If these natural survival resources are not available, some
living things will, over time, adapt to their environment
and find a way to survive anyway. The process of
adaptation occurs in all living things. For example,
some plants that live deep below the surface of the ocean
never see sunlight, yet they are able to survive.
- The Plant Tracker
- Turfgrass Information Center
Sometimes, plants and animals that share a habitat find a
way to share the natural resources, allowing both to
survive. Many organisms live together in relationships where
one depends upon the other. This interdependent relationship
is known as mutualism.
- The Yucca Plant and Yucca Moth: Mutualism
Even more common, however, is the relationship between
plants and animals and the supply of oxygen. Through
respiration, many animals take in oxygen and produce
carbon dioxide. For many plants, the respiration process
uses carbon dioxide to produce oxygen through
- What is Photosynthesis?
- Contact Information:
Arizona State University
Animals have strong survival instincts. An instinct
is a behavior with which an animal is born. For example,
from birth, a puppy instinctively knows to suck milk from
its mother. Instincts help animals find food, mate,
reproduce, and raise their young. Survival instincts also
lead animals to migrate or move to a better habitat.
Some animals migrate only short distances. Others, like the
wildebeest on the African Serengeti, are continually
migrating great distances. Why do they migrate? To find
better living conditions.
Instead of migrating, some animals instinctively protect
themselves from changes in living conditions through
hibernation. In seasonal habitats, some animals
survive the winter by going into deep sleep during which the
animal lives off of its stored fat and uses very little
energy. This way, the scarcity of sunlight, food, and warmth
don't risk the animal's survival. Bears are certainly the
best known hibernators, but not the only.
- The Bear Den
- Bear Photos
Living things continually face threats to their survival and
life cycle. Sometimes, the threats are natural and
uncontrollable, like sudden changes in climate. For example,
plants can be threatened by an unexpected drop in
temperature. Sometimes, however, the threats are unnatural,
manmade, and controllable. Pesticides, for example,
threaten the survival of insects that feed on plants.
However, animals that also feed on the plants can be
threatened by the pesticide too. Yet, the animals need to be
able to eat the plants. So, how to control the insects,
protect the plants, and feed the animals all at once?
Nematodes are one possibility. The nematode is a
parasite that feeds on the insect without hurting the plant.
- DDT: An Introduction
- Beneficial Nematodes
- Nematodes as Biological Control Agents
Survival is a daily challenge for all living things.
Meanwhile, other concerns also must be addressed. Plants and
animals reproduce at different stages of their life
cycle and in different ways. Flowers, for example, have both
male and female reproductive organs. The male organ, called
the stamen produces pollen which, through
pollination, gets moved and attached to the sticky
pistil. The pollen then grows down into the pistil
until it reaches the ovary which houses and protects
the ovule. Once the male pollen cells join with
female cells, fertilization occurs. The fertilized
embryo grows into a seed that can grow into a new plant.
Many flowers require cross-pollination. The pollen from the
stamen of one blossom is intended to fertilize the ovule of
another blossom. If two tulips are growing side by side, the
pollen from the first tulip should attach to the pistil of
the second tulip. How? Most often the wind or insects
transport the pollen from flower to flower. The bee is the
best equipped agent of fertilization for the flower. The
attractive color, scent, and flavor of a flower draw the bee
to the pistil where it "drinks" the flower's juices. As the
bee flies away, it touches the stamen, picks up some pollen,
and carries it to another flower's pistil. This mutually
beneficial relationship is known as symbiosis.