Biology - PowerPoint PPT Presentation

About This Presentation
Title:

Biology

Description:

Biology CST Review PowerPoint in Ecology Biology CST Review PowerPoint in Ecology ACCORDING TO THE BLUEPRINTS 6. Stability in an ecosystem is a balance between ... – PowerPoint PPT presentation

Number of Views:73
Avg rating:3.0/5.0
Slides: 18
Provided by: setu78
Category:

less

Transcript and Presenter's Notes

Title: Biology


1
Biology
  • CST Review PowerPoint in Ecology

2
ACCORDING TO THE BLUEPRINTS
6. Stability in an ecosystem is a balance between
competing effects. As a basis for understanding
this concept a. Students know biodiversity is
the sum total of different kinds of organisms and
is affected by alterations of habitats. b.
Students know how to analyze changes in an
ecosystem resulting from changes in climate,
human activity, introduction of nonnative
species, or changes in population size. c.
Students know how fluctuations in population size
in an ecosystem are determined by the relative
rates of birth, immigration, emigration, and
death. d. Students know how water, carbon, and
nitrogen cycle between abiotic resources and
organic matter in the ecosystem and how oxygen
cycles through photosynthesis and respiration.
e. Students know a vital part of an ecosystem is
the stability of its producers and decomposers.
f. Students know at each link in a food web some
energy is stored in newly made structures but
much energy is dissipated into the environment as
heat. This dissipation may be represented in an
energy pyramid.
3
Biodiversity
  • Biodiversity is the variation of life forms
    within a given ecosystem, biome, or on the entire
    Earth. Biodiversity is often used as a measure of
    the health of biological systems. The
    biodiversity found on Earth today consists of
    many millions of distinct biological species.
  • Today there is concern about the mass reduction
    in biodiversity caused primarily by the impact
    humans are having on the environment,
    particularly the destruction of plant and animal
    habitats.

4
Question Name some ecosystems that show high
biodiversity and low biodiversity. Question Why
are ecosystems healthy if they exhibit high
biodiversity? Question What human practices can
lead to a reduction in biodiversity? Question
Why should a loss in biodiversity be of great
concern to us?
5
Introduction of Non-native Species
  • An introduced, alien, exotic, non-indigenous, or
    non-native species, or simply an introduction, is
    a species living outside its native
    distributional range, which has arrived there by
    human activity, either deliberate or accidental.
  • Some introduced species are damaging to the
    ecosystem they are introduced into, others
    negatively affect agriculture and other human
    uses of natural resources, or impact on the
    health of animals and humans.
  • The greatest impact is caused by introduced
    species that change an entire habitat, because
    many native species thrive only in a particular
    habitat.
  • Other invaders, though they do not change a
    habitat, endanger single species or even entire
    groups of them in various ways.

Water hyacinth from South America
6
POPULATIONS
-A population is a group of organisms of the same
species that live in a particular area. -The
number of organisms in a population changes over
time because of the following births, deaths,
immigration, and emigration. -Births and
immigration increase the size of the population
whereas, deaths and emigration decrease the size.
Immigration Individuals arrive at the habitat.
Emigration Individuals leave the ecosystem.
7
Population growth is the change in a population
over time, and can be quantified as the change in
the number of individuals of any species in a
population using "per unit time" for measurement.
Many factors influence population growth, for
example, availability of resources, presence of
predators, diseases, etc.
8
Population Density
Population density may be defined as simply the
number of individual organisms per unit
area. Distribution can be uniform, random, or
clumped.
Uniform
Random
Clumped
9
Energy in the Ecosystem
  • The source of all food is the activity of
    autotrophs, mainly photosynthesis by plants.
  • They are called producers because only they can
    manufacture food from inorganic raw materials.
  • This food feeds herbivores, called primary
    consumers.
  • Carnivores that feed on herbivores are called
    secondary consumers.
  • Carnivores that feed on other carnivores are
    tertiary (or higher) consumers.
  • Such a path of food consumption is called a food
    chain.
  • Each level of consumption in a food chain is
    called a trophic level.

GRASS GRASSHOPPER TOAD
SNAKE HAWK
10
Decomposers (or saprotrophs) are organisms that
break down the dead or decaying organisms, and in
doing so carry out the natural process of
decomposition. Like herbivores and predators,
decomposers are heterotrophic, meaning that they
use organic substrates to get their energy,
carbon and nutrients for growth and development.
Decomposers use deceased organisms and non-living
organic compounds as their food source. The
primary examples are bacteria and fungi.
11
Pyramids of Energy and Biomass
An ecological pyramid is a graphical
representation designed to show the biomass at
each trophic level in a given ecosystem. Biomass
pyramids show the abundance or biomass of
organisms at each trophic level. Ecological
pyramids begin with producers on the bottom (such
as plants) and proceed through the various
trophic levels (such as herbivores that eat
plants, then carnivores that eat herbivores, then
carnivores that eat those carnivores, and so on).
The highest level is the top of the food chain.
Loss of Matter and Energy - At each trophic level
along a food chain, there is always a 'loss' of
matter and energy in the forms of waste (e.g.
carbon dioxide, feces), and heat and kinetic
energy (e.g. constant body temperature of
mammals, the energy used to move). Up to 90 of
matter and energy can be 'lost' at each level.
12
10 Efficiency in Energy Transfer!
Loss of Matter and Energy - At each trophic level
along a food chain, there is always a 'loss' of
matter and energy in the forms of waste (e.g.
carbon dioxide, feces), and heat and kinetic
energy (e.g. constant body temperature of
mammals, the energy used to move). Up to 90 of
matter and energy can be 'lost' at each level.
13
Carbon Cycle Five major reservoirs of Carbon a.
Atmosphere b. The terrestrial biosphere (soil,
freshwater). c. Oceans d. The sediments
including fossil fuels. e. The earth's interior,
carbon from the earth's mantle and crust
14
The Carbon Cycle
-Plants fix the Carbon from CO2 into glucose
through photosynthesis using light
energy. -Oxygen gas is one of the products of
photosynthesis. -Cell Respiration in both animals
and plants break down glucose to yield energy,
producing CO2 as a by-product. -O2 and CO2 cycles
from plants and animals via the complementary
processes of photosynthesis and respiration.
Decomposition and combustion are two other
processes that contribute CO2 gas into the
atmosphere.
15
The Nitrogen Cycle
  • Key processes
  • Nitrogen-fixation
  • Nitrification
  • Denitrification

2
3
1
1. Nitrogen fixation- is the process by which
nitrogen (N2) in the atmosphere is converted into
ammonia. This process is essential for life
because fixed nitrogen is required to
biosynthesize the basic building blocks of life,
e.g. nucleotides for DNA and amino acids for
proteins.
16
Nitrogen Cycle, continued
-Certain bacteria, called Nitrogen-fixing
bacteria, live in nodules found in the roots of
some plants. These bacteria possess the enzymes
that can fix nitrogen gas into ammonia. 2.
Nitrification- Nitrifying bacteria from the soil,
can convert the ammonia produced by decay, into
nitrates, a process called nitrification.
Plants can directly use N in the form of
nitrates. 3. Denitrification- Denitrification
reduces nitrates to nitrogen gas, thus
replenishing the atmosphere.
Legumes such as peas, clover, and beans have
nitrogen-fixing bacteria in their roots. This
enables them to grow in nitrogen-poor soil.
Plants take up nitrates through their roots, and
convert them into proteins and other compounds.
17
Ecological Relationships
  • Organisms within ecosystems may be involved in
    any of these relationships
  • Symbiosis- interaction between two organisms
    where at least 1 benefits.
  • a. Commensalism- one species benefits, the
    other species is not affected.
  • b. Mutualism- both species benefit.
  • 2. Parasitism-one species benefits, the other
  • species is harmed.
  • 3. Predation- one species preys (kills for
    food)
  • another species.
  • 4. Competition-
  • exists when species
  • fight for food and
  • other resources.
  • This may be intra-
  • or inter-specific.

This is an example of commensalism- he barnacle
gains a place to live and, presumably, the
scallop is not harmed.
A lamprey, is an ectoparasite.
Write a Comment
User Comments (0)
About PowerShow.com