Life On Earth Nat5 Flashcards
1
Q
What is a species?
A
À species is a group of organisms which can interbreed to produce a fertile offspring
2
Q
What is a habitat?
A
A habitat is where an organism lives
3
Q
What is a ecosystem?
A
An ecosystem is living organisms (community) in a particular habitat and the non living components.
4
Q
What is a population?
A
A group of organisms of one species.
5
Q
What is a community?
A
A community is all living organisms together in a ecosystem
6
Q
Examples of an ecosystem ?
A
Pond Coral Reef Desert Forest Rainforest Swamp
7
Q
What is Biodiversity?
A
The variation of life
8
Q
What is producer?
A
They are organisms that make there own food.( they are usually green plants)
9
Q
What are consumers?
A
Consumers are organisms that eat other organisms in the food chain.
10
Q
What are herbivores ?
A
Only eat plants
11
Q
What are carnivores?
A
Only eat animals
12
Q
What are omnivores?
A
They eat both animals and plants
13
Q
What are predators?
A
Animals that hunt
14
Q
What are preys?
A
Animals that are hunted
15
Q
What are primary consumers?
A
Primary consumers are the first to consume any energy and eat the producers. (They are herbivores)
16
Q
What are the secondary consumers?
A
Second organism to consume any energy and eats the primary consumer. They are carnivores.
17
Q
What is a food chain?
A
A food chain is a diagram that shows interconnected food chains.
18
Q
What is a niche
A
a niche is the fit of a species living under specific environmental conditions. The ecological niche describes how an organism or population responds to the distribution of resources and competitors and how it in turn alters those same factors
19
Q
When does competition occur?
A
Competition occurs between plants and animals in a ecosystem when resources are in short supplies.
20
Q
What are limiting factors for animals?
A
Food, water, mates and space
21
Q
What are the limiting factors for plants?
A
Water, nutrients, light and space
22
Q
What is interspecific competition?
A
It is competition between the different species.
23
Q
What is intraspecific?
A
It is competition between the same species.
24
Q
What are quadrates?
A
They are a way of sampling slow moving organisms.
25
What is a pitfall trap?
It’s is a way of sampling small invertebrates living on the ground.
26
What is a abiotic factor?
Are a non living variable where organisms live
27
How can we mesure abiotic factors?
Light meter, moisture meter, pH meter and thermometer
28
What should you always do with sampling techniques?
Repeat for reliability
29
Examples of abiotic factors?
Light intensity, moisture, pH and temperature
30
What is a transect line?
A transect line is set up a to investigate the affect of an abiotic factor on the distribution of organisms
31
What are biotic factors ?
They are all factors that effect a species due to the act of living things.
32
What are abiotic factors?
They are non living factors which affect species
33
What do biotic factors include?
- Completion for resources
- Diseases
- Food availability
- Grazing
- Predation
34
What are keys used for?
Keys are used for identifying organisms that are sampled
35
What are indicators species?
They are species that by there presence of absence indicate environmental quality.
36
What is the first stage of photosynthesis?
Light reactions
37
What is the second stage of photosynthesis?
Carbon fixation
38
What is photolysis?
It is when light energy is used to split water molecules into hydrogen and oxygen
39
How does the process of light reaction work?
The light energy is trapped by the chlorophyll in the chloroplast and then it’s converted into chemical energy .
The energy is used to generate ATP
40
Where does the water come from in photosynthesis?
Soil
41
How does water get into the plant?
Water is obtained through the roots of the plant. This is called osmis
42
What is the product of stage 1?
Oxygen
43
What is the second stage of photosynthesis?
Carbon fixation
44
Why is the carbon fixation stage known a the temperature dependant stage?
It is a series of enzymes controlled reaction. Enzymes require a optimum temperature to work best.
45
How does carbon dioxide get in the plant?
Diffusion through the tiny pores on the surface of the leaf
46
What are the things do you need to make sugar?
Hydrogen, carbon dioxide and ATP
47
What can the chemical energy in sugar used for?
- Respiration
- Stored as starch
- Made into cellulose for structural support for the plant
48
What is it meant by limiting factors?
Factors that prevent photosynthesis from occurring
49
What are the limiting factors?
Light intensity, carbon dioxide concentration and temperature
50
What does hydrogencarbonate tell us?
If carbon dioxide is present
51
The colours that hydrogencarbonate indicators change?
Atmosphere air- orange/red
Carbon dioxide- Yellow (photosynthesis isn’t taking place)
Carbon dioxide removed- deep purple (photosynthesis is taking place)
52
Why will plants photosynthesise more slowly when there is less carbon dioxide?
Carbon dioxide is a raw material so the plant will need to photosynthesise
53
Examples of using energy?
Movement, growth, heat and undigested materials
54
Can energy be passed to another organism by eating another organism?
Only the energy used for growth is passed on. (10%)
55
What can pyramids of numbers used for?
The number of organisms at each stage of the food chain
56
What can pyramids of energy used for?
Quantity of energy at each level of the food chain
57
Why can pyramids of number not be accurate?
Because sometimes the organism can support the food chain because its size, for example a tree.
58
What can be done to increase food yields?
Fertilisers and pesticides
59
Why would nitrates help improve crop yield ?
nitrates is needed by all living organisms to make protein.
Protein is used for growth.
60
What do nitrates produce?
Amino acids which are synthesised into plant proteins
61
What are pesticides?
It is a chemical which is applied to the plants which kill pests and weeds
62
What would happen to the fertiliser if too much was sprayed on the crops?
Fertilisers can leach into fresh water, adding extra, unwanted nitrates.
63
What can too much nitrates do?
If too much nitrates get into the water, tiny organisms called algae feed on the nitrates. This will increase algal populations which can cause algal blooms.
64
What do algal blooms do?
They reduce light levels by preventing sunlight from reaching the plants under the water. These aquatic plants will die as they will not be able to photosynthesise.
65
What will happen to the algae and the plants when they eventually die?
These dead plants, as well as dead algae, become the food for bacteria which increase greatly in number as there is more food for them.
66
What can be used instead fertilisers?
GM
67
What do you think could be used instead of pesticides to remove pests from crop?
An alternative to the use of pesticides is biological control.
68
What is bioccumulation?
This happens due to the pesticides being taken up by plants. These plants are eaten by the primary consumer which are then eaten by the secondary consumer.
At each stage of the food chain, the toxins remain in the tissues of the consumers and so the toxicity increases and can reach lethal levels.
69
What is a mutation?
A random change in the genetic material
70
How often do mutations occur?
Mutations are usually randomly occurring and at low frequencies (ROLF).
71
What effect can mutations have on organisms ?
It can increase the organisms ability to survive and reproduce. It can also decreases the organism ability to survive and reproduce.
72
Examples of mutations?
- Attached and detached
- Sickle cell trait ( it provides protection against malaria)
- Cystic fibrosis - lungs and digestive system become clogged with thick sticky mucus
73
What can speed up the rate of mutations?
Radiation- UV radiation, X-rays and gamma rays
| Chemicals- such as bromine, mustard gas, nicotine and tar
74
What role do mutations have in evolution?
Mutations are the only source of new variation in living things.
Mutations create new alleles which may be selected during natural selection.
75
What are alleles?
Different forms of the same gene are called alleles.
76
What is an adaptation?
It is an inherited characteristic that makes an organism well suited to its environment and niche.
77
What would cause an organism to have to adapt?
Adaptations occur in response to changing environmental conditions.
78
What is selection pressure?
Selection pressures are external agents which affect an organism’s ability to survive in a given environment.
79
What are types of selection pressures ?
Types of selection pressures include:
•Resource availability – presence of sufficient food, habitat (shelter/territory) and mates
•Environmental conditions – temperature, weather conditions or geographical access
•Biological factors – predators and pathogens (diseases)
80
What examples of genes which could be advantageous?
* Speed
* Aggression
* Resistance to disease
* Coat thickness
* Coat colour
* Quicker reactions
81
The process of natural selection?
- More offspring are produced than the environment can support.
- Offspring show variation due to different combinations of alleles.
- Struggle for survival due to selection pressures.
- The individuals best adapted to their environment survive to reproduce
- The favourable alleles that provide a selective advantage are passed onto the next generation
82
What is speciation?
Speciation is the formation of two or more species from an original ancestral species.
83
How does speciation?
- Part of a population becomes isolated by an isolation barrier
- Random mutations occur in each sub population
- Natural selection selects for different advantageous mutations in each sub population due to different selection pressures
- Each sub-population evolves until they become genetically different
- If the barrier is removed, the sub populations can no longer interbreed to produce fertile offspring – two new species
84
What are the possible isolation barriers?
* Geographical (e.g. rivers, seas, mountains, canyons, etc)
| * Ecological – barrier caused by adaptation to living conditions such as pH or salinity of water.
