B3 Flashcards
(31 cards)
What is a species?
A group of organisms that can breed together to produce fertile offspring.
What are two examples of adaptations?
1) A cactus living in hot dry conditions by storing water in their stem.
2) A camel storing fat in its hump/
What are species adapted to?
living in their environment.
What is interdependence?
the mutual dependence between things.
What does interdependence mean in terms of the food web?
That any change affects one species in a food web is likely to affect all in that web.
What can the introduction of a new species lead to?
extinction if the species is a competitor, predator or causes diseases.
What are nearly all organisms on Earth dependent on?
Energy from the Sun
Why do the plants need the sun?
because the absorb a small percentage of the energy from the sun to produce their own food by photosynthesis.
Where do plans store the energy they absorb from the sun?
In chemicals that make up the plants cells and tissues.
Why is some energy lost in a transfer from a plant to an animal
- Some parts of the plant aren’t eaten by the animal.
- The animal uses some of the plan’ts animals for respiration and during respiration some energy is lost as heat.
- The waste products of the animal, for instance urine, contain some energy.
What is detritus?
Party decayed material.
What is a detritivore?
an animal that feeds on detritus and breaks it down.
How does carbon enter the carbon cycle?
as CO2 in the air. Plants fix this carbon, so that it can be used and stored by organisms, by photosynthesis.
How is carbon returned to the air?
- as a product of respiration, when plants and animals release energy from food.
- through the decomposition of dead organisms by soil microorganisms such as bacteria and fungi.
- by combustion of organic materials.
How do plants take in nitrogen?
Plants take up nitrogen from the soil through their roots, in the form of nitrogen compounds including nitrates. These are converted into proteins.
How are nitrates released back into the soil?
as animals excrete waste and as plants and animals die and are decomposed by microorganisms.
How does nitrogen enter the nitrogen cycle?
- Nitrogen molecules in the air are split by lightning. Nitrogen atoms then combine with oxygen in the air to form nitrates, which are washed into the soil by rain.
- Nitrogen-fixing bacteria- found in the soil and in the roots of leguminous plants such as beans and peas, converting nitrogen in the air into nitrates
When does nitrogen leave the cycle?
When denitrifying bacteria convert nitrates in the soil into nitrogen gas. This process is called dentrification.
How can environmental change be measured?
- non living indicators, e.g. CO2 levels, temperature and nitrate levels.
- living indicators, such as phytoplankton, lichens and aquatic organisms such as mayfly larvae.
What do interpretation of data from non-living indicators and living indicators help scientists to monitor?
changes and trends over a period of time.
When did life on earth begin?
3500 million years ago.
What is the process of evolution?
Millions of years ago, the first forms of life were very simple. Over millions of years, these simple forms gave rise to all different species of organisms we see today, along with ones that are no extinct.
What do fossils show?
Evidence of how organisms changed over time found in fossils.
What are fossils?
The remains of organisms or other traces of their lives such as footprints or eggs that have turned into rock.
