusion.

• two species competing for the same

G1 Community Ecology

Fundamental = where the species is designed to live the best

G1 Community Ecology

G1 Community Ecology

G.1.9 Define biomass - each tier represents the dry weight of all organisms in one

trophic level

Trophic level Dry weight (g/m2)

G2 Ecosystems and biomes

production.

Gross Production = the amount of light energy converted to chemical energy by autotrophs in an ecosystem

Net Production = Energy able to be passed on by producers to consumers

G2 Ecosystems and biomes

G2 Ecosystems and biomes

secondary succession.

• Primary succession occurs where no soil exists when succession begins

G2 Ecosystems and Biomes

• G.2.7 Outline the changes in species diversity and

production during

primary succession. • Not very diverse:

Lichen pioneer species

G2 Ecosystems and Biomes

• G.2.8 Explain the effects of living organisms on the abiotic environment, with reference to the changes occurring during primary succession. • Small amount of soil formed by the lichens is

colonized by mosses, which do not have roots and require little soil

• As the seedless plants live and die

G2 Ecosystems and biomes

biosphere.

• Biome = Communities on earth that contain similar plant and animal

inhabitants

• Biosphere = part of Earth that can contain life

G2 Ecosystems and Biomes

• G.2.11 Outline the characteristics (temperature, moisture, vegetation) of six major biomes.

• Desert

• Grassland • Shrubland

• Temperate deciduous forest • Tropical rainforest

• G.1.3 Describe one method of random

sampling, based on quadrat methods, that is used to compare the population size of two plant or two animal species.

1) Mark off a large 10 x 10 meter grid area

2) Toss a 1 x 1 meter square into the grid area randomly 3) Identify and count all the larger plant species first

4) Smaller plant species, like grass, divide your square into several smaller 10 x 10 cm squares. Count the number of

individual plants in several of those smaller squares, average, and multiply by 100 to get an estimate.

G3 Impacts of humans on

ecosystems

• G.3.1 Calculate the Simpson diversity index for two communities.

• N – total number of individual organisms (all species combined)

G3 Impacts of humans on

ecosystems

• G.3.2 Analyse the biodiversity of the two local communities using the Simpson index.

• High Index (closer to one) – Higher the biodiversity

• This index ranges from zero to one and is

Internal Assessment

5.3 Populations

5.3.1

Outline how population size can be affected by natality, immigration, mortality and emigration. • Natality – offspring are produced and added to

the population

• Mortality – individuals die and are lost from the population

• Immigration – individuals move into the area

from somewhere else and add to the population • Emigration – individuals move out of the area

5.3 Populations

5.3.2

Draw a graph showing the sigmoid

5.3 Populations

Population increases exponentially because the natality rate is higher than the mortality rate. This is because there is an

5.3 Populations

Difference between natality and mortality rates are not as great, but natality is still higher so population continues to grow, but at a slower rate.

5.3 Populations

Plateau Phase

Natality and mortality are equal so the population size stays constant.

Limiting Factors:

shortage of food or other resources increase in predators

more diseases or parasites

5.3 Populations

Define carrying capacity.

The maximum

5.3 Populations

In a random sample, every individual in a population has an equal chance of being selected.

Describe one technique used to estimate the

population size of an animal species based on a capture-mark-release-recapture method.(2)

• Various mark and recapture methods exist.

• Knowledge of the Lincoln index (which involves one mark, release and recapture cycle) is

5.3 Populations

population size =

where . . .

• n1= number of individuals initially caught, marked and released • n2 = total number of individuals caught in the second sample • n3 = number of marked individuals in the second sample

3

2

1

5.3 Populations

5.2 Greenhouse effect

Draw the carbon cycle to show the processes involved.

• The details of the carbon cycle should

include the interaction of living organisms and the biosphere through the processes of photosynthesis, respiration, fossilization and combustion. Recall of specific

5.2 Greenhouse Effect

Analyze the changes in concentration of atmospheric carbon dioxide using

historical records.

5.2 Greenhouse effect

• Explain the relationship between rises in concentrations of atmospheric carbon

Greenhouse Effect

Light from the sun has short wavelengths and can pass through most of the

atmosphere.

This sunlight warms the earth which in turn emits long wave radiation.

This long wave radiation is bounced back by the greenhouse gases, such as carbon

5.2 The greenhouse effect

5.2.6 Outline the

consequences of a global temperature rise on arctic

ecosystems.

- Loss of ice habitat

G3 Impacts of humans of

ecosystems

• Ozone layer absorbs UV radiation

• CFCs are causing a hole in the ozone

layer

• Excessive UV

radiation can cause:

– Skin cancer

G3 Impacts of humans on

ecosystems

• G.3.4/5 List 3 examples of introduced/alien species and discuss the impact.

-Purple Loosestrife

-spread alarmingly fast,

- removed from their natural controlling agents.

- dramatic disruption in water flow in rivers and canals,

G3 Impacts of humans on

ecosystems

• Zebra mussels were first detected in the Great Lakes in 1988 and have caused widespread damage in the ecosystem.

• Zebra Mussels are edible, but most experts advise against eating any found in areas of pollution concern since zebra mussels accumulate

G3 Impacts of humans on

ecosystems

- Round Goby

- Survives well in

degraded environmental conditions

-Competitive advantage compared to native

species.

-Heavy feeding on invasive mussels

(zebra and quagga) results in greater biomagnification

Define biomagnification –

G3 Impacts of humans on

ecosystems

• How can we keep invasive species in check via a biological mechanism?

– Decide on a local area that is currently being impacted negatively by an invasive species.

– Find out what that negative impact is and which of the invasive species is causing it.

– Research a BIOLOGICAL means of controlling that species in order to stop the negative impact. – Put together a proposal illustrating your method of