8. Adaptation and Environment Flashcards
How is the flea adapted?
- Sharp mouthparts -> Helps break the host’s skin and suck blood
- Flattened body -> Not easily brushed off
- Hard body -> Protection against animals
- Long hind legs -> Helps jump between hosts
How is the tapeworm adapted?
1) Suckers and hooks -> Help attach tapeworm to intestine wall
2) Long, flattened body -> Fits inside intestine + large SA for food absorption
3) Many segments -> Produce lots of eggs
4) Thick outer cuticle -> Stops tapeworm being digested
5) No gut -> Tapeworm absorbs digested food
How are organisms adapted to extreme environments?
Desert animals - large Surface Area : Volume to lose heat
Arctic animals - small Surface Area : Volume to lose less heat
Thermophilic bacteria - Hot springs, sulphur for respiration, survive in low pH conditions
Acidophile - Hot acidic springs, low respiration rate, live in volcanic vents
What is malaria?
A life-threatening disease caused by the single-celled malaria parasite.
What type of organism is the malaria parasite?
Single-celled
In which organisms does malaria’s life cycle take place?
Partly in animals and partly in mosquitos.
Do mosquitos cause malaria?
No, they just pass on the parasite when they bite animals to feed.
How many forms does the malaria parasite have and why?
4 - each one is adapted for living in a different place in the animal or mosquito.
What are the 4 forms of the malaria parasite?
1) Gametocytes
2) Sporozoites
3) Merozoites
4) Schizonts
Describe the life cycle of the malaria parasite.
1) Gametocytes
- Mosquito sucks up blood containing gametocytes
- Gametocytes reproduce sexually
- Gametocytes go to salivary glands + become sporozoites
2) Sporozoites
- Mosquito bites animal + transfers sporozoites to blood
- Sporozoites pass through blood to liver, where they enter liver cells
- Inside cells, sporozoites rapidly divide asexually to produce merozoites
3) Merozoites
- Many merozoites released into blood
- Merozoites invade RBCs
- EITHER 4a or 4b happens
4a) Schizonts
- Merozoite grows + its nucleus divides asexually, producing a cell with many nuclei (schizont)
- Each schizont divides -> Produces many merozoites
- RBC bursts, releasing merozoites and toxins (triggering fever attacks)
- Merozoites each invade a RBC and cycle repeats
(- Infected RBCs usually burst at the same time, resulting in cycles of fever attacks)
4b) Gametocytes Again
- Some merozoites enter sexual reproduction -> Produce gametocytmes
- RBCs containing gametocytes are sucked up by mosquito -> Cycle repeats
How is the malaria parasite adapted?
- Merozoites have sticky protein molecules on surface to help them catch a RBC to invade.
- In animals, the parasites are adapted to live inside cells, making it hard for the immune system to detect and destroy them.
How can the 4 forms of malaria be remembered?
GAMEs and SPORts or MERingues and SCHnapps
What are adaptations?
Characteristics that allow organisms to live in certain environmental conditions.
What are the 3 types of adaptation?
- Structural
- Behavioural
- Functional
What are structural adaptations?
Features of an organism’s body structure (e.g. shape or colour)
Give an example of a structural adaptation.
- Polar bears have white fur for camouflage.
- Whales have a thick layer of blubber for warmth.
- Camels have a large SA:V ratio.
What are behavioural adaptations?
The ways in which organisms behave.
Give an example of a behavioural adaptation.
Swallows migrate to warmer climates in the winter to avoid the problems of living in cold conditions.
What are functional adaptations?
Things that go on inside an organism’s body that can be related to processes like reproduction and metabolism.
Give an example of a functional adaptation.
- Brown bears lower their metabolism while they hibernate to conserve energy.
- Desert animals produce very little sweat and small amounts of concentrated urine to conserve water.
What are extremophiles?
Microorganisms which are adapted to live in very extreme conditions like hot volcanic vents, salty lakes or at high pressure on the sea bed.
Where do fleas live and how do they feed?
- Live in the fur of mammals
* Feed by sucking blood from the host
Where do tapeworms live and how do they feed?
- Live in the intestines of mammals and other animals
* Feed by absorbing digested food
What do plants compete for?
- Light
- Space
- Water
- Minerals
What do animals compete for?
- Space
- Food
- Water
- Mates
Who do organisms compete with?
Other species as well as their own species.
Give an example of competition between species.
Red and grey squirrels live in the same habitat and eat the same food. The competition means that the red squirrel population is in decline.
Give some examples of living factors which affect the environment.
A change in:
1) The number or types of competitions
Give some examples of non-living factors which affect the environment.
A change in:
1) Average temperature
2) Availability of nutrients
3) Amount of light
4) Average rainfall
5) Availability of oxygen and CO2
6) Availability of nesting sites, shelter and habitats
What are communities?
Groups of populations of different species that interact with each other.
How can environmental changes affect populations?
- Population sizes can increase or decrease
* Distribution of populations can change
Give a reason why a population size may increase.
Number of prey may increase -> more food available -> more predators survive and reproduce -> their numbers increase too.
Give some reasons why a population size may decrease.
E.g. Number of bees is the US is decreasing and it could be because:
1) Pesticides -> May have negative effect on bees
2) Less food -> Not many nectar-rich plants
3) More disease -> Bees killed by pathogens
Give a reason why a population’s distribution may change.
Change in temperature may affect where an organism lives.
What are the two ways that environmental change can be measured?
- Living indicators
* Non-living indicators
What are living indicators?
Organisms that are very sensitive to changes in their environment, which can be studied to see the effect of human activity.
How can air pollution be measured using a living indicator?
Lichen are very sensitive to sulphur dioxide. The number and type of lichen in an area show how clean the air is.
What happens when raw sewage is released into a river?
- Bacteria increases.
- Bacteria uses up the oxygen.
- Mayfly larvae are sensitive to oxygen.
- So, if you find mayfly larvae, the river must be clean.
What do invertebrates tell us about a river?
- Some species prefer clean conditions (e.g. mayfly larvae), so they show that the water is clean.
- Other species are adapted to live in polluted areas (e.g. rat-tailed maggots), so they show that the water is polluted.
What are non-living indicators?
Factors such as oxygen levels, temperature and rainfall.
What are the four pieces of equipment that scientists use to measure non-living indicators?
- Satellites -> Temperature of sea surface
- Automatic weather stations -> Atmospheric temperature
- Rain gauges -> Rainfall
- Dissolved oxygen meters -> Concentration of dissolved oxygen in water
What are the advantages and disadvantages of looking at living indicators?
ADV
• Quick, cheap and easy
• Long term because organisms change over a long time
DIS
• Results can be affected by other factors
What are the advantages and disadvantages of looking at non-living indicators?
ADV • Reliable, numerical data that is easy to compare • Exact pollutants can be identified DIS • Expensive • Trained workers needed • Only gives a snapshot of conditions
What is a habitat?
The place where an organism lives (e.g. A playing field)
What is the distribution of an organism?
Where an organism is found (e.g. In a part of a playing field)
Where an organism is found is affected by…
…environmental factors
What are the two ways to study the distribution of an organism?
- Measure how common an organism is in two sample areas and compare them, e.g. using quadrats
- Study how distribution changes across an area, e.g. by placing quadrats along a transect
These both give quantitive data.
What is a quadrat?
A square frame enclosing a known area
How can a quadrat be used to compare two sample areas?
- Place the quadrat at a RANDOM point in the first area (using coordinates and a random number generator)
- Count all of the organisms (of a species) in the quadrat
- Repeat 1 and 2 many times
- Work out the mean amount of organisms per quadrat
- Repeat 1 to 4 in another sample area
- Compare the two areas
How do you work out the population size of an organism in an area?
- Find the mean number of organisms per m2
2. Multiply the mean by the total area
How do you use a transect to study the distribution of organisms along a line?
- Mark out a line
- Collect data by:
a) Simply counting the organisms along that line
b) Placing a quadrat at intervals along the line
When collecting environmental need to think about…
1) Reproducibility and repeatability
2) Validity
How can you make your experiment more reproducible?
Use large sample sizes
e.g. Use as many quadrats and transacts as possible. Bigger sample are more representative of the whole population.
What does repeatable mean?
That the experiment can be repeated in the same area by the same person, with the same equipment and method, and the results will be the same.
What does reproducible mean?
That the experiment can be repeated by another person, or using different equipment and method, and the results will be the same.
When can an experiment’s results be considered valid?
When they:
• Are repeatable
• Are reproducible
• Answer the original question (while controlling all variables)
How can you ensure that a result is valid?
- You just make sure it answers the original question (i.e. Make sure all variables are controlled, except the independent variable).
- Also, make sure it is reproducible and repeatable.
- Use random sampling.
Why must all variable be controlled when comparing the distribution of organisms?
It makes it clear whether the link is correlation or causation.
