ADAPTATIONS TROPISMS &

A TROPISM IS A PLANT’S DIRECTED GROWTH TOWARDS OR AWAY FROM A STIMULUS. Tropisms

We will cover 4 tropisms. GravitropismGravitropism HydrotropismHydrotropism PhototropismPhototropism ThigmotropismThigmotropism

Gravitropism is a plant’s movement and growth in response to gravitational pull. The roots grow into the soil while the shoots grow in the opposite direction towards the light. Plants use gravity for orientation

Phototropism is a plant's growth response to light. More sunlight energy means more photosynthesis. Plants need light to grow.

Thigmotropism is a plant's response and movement to physical contact. For instance, climbing plants with coil-like structures (tendrils), first bend and turn until they touch a suitable supporting object, then they coil around it.

Hydrotropism is a plants growth response to water. Roots, grow towards moist soils to avoid draught stress. Once a root cap has sensed water it bends and then the root grows towards it.

HOW PLANTS ADAPT IN DIFFERENT BIOMES

Desert – Abiotic Factors Very DRY Very DRY A lot of direct sunlight on plants A lot of direct sunlight on plants Soil is sandy or rocky; doesn’t hold much water Soil is sandy or rocky; doesn’t hold much water Plants lose a lot of water Plants lose a lot of water

Desert – Plant Adaptations SMALL SPINES instead of leaves – slows water loss Deep tap roots or extensive surface roots. Some have WAXY COATINGS on stems and leaves Some have fuzzy or hairy leaves to trap condensation Many plants use wind to spread seeds (tumbleweeds)

Grassland – Abiotic Factors HOT summers and COLD winters Rainfall is uncertain; drought is common Soil is very rich in organic matter Windy

Grassland – Plant Adaptations Prairie grasses have NARROW leaves – lose less water SOFT STEMS allow grasses to bend in wind Extensive fibrous roots to find water Grass grows from BASE, not tip; can GROW BACK easily if burned or eaten Are WIND POLLINATED

Tropical Rain Forest – Abiotic Factors Warm and RAINY! DARK because of thick plant growth in the canopy.

Tropical Rain Forest – Plant Adaptations Broad leaved for more photosynthesis. DRIP TIPS & WAXY SURFACES allow water to run off Some plants GROW on others to reach sunlight - epiphytes (Orchid on tree)

Deciduous Forest – Abiotic Factors 4 distinct seasons Plenty of rain DARK under taller trees

Deciduous Forest – Plant Adaptations BROAD LEAVES to catch sunlight THICK BARK to protect against the cold Deciduous trees DROP LEAVES in winter to avoid losing water Some seeds have WING SHAPES to be caught and spread by the WIND Maple seed

Today you will need Your folder Something to write with Your seeds Notes off of the podium A Pre AP text book An on level text book

Plant Unit Table of contents DateAssignment 3/17Plant intro and Tissues Note 3/18Plant Quiz #1 Leaves & Photosynthesis Notes 3/19Plant Quiz #2 Stomata Lab (PAP Only) 3/20Plant Reproduction Notes 3/21Plant Quiz #3 Flower Dissection Lab 3/24Tropisms & Adaptation Notes

Taiga – Abiotic Factors COLD, DRY winters/WARM summers Some areas have PERMAFROST (permanently frozen ground)

Taiga – Plant Adaptations Many trees are evergreens – can photosynthesize anytime temperature is high enough Needle-like leaves to reduce water loss and shed snow in winter Dark needles allow more solar heat to be absorbed

Tundra – Abiotic Factors COLD year-round! All ground is PERMAFROST! (permanently frozen) DRY – only gets a little bit of snow or ice

Tundra – Plant Adaptations Small and low- growing (mosses, grasses & sedges) Dark in color to help absorb solar heat Grow in clumps to help protect each other from wind and cold

Seed Dispersal Fruit Sticky Burrs Plant Adaptations Involving Animals

ChemicalDefense Chemical Defense Poisonous / Deadly When Eaten MilkweedMilkweed Skin Irritant Plant Adaptations Involving Animals Poison Ivy Bull Nettle FoxgloveFoxglove

Physical Defense Spines and/or Thorns Plant Adaptations Involving Animals CactiCacti RosesRoses