B3- Life on Earth

HideShow resource information
  • Created by: ElishaG
  • Created on: 10-05-16 14:40
Give the definition of species.
A species is a group of organisms that can breed together to produce fertile offspring.
1 of 64
Why is adapting good thing?
Mean a species is more likely to survive and go on to produce offspring. Means a species is likely to continue existing.
2 of 64
How is a cactus well adapted?
1-rounded shape,small surface area-reduce water loss.2)cuticle(thick waxy layer) reduce waterloss.3)Store water in stem-surive when little water around.4)Shallow,extensive roots-water absorbed quickly.
3 of 64
How are fish well adapted?
1)Gills extract oxygen from water for respiration.2)Tail fins with large surface area-propel through water.Other fins keep stable.3)streamlined body.4)Swim bladder-allows to change depth.
4 of 64
What are the differences in the same species called?
Variation. If it's genetic, it's passed onto offspring.
5 of 64
What are the causes of genetic variation?
When genes change.
6 of 64
What is the term called when genes change?What is it caused by?
mutations. Caused by outside factors e.g. radiation or chemicals. Or by mistakes during cell division.
7 of 64
What can mutations in body cells lead to?
Usually little or no effect. May lead to cancer.
8 of 64
Why do mutations have a bigger effect in sex cells?
Because mutation will be passed onto all cells.
9 of 64
What can mutations in gametes cause?
Offspring to develop new characeristics. Some may be harmful to organsim but others may help it to survive.
10 of 64
What does natural selection cause?
11 of 64
Explain Natural selection.
1-Resources limited, animals compete to survive(only some will)2-Some varieties of species more likely to survive(will reproduce and pass on genes)3-more of species will get desired characteristics. 4-Over generations best features naturally selected
12 of 64
What is selective breeding?
Involves humans choosing features they want to appear in next generation. Features don't tend to help with survival.
13 of 64
How long ago did life on Earth begin?
3500 million years ago.
14 of 64
What were the very first living things like?What are living things like now?
Very simple. But life then evolved to become more complex and varied.
15 of 64
Describe evolution.
1-sometimes, groups of same species can become isolated from each other.2-number of factors can then make the species different so they become 2 species. 3)different mutations create new features in both species.(answer continues on next card)
16 of 64
Evolution answer continued.
4-Natural selection works on beneficial features so they spread through each of the populations.5)Environmental changes play a part, e.g. climate change- animals will adapt differently.
17 of 64
What is the evidence for evolution?
1) fossil records-show species getting more and more complex. 2)DNA- all living things have similrities in DNA as have all evolved from same simple life. Scientists use similarities and differences in DNA to work out how life evolved.
18 of 64
Who thought of natural selection and why?
Charles Darwin, came up with it by making observations of organisms and applying creative thoughts to his findings.
19 of 64
Who else had an evolution theory?What was it?
Lamarck. Thought if a characteristic was used a lot, it would be more developed and then passed onto offspring.
20 of 64
Why did people believe Darwin's theory over Lamarck's?
People concluded that acquired characteristics aren't based on genetics so can't be passed on to the next generation.
21 of 64
What is the definition of biodiversity?
Biodiversity is the number of different species in a given area, for example a forest.
22 of 64
What does biodiversity include?
The number of different species on Earth. The range of different types of organisms. The genetic variation between organisms of the same species.
23 of 64
Why is maintaining biodiversity important?
More plants we have, the more resources for developing new food crops. Many medicines discovered using chemicals made by living things. When an organism becomes extinct, can no longer use the unique chemicals they produce.
24 of 64
What is the rate of extinction doing right now?What is the correlation?
Rate of extinction is increasing. There's a correlation between growth of world population and number of species extinctions, suggests lot of extinction is due to humans.
25 of 64
Give an example of a species humans have directly caused to become extinct.
the Tasmanian wolf was hunted to extinction.
26 of 64
Give a way that humans can cause extinction indirectly.
Destroying habitats or by introducing new species that other organisms cannot compete with.
27 of 64
What is classification about?
Organising organisms into groups.
28 of 64
How do scientists group organisms together?
Organisms are grouped according to their characteristics, genetics(DNA similarities) and physical features e.g. all vertebrates have a backbone.
29 of 64
What are the five kingdoms?
Bacteria, fungi, algae, plants and animals. Kingdoms are then divided into more and more groups until you get to a species.
30 of 64
What happens as you go down the groups?
Types of organism decrease but the common characteristics increase.
31 of 64
Why is classification useful?
1)Shows evolutionary relationships between organisms e.g. organisms in similar classification groups have evolved from same ancestor organism.2)Evolutionary relationships can be shown for all living and fossilised organisms that have been classified.
32 of 64
What do organisms need in order to survive?
1)Light needed by plants to make food.2)Food,for animals. Minerals,for plants.3)Oxygen(for plants and animals) and carbon dioxide, for plants.4)Water(vital for all living organisms).
33 of 64
What is interdependence?
The fact that organisms depend on other organisms (usually for food).
34 of 64
Rapid changes in the environment can cause extinction, what are these changes?
1)Environmenta conditions change e.g.destruction of habitat, and species can't adapt to change.2)New species introduced, which is a competitor, predator or disease organism of that species.3)Organism in its food web that it relies on becomes extinct.
35 of 64
Where does almost all of the energy come from in an ecosystem?
The Sun.
36 of 64
How is energy transferred between organisms?
When animals eat plants or other organisms. Also when detritivores and decomposers feed on parts of dead organisms and waste matter.
37 of 64
How is energy lost in an ecosystem?
Respiration, heat, waste products and uneaten parts.
38 of 64
Why can't a food chain have more than around 5 stages?
Energy is lost at each stage, so that there's not enough left to support more organisms.
39 of 64
How do you calculate efficiency?
(energy available at next stage/energy available at previous stage)x100
40 of 64
What does the carbon cycle show?
How carbon is recycled.
41 of 64
Describe the carbon cycle.(you also need to know how to draw this)
1)Powered by photosynthesis.2)In photosynthesis plants convert carbon from CO2 into sugars,3)Eating passes carbon compounds along to aniamls in a food chain/web.4)Both plant and animal respiration releases CO2 back into air.Continued on next card.
42 of 64
Carbon cycle continued.
5)plants and animals die and decompose.6)When they decompose, broken down by microorganisms, the decomposers then release CO2 back in air by respiration as they break down food.7)Combustion of fossil fuels releases CO2 into atmosphere.
43 of 64
Describe the Nitrogen cycle.(You need to know how to draw this out)
1)Nitrogen very unreactive so can't be directly used by plants and animals.2)Nitrogen needed to make proteins for growth.3)Plants get nitrogen from soil but needs to be turned into nitrates first.Animals only get proteins by eating plants, eachother
44 of 64
Describe the Nitrogen cycle continued.
4)Nitrogen fixation-process if turning Nitrogen from air into nitrates. 5)Decomposers break proteins down in dead plants and animals and urea into ammonia,Ammonia then turned into nitrates by nitrifying bacteria.
45 of 64
How does nitrogen fixation occur?
1)lighting, lots of energy makes nitrogen react with oxygen to give nitrates. 2)Nitrogen fixing bacteria in roots and soil.
46 of 64
What are the four types of microorganisms involved in the nitrogen cycle?
1)Decomposers-decompose proteins and urea into ammonia.2)Nitrifying bacteria-turn ammonia into nitrates (nitrification).3)Nitrogen-fixing bacteria=turn nitrogen gas into nitrogen compounds.4)Denitrifying bacteria- turn nitrates back to Nitrogen gas.
47 of 64
How can environmental change be measured?
With non-living and living indicators.
48 of 64
What are three non-living indicators?
Temperature, Nitrate levels and carbon dioxide levels.
49 of 64
How is temperature used to measure environmental change?
The temperature of an environment will vary all the time. But temperature measurements taken using instruments, like a thermometer, over a long period of time could indicate that the climate is changing, e.g. global warming.
50 of 64
How are nitrate levels used to measure environmental changes?
Nitrate levels can be used as an indicator in a body of water. An increase in nitrate levels could be caused by sewage or fertilisers entering water- which could show water is being polluted.
51 of 64
How are carbon dioxide levels used to measure environmental changes?
They can be used to measure environmental change in the air. An increase in carbon dioxide could be caused y many factors, including human activities, such as burning fossil fuels. Increases in carbon dioxide increase the rate of global warming.
52 of 64
What are three non-living indicators?
Lichen,Mayfly Nymphs, Phytoplankton.
53 of 64
How are lichens used to measure environmental changes?
Air pollution can be monitored by looking at some types of lichen, which are very sensitive to sulfur dioxide in the atmosphere. The number and type of lichen at a location will show how clean the air is.
54 of 64
How are mayfly nymphs used to measure environmental change?
If raw sewage is released into a river, bacteria population in water increases and uses up oxygen.Animals like mayfly nymphs are good living indicator for water pollution as they are sensitive to oxygen levels in water- only found in clean water.
55 of 64
How are phytoplankton used to measure environmental changes?
Phytoplankton(microscopic algae)populations increase when levels of nitrates and phospahtes increase- called algal bloom. Adding fertilisers+ sewage to rivers and lakes causes increase in nitrates and phosphates.Algal blooms indicate water pollution
56 of 64
Which indicators are better?Why?
Living indicators because they show the area over a period of time but non-living indicators show the levels at that time.
57 of 64
Why won't the environment be the same for future generations?
Because human activity damages the environment (e.g. pollution) and some of the damage cannot be repaired e.g. rainforest destruction.
58 of 64
Why won't resources be around for future generations to use?
Because we use fossil fuels but they are limited, one day they will run out.
59 of 64
What is sustainability?
Sustainability is meeting the needs of today's population without harming the environment so that future generations can still meet their own needs.
60 of 64
Why is maintaining biodiversity an important part of sustainability?
Because loss of biodiversity means future generations won't be able to get things from the environment that we can get today e.g. food and medicines.
61 of 64
Why is throwing packaging material away not sustainable?
1)Resources used to make packaging material can't be reused- no longer available to future generations. 2)Lots of energy used to make packaging material and producing energy using fossil fuels damages environment.3)Most waste thrown into landfill
62 of 64
How can the sustainability of using packaging be improved?
1)Using renewable materials e.g. paper/card.Trees can be replaced.2)Using less energy- make packaging from recycled materials less energy needed, less fossil fuels, less harm to environment.3)creating less pollution
63 of 64
What does biodegradable mean?
Something that can break down naturally by microorganisms.
64 of 64

Other cards in this set

Card 2


Why is adapting good thing?


Mean a species is more likely to survive and go on to produce offspring. Means a species is likely to continue existing.

Card 3


How is a cactus well adapted?


Preview of the front of card 3

Card 4


How are fish well adapted?


Preview of the front of card 4

Card 5


What are the differences in the same species called?


Preview of the front of card 5
View more cards


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Everything resources »